Tilemaps can now load their own physics engines from map properties. The gravity for the arcade simulation is acting a little funny when populated from the map properties.

CMakeLists.txt

@@ -69,6 +69,8 @@ add_library(akgl SHARED
   src/heap.c
   src/json_helpers.c
   src/registry.c
+  src/renderer.c
+  src/physics.c
   src/sprite.c
   src/staticstring.c
   src/tilemap.c
@@ -142,6 +144,8 @@ install(FILES "include/akgl/controller.h" DESTINATION "include/akgl/")
 install(FILES "include/akgl/heap.h" DESTINATION "include/akgl/")
 install(FILES "include/akgl/iterator.h" DESTINATION "include/akgl/")
 install(FILES "include/akgl/json_helpers.h" DESTINATION "include/akgl/")
+install(FILES "include/akgl/renderer.h" DESTINATION "include/akgl/")
+install(FILES "include/akgl/physics.h" DESTINATION "include/akgl/")
 install(FILES "include/akgl/registry.h" DESTINATION "include/akgl/")
 install(FILES "include/akgl/sprite.h" DESTINATION "include/akgl/")
 install(FILES "include/akgl/staticstring.h" DESTINATION "include/akgl/")

include/akgl/SDL_GameControllerDB.h

@@ -1,9 +1,9 @@
 #ifndef _SDL_GAMECONTROLLERDB_H_
 #define _SDL_GAMECONTROLLERDB_H_
 
-// Taken from https://raw.githubusercontent.com/mdqinc/SDL_GameControllerDB/refs/heads/master/gamecontrollerdb.txt on Tue May 26 01:00:21 PM EDT 2026
+// Taken from https://raw.githubusercontent.com/mdqinc/SDL_GameControllerDB/refs/heads/master/gamecontrollerdb.txt on Tue Jun  2 04:45:53 PM EDT 2026
 
