WIP

include/akgl/SDL_GameControllerDB.h

@@ -1,7 +1,7 @@
 #ifndef _SDL_GAMECONTROLLERDB_H_
 #define _SDL_GAMECONTROLLERDB_H_
 
-// Taken from https://raw.githubusercontent.com/mdqinc/SDL_GameControllerDB/refs/heads/master/gamecontrollerdb.txt on Fri May 15 11:05:32 AM EDT 2026
+// Taken from https://raw.githubusercontent.com/mdqinc/SDL_GameControllerDB/refs/heads/master/gamecontrollerdb.txt on Tue May 26 01:00:21 PM EDT 2026
 
 #define AKGL_SDL_GAMECONTROLLER_DB_LEN         2228
 

include/akgl/actor.h

@@ -18,8 +18,8 @@
 #define AKGL_ACTOR_STATE_MOVING_RIGHT          1 << 8               // 256         0000 0001 0000 0000
 #define AKGL_ACTOR_STATE_MOVING_UP             1 << 9               // 512         0000 0010 0000 0000
 #define AKGL_ACTOR_STATE_MOVING_DOWN           1 << 10              // 1024        0000 0100 0000 0000
-#define AKGL_ACTOR_STATE_UNDEFINED_11          1 << 11              // 2048        0000 1000 0000 0000
-#define AKGL_ACTOR_STATE_UNDEFINED_12          1 << 12              // 4096        0001 0000 0000 0000
+#define AKGL_ACTOR_STATE_MOVING_IN             1 << 11              // 2048        0000 1000 0000 0000
+#define AKGL_ACTOR_STATE_MOVING_OUT            1 << 12              // 4096        0001 0000 0000 0000
 #define AKGL_ACTOR_STATE_UNDEFINED_13          1 << 13              // 8192        0010 0000 0000 0000
 #define AKGL_ACTOR_STATE_UNDEFINED_14          1 << 14              // 16384       0100 0000 0000 0000
 #define AKGL_ACTOR_STATE_UNDEFINED_15          1 << 15              // 32768       1000 0000 0000 0000
@@ -70,25 +70,42 @@ typedef struct akgl_Actor {
     bool movement_controls_face;
     void *actorData;
     bool visible;
-    SDL_Time logictimer;
+    SDL_Time movetimer;
+    // Velocity. Combined effect of all forces acting on the actor resulting
+    // in energy along an axis.
+    float32_t vx;
+    float32_t vy;
+    float32_t vz;
+    // Gravity. Forces acting on the actor on a given axis due to the forces
+    // of gravity and drag.
+    float32_t gx;
+    float32_t gy;
+    float32_t gz;
+    // Thrust. Energy originating only from the actor's own acceleration on a
+    // given axis, before the effects of gravity and drag.
+    float32_t tx;
+    float32_t ty;
+    float32_t tz;
+    // Position.
     float32_t x;
     float32_t y;
+    float32_t z;
     float32_t scale;
     struct akgl_Actor *children[AKGL_ACTOR_MAX_CHILDREN];
     struct akgl_Actor *parent;
     akerr_ErrorContext AKERR_NOIGNORE *(*updatefunc)(struct akgl_Actor *obj);
-    akerr_ErrorContext AKERR_NOIGNORE *(*renderfunc)(struct akgl_Actor *obj, SDL_Renderer *renderer);
+    akerr_ErrorContext AKERR_NOIGNORE *(*renderfunc)(struct akgl_Actor *obj);
     akerr_ErrorContext AKERR_NOIGNORE *(*facefunc)(struct akgl_Actor *obj);
-    akerr_ErrorContext AKERR_NOIGNORE *(*movementlogicfunc)(struct akgl_Actor *obj, SDL_Time curtimems);
+    akerr_ErrorContext AKERR_NOIGNORE *(*movementlogicfunc)(struct akgl_Actor *obj, float32_t dt);
     akerr_ErrorContext AKERR_NOIGNORE *(*changeframefunc)(struct akgl_Actor *obj, akgl_Sprite *curSprite, SDL_Time curtimems);
     akerr_ErrorContext AKERR_NOIGNORE *(*addchild)(struct akgl_Actor *obj, struct akgl_Actor *child);
 } akgl_Actor;
 
 akerr_ErrorContext AKERR_NOIGNORE *akgl_actor_initialize(akgl_Actor *obj, char *name);
 akerr_ErrorContext AKERR_NOIGNORE *akgl_actor_set_character(akgl_Actor *obj, char *basecharname);
-akerr_ErrorContext AKERR_NOIGNORE *akgl_actor_render(akgl_Actor *obj, SDL_Renderer *renderer);
+akerr_ErrorContext AKERR_NOIGNORE *akgl_actor_render(akgl_Actor *obj);
 akerr_ErrorContext AKERR_NOIGNORE *akgl_actor_update(akgl_Actor *obj);
-akerr_ErrorContext AKERR_NOIGNORE *akgl_actor_logic_movement(akgl_Actor *obj, SDL_Time curtimems);
+akerr_ErrorContext AKERR_NOIGNORE *akgl_actor_logic_movement(akgl_Actor *obj, float32_t dt);
 akerr_ErrorContext AKERR_NOIGNORE *akgl_actor_logic_changeframe(akgl_Actor *obj, akgl_Sprite *curSprite, SDL_Time curtimems);
 akerr_ErrorContext AKERR_NOIGNORE *akgl_actor_automatic_face(akgl_Actor *obj);
 akerr_ErrorContext AKERR_NOIGNORE *akgl_actor_add_child(akgl_Actor *obj, akgl_Actor *child);

include/akgl/character.h

@@ -9,14 +9,18 @@
 #define AKGL_MAX_HEAP_CHARACTER                256
 
 typedef struct akgl_Character {
-  uint8_t refcount;
-  char name[AKGL_SPRITE_MAX_CHARACTER_NAME_LENGTH];
-  SDL_PropertiesID state_sprites;
-  uint64_t movementspeed;
-  float32_t vx;
-  float32_t vy;
-  akerr_ErrorContext AKERR_NOIGNORE *(*sprite_add)(struct akgl_Character *, akgl_Sprite *, int);
-  akerr_ErrorContext AKERR_NOIGNORE *(*sprite_get)(struct akgl_Character *, int, akgl_Sprite **);
+    uint8_t refcount;
+    char name[AKGL_SPRITE_MAX_CHARACTER_NAME_LENGTH];
+    SDL_PropertiesID state_sprites;
+    uint64_t speedtime;
+    float32_t ax;
+    float32_t ay;
+    float32_t az;
+    float32_t sx;
+    float32_t sy;
+    float32_t sz;
+    akerr_ErrorContext AKERR_NOIGNORE *(*sprite_add)(struct akgl_Character *, akgl_Sprite *, int);
+    akerr_ErrorContext AKERR_NOIGNORE *(*sprite_get)(struct akgl_Character *, int, akgl_Sprite **);
 } akgl_Character;
 
 

include/akgl/controller.h

@@ -44,4 +44,6 @@ akerr_ErrorContext AKERR_NOIGNORE *akgl_controller_handle_removed(void *appstate
 akerr_ErrorContext AKERR_NOIGNORE *akgl_controller_pushmap(int controlmapid, akgl_Control *control);
 
 akerr_ErrorContext AKERR_NOIGNORE *akgl_controller_default(int controlmapid, char *actorname, int kbid, int jsid);
+
+akerr_ErrorContext AKERR_NOIGNORE *akgl_controller_open_gamepads(void);
 #endif // _CONTROLLER_H_

include/akgl/error.h

@@ -1,6 +1,18 @@
 #ifndef _ERROR_H_
 #define _ERROR_H_
 
+// This macro is used to silence warnings on string concatenation operations that may fail.
+// e.g., combining two element of PATH_MAX into a string buffer of AKGL_STRING_MAX_LENGTH.
+// We have to draw a line in the sand somewhere or we will just let our buffers grow forever
+// to keep the compiler happy.
+#define DISABLE_GCC_WARNING_FORMAT_TRUNCATION	\
+    _Pragma("GCC diagnostic push") \
+    _Pragma("GCC diagnostic ignored \"-Wformat-truncation\"")
+
+#define RESTORE_GCC_WARNINGS \
+    _Pragma("GCC diagnostic pop")
+
 #define AKGL_ERR_SDL               AKERR_LAST_ERRNO_VALUE + 1
+#define AKGL_ERR_LOGICINTERRUPT    AKERR_LAST_ERRNO_VALUE + 2
 
 #endif // _ERROR_H_

include/akgl/game.h

@@ -2,9 +2,11 @@
 #define _AKGL_GAME_H_
 
 #include <stdint.h>
-#include "types.h"
 #include <SDL3_mixer/SDL_mixer.h>
+#include "types.h"
 #include "tilemap.h"
+#include "renderer.h"
+#include "physics.h"
 
 #define AKGL_VERSION                     "0.1.0"
 
@@ -32,6 +34,7 @@ typedef struct {
     char name[256];
     char uri[256];
     akgl_GameState state;
+    SDL_Mutex *statelock;
     int16_t fps;
     SDL_Time gameStartTime;
     SDL_Time lastIterTime;
@@ -41,15 +44,17 @@ typedef struct {
 } akgl_Game;
 
 extern SDL_Window *window;
-extern SDL_Renderer *renderer;
 extern akgl_Tilemap gamemap;
 extern MIX_Audio *bgm;
 extern MIX_Mixer *akgl_mixer;
 extern MIX_Track *akgl_tracks[AKGL_GAME_AUDIO_MAX_TRACKS];
 extern SDL_FRect camera;
 extern akgl_Game game;
+extern akgl_RenderBackend renderer;
+extern akgl_PhysicsBackend physics;
 
 #define AKGL_BITMASK_HAS(x, y) (x & y) == y
+#define AKGL_BITMASK_HASNOT(x, y) (x & y) != y
 #define AKGL_BITMASK_ADD(x, y) x |= y
 #define AKGL_BITMASK_DEL(x, y) x &= ~(y)
 #define AKGL_BITMASK_CLEAR(x)  x = 0;
@@ -60,5 +65,8 @@ void akgl_game_updateFPS();
 akerr_ErrorContext AKERR_NOIGNORE *akgl_game_save(char *fpath);
 akerr_ErrorContext AKERR_NOIGNORE *akgl_game_load(char *fpath);
 void akgl_game_lowfps(void);
-
+akerr_ErrorContext AKERR_NOIGNORE *akgl_game_state_lock(void);
+akerr_ErrorContext AKERR_NOIGNORE *akgl_game_state_unlock(void);
+akerr_ErrorContext AKERR_NOIGNORE *akgl_game_update(akgl_Iterator *opflags);
+    
 #endif //_AKGL_GAME_H_

include/akgl/heap.h

@@ -30,6 +30,7 @@ extern akgl_Character HEAP_CHARACTER[AKGL_MAX_HEAP_CHARACTER];
 extern akgl_String HEAP_STRING[AKGL_MAX_HEAP_STRING];
 
 akerr_ErrorContext AKERR_NOIGNORE *akgl_heap_init();
+akerr_ErrorContext AKERR_NOIGNORE *akgl_heap_init_actor();
 akerr_ErrorContext AKERR_NOIGNORE *akgl_heap_next_actor(akgl_Actor **dest);
 akerr_ErrorContext AKERR_NOIGNORE *akgl_heap_next_sprite(akgl_Sprite **dest);
 akerr_ErrorContext AKERR_NOIGNORE *akgl_heap_next_spritesheet(akgl_SpriteSheet **dest);

include/akgl/physics.h

@@ -0,0 +1,40 @@
+#ifndef _PHYSICS_H_
+#define _PHYSICS_H_
+
+#include <SDL3/SDL.h>
+#include <akerror.h>
+#include <akgl/actor.h>
+#include <akgl/iterator.h>
+
+typedef struct akgl_PhysicsBackend {
+    akerr_ErrorContext AKERR_NOIGNORE *(*simulate)(struct akgl_PhysicsBackend *self, akgl_Iterator *opflags);
+    akerr_ErrorContext AKERR_NOIGNORE *(*gravity)(struct akgl_PhysicsBackend *self, akgl_Actor *actor, float32_t dt);
+    akerr_ErrorContext AKERR_NOIGNORE *(*collide)(struct akgl_PhysicsBackend *self, akgl_Actor *a1, akgl_Actor *a2);
+    akerr_ErrorContext AKERR_NOIGNORE *(*move)(struct akgl_PhysicsBackend *self, akgl_Actor *actor, float32_t dt);
+
+    double drag_x;
+    double drag_y;
+    double drag_z;
+    double gravity_x;
+    double gravity_y;
+    double gravity_z;
+    SDL_Time gravity_time;
+    SDL_Time timer_gravity;
+    
+} akgl_PhysicsBackend;
+
+akerr_ErrorContext AKERR_NOIGNORE *akgl_physics_null_gravity(akgl_PhysicsBackend *self, akgl_Actor *actor, float32_t dt);
+akerr_ErrorContext AKERR_NOIGNORE *akgl_physics_null_collide(akgl_PhysicsBackend *self, akgl_Actor *a1, akgl_Actor *a2);
+akerr_ErrorContext AKERR_NOIGNORE *akgl_physics_null_move(akgl_PhysicsBackend *self, akgl_Actor *actor, float32_t dt);
+akerr_ErrorContext AKERR_NOIGNORE *akgl_physics_init_null(akgl_PhysicsBackend *self);
+
+
+akerr_ErrorContext AKERR_NOIGNORE *akgl_physics_ss_gravity(akgl_PhysicsBackend *self, akgl_Actor *actor, float32_t dt);
+akerr_ErrorContext AKERR_NOIGNORE *akgl_physics_ss_collide(akgl_PhysicsBackend *self, akgl_Actor *a1, akgl_Actor *a2);
+akerr_ErrorContext AKERR_NOIGNORE *akgl_physics_ss_move(akgl_PhysicsBackend *self, akgl_Actor *actor, float32_t dt);
+akerr_ErrorContext AKERR_NOIGNORE *akgl_physics_init_sidescroller(akgl_PhysicsBackend *self);
+
+
+akerr_ErrorContext AKERR_NOIGNORE *akgl_physics_simulate(akgl_PhysicsBackend *self, akgl_Iterator *opflags);
+
+#endif // _PHYSICS_H_

include/akgl/renderer.h

@@ -0,0 +1,29 @@
+#ifndef _RENDERER_H_
+#define _RENDERER_H_
+
+#include <SDL3/SDL.h>
+
+#include <akerror.h>
+
+#include <akgl/iterator.h>
+
+typedef struct akgl_RenderBackend {
+    SDL_Renderer *sdl_renderer;
+    akerr_ErrorContext AKERR_NOIGNORE *(*shutdown)(struct akgl_RenderBackend *self);
+    akerr_ErrorContext AKERR_NOIGNORE *(*frame_start)(struct akgl_RenderBackend *self);
+    akerr_ErrorContext AKERR_NOIGNORE *(*frame_end)(struct akgl_RenderBackend *self);
+    akerr_ErrorContext AKERR_NOIGNORE *(*draw_texture)(struct akgl_RenderBackend *self, SDL_Texture *texture, SDL_FRect *src, SDL_FRect *dest, double angle, SDL_FPoint *center, SDL_FlipMode flip);
+    akerr_ErrorContext AKERR_NOIGNORE *(*draw_mesh)(struct akgl_RenderBackend *self);
+    akerr_ErrorContext AKERR_NOIGNORE *(*draw_world)(struct akgl_RenderBackend *self, akgl_Iterator *opflags);
+} akgl_RenderBackend;
+
+akerr_ErrorContext AKERR_NOIGNORE *akgl_render_2d_shutdown(akgl_RenderBackend *self);
+akerr_ErrorContext AKERR_NOIGNORE *akgl_render_2d_frame_start(akgl_RenderBackend *self);
+akerr_ErrorContext AKERR_NOIGNORE *akgl_render_2d_frame_end(akgl_RenderBackend *self);
+akerr_ErrorContext AKERR_NOIGNORE *akgl_render_2d_draw_texture(akgl_RenderBackend *self, SDL_Texture *texture, SDL_FRect *src, SDL_FRect *dest, double angle, SDL_FPoint *center, SDL_FlipMode flip);
+akerr_ErrorContext AKERR_NOIGNORE *akgl_render_2d_draw_mesh(akgl_RenderBackend *self);
+akerr_ErrorContext AKERR_NOIGNORE *akgl_render_2d_draw_world(akgl_RenderBackend *self, akgl_Iterator *opflags);
+
+akerr_ErrorContext AKERR_NOIGNORE *akgl_render_init2d(akgl_RenderBackend *self);
+
+#endif // _RENDERER_H_