-#define AKGL_SDL_GAMECONTROLLER_DB_LEN         2228
+#define AKGL_SDL_GAMECONTROLLER_DB_LEN         2229
 
 const char *SDL_GAMECONTROLLER_DB[] = {
     "03000000300f00000a01000000000000,3 In 1 Conversion Box,a:b2,b:b1,back:b9,dpdown:h0.4,dpleft:h0.8,dpright:h0.2,dpup:h0.1,leftshoulder:b6,leftstick:b10,lefttrigger:b4,leftx:a0,lefty:a1,rightshoulder:b7,rightstick:b11,righttrigger:b5,rightx:a3,righty:a2,start:b8,x:b3,y:b0,platform:Windows",
@@ -708,7 +708,7 @@ const char *SDL_GAMECONTROLLER_DB[] = {
     "03000000730700000601000000000000,Sega Saturn Controller,a:b0,b:b1,dpdown:h0.4,dpleft:h0.8,dpright:h0.2,dpup:h0.1,leftshoulder:b6,lefttrigger:b7,leftx:a0,lefty:a1,rightshoulder:b5,righttrigger:b2,start:b9,x:b3,y:b4,platform:Windows",
     "03000000b40400000a01000000000000,Sega Saturn Controller,a:b0,b:b1,dpdown:+a1,dpleft:-a0,dpright:+a0,dpup:-a1,leftshoulder:b6,lefttrigger:b7,rightshoulder:b5,righttrigger:b2,start:b8,x:b3,y:b4,platform:Windows",
     "030000003b07000004a1000000000000,SFX,a:b0,b:b2,back:b7,leftshoulder:b6,lefttrigger:b4,leftx:a0,lefty:a1,rightshoulder:b9,righttrigger:b5,start:b8,x:b1,y:b3,platform:Windows",
-    "03000000632500002705000000000000,ShanWan Q36,a:b0,b:b1,back:b10,dpdown:h0.4,dpleft:h0.8,dpright:h0.2,dpup:h0.1,leftshoulder:b6,lefttrigger:b8,rightshoulder:b7,righttrigger:b9,start:b11,x:b3,y:b4,platform:Windows",
+    "03000000632500002705000000000000,ShanWan Gamepad,a:b0,b:b1,x:b3,y:b4,back:b10,dpdown:h0.4,dpleft:h0.8,dpright:h0.2,dpup:h0.1,leftx:a0,-lefty:-a1,+lefty:+a2,leftshoulder:b6,lefttrigger:b8,rightshoulder:b7,righttrigger:b9,start:b11,leftstick:b13,rightstick:b14,platform:Windows",
     "03000000f82100001900000000000000,Shogun Bros Chameleon X1,a:b2,b:b1,back:b9,dpdown:h0.4,dpleft:h0.8,dpright:h0.2,dpup:h0.1,leftshoulder:b6,lefttrigger:b4,leftx:a0,lefty:a1,rightshoulder:b7,righttrigger:b5,rightx:a2,righty:a3,start:b8,x:b3,y:b0,platform:Windows",
     "03000000120c00001c1e000000000000,SnakeByte 4S PS4 Controller,a:b1,b:b2,back:b8,dpdown:h0.4,dpleft:h0.8,dpright:h0.2,dpup:h0.1,guide:b12,leftshoulder:b4,leftstick:b10,lefttrigger:a3,leftx:a0,lefty:a1,rightshoulder:b5,rightstick:b11,righttrigger:a4,rightx:a2,righty:a5,start:b9,touchpad:b13,x:b0,y:b3,platform:Windows",
     "03000000140300000918000000000000,SNES Controller,a:b0,b:b1,back:b6,dpdown:+a1,dpleft:-a0,dpright:+a0,dpup:-a1,leftshoulder:b4,rightshoulder:b5,start:b7,x:b2,y:b3,platform:Windows",
@@ -780,6 +780,7 @@ const char *SDL_GAMECONTROLLER_DB[] = {
     "030000005f140000c501000000000000,Trust Gamepad,a:b2,b:b1,back:b8,dpdown:h0.4,dpleft:h0.8,dpright:h0.2,dpup:h0.1,guide:b12,leftshoulder:b4,leftstick:b10,lefttrigger:b6,leftx:a0,lefty:a1,rightshoulder:b5,rightstick:b11,righttrigger:b7,rightx:a2,righty:a3,start:b9,x:b3,y:b0,platform:Windows",
     "03000000b80500000210000000000000,Trust Gamepad,a:b2,b:b1,back:b8,dpdown:h0.4,dpleft:h0.8,dpright:h0.2,dpup:h0.1,guide:b12,leftshoulder:b4,leftstick:b10,lefttrigger:b6,leftx:a0,lefty:a1,rightshoulder:b5,rightstick:b11,righttrigger:b7,rightx:a2,righty:a3,start:b9,x:b3,y:b0,platform:Windows",
     "030000005f1400002a01000000000000,Trust Predator GM1200,a:b0,b:b1,dpdown:+a1,dpleft:-a0,dpright:+a0,dpup:-a1,leftshoulder:b6,lefttrigger:b7,rightshoulder:b5,righttrigger:b2,x:b3,y:b4,platform:Windows",
+    "03000000580400000a10000000000000,Trust Sight Fighter,a:b0,b:b1,x:b3,y:b4,back:b5,start:b2,leftshoulder:b6,rightshoulder:b7,leftx:a0,lefty:a1,lefttrigger:b8,righttrigger:b9,platform:Windows",
     "030000004f04000087b6000000000000,TWCS Throttle,dpdown:b8,dpleft:b9,dpright:b7,dpup:b6,leftstick:b5,lefttrigger:-a5,leftx:a0,lefty:a1,righttrigger:+a5,platform:Windows",
     "03000000411200000450000000000000,Twin Shock,a:b2,b:b1,back:b8,dpdown:h0.4,dpleft:h0.8,dpright:h0.2,dpup:h0.1,leftshoulder:b6,leftstick:b9,lefttrigger:b4,leftx:a0,lefty:a1,rightshoulder:b7,rightstick:b10,righttrigger:b5,rightx:a3,righty:a4,start:b11,x:b3,y:b0,platform:Windows",
     "03000000d90400000200000000000000,TwinShock PS2 Controller,a:b2,b:b1,back:b8,dpdown:h0.4,dpleft:h0.8,dpright:h0.2,dpup:h0.1,leftshoulder:b6,leftstick:b10,lefttrigger:b4,leftx:a0,lefty:a1,rightshoulder:b7,rightstick:b11,righttrigger:b5,rightx:a3,righty:a2,start:b9,x:b3,y:b0,platform:Windows",