include/akgl/staticstring.h

@@ -3,8 +3,9 @@
 
 #include "string.h"
 #include <akerror.h>
+#include <limits.h>
 
-#define AKGL_MAX_STRING_LENGTH            256
+#define AKGL_MAX_STRING_LENGTH            PATH_MAX
 
 typedef struct
 {
@@ -13,5 +14,5 @@ typedef struct
 } akgl_String;
 
 akerr_ErrorContext AKERR_NOIGNORE *akgl_string_initialize(akgl_String *obj, char *init);
-
+akerr_ErrorContext AKERR_NOIGNORE *akgl_string_copy(akgl_String *src, akgl_String *dst, int count);
 #endif //_STRING_H_

include/akgl/tilemap.h

@@ -1,6 +1,7 @@
 #ifndef _TILEMAP_H_
 #define _TILEMAP_H_
 
+#include <limits.h>
 #include "actor.h"
 #include "staticstring.h"
 #include <jansson.h>
@@ -11,7 +12,7 @@
 #define AKGL_TILEMAP_MAX_TILESETS                     16
 #define AKGL_TILEMAP_MAX_TILES_PER_IMAGE              65536
 #define AKGL_TILEMAP_MAX_TILESET_NAME_SIZE            512
-#define AKGL_TILEMAP_MAX_TILESET_FILENAME_SIZE        512
+#define AKGL_TILEMAP_MAX_TILESET_FILENAME_SIZE        PATH_MAX
 #define AKGL_TILEMAP_MAX_OBJECT_NAME_SIZE             512
 #define AKGL_TILEMAP_MAX_OBJECTS_PER_LAYER            128
 
@@ -100,8 +101,8 @@ typedef struct {
 } akgl_Tilemap;
 
 akerr_ErrorContext AKERR_NOIGNORE *akgl_tilemap_load(char *fname, akgl_Tilemap *dest);
-akerr_ErrorContext AKERR_NOIGNORE *akgl_tilemap_draw(SDL_Renderer *renderer, akgl_Tilemap *dest, SDL_FRect *viewport, int layeridx);
-akerr_ErrorContext AKERR_NOIGNORE *akgl_tilemap_draw_tileset(SDL_Renderer *renderer, akgl_Tilemap *dest, int tilesetidx);
+akerr_ErrorContext AKERR_NOIGNORE *akgl_tilemap_draw(akgl_Tilemap *dest, SDL_FRect *viewport, int layeridx);
+akerr_ErrorContext AKERR_NOIGNORE *akgl_tilemap_draw_tileset(akgl_Tilemap *dest, int tilesetidx);
 
 /*
  * These functions are part of the internal API and should not be called by the user.
@@ -112,11 +113,11 @@ akerr_ErrorContext AKERR_NOIGNORE *akgl_get_json_tilemap_property(json_t *obj, c
 akerr_ErrorContext AKERR_NOIGNORE *akgl_get_json_properties_string(json_t *obj, char *key, akgl_String **dest);
 akerr_ErrorContext AKERR_NOIGNORE *akgl_get_json_properties_integer(json_t *obj, char *key, int *dest);
 akerr_ErrorContext AKERR_NOIGNORE *akgl_tilemap_compute_tileset_offsets(akgl_Tilemap *dest, int tilesetidx);
-akerr_ErrorContext AKERR_NOIGNORE *akgl_tilemap_load_layer_objects(akgl_Tilemap *dest, json_t *root, int layerid);
-akerr_ErrorContext AKERR_NOIGNORE *akgl_tilemap_load_layer_tile(akgl_Tilemap *dest, json_t *root, int layerid);
-akerr_ErrorContext AKERR_NOIGNORE *akgl_tilemap_load_layers(akgl_Tilemap *dest, json_t *root);
-akerr_ErrorContext AKERR_NOIGNORE *akgl_tilemap_load_tilesets_each(json_t *tileset, akgl_Tilemap *dest, int tsidx);
-akerr_ErrorContext AKERR_NOIGNORE *akgl_tilemap_load_tilesets(akgl_Tilemap *dest, json_t *root);
+akerr_ErrorContext AKERR_NOIGNORE *akgl_tilemap_load_layer_objects(akgl_Tilemap *dest, json_t *root, int layerid, akgl_String *dirname);
+akerr_ErrorContext AKERR_NOIGNORE *akgl_tilemap_load_layer_tile(akgl_Tilemap *dest, json_t *root, int layerid, akgl_String *dirname);
+akerr_ErrorContext AKERR_NOIGNORE *akgl_tilemap_load_layers(akgl_Tilemap *dest, json_t *root, akgl_String *dirname);
+akerr_ErrorContext AKERR_NOIGNORE *akgl_tilemap_load_tilesets_each(json_t *tileset, akgl_Tilemap *dest, int tsidx, akgl_String *dirname);
+akerr_ErrorContext AKERR_NOIGNORE *akgl_tilemap_load_tilesets(akgl_Tilemap *dest, json_t *root, akgl_String *dirname);
 akerr_ErrorContext AKERR_NOIGNORE *akgl_tilemap_release(akgl_Tilemap *dest);
 akerr_ErrorContext AKERR_NOIGNORE *akgl_tilemap_scale_actor(akgl_Tilemap *map, akgl_Actor *actor);
 

include/akgl/util.h

@@ -2,6 +2,7 @@
 #define _UTIL_H_
 
 #include <akerror.h>
+#include <akgl/staticstring.h>
 
 typedef struct point {
   int x;
@@ -22,6 +23,8 @@ akerr_ErrorContext AKERR_NOIGNORE *akgl_rectangle_points(RectanglePoints *dest,
 akerr_ErrorContext AKERR_NOIGNORE *akgl_collide_point_rectangle(point *p, RectanglePoints *r, bool *collide);
 akerr_ErrorContext AKERR_NOIGNORE *akgl_collide_rectangles(SDL_FRect *r1, SDL_FRect *r2, bool *collide);
 
+akerr_ErrorContext AKERR_NOIGNORE *akgl_path_relative(char *root, char *path, akgl_String *dst);
+
 // These are REALLY slow routines that are only useful in testing harnesses
 akerr_ErrorContext AKERR_NOIGNORE *akgl_compare_sdl_surfaces(SDL_Surface *s1, SDL_Surface *s2);
 akerr_ErrorContext AKERR_NOIGNORE *akgl_render_and_compare(SDL_Texture *t1, SDL_Texture *t2, int x, int y, int w, int h, char *writeout);

src/actor.c

@@ -3,6 +3,7 @@
 #include <string.h>
 #include <akerror.h>
 
+#include <akgl/physics.h>
 #include <akgl/game.h>
 #include <akgl/sprite.h>
 #include <akgl/actor.h>
@@ -112,27 +113,14 @@ akerr_ErrorContext *akgl_actor_logic_changeframe(akgl_Actor *obj, akgl_Sprite *c
     SUCCEED_RETURN(errctx);
 }
 
-akerr_ErrorContext *akgl_actor_logic_movement(akgl_Actor *obj, SDL_Time curtime)
+// raises AKGL_ERR_LOGICINTERRUPT if we don't want the physics object to process us
+akerr_ErrorContext *akgl_actor_logic_movement(akgl_Actor *obj, float32_t dt)
 {
     PREPARE_ERROR(errctx);
-    FAIL_ZERO_RETURN(errctx, obj, AKERR_NULLPOINTER, "Null actor reference");
-    if ( obj->parent != NULL ) {
-	// Children don't move independently of their parents, they just have an offset
-	SUCCEED_RETURN(errctx);
-    } else { 
-	if ( AKGL_BITMASK_HAS(obj->state, AKGL_ACTOR_STATE_MOVING_LEFT) ) {
-	    obj->x -= obj->basechar->vx;
-	}
-	if ( AKGL_BITMASK_HAS(obj->state, AKGL_ACTOR_STATE_MOVING_RIGHT) ) {
-	    obj->x += obj->basechar->vx;
-	}
-	if ( AKGL_BITMASK_HAS(obj->state, AKGL_ACTOR_STATE_MOVING_UP) ) {
-	    obj->y -= obj->basechar->vy;
-	}
-	if ( AKGL_BITMASK_HAS(obj->state, AKGL_ACTOR_STATE_MOVING_DOWN) ) {
-	    obj->y += obj->basechar->vy;
-	}
-    }
+    FAIL_ZERO_RETURN(errctx, obj, AKERR_NULLPOINTER, "obj");
+    FAIL_ZERO_RETURN(errctx, obj, AKERR_NULLPOINTER, "obj->basechar");
+    // Effectively a NOOP, this is handled by the physics engine now
+    // These functions are still present in case the library user wants per-actor behavior
     SUCCEED_RETURN(errctx);
 }
 
@@ -145,21 +133,11 @@ akerr_ErrorContext *akgl_actor_update(akgl_Actor *obj)
     FAIL_ZERO_RETURN(errctx, obj, AKERR_NULLPOINTER, "NULL actor reference");
     FAIL_ZERO_RETURN(errctx, obj->basechar, AKERR_NULLPOINTER, "Actor has NULL base character reference");
 
-    ATTEMPT {
-	SDL_GetCurrentTime(&curtime);
-	CATCH(errctx, obj->facefunc(obj));
-	// is it time to apply movement logic?
-	if ( (curtime - obj->logictimer) >= obj->basechar->movementspeed ) {
-	    CATCH(errctx, obj->movementlogicfunc(obj, curtime));
-	    obj->logictimer = curtime;
-	}
-    } CLEANUP {
-    } PROCESS(errctx) {
-    } FINISH(errctx, false);
+    SDL_GetCurrentTime(&curtime);
+    PASS(errctx, obj->facefunc(obj));
 
     ATTEMPT {
 	CATCH(errctx, akgl_character_sprite_get(obj->basechar, obj->state, &curSprite));
-	// is it time to change frames?
 	if ( ((curtime) - obj->curSpriteFrameTimer) >= curSprite->speed) {
 	    CATCH(errctx, obj->changeframefunc(obj, curSprite, curtime));
 	    obj->curSpriteFrameTimer = curtime;
@@ -167,6 +145,8 @@ akerr_ErrorContext *akgl_actor_update(akgl_Actor *obj)
     } CLEANUP {
     } PROCESS(errctx) {
     } HANDLE(errctx, AKERR_KEY) {
+	// TODO : Why are we passing this error? It could only come from akgl_character_sprite_get
+	// or changeframefunc, both of which should never return AKERR_KEY...
 	SUCCEED_RETURN(errctx);
     } FINISH(errctx, true);
     
@@ -179,7 +159,6 @@ static akerr_ErrorContext *actor_visible(akgl_Actor *obj, SDL_FRect *camera, boo
     akgl_Sprite *curSprite = NULL;
   
     FAIL_ZERO_RETURN(errctx, obj, AKERR_NULLPOINTER, "NULL actor");
-    FAIL_ZERO_RETURN(errctx, renderer, AKERR_NULLPOINTER, "NULL renderer");
     FAIL_ZERO_RETURN(errctx, obj->basechar, AKERR_NULLPOINTER, "Actor has NULL base character reference");
   
     ATTEMPT {
@@ -203,7 +182,7 @@ static akerr_ErrorContext *actor_visible(akgl_Actor *obj, SDL_FRect *camera, boo
     SUCCEED_RETURN(errctx);
 }
 
-akerr_ErrorContext *akgl_actor_render(akgl_Actor *obj, SDL_Renderer *renderer)
+akerr_ErrorContext *akgl_actor_render(akgl_Actor *obj)
 {
     PREPARE_ERROR(errctx);
     akgl_Sprite *curSprite = NULL;
@@ -212,7 +191,6 @@ akerr_ErrorContext *akgl_actor_render(akgl_Actor *obj, SDL_Renderer *renderer)
     SDL_FRect dest;
     
     FAIL_ZERO_RETURN(errctx, obj, AKERR_NULLPOINTER, "NULL actor");
-    FAIL_ZERO_RETURN(errctx, renderer, AKERR_NULLPOINTER, "NULL renderer");
     FAIL_ZERO_RETURN(errctx, obj->basechar, AKERR_NULLPOINTER, "Actor has NULL base character reference");
   
     ATTEMPT {
@@ -229,7 +207,7 @@ akerr_ErrorContext *akgl_actor_render(akgl_Actor *obj, SDL_Renderer *renderer)
     if ( ! visible ) {
 	SUCCEED_RETURN(errctx);
     }
-    
+
     if ( (obj->curSpriteFrameId > curSprite->frames) ) {
 	// This isn't necessarily an error - this actor's frame index is outside the range of
 	// their current sprite. There are a number of reasons this could happen, and it will
@@ -258,7 +236,7 @@ akerr_ErrorContext *akgl_actor_render(akgl_Actor *obj, SDL_Renderer *renderer)
     dest.w = curSprite->width * obj->scale;
     dest.h = curSprite->width * obj->scale;
 
-    SDL_RenderTexture(renderer, curSprite->sheet->texture, &src, &dest);
+    PASS(errctx, renderer.draw_texture(&renderer, curSprite->sheet->texture, &src, &dest, 0, NULL, SDL_FLIP_NONE));
     SUCCEED_RETURN(errctx);
 }
 
@@ -281,39 +259,6 @@ akerr_ErrorContext *akgl_actor_add_child(akgl_Actor *obj, akgl_Actor *child)
   FAIL_RETURN(errctx, AKERR_OUTOFBOUNDS, "Parent object has no remaining child slots left");
 }
 
-// SDL iterator so we can't return error information here, void only
-// this means we don't have anywhere to send exceptions up to, so if we hit an error, we log and exit(1) here
-void akgl_registry_iterate_actor(void *userdata, SDL_PropertiesID registry, const char *name)
-{
-    PREPARE_ERROR(errctx);
-    akgl_Iterator *opflags = (akgl_Iterator *)userdata;
-	
-    ATTEMPT {
-	FAIL_ZERO_BREAK(errctx, name, AKERR_NULLPOINTER, "registry_iterate_actor received NULL property name");
-	FAIL_ZERO_BREAK(errctx, opflags, AKERR_NULLPOINTER, "received NULL iterator flags");
-	akgl_Actor *obj = (akgl_Actor *)SDL_GetPointerProperty(registry, name, NULL);
-	FAIL_ZERO_BREAK(errctx, obj, AKERR_KEY, "registry_iterate_actor received property name that was not in the registry");
-	if ( AKGL_BITMASK_HAS(opflags->flags, AKGL_ITERATOR_OP_LAYERMASK) ) {
-	    if ( obj->layer != opflags->layerid ) {
-		break;
-	    }
-	}
-	if ( AKGL_BITMASK_HAS(opflags->flags, AKGL_ITERATOR_OP_UPDATE) ) {
-	    CATCH(errctx, obj->updatefunc(obj));
-	}
-	if ( AKGL_BITMASK_HAS(opflags->flags, AKGL_ITERATOR_OP_TILEMAPSCALE) ) {
-	    CATCH(errctx, akgl_tilemap_scale_actor(&gamemap, obj));
-	} else {
-	    obj->scale = 1.0;
-	}
-	if ( AKGL_BITMASK_HAS(opflags->flags, AKGL_ITERATOR_OP_RENDER) ) {
-	    CATCH(errctx, obj->renderfunc(obj, renderer));
-	}
-    } CLEANUP {
-    } PROCESS(errctx) {
-    } FINISH_NORETURN(errctx);
-}
-
 akerr_ErrorContext AKERR_NOIGNORE *akgl_Actor_cmhf_left_on(akgl_Actor *obj, SDL_Event *event)
 {
     PREPARE_ERROR(errctx);
@@ -332,6 +277,8 @@ akerr_ErrorContext AKERR_NOIGNORE *akgl_Actor_cmhf_left_off(akgl_Actor *obj, SDL
     FAIL_ZERO_RETURN(errctx, obj, AKERR_NULLPOINTER, "NULL actor");
     FAIL_ZERO_RETURN(errctx, event, AKERR_NULLPOINTER, "NULL event");
     //SDL_Log("event %d (button %d / key %d) stops moving actor left", event->type, event->gbutton.which, event->key.key);
+    obj->tx = 0;
+    obj->vx = 0;
     AKGL_BITMASK_DEL(obj->state, AKGL_ACTOR_STATE_MOVING_LEFT);
     //SDL_Log("new target actor state: %b", obj->state);
     SUCCEED_RETURN(errctx);
@@ -355,6 +302,8 @@ akerr_ErrorContext AKERR_NOIGNORE *akgl_Actor_cmhf_right_off(akgl_Actor *obj, SD
     FAIL_ZERO_RETURN(errctx, obj, AKERR_NULLPOINTER, "NULL actor");
     FAIL_ZERO_RETURN(errctx, event, AKERR_NULLPOINTER, "NULL event");
     //SDL_Log("event %d (button %d / key %d) stops moving actor right", event->type, event->gbutton.which, event->key.key);
+    obj->tx = 0;
+    obj->vx = 0;
     AKGL_BITMASK_DEL(obj->state, AKGL_ACTOR_STATE_MOVING_RIGHT);
     //SDL_Log("new target actor state: %b", obj->state);
     SUCCEED_RETURN(errctx);
@@ -378,6 +327,8 @@ akerr_ErrorContext AKERR_NOIGNORE *akgl_Actor_cmhf_up_off(akgl_Actor *obj, SDL_E
     FAIL_ZERO_RETURN(errctx, obj, AKERR_NULLPOINTER, "NULL actor");
     FAIL_ZERO_RETURN(errctx, event, AKERR_NULLPOINTER, "NULL event");
     //SDL_Log("event %d (button %d / key %d) stops moving actor up", event->type, event->gbutton.which, event->key.key);
+    obj->ty = 0;
+    obj->vy = 0;
     AKGL_BITMASK_DEL(obj->state, AKGL_ACTOR_STATE_MOVING_UP);
     //SDL_Log("new target actor state: %b", obj->state);
     SUCCEED_RETURN(errctx);
@@ -401,6 +352,8 @@ akerr_ErrorContext AKERR_NOIGNORE *akgl_Actor_cmhf_down_off(akgl_Actor *obj, SDL
     FAIL_ZERO_RETURN(errctx, obj, AKERR_NULLPOINTER, "NULL actor");
     FAIL_ZERO_RETURN(errctx, event, AKERR_NULLPOINTER, "NULL event");
     //SDL_Log("event %d (button %d / key %d) stops moving actor down", event->type, event->gbutton.which, event->key.key);
+    obj->ty = 0;
+    obj->vy = 0;
     AKGL_BITMASK_DEL(obj->state, AKGL_ACTOR_STATE_MOVING_DOWN);
     //SDL_Log("new target actor state: %b", obj->state);
     SUCCEED_RETURN(errctx);

src/character.c

@@ -185,10 +185,12 @@ akerr_ErrorContext *akgl_character_load_json(char *filename)
 	    "Error while loading character from %s on line %d: %s", filename, error.line, error.text
 	    );
 	CATCH(errctx, akgl_character_load_json_inner(json, obj));
-	CATCH(errctx, akgl_get_json_integer_value(json, "movementspeed", (int *)&obj->movementspeed));
-	obj->movementspeed = obj->movementspeed * AKGL_TIME_ONESEC_MS;
-	CATCH(errctx, akgl_get_json_number_value(json, "velocity_x", &obj->vx));
-	CATCH(errctx, akgl_get_json_number_value(json, "velocity_y", &obj->vy));
+	CATCH(errctx, akgl_get_json_integer_value(json, "speedtime", (int *)&obj->speedtime));
+	obj->speedtime = obj->speedtime * AKGL_TIME_ONESEC_MS;
+	CATCH(errctx, akgl_get_json_number_value(json, "speed_x", &obj->sx));
+	CATCH(errctx, akgl_get_json_number_value(json, "speed_y", &obj->sy));
+	CATCH(errctx, akgl_get_json_number_value(json, "acceleration_x", &obj->ax));
+	CATCH(errctx, akgl_get_json_number_value(json, "acceleration_y", &obj->ay));
     } CLEANUP {
 	//IGNORE(akgl_heap_release_string(tmpstr));
 	if ( errctx != NULL ) {

src/controller.c

@@ -22,6 +22,33 @@ akerr_ErrorContext AKERR_NOIGNORE *akgl_controller_list_keyboards(void)
     SUCCEED_RETURN(e);
 }
 
+akerr_ErrorContext AKERR_NOIGNORE *akgl_controller_open_gamepads(void)
+{
+    int count = 0;
+    int i = 0;
+    SDL_JoystickID *gamepads = NULL;
+    SDL_Gamepad *gamepad = NULL;
+
+    PREPARE_ERROR(e);
+    if ( SDL_HasGamepad() ) {
+	gamepads = SDL_GetGamepads(&count);
+	if ( count > 0 ) {
+	    FAIL_ZERO_RETURN(e, gamepads, AKERR_NULLPOINTER, "%s", SDL_GetError());
+	    for ( i = 0; i < count ; i++ ) {
+		gamepad = SDL_OpenGamepad(gamepads[i]);
+		FAIL_ZERO_RETURN(e, gamepad, AKERR_NULLPOINTER, "%s", SDL_GetError());
+		SDL_Log("Gamepad %d is %s", i, SDL_GetGamepadNameForID(gamepads[i]));
+	    }
+	    SDL_free(gamepads);
+	} else {
+	    SDL_Log("No gamepads enumerated");
+	}
+    } else {
+	SDL_Log("No gamepads connected");
+    }
+    SUCCEED_RETURN(e);
+}
+
 akerr_ErrorContext *akgl_controller_handle_event(void *appstate, SDL_Event *event)
 {
     int i = 0;
@@ -32,7 +59,7 @@ akerr_ErrorContext *akgl_controller_handle_event(void *appstate, SDL_Event *even
     PREPARE_ERROR(errctx);
     FAIL_ZERO_RETURN(errctx, appstate, AKERR_NULLPOINTER, "NULL appstate");
     FAIL_ZERO_RETURN(errctx, event, AKERR_NULLPOINTER, "NULL event");
-    
+
     ATTEMPT {
 	for ( i = 0 ; i < AKGL_MAX_CONTROL_MAPS; i++ ) {
 	    curmap = &GAME_ControlMaps[i];
@@ -56,6 +83,13 @@ akerr_ErrorContext *akgl_controller_handle_event(void *appstate, SDL_Event *even
 		     event->key.which == curmap->kbid &&
 		     event->key.key == curcontrol->key)
 		    );
+		if ( event->type == 768 && event->key.which == 11 && event->key.key == 13 ) {
+		    SDL_Log("Event type=%d, keyboard=%d, key=%d", event->type, event->key.which, event->key.key);
+		    SDL_Log("ControlMap[%d].Controls[%d] keyboard=%d, key=%d", i, j, curmap->kbid, curcontrol->key);
+		    SDL_Log("event %d -> control on %d off %d", event->type, curcontrol->event_on, curcontrol->event_off);
+		    SDL_Log("eventButtonComboMatch for controlmap %d id %d = %d",
+			    i, j, eventButtonComboMatch);
+		}
 		if ( event->type == curcontrol->event_on && eventButtonComboMatch) {
 		    CATCH(errctx, curcontrol->handler_on(curmap->target, event));
 		    goto _akgl_controller_handle_event_success;

src/draw.c

@@ -20,11 +20,11 @@ void akgl_draw_background(int w, int h)
         for (x = 0; x < w; x += dx) {
             /* use an 8x8 checkerboard pattern */
             i = (((x ^ y) >> 3) & 1);
-            SDL_SetRenderDrawColor(renderer, col[i].r, col[i].g, col[i].b, col[i].a);
+            SDL_SetRenderDrawColor(renderer.sdl_renderer, col[i].r, col[i].g, col[i].b, col[i].a);
 
             rect.x = (float)x;
             rect.y = (float)y;
-            SDL_RenderFillRect(renderer, &rect);
+            SDL_RenderFillRect(renderer.sdl_renderer, &rect);
         }
     }
 }

src/game.c

@@ -15,10 +15,12 @@
 #include <akgl/registry.h>
 #include <akgl/staticstring.h>
 #include <akgl/iterator.h>
+#include <akgl/physics.h>
 #include <akgl/SDL_GameControllerDB.h>
 
 SDL_Window *window = NULL;
-SDL_Renderer *renderer = NULL;
+akgl_RenderBackend renderer;
+akgl_PhysicsBackend physics;
 akgl_Frame ball;
 akgl_Frame paddle1;
 akgl_Frame paddle2;
@@ -42,28 +44,32 @@ akerr_ErrorContext AKERR_NOIGNORE *akgl_game_init()
     int screenheight = 0;
     
     int i = 0;
-    PREPARE_ERROR(errctx);
+    PREPARE_ERROR(e);
     ATTEMPT {
 	strncpy((char *)&game.libversion, AKGL_VERSION, 32);
 	game.gameStartTime = SDL_GetTicksNS();
 	game.lastIterTime = game.gameStartTime;
 	game.lastFPSTime = game.gameStartTime;
 	game.lowfpsfunc = &akgl_game_lowfps;
-	FAIL_ZERO_BREAK(errctx, strlen((char *)&game.name), AKERR_NULLPOINTER, "Must provide game name");
-	FAIL_ZERO_BREAK(errctx, strlen((char *)&game.version), AKERR_NULLPOINTER, "Must provide game version");
-	FAIL_ZERO_BREAK(errctx, strlen((char *)&game.uri), AKERR_NULLPOINTER, "Must provide game uri");
-	CATCH(errctx, akgl_heap_init());
-	CATCH(errctx, akgl_registry_init_actor());
-	CATCH(errctx, akgl_registry_init_sprite());
-	CATCH(errctx, akgl_registry_init_spritesheet());
-	CATCH(errctx, akgl_registry_init_character());
-	CATCH(errctx, akgl_registry_init_font());
-	CATCH(errctx, akgl_registry_init_music());
-	CATCH(errctx, akgl_registry_init_properties());
-	CATCH(errctx, akgl_registry_init_actor_state_strings());
+	game.statelock = SDL_CreateMutex();
+	FAIL_ZERO_RETURN(e, game.statelock, AKGL_ERR_SDL, "%s", SDL_GetError());
+	CATCH(e, akgl_game_state_lock());
+	FAIL_ZERO_BREAK(e, strlen((char *)&game.name), AKERR_NULLPOINTER, "Must provide game name");
+	FAIL_ZERO_BREAK(e, strlen((char *)&game.version), AKERR_NULLPOINTER, "Must provide game version");
+	FAIL_ZERO_BREAK(e, strlen((char *)&game.uri), AKERR_NULLPOINTER, "Must provide game uri");
+	CATCH(e, akgl_heap_init());
+	CATCH(e, akgl_registry_init_actor());
+	CATCH(e, akgl_registry_init_sprite());
+	CATCH(e, akgl_registry_init_spritesheet());
+	CATCH(e, akgl_registry_init_character());
+	CATCH(e, akgl_registry_init_font());
+	CATCH(e, akgl_registry_init_music());
+	CATCH(e, akgl_registry_init_properties());
+	CATCH(e, akgl_registry_init_actor_state_strings());
     } CLEANUP {
-    } PROCESS(errctx) {
-    } FINISH(errctx, true)
+	//IGNORE(akgl_game_state_unlock());
+    } PROCESS(e) {
+    } FINISH(e, true)
 	  
     SDL_SetAppMetadata(game.name, game.version, game.uri);
 
@@ -72,7 +78,7 @@ akerr_ErrorContext AKERR_NOIGNORE *akgl_game_init()
     }
     
     FAIL_ZERO_RETURN(
-	errctx,
+	e,
 	SDL_Init(SDL_INIT_VIDEO | SDL_INIT_GAMEPAD | SDL_INIT_AUDIO),
 	AKGL_ERR_SDL,
 	"Couldn't initialize SDL: %s",
@@ -82,36 +88,11 @@ akerr_ErrorContext AKERR_NOIGNORE *akgl_game_init()
 
     for ( i = 0; i < AKGL_SDL_GAMECONTROLLER_DB_LEN ; i++ ) {
 	if ( SDL_AddGamepadMapping(SDL_GAMECONTROLLER_DB[i]) == -1 ) {
-	    FAIL_ZERO_RETURN(errctx, 0, AKGL_ERR_SDL, "%s", SDL_GetError());
+	    FAIL_ZERO_RETURN(e, 0, AKGL_ERR_SDL, "%s", SDL_GetError());
 	}
     }
-    SUCCEED_RETURN(errctx);
-}
+    PASS(e, akgl_controller_open_gamepads());
 
-akerr_ErrorContext AKERR_NOIGNORE *akgl_game_init_screen()
-{
-    akgl_String *width = NULL;
-    akgl_String *height = NULL;
-    int screenwidth;
-    int screenheight;
-
-    PREPARE_ERROR(e);
-    
-    PASS(e, akgl_get_property("game.screenwidth", &width, "0"));
-    PASS(e, akgl_get_property("game.screenheight", &height, "0"));
-    PASS(e, aksl_atoi(width->data, &screenwidth));
-    PASS(e, aksl_atoi(height->data, &screenheight));
-    SDL_Log("Initializing screen (%sx%s = %dx%d)", width->data, height->data, screenwidth, screenheight);
-    PASS(e, akgl_heap_release_string(width));
-    PASS(e, akgl_heap_release_string(height));
-    
-    FAIL_ZERO_RETURN(
-	e,
-	SDL_CreateWindowAndRenderer(game.uri, screenwidth, screenheight, 0, &window, &renderer),
-	AKGL_ERR_SDL,
-	"Couldn't create window/renderer: %s",
-	SDL_GetError());
-    
     FAIL_ZERO_RETURN(
 	e,
 	MIX_Init(),
@@ -132,12 +113,30 @@ akerr_ErrorContext AKERR_NOIGNORE *akgl_game_init_screen()
 	AKGL_ERR_SDL,
 	"Couldn't initialize front engine: %s",
 	SDL_GetError());
+    PASS(e, akgl_game_state_unlock());
+    SUCCEED_RETURN(e);
+}
 