include/akgl/actor.h

@@ -76,16 +76,25 @@ typedef struct akgl_Actor {
     float32_t vx;
     float32_t vy;
     float32_t vz;
-    // Gravity. Forces acting on the actor on a given axis due to the forces
+    // Environmental velocity. These are the forces acting on the actor by the
-    // of gravity and drag.
+    // environment (such as gravity and atmospheric drag)
-    float32_t gx;
+    float32_t ex;
-    float32_t gy;
+    float32_t ey;
-    float32_t gz;
+    float32_t ez;
     // 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;
+    // Acceleration. These are borrowed from the base character object.
+    // A given axis resets to 0 when the actor stops moving in a given axis.
+    float32_t ax;
+    float32_t ay;
+    float32_t az;
+    // Max speed. These are borrowed from the base character object.
+    float32_t sx;
+    float32_t sy;
+    float32_t sz;
     // Position.
     float32_t x;
     float32_t y;

include/akgl/game.h

@@ -44,14 +44,19 @@ typedef struct {
 } akgl_Game;
 
 extern SDL_Window *window;
-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 SDL_FRect _akgl_camera;
 extern akgl_Game game;
-extern akgl_RenderBackend renderer;
+extern akgl_RenderBackend _akgl_renderer;
-extern akgl_PhysicsBackend physics;
+extern akgl_PhysicsBackend _akgl_physics;
+extern akgl_Tilemap _akgl_gamemap;
+
+extern akgl_Tilemap *gamemap;
+extern akgl_RenderBackend *renderer;
+extern akgl_PhysicsBackend *physics;
+extern SDL_FRect *camera;
 
 #define AKGL_BITMASK_HAS(x, y) (x & y) == y
 #define AKGL_BITMASK_HASNOT(x, y) (x & y) != y

include/akgl/json_helpers.h

@@ -8,10 +8,13 @@ akerr_ErrorContext AKERR_NOIGNORE *akgl_get_json_object_value(json_t *obj, char
 akerr_ErrorContext AKERR_NOIGNORE *akgl_get_json_boolean_value(json_t *obj, char *key, bool *dest);
 akerr_ErrorContext AKERR_NOIGNORE *akgl_get_json_integer_value(json_t *obj, char *key, int *dest);
 akerr_ErrorContext AKERR_NOIGNORE *akgl_get_json_number_value(json_t *obj, char *key, float *dest);
+akerr_ErrorContext AKERR_NOIGNORE *akgl_get_json_double_value(json_t *obj, char *key, double *dest);
 akerr_ErrorContext AKERR_NOIGNORE *akgl_get_json_string_value(json_t *obj, char *key, akgl_String **dest);
 akerr_ErrorContext AKERR_NOIGNORE *akgl_get_json_array_value(json_t *obj, char *key, json_t **dest);
 akerr_ErrorContext AKERR_NOIGNORE *akgl_get_json_array_index_object(json_t *array, int index, json_t **dest);
 akerr_ErrorContext AKERR_NOIGNORE *akgl_get_json_array_index_integer(json_t *array, int index, int *dest);
 akerr_ErrorContext AKERR_NOIGNORE *akgl_get_json_array_index_string(json_t *array, int index, akgl_String **dest);
 
+akerr_ErrorContext AKERR_NOIGNORE *akgl_get_json_with_default(akerr_ErrorContext *e, void *defval, void *dest, uint32_t defsize);
+
 #endif // _JSON_HELPERS_H_

include/akgl/physics.h

@@ -5,6 +5,7 @@
 #include <akerror.h>
 #include <akgl/actor.h>
 #include <akgl/iterator.h>
+#include <akgl/staticstring.h>
 
 typedef struct akgl_PhysicsBackend {
     akerr_ErrorContext AKERR_NOIGNORE *(*simulate)(struct akgl_PhysicsBackend *self, akgl_Iterator *opflags);
@@ -20,7 +21,6 @@ typedef struct akgl_PhysicsBackend {
     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);
@@ -29,11 +29,12 @@ akerr_ErrorContext AKERR_NOIGNORE *akgl_physics_null_move(akgl_PhysicsBackend *s
 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_arcade_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_arcade_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_arcade_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_init_arcade(akgl_PhysicsBackend *self);
 