-    camera.x = 0;
-    camera.y = 0;
-    camera.w = screenwidth;
-    camera.h = screenheight;
-    SUCCEED(e);
+akerr_ErrorContext AKERR_NOIGNORE *akgl_game_state_lock(void)
+{
+    PREPARE_ERROR(e);
+    SDL_Time totaltime = 0;
+
+    while ( totaltime < AKGL_TIME_ONESEC_MS ) {
+	if ( SDL_TryLockMutex(game.statelock) == true ) {
+	    SUCCEED_RETURN(e);
+	}
+	totaltime += 100;
+	SDL_Delay(100);
+    }
+    FAIL_RETURN(e, AKGL_ERR_SDL, "%s", SDL_GetError());
+}
+
+akerr_ErrorContext AKERR_NOIGNORE *akgl_game_state_unlock(void)
+{
+    PREPARE_ERROR(e);
+    SDL_UnlockMutex(game.statelock);
+    SUCCEED_RETURN(e);
 }
 
 void akgl_game_updateFPS()
@@ -164,119 +163,119 @@ void akgl_game_save_actorname_iterator(void *userdata, SDL_PropertiesID props, c
 {
     FILE *fp = (FILE *)userdata;
     akgl_Actor *actor = NULL;
-    PREPARE_ERROR(errctx);
+    PREPARE_ERROR(e);
     ATTEMPT {
-	FAIL_ZERO_BREAK(errctx, fp, AKERR_NULLPOINTER, "NULL file pointer");
-	CATCH(errctx, aksl_fwrite((char *)name, 1, AKGL_ACTOR_MAX_NAME_LENGTH, fp));
+	FAIL_ZERO_BREAK(e, fp, AKERR_NULLPOINTER, "NULL file pointer");
+	CATCH(e, aksl_fwrite((char *)name, 1, AKGL_ACTOR_MAX_NAME_LENGTH, fp));
 	actor = SDL_GetPointerProperty(props, name, NULL);
-	CATCH(errctx, aksl_fwrite(&actor, 1, sizeof(akgl_Actor *), fp));
+	CATCH(e, aksl_fwrite(&actor, 1, sizeof(akgl_Actor *), fp));
     } CLEANUP {
-    } PROCESS(errctx) {
-    } FINISH_NORETURN(errctx);
+    } PROCESS(e) {
+    } FINISH_NORETURN(e);
 }
 
 void akgl_game_save_spritename_iterator(void *userdata, SDL_PropertiesID props, const char *name)
 {
     FILE *fp = (FILE *)userdata;
     akgl_Sprite *sprite = NULL;
-    PREPARE_ERROR(errctx);
+    PREPARE_ERROR(e);
     ATTEMPT {
-	FAIL_ZERO_BREAK(errctx, fp, AKERR_NULLPOINTER, "NULL file pointer");
+	FAIL_ZERO_BREAK(e, fp, AKERR_NULLPOINTER, "NULL file pointer");
 	sprite = SDL_GetPointerProperty(props, name, NULL);
-	CATCH(errctx, aksl_fwrite((char *)name, 1, AKGL_SPRITE_MAX_NAME_LENGTH, fp));
-	CATCH(errctx, aksl_fwrite(&sprite, 1, sizeof(akgl_Sprite *), fp));
+	CATCH(e, aksl_fwrite((char *)name, 1, AKGL_SPRITE_MAX_NAME_LENGTH, fp));
+	CATCH(e, aksl_fwrite(&sprite, 1, sizeof(akgl_Sprite *), fp));
     } CLEANUP {
-    } PROCESS(errctx) {
-    } FINISH_NORETURN(errctx);
+    } PROCESS(e) {
+    } FINISH_NORETURN(e);
 }
 
 void akgl_game_save_spritesheetname_iterator(void *userdata, SDL_PropertiesID props, const char *name)
 {
     FILE *fp = (FILE *)userdata;
     akgl_SpriteSheet *spritesheet = NULL;
-    PREPARE_ERROR(errctx);
+    PREPARE_ERROR(e);
     ATTEMPT {
-	FAIL_ZERO_BREAK(errctx, fp, AKERR_NULLPOINTER, "NULL file pointer");
+	FAIL_ZERO_BREAK(e, fp, AKERR_NULLPOINTER, "NULL file pointer");
 	spritesheet = SDL_GetPointerProperty(props, name, NULL);
-	CATCH(errctx, aksl_fwrite((char *)name, 1, AKGL_SPRITE_SHEET_MAX_FILENAME_LENGTH, fp));
-	CATCH(errctx, aksl_fwrite(&spritesheet, 1, sizeof(akgl_SpriteSheet *), fp));
+	CATCH(e, aksl_fwrite((char *)name, 1, AKGL_SPRITE_SHEET_MAX_FILENAME_LENGTH, fp));
+	CATCH(e, aksl_fwrite(&spritesheet, 1, sizeof(akgl_SpriteSheet *), fp));
     } CLEANUP {
-    } PROCESS(errctx) {
-    } FINISH_NORETURN(errctx);
+    } PROCESS(e) {
+    } FINISH_NORETURN(e);
 }
 
 void akgl_game_save_charactername_iterator(void *userdata, SDL_PropertiesID props, const char *name)
 {
     FILE *fp = (FILE *)userdata;
-    PREPARE_ERROR(errctx);
+    PREPARE_ERROR(e);
     akgl_Character *character = NULL;
     ATTEMPT {
-	FAIL_ZERO_BREAK(errctx, fp, AKERR_NULLPOINTER, "NULL file pointer");
+	FAIL_ZERO_BREAK(e, fp, AKERR_NULLPOINTER, "NULL file pointer");
 	character = SDL_GetPointerProperty(props, name, NULL);
-	CATCH(errctx, aksl_fwrite((char *)name, 1, AKGL_SPRITE_MAX_CHARACTER_NAME_LENGTH, fp));
-	CATCH(errctx, aksl_fwrite(&character, 1, sizeof(akgl_Character *), fp));
+	CATCH(e, aksl_fwrite((char *)name, 1, AKGL_SPRITE_MAX_CHARACTER_NAME_LENGTH, fp));
+	CATCH(e, aksl_fwrite(&character, 1, sizeof(akgl_Character *), fp));
     } CLEANUP {
-    } PROCESS(errctx) {
-    } FINISH_NORETURN(errctx);
+    } PROCESS(e) {
+    } FINISH_NORETURN(e);
 }
 
 akerr_ErrorContext AKERR_NOIGNORE *akgl_game_save_actors(FILE *fp)
 {
-    PREPARE_ERROR(errctx);
+    PREPARE_ERROR(e);
     char nullval = 0x00;
     
     ATTEMPT {
-	FAIL_ZERO_BREAK(errctx, fp, AKERR_NULLPOINTER, "NULL file pointer");
+	FAIL_ZERO_BREAK(e, fp, AKERR_NULLPOINTER, "NULL file pointer");
 	// write the actor name pointer table
 	SDL_EnumerateProperties(
 	    AKGL_REGISTRY_ACTOR,
 	    &akgl_game_save_actorname_iterator,
 	    (void *)fp);
-	CATCH(errctx, aksl_fwrite((void *)&nullval, 1, AKGL_ACTOR_MAX_NAME_LENGTH, fp));
-	CATCH(errctx, aksl_fwrite((void *)&nullval, 1, sizeof(akgl_Actor *), fp));
+	CATCH(e, aksl_fwrite((void *)&nullval, 1, AKGL_ACTOR_MAX_NAME_LENGTH, fp));
+	CATCH(e, aksl_fwrite((void *)&nullval, 1, sizeof(akgl_Actor *), fp));
 	// write the sprite name pointer table
 	SDL_EnumerateProperties(
 	    AKGL_REGISTRY_SPRITE,
 	    &akgl_game_save_spritename_iterator,
 	    (void *)fp);
-	CATCH(errctx, aksl_fwrite((void *)&nullval, 1, AKGL_SPRITE_MAX_NAME_LENGTH, fp));
-	CATCH(errctx, aksl_fwrite((void *)&nullval, 1, sizeof(akgl_Sprite *), fp));
+	CATCH(e, aksl_fwrite((void *)&nullval, 1, AKGL_SPRITE_MAX_NAME_LENGTH, fp));
+	CATCH(e, aksl_fwrite((void *)&nullval, 1, sizeof(akgl_Sprite *), fp));
 	// write the spritesheet name pointer table
 	SDL_EnumerateProperties(
 	    AKGL_REGISTRY_SPRITESHEET,
 	    &akgl_game_save_spritesheetname_iterator,
 	    (void *)fp);
-	CATCH(errctx, aksl_fwrite((void *)&nullval, 1, AKGL_SPRITE_SHEET_MAX_FILENAME_LENGTH, fp));
-	CATCH(errctx, aksl_fwrite((void *)&nullval, 1, sizeof(akgl_SpriteSheet *), fp));
+	CATCH(e, aksl_fwrite((void *)&nullval, 1, AKGL_SPRITE_SHEET_MAX_FILENAME_LENGTH, fp));
+	CATCH(e, aksl_fwrite((void *)&nullval, 1, sizeof(akgl_SpriteSheet *), fp));
 	// write the character name pointer table
 	SDL_EnumerateProperties(
 	    AKGL_REGISTRY_CHARACTER,
 	    &akgl_game_save_charactername_iterator,
 	    (void *)fp);
-	CATCH(errctx, aksl_fwrite((void *)&nullval, 1, AKGL_SPRITE_MAX_CHARACTER_NAME_LENGTH, fp));
-	CATCH(errctx, aksl_fwrite((void *)&nullval, 1, sizeof(akgl_Character *), fp));
+	CATCH(e, aksl_fwrite((void *)&nullval, 1, AKGL_SPRITE_MAX_CHARACTER_NAME_LENGTH, fp));
+	CATCH(e, aksl_fwrite((void *)&nullval, 1, sizeof(akgl_Character *), fp));
     } CLEANUP {
-    } PROCESS(errctx) {
-    } FINISH(errctx, true);
-    SUCCEED_RETURN(errctx);
+    } PROCESS(e) {
+    } FINISH(e, true);
+    SUCCEED_RETURN(e);
 }
 
 akerr_ErrorContext AKERR_NOIGNORE *akgl_game_save(char *fpath)
 {
     FILE *fp = NULL;
-    PREPARE_ERROR(errctx);
+    PREPARE_ERROR(e);
 
     ATTEMPT {
-	FAIL_ZERO_BREAK(errctx, fpath, AKERR_NULLPOINTER, "NULL file path");
-	CATCH(errctx, aksl_fopen(fpath, "wb", &fp));
-	CATCH(errctx, aksl_fwrite(&game, 1, sizeof(akgl_Game), fp));
-	CATCH(errctx, akgl_game_save_actors(fp));
-    } PROCESS(errctx) {
+	FAIL_ZERO_BREAK(e, fpath, AKERR_NULLPOINTER, "NULL file path");
+	CATCH(e, aksl_fopen(fpath, "wb", &fp));
+	CATCH(e, aksl_fwrite(&game, 1, sizeof(akgl_Game), fp));
+	CATCH(e, akgl_game_save_actors(fp));
+    } PROCESS(e) {
     } CLEANUP {
 	if ( fp != NULL )
 	    fclose(fp);
-    } FINISH(errctx, true);
-    SUCCEED_RETURN(errctx); // SUCCEED_NORETURN if in main().
+    } FINISH(e, true);
+    SUCCEED_RETURN(e); // SUCCEED_NORETURN if in main().
 }
 
 akerr_ErrorContext AKERR_NOIGNORE *akgl_game_load_objectnamemap(FILE *fp, SDL_PropertiesID map, int namelength, int ptrlength, SDL_PropertiesID registry)
@@ -286,10 +285,10 @@ akerr_ErrorContext AKERR_NOIGNORE *akgl_game_load_objectnamemap(FILE *fp, SDL_Pr
     char objname[namelength];
     int retval = 0;
     
-    PREPARE_ERROR(errctx);
+    PREPARE_ERROR(e);
     while ( 1 ) {
-	CATCH(errctx, aksl_fread((void *)&objname, 1, namelength, fp));
-	CATCH(errctx, aksl_fread((void *)&ptr, 1, ptrlength, fp));
+	CATCH(e, aksl_fread((void *)&objname, 1, namelength, fp));
+	CATCH(e, aksl_fread((void *)&ptr, 1, ptrlength, fp));
 	// End of the map
 	if ( ptr == 0x00 && objname[0] == 0x00 ) {
 	    break;
@@ -302,43 +301,43 @@ akerr_ErrorContext AKERR_NOIGNORE *akgl_game_load_objectnamemap(FILE *fp, SDL_Pr
 	
 	// SDL_Properties objects can only use string keys, so we can't use the
 	// old pointer as a key without first converting it to a string.
-	CATCH(errctx, aksl_memset((void *)&ptrstring, 0x00, 32));
+	CATCH(e, aksl_memset((void *)&ptrstring, 0x00, 32));
 	snprintf((char *)&ptrstring, 32, "%p", ptr);
 	SDL_SetPointerProperty(
 	    map,
 	    ptrstring,
 	    SDL_GetPointerProperty(registry, objname, NULL));
     };
-    SUCCEED_RETURN(errctx);
+    SUCCEED_RETURN(e);
 }
 
 akerr_ErrorContext AKERR_NOIGNORE *akgl_game_load_versioncmp(char *versiontype, char *newversion, char *curversion)
 {
     semver_t current_version = {};
     semver_t compare_version = {};
-    PREPARE_ERROR(errctx);
-    FAIL_ZERO_RETURN(errctx, versiontype, AKERR_NULLPOINTER, "NULL argument");
-    FAIL_ZERO_RETURN(errctx, curversion, AKERR_NULLPOINTER, "NULL argument");
-    FAIL_ZERO_RETURN(errctx, newversion, AKERR_NULLPOINTER, "NULL argument");
+    PREPARE_ERROR(e);
+    FAIL_ZERO_RETURN(e, versiontype, AKERR_NULLPOINTER, "NULL argument");
+    FAIL_ZERO_RETURN(e, curversion, AKERR_NULLPOINTER, "NULL argument");
+    FAIL_ZERO_RETURN(e, newversion, AKERR_NULLPOINTER, "NULL argument");
     
     ATTEMPT {
 	// Check save game library version	
 	FAIL_NONZERO_BREAK(
-	    errctx,
+	    e,
 	    semver_parse((const char *)curversion, &current_version),
 	    AKERR_VALUE,
 	    "Invalid semantic %s version in current game: %s",
 	    versiontype,
 	    (char *)curversion);
 	FAIL_NONZERO_BREAK(
-	    errctx,
+	    e,
 	    semver_parse((const char *)newversion, &compare_version),
 	    AKERR_VALUE,
 	    "Invalid semantic %s version in save game: %s",
 	    versiontype,
 	    (char *)&newversion);
 	FAIL_ZERO_BREAK(
-	    errctx,
+	    e,
 	    semver_satisfies(compare_version, current_version, "="),
 	    AKERR_API,
 	    "Incompatible save game %s version (%s != %s)",
@@ -348,9 +347,9 @@ akerr_ErrorContext AKERR_NOIGNORE *akgl_game_load_versioncmp(char *versiontype,
     } CLEANUP {
 	semver_free(&current_version);
 	semver_free(&compare_version);
-    } PROCESS(errctx) {
-    } FINISH(errctx, true);
-    SUCCEED_RETURN(errctx);
+    } PROCESS(e) {
+    } FINISH(e, true);
+    SUCCEED_RETURN(e);
 }
 
 akerr_ErrorContext AKERR_NOIGNORE *akgl_game_load(char *fpath)
@@ -362,21 +361,21 @@ akerr_ErrorContext AKERR_NOIGNORE *akgl_game_load(char *fpath)
     SDL_PropertiesID charactermap;
     FILE *fp = NULL;
     
-    PREPARE_ERROR(errctx);
-    FAIL_ZERO_RETURN(errctx, fpath, AKERR_NULLPOINTER, "NULL file path");
+    PREPARE_ERROR(e);
+    FAIL_ZERO_RETURN(e, fpath, AKERR_NULLPOINTER, "NULL file path");
     
     ATTEMPT {
-	CATCH(errctx, aksl_fopen(fpath, "rb", &fp));
-	CATCH(errctx, aksl_fread((void *)&savegame, 1, sizeof(akgl_Game), fp));
-	CATCH(errctx, akgl_game_load_versioncmp("library", (char *)&savegame.libversion, (char *)AKGL_VERSION));
-	CATCH(errctx, akgl_game_load_versioncmp("game", (char *)&savegame.version, (char *)&game.version));
+	CATCH(e, aksl_fopen(fpath, "rb", &fp));
+	CATCH(e, aksl_fread((void *)&savegame, 1, sizeof(akgl_Game), fp));
+	CATCH(e, akgl_game_load_versioncmp("library", (char *)&savegame.libversion, (char *)AKGL_VERSION));
+	CATCH(e, akgl_game_load_versioncmp("game", (char *)&savegame.version, (char *)&game.version));
 	FAIL_NONZERO_RETURN(
-	    errctx,
+	    e,
 	    strncmp((char *)&savegame.name, (char *)&game.name, 256),
 	    AKERR_API,
 	    "Savegame is not compatible with this game");
 	FAIL_NONZERO_RETURN(
-	    errctx,
+	    e,
 	    strncmp((char *)&savegame.uri, (char *)&game.uri, 256),
 	    AKERR_API,
 	    "Savegame is not compatible with this game");
@@ -384,23 +383,64 @@ akerr_ErrorContext AKERR_NOIGNORE *akgl_game_load(char *fpath)
 	memcpy((void *)&game, (void *)&savegame, sizeof(akgl_Game));
 	// Load actor name map
 	actormap = SDL_CreateProperties();
-	CATCH(errctx, akgl_game_load_objectnamemap(fp, actormap, AKGL_ACTOR_MAX_NAME_LENGTH, sizeof(akgl_Actor *), AKGL_REGISTRY_ACTOR)); 
+	CATCH(e, akgl_game_load_objectnamemap(fp, actormap, AKGL_ACTOR_MAX_NAME_LENGTH, sizeof(akgl_Actor *), AKGL_REGISTRY_ACTOR)); 
 	// Load sprite name map
 	spritemap = SDL_CreateProperties();
-	CATCH(errctx, akgl_game_load_objectnamemap(fp, spritemap, AKGL_ACTOR_MAX_NAME_LENGTH, sizeof(akgl_Sprite *), AKGL_REGISTRY_SPRITE)); 
+	CATCH(e, akgl_game_load_objectnamemap(fp, spritemap, AKGL_ACTOR_MAX_NAME_LENGTH, sizeof(akgl_Sprite *), AKGL_REGISTRY_SPRITE)); 
 	// Load spritesheet name map
 	spritesheetmap = SDL_CreateProperties();
-	CATCH(errctx, akgl_game_load_objectnamemap(fp, spritesheetmap, AKGL_ACTOR_MAX_NAME_LENGTH, sizeof(akgl_SpriteSheet *), AKGL_REGISTRY_SPRITESHEET)); 
+	CATCH(e, akgl_game_load_objectnamemap(fp, spritesheetmap, AKGL_ACTOR_MAX_NAME_LENGTH, sizeof(akgl_SpriteSheet *), AKGL_REGISTRY_SPRITESHEET)); 
 	// Load character name map
 	charactermap = SDL_CreateProperties();
-	CATCH(errctx, akgl_game_load_objectnamemap(fp, charactermap, AKGL_ACTOR_MAX_NAME_LENGTH, sizeof(akgl_Character *), AKGL_REGISTRY_CHARACTER)); 
+	CATCH(e, akgl_game_load_objectnamemap(fp, charactermap, AKGL_ACTOR_MAX_NAME_LENGTH, sizeof(akgl_Character *), AKGL_REGISTRY_CHARACTER)); 
         // Now that we have all of our pointer maps built, we can load the actual binary objects and reset their pointers	
     } CLEANUP {
 	if ( fp != NULL ) {
 	    fclose(fp);
 	}
-    } PROCESS(errctx) {
-    } FINISH(errctx, true);
+    } PROCESS(e) {
+    } FINISH(e, true);
     
-    SUCCEED_RETURN(errctx);
+    SUCCEED_RETURN(e);
+}
+
+akerr_ErrorContext AKERR_NOIGNORE *akgl_game_update(akgl_Iterator *opflags)
+{
+    PREPARE_ERROR(e);
+    akgl_Iterator defflags = {
+	.flags = (AKGL_ITERATOR_OP_LAYERMASK | AKGL_ITERATOR_OP_LAYERMASK),
+	.layerid = 0
+    };
+    SDL_Time curTime = SDL_GetTicksNS();
+    akgl_Actor *actor = NULL;
+
+    if ( opflags == NULL ) {
+	opflags = &defflags;
+    }
+    
+    PASS(e, akgl_game_state_lock());
+
+    akgl_game_updateFPS();
+
+    for ( int i = 0; i < AKGL_TILEMAP_MAX_LAYERS; i++ ) {
+	if ( opflags == &defflags ) {
+	    opflags->layerid = i;
+	}
+	for ( int j = 0; j < AKGL_MAX_HEAP_ACTOR; j++ ) {
+	    actor = &HEAP_ACTOR[j];
+	    if ( actor->refcount == 0 ) {
+		continue;
+	    }
+	    if ( AKGL_BITMASK_HAS(opflags->flags, AKGL_ITERATOR_OP_TILEMAPSCALE) ) {
+		PASS(e, akgl_tilemap_scale_actor(&gamemap, actor));
+	    } else {
+		actor->scale = 1.0;
+	    }
+	    PASS(e, actor->updatefunc(actor)); 
+	} 
+    }
+    PASS(e, physics.simulate(&physics, NULL));
+    PASS(e, renderer.draw_world(&renderer, NULL));
+    PASS(e, akgl_game_state_unlock());
+    SUCCEED_RETURN(e);
 }

src/heap.c

@@ -20,9 +20,7 @@ akerr_ErrorContext *akgl_heap_init()
     PREPARE_ERROR(errctx);
     int i = 0;
     akerr_name_for_status(AKGL_ERR_SDL, "SDL Error");
-    for ( i = 0; i < AKGL_MAX_HEAP_ACTOR; i++) {
-	memset(&HEAP_ACTOR[i], 0x00, sizeof(akgl_Actor));
-    }
+    PASS(errctx, akgl_heap_init_actor());
     for ( i = 0; i < AKGL_MAX_HEAP_SPRITE; i++) {
 	memset(&HEAP_SPRITE[i], 0x00, sizeof(akgl_Sprite));
     }
@@ -38,6 +36,15 @@ akerr_ErrorContext *akgl_heap_init()
     SUCCEED_RETURN(errctx);
 }
 
+akerr_ErrorContext *akgl_heap_init_actor(void)
+{
+    PREPARE_ERROR(e);
+    for ( int i = 0; i < AKGL_MAX_HEAP_ACTOR; i++) {
+	memset(&HEAP_ACTOR[i], 0x00, sizeof(akgl_Actor));
+    }
+    SUCCEED_RETURN(e);
+}
+
 akerr_ErrorContext *akgl_heap_next_actor(akgl_Actor **dest)
 {
     PREPARE_ERROR(errctx);
@@ -115,7 +122,7 @@ akerr_ErrorContext *akgl_heap_release_actor(akgl_Actor *ptr)
     if ( ptr->refcount == 0 ) {
 	for ( i = 0; i < AKGL_ACTOR_MAX_CHILDREN; i++ ) {
 	    if ( ptr->children[i] != NULL ) {
-		CATCH_AND_RETURN(errctx, akgl_heap_release_actor(ptr->children[i]));
+		PASS(errctx, akgl_heap_release_actor(ptr->children[i]));
 	    }
 	}
 	SDL_ClearProperty(AKGL_REGISTRY_ACTOR, (char *)&ptr->name);

src/physics.c

@@ -0,0 +1,193 @@
+#include <akstdlib.h>
+#include <akgl/physics.h>
+#include <akgl/actor.h>
+#include <akgl/game.h>
+#include <akgl/error.h>
+#include <akgl/heap.h>
+#include <akgl/registry.h>
+
+akerr_ErrorContext AKERR_NOIGNORE *akgl_physics_null_gravity(akgl_PhysicsBackend *self, akgl_Actor *actor, float32_t dt)
+{
+    PREPARE_ERROR(e);
+    FAIL_ZERO_RETURN(e, self, AKERR_NULLPOINTER, "self");
+    SUCCEED_RETURN(e);
+}
+
+akerr_ErrorContext AKERR_NOIGNORE *akgl_physics_null_collide(akgl_PhysicsBackend *self, akgl_Actor *a1, akgl_Actor *a2)
+{
+    PREPARE_ERROR(e);
+    FAIL_ZERO_RETURN(e, self, AKERR_NULLPOINTER, "self");
+    SUCCEED_RETURN(e);
+}
+
+akerr_ErrorContext AKERR_NOIGNORE *akgl_physics_null_move(struct akgl_PhysicsBackend *self, akgl_Actor *actor, float32_t dt)
+{
+    PREPARE_ERROR(e);
+    FAIL_ZERO_RETURN(e, self, AKERR_NULLPOINTER, "self");
+    SUCCEED_RETURN(e);
+}
+
+akerr_ErrorContext AKERR_NOIGNORE *akgl_physics_init_null(akgl_PhysicsBackend *self)
+{
+    PREPARE_ERROR(e);
+    FAIL_ZERO_RETURN(e, self, AKERR_NULLPOINTER, "self");
+    
+    self->gravity = akgl_physics_null_gravity;
+    self->collide = akgl_physics_null_collide;
+    self->move = akgl_physics_null_move;
+    self->simulate = akgl_physics_simulate;
+
+    SUCCEED_RETURN(e);
+}
+
+
+akerr_ErrorContext AKERR_NOIGNORE *akgl_physics_ss_gravity(akgl_PhysicsBackend *self, akgl_Actor *actor, float32_t dt)
+{
+    PREPARE_ERROR(e);
+    FAIL_ZERO_RETURN(e, self, AKERR_NULLPOINTER, "self");
+    FAIL_ZERO_RETURN(e, actor, AKERR_NULLPOINTER, "actor");
+    
+    // Assume the X origin is - (screen left)
+    actor->gx -= (self->gravity_x * dt);
+    // Assume Y origin is + (down screen)
+    actor->gy += (self->gravity_y * dt);
+    // Assume Z origin is - (behind the camera)
+    actor->gz -= (self->gravity_z * dt);
+
+    // Counteract velocity with atmospheric drag
+    actor->gx += actor->vx * self->drag_x * dt;
+    actor->gy -= actor->vy * self->drag_y * dt;
+    actor->gz += actor->vz * self->drag_z * dt;
+
+    SUCCEED_RETURN(e);
+}
+
+akerr_ErrorContext AKERR_NOIGNORE *akgl_physics_ss_collide(akgl_PhysicsBackend *self, akgl_Actor *a1, akgl_Actor *a2)
+{
+    PREPARE_ERROR(e);
+    FAIL_ZERO_RETURN(e, self, AKERR_NULLPOINTER, "self");
+    FAIL_RETURN(e, AKERR_API, "Not implemented");
+    SUCCEED_RETURN(e);
+}
+
+akerr_ErrorContext AKERR_NOIGNORE *akgl_physics_ss_move(struct akgl_PhysicsBackend *self, akgl_Actor *actor, float32_t dt)
+{
+    PREPARE_ERROR(e);
+    FAIL_ZERO_RETURN(e, self, AKERR_NULLPOINTER, "self");
+    FAIL_ZERO_RETURN(e, actor, AKERR_NULLPOINTER, "actor");
+    if ( AKGL_BITMASK_HAS(actor->state, AKGL_ACTOR_STATE_MOVING_LEFT) ) {
+	actor->x += (-actor->vx * dt) + (actor->gx * dt);
+    }
+    if ( AKGL_BITMASK_HAS(actor->state, AKGL_ACTOR_STATE_MOVING_RIGHT) ) {
+	actor->x += (actor->vx * dt) + (actor->gx * dt);
+    }
+    if ( AKGL_BITMASK_HAS(actor->state, AKGL_ACTOR_STATE_MOVING_UP) ) {
+	actor->y += (-actor->vy * dt) + (actor->gy * dt);
+    }
+    if ( AKGL_BITMASK_HAS(actor->state, AKGL_ACTOR_STATE_MOVING_DOWN) ) {
+	actor->y += (actor->vy * dt) + (actor->gy * dt);
+    }
+    
+    SUCCEED_RETURN(e);
+}
+
+akerr_ErrorContext AKERR_NOIGNORE *akgl_physics_init_sidescroller(akgl_PhysicsBackend *self)
+{
+    akgl_String *tmp;
+    PREPARE_ERROR(e);
+    FAIL_ZERO_RETURN(e, self, AKERR_NULLPOINTER, "self");
+    PASS(e, akgl_heap_next_string(&tmp));
+    
+    self->gravity = akgl_physics_ss_gravity;
+    self->collide = akgl_physics_ss_collide;
+    self->move = akgl_physics_ss_move;
+    self->simulate = akgl_physics_simulate;
+
+    ATTEMPT {
+	CATCH(e, akgl_get_property("physics.gravity.x", &tmp, "0.0"));
+	CATCH(e, aksl_atof(tmp->data, &self->gravity_x));
+	CATCH(e, akgl_get_property("physics.gravity.y", &tmp, "0.0"));
+	CATCH(e, aksl_atof(tmp->data, &self->gravity_y));
+	CATCH(e, akgl_get_property("physics.gravity.z", &tmp, "0.0"));
+	CATCH(e, aksl_atof(tmp->data, &self->gravity_z));
+	CATCH(e, akgl_get_property("physics.drag.x", &tmp, "0.0"));
+	CATCH(e, aksl_atof(tmp->data, &self->drag_x));
+	CATCH(e, akgl_get_property("physics.drag.y", &tmp, "0.0"));
+	CATCH(e, aksl_atof(tmp->data, &self->drag_y));
+	CATCH(e, akgl_get_property("physics.drag.z", &tmp, "0.0"));
+	CATCH(e, aksl_atof(tmp->data, &self->drag_z));
+    } CLEANUP {
+	IGNORE(akgl_heap_release_string(tmp));
+    } PROCESS(e) {
+    } FINISH(e, true);
+    
+    SUCCEED_RETURN(e);
+}
+
+akerr_ErrorContext AKERR_NOIGNORE *akgl_physics_simulate(akgl_PhysicsBackend *self, akgl_Iterator *opflags)
+{
+    PREPARE_ERROR(e);
+    akgl_Iterator defflags = {
+	.flags = 0,
+	.layerid = 0
+    };
+    SDL_Time curtime = SDL_GetTicksNS();
+    float32_t dt = (float32_t)(curtime - self->gravity_time) / (float32_t)AKGL_TIME_ONESEC_NS;
+    akgl_Actor *actor = NULL;
+
+    FAIL_ZERO_RETURN(e, self, AKERR_NULLPOINTER, "self");
+    FAIL_ZERO_RETURN(e, self->move, AKERR_NULLPOINTER, "self->move");
+
+    if ( opflags == NULL ) {
+	opflags = &defflags;
+    }
+    
+
+    for ( int i = 0; i < AKGL_MAX_HEAP_ACTOR; i++ ) {
+	actor = &HEAP_ACTOR[i];
+	if ( actor->refcount == 0 ) {
+	    continue;
+	}
+	if ( actor->parent != NULL ) {
+	    // Children don't move independently of their parents, they just have an offset
+	    continue;
+	} else if ( actor->basechar == NULL ) {
+	    continue;
+	}
+	if ( AKGL_BITMASK_HAS(opflags->flags, AKGL_ITERATOR_OP_LAYERMASK) ) {
+	    if ( actor->layer != opflags->layerid ) {
+		continue;
+	    }
+	}
+	if ( AKGL_BITMASK_HAS(actor->state, AKGL_ACTOR_STATE_MOVING_LEFT) ||
+	    AKGL_BITMASK_HAS(actor->state, AKGL_ACTOR_STATE_MOVING_RIGHT) ) {
+	    actor->tx += actor->basechar->ax * dt;
+	}
+	if ( AKGL_BITMASK_HAS(actor->state, AKGL_ACTOR_STATE_MOVING_UP) ||
+	    AKGL_BITMASK_HAS(actor->state, AKGL_ACTOR_STATE_MOVING_DOWN) ) {
+	    actor->ty += actor->basechar->ay * dt;
+	}
+	// velocity equals thrust unless thrust exceeds max speed
+	if ( actor->tx > actor->basechar->sx ) {
+	    actor->vx = actor->basechar->sx;
+	} else {
+	    actor->vx = actor->tx;
+	}
+	if ( actor->ty > actor->basechar->sy ) {
+	    actor->vy = actor->basechar->sy;
+	} else {
+	    actor->vy = actor->ty;
+	}
+	ATTEMPT {
+	    CATCH(e, actor->movementlogicfunc(actor, dt));
+	    PASS(e, self->gravity(self, actor, dt));
+	    PASS(e, self->move(self, actor, dt)); 
+	} CLEANUP {
+	} PROCESS(e) {
+	} HANDLE(e, AKGL_ERR_LOGICINTERRUPT) {
+	    // noop
+	} FINISH(e, true);
+    }
+    self->gravity_time = curtime; 
+    SUCCEED_RETURN(e);
+}