+akerr_ErrorContext AKERR_NOIGNORE *akgl_physics_factory(akgl_PhysicsBackend *self, akgl_String *type);
 
 akerr_ErrorContext AKERR_NOIGNORE *akgl_physics_simulate(akgl_PhysicsBackend *self, akgl_Iterator *opflags);
 

include/akgl/tilemap.h

@@ -2,8 +2,9 @@
 #define _TILEMAP_H_
 
 #include <limits.h>
-#include "actor.h"
+#include <akgl/actor.h>
-#include "staticstring.h"
+#include <akgl/staticstring.h>
+#include <akgl/physics.h>
 #include <jansson.h>
 
 #define AKGL_TILEMAP_MAX_WIDTH                        512
@@ -98,6 +99,10 @@ typedef struct {
     float p_rate;
     akgl_Tileset tilesets[AKGL_TILEMAP_MAX_TILESETS];
     akgl_TilemapLayer layers[AKGL_TILEMAP_MAX_LAYERS];
+
+    // Different levels may have different physics.
+    bool use_own_physics;
+    akgl_PhysicsBackend physics;
 } akgl_Tilemap;
 
 akerr_ErrorContext AKERR_NOIGNORE *akgl_tilemap_load(char *fname, akgl_Tilemap *dest);

src/actor.c

@@ -51,6 +51,10 @@ akerr_ErrorContext *akgl_actor_set_character(akgl_Actor *obj, char *basecharname
     obj->basechar = SDL_GetPointerProperty(AKGL_REGISTRY_CHARACTER, basecharname, NULL);
 
     FAIL_ZERO_RETURN(errctx, obj->basechar, AKERR_NULLPOINTER, "Character not found in the registry");
+    obj->ax = 0;
+    obj->ay = 0;
+    obj->sx = obj->basechar->sx;
+    obj->sy = obj->basechar->sy;
     SUCCEED_RETURN(errctx);
 }
 
@@ -113,14 +117,25 @@ akerr_ErrorContext *akgl_actor_logic_changeframe(akgl_Actor *obj, akgl_Sprite *c
     SUCCEED_RETURN(errctx);
 }
 
-// raises AKGL_ERR_LOGICINTERRUPT if we don't want the physics object to process us
+// raises AKGL_ERR_LOGICINTERRUPT if we don't want the physics simulator to process us
-akerr_ErrorContext *akgl_actor_logic_movement(akgl_Actor *obj, float32_t dt)
+akerr_ErrorContext *akgl_actor_logic_movement(akgl_Actor *actor, float32_t dt)
 {
     PREPARE_ERROR(errctx);
-    FAIL_ZERO_RETURN(errctx, obj, AKERR_NULLPOINTER, "obj");
+    FAIL_ZERO_RETURN(errctx, actor, AKERR_NULLPOINTER, "actor");
-    FAIL_ZERO_RETURN(errctx, obj, AKERR_NULLPOINTER, "obj->basechar");
+    FAIL_ZERO_RETURN(errctx, actor, AKERR_NULLPOINTER, "actor->basechar");
-    // Effectively a NOOP, this is handled by the physics engine now
+    actor->sx = actor->basechar->sx;
-    // These functions are still present in case the library user wants per-actor behavior
+    actor->sy = actor->basechar->sy;
+    actor->sz = actor->basechar->sz;
+    if ( AKGL_BITMASK_HAS(actor->state, AKGL_ACTOR_STATE_MOVING_LEFT) ) {
+	actor->ax = -actor->basechar->ax;
+    } else if ( AKGL_BITMASK_HAS(actor->state, AKGL_ACTOR_STATE_MOVING_RIGHT) ) {
+	actor->ax = actor->basechar->ax;
+    }
+    if ( AKGL_BITMASK_HAS(actor->state, AKGL_ACTOR_STATE_MOVING_UP) ) {
+	actor->ay = -actor->basechar->ay;
+    } else if ( AKGL_BITMASK_HAS(actor->state, AKGL_ACTOR_STATE_MOVING_DOWN) ) {
+	actor->ay = actor->basechar->ay;
+    }
     SUCCEED_RETURN(errctx);
 }
 