src/registry.c

@@ -10,14 +10,14 @@
 #include <akgl/actor.h>
 #include <akgl/json_helpers.h>
 
-SDL_PropertiesID AKGL_REGISTRY_ACTOR;
-SDL_PropertiesID AKGL_REGISTRY_ACTOR_STATE_STRINGS;
-SDL_PropertiesID AKGL_REGISTRY_SPRITE;
-SDL_PropertiesID AKGL_REGISTRY_SPRITESHEET;
-SDL_PropertiesID AKGL_REGISTRY_CHARACTER;
-SDL_PropertiesID AKGL_REGISTRY_MUSIC;
-SDL_PropertiesID AKGL_REGISTRY_FONT;
-SDL_PropertiesID AKGL_REGISTRY_PROPERTIES;
+SDL_PropertiesID AKGL_REGISTRY_ACTOR = 0;
+SDL_PropertiesID AKGL_REGISTRY_ACTOR_STATE_STRINGS = 0;
+SDL_PropertiesID AKGL_REGISTRY_SPRITE = 0;
+SDL_PropertiesID AKGL_REGISTRY_SPRITESHEET = 0;
+SDL_PropertiesID AKGL_REGISTRY_CHARACTER = 0;
+SDL_PropertiesID AKGL_REGISTRY_MUSIC = 0;
+SDL_PropertiesID AKGL_REGISTRY_FONT = 0;
+SDL_PropertiesID AKGL_REGISTRY_PROPERTIES = 0;
 
 akerr_ErrorContext *akgl_registry_init()
 {
@@ -39,6 +39,9 @@ akerr_ErrorContext *akgl_registry_init()
 akerr_ErrorContext *akgl_registry_init_actor()
 {
     PREPARE_ERROR(errctx);
+    if ( AKGL_REGISTRY_ACTOR != 0 ) {
+	SDL_DestroyProperties(AKGL_REGISTRY_ACTOR);
+    }
     AKGL_REGISTRY_ACTOR = SDL_CreateProperties();
     FAIL_ZERO_RETURN(errctx, AKGL_REGISTRY_ACTOR, AKERR_NULLPOINTER, "Error initializing actor registry");
     SUCCEED_RETURN(errctx);
@@ -149,7 +152,7 @@ akerr_ErrorContext AKERR_NOIGNORE *akgl_registry_load_properties(char *fname)
 	} FINISH(errctx, true);
     }
     SDL_Log("Properties loaded");
-    SUCCEED(errctx);
+    SUCCEED_RETURN(errctx);
 }
 
 akerr_ErrorContext AKERR_NOIGNORE *akgl_set_property(char *name, char *src)

src/renderer.c

@@ -0,0 +1,136 @@
+#include <SDL3/SDL.h>
+
+#include <akgl/renderer.h>
+#include <akgl/staticstring.h>
+#include <akgl/registry.h>
+#include <akgl/heap.h>
+#include <akgl/game.h>
+
+#include <akerror.h>
+#include <akstdlib.h>
+
+akerr_ErrorContext AKERR_NOIGNORE *akgl_render_init2d(akgl_RenderBackend *self)
+{
+    akgl_String *width = NULL;
+    akgl_String *height = NULL;
+    int screenwidth;
+    int screenheight;
+    PREPARE_ERROR(e);
+    FAIL_ZERO_RETURN(e, self, AKERR_NULLPOINTER, "self");
+
+    PASS(e, akgl_get_property("game.screenwidth", &width, "0"));
+    PASS(e, akgl_get_property("game.screenheight", &height, "0"));
+    PASS(e, aksl_atoi(width->data, &screenwidth));
+    PASS(e, aksl_atoi(height->data, &screenheight));
+    SDL_Log("Initializing screen (%sx%s = %dx%d)", width->data, height->data, screenwidth, screenheight);
+    PASS(e, akgl_heap_release_string(width));
+    PASS(e, akgl_heap_release_string(height));
+    
+    FAIL_ZERO_RETURN(
+	e,
+	SDL_CreateWindowAndRenderer(game.uri, screenwidth, screenheight, 0, &window, &self->sdl_renderer),
+	AKGL_ERR_SDL,
+	"Couldn't create window/renderer: %s",
+	SDL_GetError());
+    
+    camera.x = 0;
+    camera.y = 0;
+    camera.w = screenwidth;
+    camera.h = screenheight;
+
+    self->shutdown = &akgl_render_2d_shutdown;
+    self->frame_start = &akgl_render_2d_frame_start;
+    self->frame_end = &akgl_render_2d_frame_end;
+    self->draw_texture = &akgl_render_2d_draw_texture;
+    self->draw_mesh = &akgl_render_2d_draw_mesh;
+    self->draw_world = &akgl_render_2d_draw_world;
+    SUCCEED_RETURN(e);
+}
+
+
+akerr_ErrorContext AKERR_NOIGNORE *akgl_render_2d_shutdown(akgl_RenderBackend *self)
+{
+    PREPARE_ERROR(e);
+    SUCCEED_RETURN(e);
+}
+
+akerr_ErrorContext AKERR_NOIGNORE *akgl_render_2d_frame_start(akgl_RenderBackend *self)
+{
+    PREPARE_ERROR(e);
+    FAIL_ZERO_RETURN(e, self->sdl_renderer, AKERR_NULLPOINTER, "No valid SDL rendering backend");
+    SDL_SetRenderDrawColor(self->sdl_renderer, 0, 0, 0, 255);
+    SDL_RenderClear(self->sdl_renderer);
+    SUCCEED_RETURN(e);
+}
+
+akerr_ErrorContext AKERR_NOIGNORE *akgl_render_2d_frame_end(akgl_RenderBackend *self)
+{
+    PREPARE_ERROR(e);
+    FAIL_ZERO_RETURN(e, self->sdl_renderer, AKERR_NULLPOINTER, "No valid SDL rendering backend");
+    SDL_RenderPresent(self->sdl_renderer);
+    SUCCEED_RETURN(e);
+}
+
+akerr_ErrorContext AKERR_NOIGNORE *akgl_render_2d_draw_texture(akgl_RenderBackend *self, SDL_Texture *texture, SDL_FRect *src, SDL_FRect *dest, double angle, SDL_FPoint *center, SDL_FlipMode flip)
+{
+    PREPARE_ERROR(e);
+    FAIL_ZERO_RETURN(e, self, AKERR_NULLPOINTER, "self");
+    FAIL_ZERO_RETURN(e, texture, AKERR_NULLPOINTER, "texture");
+    //FAIL_ZERO_RETURN(e, src, AKERR_NULLPOINTER, "src");
+    //FAIL_ZERO_RETURN(e, dest, AKERR_NULLPOINTER, "dest");
+
+    if ( angle != 0 ) {
+	FAIL_ZERO_RETURN(e, center, AKERR_NULLPOINTER, "center");
+	FAIL_ZERO_RETURN(
+	    e,
+	    SDL_RenderTextureRotated(self->sdl_renderer, texture, src, dest, angle, center, flip),
+	    AKERR_NULLPOINTER, "%s", SDL_GetError()
+	    );
+    } else {
+	FAIL_ZERO_RETURN(
+	    e,
+	    SDL_RenderTexture(self->sdl_renderer, texture, src, dest),
+	    AKERR_NULLPOINTER, "%s", SDL_GetError()
+	    );
+    }
+    SUCCEED_RETURN(e);
+}
+
+akerr_ErrorContext AKERR_NOIGNORE *akgl_render_2d_draw_mesh(akgl_RenderBackend *self)
+{
+    PREPARE_ERROR(e);
+    FAIL_RETURN(e, AKERR_API, "Not implemented");
+}
+
+akerr_ErrorContext AKERR_NOIGNORE *akgl_render_2d_draw_world(akgl_RenderBackend *self, akgl_Iterator *opflags)
+{
+    PREPARE_ERROR(e);
+    akgl_Iterator defflags;
+    SDL_Time curTime = SDL_GetTicksNS();
+    akgl_Actor *actor = NULL;
+    int j = 0;
+
+    FAIL_ZERO_RETURN(e, self, AKERR_NULLPOINTER, "self");
+
+    if ( opflags == NULL ) {
+	opflags = &defflags;
+	PASS(e, aksl_memset((void *)opflags, 0x00, sizeof(akgl_Iterator)));
+    }
+    for ( int i = 0; i < AKGL_TILEMAP_MAX_LAYERS ; i++ ) {
+	if ( i < gamemap.numlayers ) {
+	    PASS(e, akgl_tilemap_draw((akgl_Tilemap *)&gamemap, &camera, i));
+	}
+	for ( int j = 0; j < AKGL_MAX_HEAP_ACTOR ; j++ ) {
+	    actor = &HEAP_ACTOR[j];
+	    if ( actor->refcount == 0 ) {
+		continue;
+	    }
+	    if ( actor->layer != i ) {
+		continue;
+	    }
+	    PASS(e, actor->renderfunc(actor));	    
+	}
+    }
+    
+    SUCCEED_RETURN(e);    
+}

src/sprite.c

@@ -12,6 +12,7 @@
 #include <akgl/registry.h>
 #include <akgl/staticstring.h>
 #include <akgl/iterator.h>
+#include <akgl/util.h>
 
 akerr_ErrorContext *akgl_sprite_sheet_coords_for_frame(akgl_Sprite *self, SDL_FRect *srccoords, uint8_t frameid)
 {
@@ -48,11 +49,7 @@ static akerr_ErrorContext *akgl_sprite_load_json_spritesheet(json_t *json, akgl_
 	CATCH(errctx, akgl_string_initialize(tmpstr, NULL));
 	CATCH(errctx, akgl_get_json_object_value((json_t *)json, "spritesheet", &spritesheet_json));
 	CATCH(errctx, akgl_get_json_string_value((json_t *)spritesheet_json, "filename", &ss_filename));
-	if ( ss_filename->data[0] != '/' ) {
-	    SDL_snprintf((char *)&tmpstr->data, AKGL_MAX_STRING_LENGTH, "%s/%s", relative_path, ss_filename->data);
-	} else {
-	    SDL_snprintf((char *)&tmpstr->data, AKGL_MAX_STRING_LENGTH, "%s", ss_filename->data);
-	}
+	CATCH(errctx, akgl_path_relative(relative_path, ss_filename->data, tmpstr));
 	*sheet = SDL_GetPointerProperty(
 	    AKGL_REGISTRY_SPRITESHEET,
 	    (char *)&tmpstr->data,
@@ -177,7 +174,7 @@ akerr_ErrorContext *akgl_spritesheet_initialize(akgl_SpriteSheet *sheet, int spr
 	strncpy((char *)&sheet->name, filename, AKGL_SPRITE_SHEET_MAX_FILENAME_LENGTH);
       
 	//snprintf((char *)&tmpstr->data, AKGL_MAX_STRING_LENGTH, "%s%s", SDL_GetBasePath(), filename);
-	sheet->texture = IMG_LoadTexture(renderer, filename);
+	sheet->texture = IMG_LoadTexture(renderer.sdl_renderer, filename);
 	FAIL_ZERO_BREAK(errctx, sheet->texture, AKGL_ERR_SDL, "Failed loading asset %s : %s", filename, SDL_GetError());
       
 	FAIL_ZERO_BREAK(

src/staticstring.c

@@ -1,5 +1,6 @@
 #include <akerror.h>
 #include <akgl/staticstring.h>
+#include <errno.h>
 
 akerr_ErrorContext *akgl_string_initialize(akgl_String *obj, char *init)
 {
@@ -13,3 +14,17 @@ akerr_ErrorContext *akgl_string_initialize(akgl_String *obj, char *init)
   obj->refcount = 1;
   SUCCEED_RETURN(errctx);
 }
+
+akerr_ErrorContext *akgl_string_copy(akgl_String *src, akgl_String *dst, int count)
+{
+    PREPARE_ERROR(e);
+    FAIL_ZERO_RETURN(e, src, AKERR_NULLPOINTER, "NULL argument");
+    FAIL_ZERO_RETURN(e, dst, AKERR_NULLPOINTER, "NULL argument");
+    if ( count == 0 ) {
+	count = AKGL_MAX_STRING_LENGTH;
+    }
+    if ( (char *)dst->data != strncpy((char *)&dst->data, (char *)&src->data, count) ) {
+	FAIL_RETURN(e, errno, "strncpy");
+    }
+    SUCCEED_RETURN(e);
+}

src/text.c

@@ -49,12 +49,12 @@ akerr_ErrorContext AKERR_NOIGNORE *akgl_text_rendertextat(TTF_Font *font, char *
 	    color);
     }
     FAIL_ZERO_RETURN(errctx, textsurf, AKERR_NULLPOINTER, "%s", SDL_GetError());
-    texture = SDL_CreateTextureFromSurface(renderer, textsurf);
+    texture = SDL_CreateTextureFromSurface(renderer.sdl_renderer, textsurf);
     FAIL_ZERO_RETURN(errctx, texture, AKERR_NULLPOINTER, "%s", SDL_GetError());
     dest.x = x;
     dest.y = y;
     SDL_GetTextureSize(texture, &dest.w, &dest.h);
-    FAIL_ZERO_RETURN(errctx, SDL_RenderTexture(renderer, texture, NULL, &dest), AKERR_NULLPOINTER, "%s", SDL_GetError());
+    PASS(errctx, renderer.draw_texture(&renderer, texture, NULL, &dest, 0, NULL, SDL_FLIP_NONE));
     SDL_DestroyTexture(texture);
     SDL_DestroySurface(textsurf);
     SUCCEED_RETURN(errctx);

src/tilemap.c

@@ -1,9 +1,13 @@
+#include <string.h>
+#include <libgen.h>
+
 #include <SDL3/SDL.h>
 #include <SDL3_image/SDL_image.h>
 #include <SDL3_mixer/SDL_mixer.h>
-#include <string.h>
 #include <jansson.h>
+
 #include <akerror.h>
+#include <akstdlib.h>
 
 #include <akgl/tilemap.h>
 #include <akgl/actor.h>
@@ -12,6 +16,7 @@
 #include <akgl/registry.h>
 #include <akgl/staticstring.h>
 #include <akgl/game.h>
+#include <akgl/util.h>
 
 akerr_ErrorContext *akgl_get_json_tilemap_property(json_t *obj, char *key, char *type, json_t **dest)
 {
@@ -19,6 +24,7 @@ akerr_ErrorContext *akgl_get_json_tilemap_property(json_t *obj, char *key, char
     json_t *properties = NULL;
     json_t *property = NULL;
     akgl_String *tmpstr = NULL;
+    akgl_String *typestr = NULL;
     int i = 0;
     // This is not a generic JSON helper. It assumes we are receiving an object with a 'properties' key
     // inside of it. That key is an array of objects, and each object has a name, type, and value.
@@ -33,9 +39,9 @@ akerr_ErrorContext *akgl_get_json_tilemap_property(json_t *obj, char *key, char
 		CATCH(errctx, akgl_heap_release_string(tmpstr));
 		continue;
 	    }
-	    CATCH(errctx, akgl_get_json_string_value(property, "type", &tmpstr));
-	    if ( strcmp(tmpstr->data, type) != 0 ) {
-		FAIL_BREAK(errctx, AKERR_TYPE, "Object property is present but is incorrect type");
+	    CATCH(errctx, akgl_get_json_string_value(property, "type", &typestr));
+	    if ( strcmp(typestr->data, type) != 0 ) {
+		FAIL_BREAK(errctx, AKERR_TYPE, "Property %s is present but is incorrect type(expected %s got %s)", key, type, (char *)typestr->data);
 	    }
 	    *dest = property;
 	    SUCCEED_RETURN(errctx);
@@ -44,13 +50,15 @@ akerr_ErrorContext *akgl_get_json_tilemap_property(json_t *obj, char *key, char
 	if ( tmpstr != NULL ) {
 	    IGNORE(akgl_heap_release_string(tmpstr));
 	}
+	if ( typestr != NULL ) {
+	    IGNORE(akgl_heap_release_string(typestr));
+	}
     } PROCESS(errctx) {
     } FINISH(errctx, true);
   
     FAIL_RETURN(errctx, AKERR_KEY, "Property not found in properties map");
 }
 
-
 akerr_ErrorContext *akgl_get_json_properties_string(json_t *obj, char *key, akgl_String **dest)
 {
     PREPARE_ERROR(errctx);
@@ -96,38 +104,13 @@ akerr_ErrorContext *akgl_get_json_properties_number(json_t *obj, char *key, floa
     SUCCEED_RETURN(errctx);
 }
 
-akerr_ErrorContext *akgl_tilemap_load_tilesets_each(json_t *tileset, akgl_Tilemap *dest, int tsidx)
+akerr_ErrorContext *akgl_get_json_properties_float(json_t *obj, char *key, float *dest)
 {
     PREPARE_ERROR(errctx);
-    akgl_String *tmpstr = NULL;
+    json_t *property = NULL;
     ATTEMPT {
-	CATCH(errctx, akgl_get_json_integer_value((json_t *)tileset, "columns", &dest->tilesets[tsidx].columns));
-	CATCH(errctx, akgl_get_json_integer_value((json_t *)tileset, "firstgid", &dest->tilesets[tsidx].firstgid));
-	CATCH(errctx, akgl_get_json_integer_value((json_t *)tileset, "imageheight", &dest->tilesets[tsidx].imageheight));
-	CATCH(errctx, akgl_get_json_integer_value((json_t *)tileset, "imagewidth", &dest->tilesets[tsidx].imagewidth));
-	CATCH(errctx, akgl_get_json_integer_value((json_t *)tileset, "margin", &dest->tilesets[tsidx].margin));
-	CATCH(errctx, akgl_get_json_integer_value((json_t *)tileset, "spacing", &dest->tilesets[tsidx].spacing));
-	CATCH(errctx, akgl_get_json_integer_value((json_t *)tileset, "tilecount", &dest->tilesets[tsidx].tilecount));
-	CATCH(errctx, akgl_get_json_integer_value((json_t *)tileset, "tileheight", &dest->tilesets[tsidx].tileheight));
-	CATCH(errctx, akgl_get_json_integer_value((json_t *)tileset, "tilewidth", &dest->tilesets[tsidx].tilewidth));
-	
-	CATCH(errctx, akgl_get_json_string_value((json_t *)tileset, "name", &tmpstr));
-	strncpy((char *)&dest->tilesets[tsidx].name,
-		(char *)&tmpstr->data,
-		AKGL_TILEMAP_MAX_TILESET_NAME_SIZE
-	    );
-	
-	CATCH(errctx, akgl_get_json_string_value((json_t *)tileset, "image", &tmpstr));
-	
-	snprintf((char *)&dest->tilesets[tsidx].imagefilename,
-		 AKGL_TILEMAP_MAX_TILESET_FILENAME_SIZE,
-		 "%s%s",
-		 SDL_GetBasePath(),
-		 tmpstr->data
-	    );
-	
-	dest->tilesets[tsidx].texture = IMG_LoadTexture(renderer, (char *)&dest->tilesets[tsidx].imagefilename);
-	FAIL_ZERO_BREAK(errctx, dest->tilesets[tsidx].texture, AKERR_NULLPOINTER, "Failed loading tileset image : %s", SDL_GetError());
+	CATCH(errctx, akgl_get_json_tilemap_property(obj, key, "float", &property));
+	CATCH(errctx, akgl_get_json_number_value(property, "value", dest));
     } CLEANUP {
     } PROCESS(errctx) {
     } FINISH(errctx, true);
@@ -135,6 +118,46 @@ akerr_ErrorContext *akgl_tilemap_load_tilesets_each(json_t *tileset, akgl_Tilema
     SUCCEED_RETURN(errctx);
 }
 
+akerr_ErrorContext *akgl_tilemap_load_tilesets_each(json_t *tileset, akgl_Tilemap *dest, int tsidx, akgl_String *dirname)
+{
+    PREPARE_ERROR(e);
+    akgl_String *tmpstr = NULL;
+    akgl_String *tmppath = NULL;
+    
+    PASS(e, akgl_get_json_integer_value((json_t *)tileset, "columns", &dest->tilesets[tsidx].columns));
+    PASS(e, akgl_get_json_integer_value((json_t *)tileset, "firstgid", &dest->tilesets[tsidx].firstgid));
+    PASS(e, akgl_get_json_integer_value((json_t *)tileset, "imageheight", &dest->tilesets[tsidx].imageheight));
+    PASS(e, akgl_get_json_integer_value((json_t *)tileset, "imagewidth", &dest->tilesets[tsidx].imagewidth));
+    PASS(e, akgl_get_json_integer_value((json_t *)tileset, "margin", &dest->tilesets[tsidx].margin));
+    PASS(e, akgl_get_json_integer_value((json_t *)tileset, "spacing", &dest->tilesets[tsidx].spacing));
+    PASS(e, akgl_get_json_integer_value((json_t *)tileset, "tilecount", &dest->tilesets[tsidx].tilecount));
+    PASS(e, akgl_get_json_integer_value((json_t *)tileset, "tileheight", &dest->tilesets[tsidx].tileheight));
+    PASS(e, akgl_get_json_integer_value((json_t *)tileset, "tilewidth", &dest->tilesets[tsidx].tilewidth));
+
+    PASS(e, akgl_get_json_string_value((json_t *)tileset, "name", &tmpstr));
+    PASS(e, akgl_heap_next_string(&tmpstr));
+    PASS(e, akgl_heap_next_string(&tmppath));
+    ATTEMPT {
+	strncpy((char *)&dest->tilesets[tsidx].name,
+		(char *)&tmpstr->data,
+		AKGL_TILEMAP_MAX_TILESET_NAME_SIZE
+	    );
+    
+	CATCH(e, akgl_get_json_string_value((json_t *)tileset, "image", &tmpstr));    
+	CATCH(e, akgl_path_relative((char *)&dirname->data, (char *)&tmpstr->data, tmppath));
+	strncpy((char *)&dest->tilesets[tsidx].imagefilename, tmppath->data, AKGL_MAX_STRING_LENGTH);
+    } CLEANUP {
+	IGNORE(akgl_heap_release_string(tmpstr));
+	IGNORE(akgl_heap_release_string(tmppath));
+    } PROCESS(e) {
+    } FINISH(e, true);
+    
+    dest->tilesets[tsidx].texture = IMG_LoadTexture(renderer.sdl_renderer, (char *)&dest->tilesets[tsidx].imagefilename);
+    FAIL_ZERO_RETURN(e, dest->tilesets[tsidx].texture, AKERR_NULLPOINTER, "Failed loading tileset image : %s", SDL_GetError());
+    
+    SUCCEED_RETURN(e);
+}
+
 akerr_ErrorContext *akgl_tilemap_compute_tileset_offsets(akgl_Tilemap *dest, int tilesetidx)
 {
     int x_offset = 0;
@@ -190,7 +213,7 @@ akerr_ErrorContext *akgl_tilemap_compute_tileset_offsets(akgl_Tilemap *dest, int
     SUCCEED_RETURN(errctx);
 }  
  
-akerr_ErrorContext *akgl_tilemap_load_tilesets(akgl_Tilemap *dest, json_t *root)
+akerr_ErrorContext *akgl_tilemap_load_tilesets(akgl_Tilemap *dest, json_t *root, akgl_String *dirname)
 {
     PREPARE_ERROR(errctx);
     FAIL_ZERO_RETURN(errctx, dest, AKERR_NULLPOINTER, "Received NULL tilemap pointer");
@@ -205,7 +228,7 @@ akerr_ErrorContext *akgl_tilemap_load_tilesets(akgl_Tilemap *dest, json_t *root)
 	CATCH(errctx, akgl_get_json_array_value(root, "tilesets", &tilesets))
 	    for (i = 0; i < json_array_size((json_t *)tilesets); i++) {
 		CATCH(errctx, akgl_get_json_array_index_object((json_t *)tilesets, i, &jstileset));
-		CATCH(errctx, akgl_tilemap_load_tilesets_each(jstileset, dest, i));
+		CATCH(errctx, akgl_tilemap_load_tilesets_each(jstileset, dest, i, dirname));
 		CATCH(errctx, akgl_tilemap_compute_tileset_offsets(dest, i));
 		dest->numtilesets += 1;
 	    }
@@ -216,7 +239,7 @@ akerr_ErrorContext *akgl_tilemap_load_tilesets(akgl_Tilemap *dest, json_t *root)
     SUCCEED_RETURN(errctx);
 }
 
-akerr_ErrorContext *akgl_tilemap_load_layer_object_actor(akgl_TilemapObject *curobj, json_t *layerdatavalue, int layerid)
+akerr_ErrorContext *akgl_tilemap_load_layer_object_actor(akgl_TilemapObject *curobj, json_t *layerdatavalue, int layerid, akgl_String *dirname)
 {
     PREPARE_ERROR(errctx);
     akgl_String *tmpstr = NULL;
@@ -260,7 +283,7 @@ akerr_ErrorContext *akgl_tilemap_load_layer_object_actor(akgl_TilemapObject *cur
     SUCCEED_RETURN(errctx);
 }
 
-akerr_ErrorContext *akgl_tilemap_load_layer_objects(akgl_Tilemap *dest, json_t *root, int layerid)
+akerr_ErrorContext *akgl_tilemap_load_layer_objects(akgl_Tilemap *dest, json_t *root, int layerid, akgl_String *dirname)
 {
     PREPARE_ERROR(errctx);
     json_t *layerdata = NULL;
@@ -290,17 +313,17 @@ akerr_ErrorContext *akgl_tilemap_load_layer_objects(akgl_Tilemap *dest, json_t *
 
 	    CATCH(errctx, akgl_get_json_string_value((json_t *)layerdatavalue, "type", &tmpstr));
 	    if ( strcmp(tmpstr->data, "actor") == 0 ) {
-		CATCH(errctx, akgl_tilemap_load_layer_object_actor(curobj, layerdatavalue, layerid));
+		CATCH(errctx, akgl_tilemap_load_layer_object_actor(curobj, layerdatavalue, layerid, dirname));
 	    } else if ( strcmp(tmpstr->data, "perspective") == 0 ) {
 		curobj->visible = false;
 		if ( strcmp((char *)curobj->name, "p_foreground") == 0 ) {
 		    dest->p_foreground_y = curobj->y;
 		    CATCH(errctx, akgl_get_json_integer_value((json_t *)layerdatavalue, "height", &dest->p_foreground_h));
-		    CATCH(errctx, akgl_get_json_properties_number((json_t *)layerdatavalue, "scale", &dest->p_foreground_scale));
+		    CATCH(errctx, akgl_get_json_properties_float((json_t *)layerdatavalue, "scale", &dest->p_foreground_scale));
 		} else if ( strcmp((char *)curobj->name, "p_vanishing") == 0 ) {
 		    dest->p_vanishing_y = curobj->y;
 		    CATCH(errctx, akgl_get_json_integer_value((json_t *)layerdatavalue, "height", &dest->p_vanishing_h));
-		    CATCH(errctx, akgl_get_json_properties_number((json_t *)layerdatavalue, "scale", &dest->p_vanishing_scale));
+		    CATCH(errctx, akgl_get_json_properties_float((json_t *)layerdatavalue, "scale", &dest->p_vanishing_scale));
 		}	
 	    }
 		
@@ -313,7 +336,7 @@ akerr_ErrorContext *akgl_tilemap_load_layer_objects(akgl_Tilemap *dest, json_t *
     SUCCEED_RETURN(errctx);
 }
 
-akerr_ErrorContext *akgl_tilemap_load_layer_tile(akgl_Tilemap *dest, json_t *root, int layerid)
+akerr_ErrorContext *akgl_tilemap_load_layer_tile(akgl_Tilemap *dest, json_t *root, int layerid, akgl_String *dirname)
 {
     PREPARE_ERROR(errctx);
     json_t *layerdata = NULL;
@@ -322,6 +345,7 @@ akerr_ErrorContext *akgl_tilemap_load_layer_tile(akgl_Tilemap *dest, json_t *roo
 
     FAIL_ZERO_RETURN(errctx, dest, AKERR_NULLPOINTER, "NULL destination tilemap reference");
     FAIL_ZERO_RETURN(errctx, root, AKERR_NULLPOINTER, "NULL tilemap root reference");
+    FAIL_ZERO_RETURN(errctx, dirname, AKERR_NULLPOINTER, "dirname");
 
     ATTEMPT {
 	CATCH(errctx, akgl_get_json_integer_value(root, "height", &dest->layers[layerid].height));
@@ -341,7 +365,7 @@ akerr_ErrorContext *akgl_tilemap_load_layer_tile(akgl_Tilemap *dest, json_t *roo
     SUCCEED_RETURN(errctx);
 }
 
-akerr_ErrorContext *akgl_tilemap_load_layer_image(akgl_Tilemap *dest, json_t *root, int layerid)
+akerr_ErrorContext *akgl_tilemap_load_layer_image(akgl_Tilemap *dest, json_t *root, int layerid, akgl_String *dirname)
 {
     PREPARE_ERROR(errctx);
     akgl_String *tmpstr;
@@ -349,20 +373,23 @@ akerr_ErrorContext *akgl_tilemap_load_layer_image(akgl_Tilemap *dest, json_t *ro
 
     FAIL_ZERO_RETURN(errctx, dest, AKERR_NULLPOINTER, "NULL destination tilemap reference");
     FAIL_ZERO_RETURN(errctx, root, AKERR_NULLPOINTER, "NULL tilemap root reference");
+    FAIL_ZERO_RETURN(errctx, dirname, AKERR_NULLPOINTER, "dirname");
 
     ATTEMPT {
 	CATCH(errctx, akgl_heap_next_string(&tmpstr));
 	CATCH(errctx, akgl_heap_next_string(&fpath));
 	CATCH(errctx, akgl_get_json_string_value(root, "image", &tmpstr));
 
+	DISABLE_GCC_WARNING_FORMAT_TRUNCATION
 	snprintf((char *)&fpath->data,
 		 AKGL_TILEMAP_MAX_TILESET_FILENAME_SIZE,
-		 "%s%s",
-		 SDL_GetBasePath(),
+		 "%s/%s",
+		 dirname->data,
 		 tmpstr->data
 	    );
+	RESTORE_GCC_WARNINGS
 	
-	dest->layers[layerid].texture = IMG_LoadTexture(renderer, (char *)fpath->data);
+	dest->layers[layerid].texture = IMG_LoadTexture(renderer.sdl_renderer, (char *)fpath->data);
 	FAIL_ZERO_BREAK(errctx, dest->layers[layerid].texture, AKGL_ERR_SDL, "%s", SDL_GetError());
 	dest->layers[layerid].width = dest->layers[layerid].texture->w;
 	dest->layers[layerid].height = dest->layers[layerid].texture->h;
@@ -375,11 +402,12 @@ akerr_ErrorContext *akgl_tilemap_load_layer_image(akgl_Tilemap *dest, json_t *ro
     SUCCEED_RETURN(errctx);
 }
 
-akerr_ErrorContext *akgl_tilemap_load_layers(akgl_Tilemap *dest, json_t *root)
+akerr_ErrorContext *akgl_tilemap_load_layers(akgl_Tilemap *dest, json_t *root, akgl_String *dirname)
 {
     PREPARE_ERROR(errctx);
     FAIL_ZERO_RETURN(errctx, dest, AKERR_NULLPOINTER, "akgl_tilemap_load_layers received NULL tilemap pointer");
     FAIL_ZERO_RETURN(errctx, root, AKERR_NULLPOINTER, "akgl_tilemap_load_layers received NULL json object pointer");
+    FAIL_ZERO_RETURN(errctx, dirname, AKERR_NULLPOINTER, "dirname");
     json_t *layers = NULL;
     json_t *layer = NULL;
     akgl_String *tmpstr = NULL;
@@ -406,13 +434,13 @@ akerr_ErrorContext *akgl_tilemap_load_layers(akgl_Tilemap *dest, json_t *root)
 	    SDL_Log("Layer %d has type %s", layerid, tmpstr->data);
 	    if ( strncmp((char *)tmpstr->data, "objectgroup", strlen((char *)tmpstr->data)) == 0 ) {
 		dest->layers[layerid].type = AKGL_TILEMAP_LAYER_TYPE_OBJECTS;
-		CATCH(errctx, akgl_tilemap_load_layer_objects((akgl_Tilemap *)dest, (json_t *)layer, layerid));
+		CATCH(errctx, akgl_tilemap_load_layer_objects((akgl_Tilemap *)dest, (json_t *)layer, layerid, dirname));
 	    } else if ( strncmp((char *)tmpstr->data, "tilelayer", strlen((char *)tmpstr->data)) == 0 ) {
 		dest->layers[layerid].type = AKGL_TILEMAP_LAYER_TYPE_TILES;
-		CATCH(errctx, akgl_tilemap_load_layer_tile((akgl_Tilemap *)dest, (json_t *)layer, layerid));
+		CATCH(errctx, akgl_tilemap_load_layer_tile((akgl_Tilemap *)dest, (json_t *)layer, layerid, dirname));
 	    } else if ( strncmp((char *)tmpstr->data, "imagelayer", strlen((char *)tmpstr->data)) == 0 ) {
 		dest->layers[layerid].type = AKGL_TILEMAP_LAYER_TYPE_IMAGE;
-		CATCH(errctx, akgl_tilemap_load_layer_image((akgl_Tilemap *)dest, (json_t *)layer, layerid));
+		CATCH(errctx, akgl_tilemap_load_layer_image((akgl_Tilemap *)dest, (json_t *)layer, layerid, dirname));
 	    }
 	    layer = NULL;
 	    layerid += 1;
@@ -429,6 +457,7 @@ akerr_ErrorContext *akgl_tilemap_load(char *fname, akgl_Tilemap *dest)
     json_t *json = NULL;
     //akgl_String *tmpstr = NULL;
     json_error_t error;
+    akgl_String *dirnamestr = NULL;
   
     FAIL_ZERO_RETURN(errctx, fname, AKERR_NULLPOINTER, "load_tilemap received null filename");
     FAIL_ZERO_RETURN(errctx, dest, AKERR_NULLPOINTER, "load_tilemap received null tilemap");
@@ -437,10 +466,14 @@ akerr_ErrorContext *akgl_tilemap_load(char *fname, akgl_Tilemap *dest)
     dest->p_foreground_scale = 1.0;
     dest->p_vanishing_scale = 1.0;
 
+    PASS(errctx, akgl_heap_next_string(&dirnamestr));
     ATTEMPT {
 	//CATCH(errctx, akgl_heap_next_string(&tmpstr));
 	//CATCH(errctx, akgl_string_initialize(tmpstr, NULL));
 	//SDL_snprintf(tmpstr->data, AKGL_MAX_STRING_LENGTH, "%s%s", SDL_GetBasePath(), fname);
+	CATCH(errctx, aksl_realpath(fname, (char *)&dirnamestr->data));
+	dirname((char *)&dirnamestr->data);
+	
 	json = json_load_file(fname, 0, &error);
 	FAIL_ZERO_BREAK(
 	    errctx,
@@ -461,8 +494,8 @@ akerr_ErrorContext *akgl_tilemap_load(char *fname, akgl_Tilemap *dest)
 	    FAIL_RETURN(errctx, AKERR_OUTOFBOUNDS, "Map exceeds the maximum size");
 	}
 
-	CATCH(errctx, akgl_tilemap_load_layers((akgl_Tilemap *)dest, (json_t *)json));
-	CATCH(errctx, akgl_tilemap_load_tilesets((akgl_Tilemap *)dest, (json_t *)json));
+	CATCH(errctx, akgl_tilemap_load_layers((akgl_Tilemap *)dest, (json_t *)json, dirnamestr));
+	CATCH(errctx, akgl_tilemap_load_tilesets((akgl_Tilemap *)dest, (json_t *)json, dirnamestr));
 
 	if ( dest->p_foreground_y && dest->p_vanishing_y ) {
 	    // How much bigger is the foreground vs the vanishing point?
@@ -484,7 +517,7 @@ akerr_ErrorContext *akgl_tilemap_load(char *fname, akgl_Tilemap *dest)
     SUCCEED_RETURN(errctx);
 }
 
-akerr_ErrorContext *akgl_tilemap_draw(SDL_Renderer *renderer, akgl_Tilemap *map, SDL_FRect *viewport, int layeridx)
+akerr_ErrorContext *akgl_tilemap_draw(akgl_Tilemap *map, SDL_FRect *viewport, int layeridx)
 {
     PREPARE_ERROR(errctx);
     SDL_FRect dest = {.x = 0, .y = 0, .w = 0, .h = 0};;
@@ -540,7 +573,7 @@ akerr_ErrorContext *akgl_tilemap_draw(SDL_Renderer *renderer, akgl_Tilemap *map,
 	src.h = map->layers[layeridx].height;	
 	dest.w = map->layers[layeridx].width;
 	dest.h = map->layers[layeridx].height;
-	SDL_RenderTexture(renderer, map->layers[layeridx].texture, &src, &dest);
+	PASS(errctx, renderer.draw_texture(&renderer, map->layers[layeridx].texture, &src, &dest, 0, NULL, SDL_FLIP_NONE));
 	SUCCEED_RETURN(errctx);
     }
     
@@ -595,7 +628,7 @@ akerr_ErrorContext *akgl_tilemap_draw(SDL_Renderer *renderer, akgl_Tilemap *map,
 		      dest.y,
 		      dest.w,
 		      dest.h);*/
-		    SDL_RenderTexture(renderer, map->tilesets[tilesetidx].texture, &src, &dest);
+		    PASS(errctx, renderer.draw_texture(&renderer, map->tilesets[tilesetidx].texture, &src, &dest, 0, NULL, SDL_FLIP_NONE));
 		}
 	    }
 	    dest.x += map->tilewidth;
@@ -605,14 +638,14 @@ akerr_ErrorContext *akgl_tilemap_draw(SDL_Renderer *renderer, akgl_Tilemap *map,
     SUCCEED_RETURN(errctx);
 }
 
-akerr_ErrorContext *akgl_tilemap_draw_tileset(SDL_Renderer *renderer, akgl_Tilemap *map, int tilesetidx)
+akerr_ErrorContext *akgl_tilemap_draw_tileset(akgl_Tilemap *map, int tilesetidx)
 {
     PREPARE_ERROR(errctx);
     SDL_FRect dest;
     SDL_FRect src;
     int tilenum = 0;
     /*
-     * Render every tile in a tileset to the given renderer
+     * Render every tile in a tileset to the default renderer
      * (this is a debugging tool that shows that the recorded tile offsets are correct,
      * by proving that we can reconstruct the original tileset image)
      */
@@ -650,7 +683,7 @@ akerr_ErrorContext *akgl_tilemap_draw_tileset(SDL_Renderer *renderer, akgl_Tilem
 	  dest.y,
 	  dest.w,
 	  dest.h);*/
-	SDL_RenderTexture(renderer, map->tilesets[tilesetidx].texture, &src, &dest);
+	PASS(errctx, renderer.draw_texture(&renderer, map->tilesets[tilesetidx].texture, &src, &dest, 0, NULL, SDL_FLIP_NONE));
     }
     SUCCEED_RETURN(errctx);
 }

src/util.c

@@ -1,5 +1,7 @@
 #include <limits.h>
 #include <stdlib.h>
+#include <errno.h>
+#include <libgen.h>
 
 #include <SDL3/SDL.h>
 #include <SDL3_image/SDL_image.h>
@@ -9,6 +11,87 @@
 #include <akgl/heap.h>
 #include <akgl/registry.h>
 #include <akgl/game.h>
+#include <akgl/staticstring.h>
+
+#include <akstdlib.h>
+
+akerr_ErrorContext *akgl_path_relative_root(char *root, char *path, akgl_String *dst)
+{
+    PREPARE_ERROR(e);
+    akgl_String *pathbuf;
+    akgl_String *strbuf;
+    char *result;
+    int rootlen;
+    int pathlen;
+    int count;
+    
+    FAIL_ZERO_RETURN(e, root, AKERR_NULLPOINTER, "NULL argument");
+    FAIL_ZERO_RETURN(e, path, AKERR_NULLPOINTER, "NULL argument");
+    FAIL_ZERO_RETURN(e, dst, AKERR_NULLPOINTER, "NULL argument");
+
+    PASS(e, akgl_heap_next_string(&strbuf));
+    PASS(e, akgl_heap_next_string(&pathbuf));
+    
+    ATTEMPT {
+	// Is it relative to the root?
+	rootlen = strlen(root);
+	pathlen = strlen(path);
+	if ( (rootlen + pathlen) >= AKGL_MAX_STRING_LENGTH ) {
+	    FAIL_RETURN(e, AKERR_OUTOFBOUNDS, "Total path length (%d) is greater than maximum akgl_String length (%d)", (rootlen + pathlen), AKGL_MAX_STRING_LENGTH);
+	}
+	DISABLE_GCC_WARNING_FORMAT_TRUNCATION
+	CATCH(e, aksl_sprintf(&count, (char *)&pathbuf->data, "%s/%s", root, path));
+	RESTORE_GCC_WARNINGS
+	CATCH(e, aksl_realpath((char *)&pathbuf->data, (char *)&strbuf->data));
+	CATCH(e, akgl_string_copy(strbuf, dst, 0)); 
+    } CLEANUP {
+	IGNORE(akgl_heap_release_string(strbuf));
+	IGNORE(akgl_heap_release_string(pathbuf));
+    } PROCESS(e) {
+    } FINISH(e, true);
+    SUCCEED_RETURN(e);
+}
+
+akerr_ErrorContext *akgl_path_relative(char *root, char *path, akgl_String *dst)
+{
+    PREPARE_ERROR(e);
+    akgl_String *strbuf;
+    char *result;
+    
+    FAIL_ZERO_RETURN(e, root, AKERR_NULLPOINTER, "NULL argument");
+    FAIL_ZERO_RETURN(e, path, AKERR_NULLPOINTER, "NULL argument");
+    FAIL_ZERO_RETURN(e, dst, AKERR_NULLPOINTER, "NULL argument");
+
+    PASS(e, akgl_heap_next_string(&strbuf));
+    
+    ATTEMPT {
+	// Is path relative to our current working directory?
+	CATCH(e, aksl_realpath(path, (char *)&strbuf->data));
+	// Yes it is. strbuf->data contains the absolute path.
+	CATCH(e, akgl_string_copy(strbuf, dst, 0)); 
+    } CLEANUP {
+	IGNORE(akgl_heap_release_string(strbuf));
+    } PROCESS(e) {
+    } HANDLE(e, ENOENT) {
+	// Path is not relative to our current working directory
+	// Noop - execution proceeds after the break
+	return akgl_path_relative_root(root, path, dst);
+    } FINISH(e, true);
+    SUCCEED_RETURN(e);
+}
+
+akerr_ErrorContext *akgl_path_relative_from(char *path, char *from, akgl_String **dst)
+{
+    akgl_String *dirnamestr;
+    PREPARE_ERROR(e);
+    FAIL_ZERO_RETURN(e, path, AKERR_NULLPOINTER, "path");
+    FAIL_ZERO_RETURN(e, from, AKERR_NULLPOINTER, "from");
+    PASS(e, akgl_heap_next_string(&dirnamestr));
+    PASS(e, aksl_realpath(from, (char *)&dirnamestr->data));
+    dirname((char *)&dirnamestr->data);
+    
+    SUCCEED_RETURN(e);
+}
 
 akerr_ErrorContext *akgl_rectangle_points(RectanglePoints *dest, SDL_FRect *rect)
 {
@@ -119,17 +202,9 @@ akerr_ErrorContext *akgl_render_and_compare(SDL_Texture *t1, SDL_Texture *t2, in
 	FAIL_ZERO_BREAK(errctx, t2, AKERR_NULLPOINTER, "NULL texture");
 
 	CATCH(errctx, akgl_heap_next_string(&tmpstring));
-	SDL_RenderClear(renderer);
-	FAIL_ZERO_BREAK(
-	    errctx,
-	    SDL_RenderTexture(
-		renderer,
-		t1,
-		&src,
-		&dest),
-	    AKGL_ERR_SDL,
-	    "Failed to render test texture");      
-	s1 = SDL_RenderReadPixels(renderer, &read);
+	SDL_RenderClear(renderer.sdl_renderer);
+	CATCH(errctx, renderer.draw_texture(&renderer, t1, &src, &dest, 0, NULL, SDL_FLIP_NONE));
+	s1 = SDL_RenderReadPixels(renderer.sdl_renderer, &read);
 	FAIL_ZERO_BREAK(errctx, s1, AKGL_ERR_SDL, "Failed to read pixels from renderer");
 	
 	if ( writeout != NULL ) {
@@ -143,18 +218,10 @@ akerr_ErrorContext *akgl_render_and_compare(SDL_Texture *t1, SDL_Texture *t2, in
 		SDL_GetError());
 	}
 	
-	SDL_RenderClear(renderer);
+	SDL_RenderClear(renderer.sdl_renderer);
 	
-	FAIL_ZERO_BREAK(
-	    errctx,
-	    SDL_RenderTexture(
-		renderer,
-		t2,
-		&src,
-		&dest),
-	    AKGL_ERR_SDL,
-	    "Failed to render test texture");
-	s2 = SDL_RenderReadPixels(renderer, &read);
+	CATCH(errctx, renderer.draw_texture(&renderer, t1, &src, &dest, 0, NULL, SDL_FLIP_NONE));
+	s2 = SDL_RenderReadPixels(renderer.sdl_renderer, &read);
 	FAIL_ZERO_BREAK(errctx, s2, AKGL_ERR_SDL, "Failed to read pixels from renderer");
 	
 	CATCH(errctx, akgl_compare_sdl_surfaces(s1, s2));