@@ -195,7 +210,7 @@ akerr_ErrorContext *akgl_actor_render(akgl_Actor *obj)
   
     ATTEMPT {
 	CATCH(errctx, akgl_character_sprite_get(obj->basechar, obj->state, &curSprite));
-	CATCH(errctx, actor_visible(obj, &camera, &visible));
+	CATCH(errctx, actor_visible(obj, camera, &visible));
     } CLEANUP {
     } PROCESS(errctx) {
     } HANDLE(errctx, AKERR_KEY) {
@@ -227,16 +242,16 @@ akerr_ErrorContext *akgl_actor_render(akgl_Actor *obj)
     } FINISH(errctx, true);
     
     if ( obj->parent != NULL ) {
-	dest.x = (obj->parent->x + obj->x - camera.x);
+	dest.x = (obj->parent->x + obj->x - camera->x);
-	dest.y = (obj->parent->y + obj->y - camera.y);
+	dest.y = (obj->parent->y + obj->y - camera->y);
     } else {
-	dest.x = (obj->x - camera.x);
+	dest.x = (obj->x - camera->x);
-	dest.y = (obj->y - camera.y);
+	dest.y = (obj->y - camera->y);
     }
     dest.w = curSprite->width * obj->scale;
     dest.h = curSprite->width * obj->scale;
 
-    PASS(errctx, renderer.draw_texture(&renderer, curSprite->sheet->texture, &src, &dest, 0, NULL, SDL_FLIP_NONE));
+    PASS(errctx, renderer->draw_texture(renderer, curSprite->sheet->texture, &src, &dest, 0, NULL, SDL_FLIP_NONE));
     SUCCEED_RETURN(errctx);
 }
 
@@ -262,10 +277,12 @@ akerr_ErrorContext *akgl_actor_add_child(akgl_Actor *obj, akgl_Actor *child)
 akerr_ErrorContext AKERR_NOIGNORE *akgl_Actor_cmhf_left_on(akgl_Actor *obj, SDL_Event *event)
 {
     PREPARE_ERROR(errctx);
-    FAIL_ZERO_RETURN(errctx, obj, AKERR_NULLPOINTER, "NULL actor");
+    FAIL_ZERO_RETURN(errctx, obj, AKERR_NULLPOINTER, "actor");
-    FAIL_ZERO_RETURN(errctx, event, AKERR_NULLPOINTER, "NULL event");
+    FAIL_ZERO_RETURN(errctx, event, AKERR_NULLPOINTER, "event");
+    FAIL_ZERO_RETURN(errctx, obj->basechar, AKERR_NULLPOINTER, "actor->basechar");
     //SDL_Log("event %d (button %d / key %d) moves actor left", event->type, event->gbutton.which, event->key.key);
     AKGL_BITMASK_DEL(obj->state, (AKGL_ACTOR_STATE_FACE_ALL | AKGL_ACTOR_STATE_MOVING_ALL));
+    obj->ax = -(obj->basechar->ax);
     AKGL_BITMASK_ADD(obj->state, (AKGL_ACTOR_STATE_MOVING_LEFT | AKGL_ACTOR_STATE_FACE_LEFT));
     //SDL_Log("new target actor state: %b", obj->state);
     SUCCEED_RETURN(errctx);
@@ -277,6 +294,8 @@ 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->ax = 0;
+    obj->ex = 0;
     obj->tx = 0;
     obj->vx = 0;
     AKGL_BITMASK_DEL(obj->state, AKGL_ACTOR_STATE_MOVING_LEFT);
@@ -289,7 +308,9 @@ akerr_ErrorContext AKERR_NOIGNORE *akgl_Actor_cmhf_right_on(akgl_Actor *obj, SDL
     PREPARE_ERROR(errctx);
     FAIL_ZERO_RETURN(errctx, obj, AKERR_NULLPOINTER, "NULL actor");
     FAIL_ZERO_RETURN(errctx, event, AKERR_NULLPOINTER, "NULL event");
+    FAIL_ZERO_RETURN(errctx, obj->basechar, AKERR_NULLPOINTER, "actor->basechar");
     //SDL_Log("event %d (button %d / key %d) moves actor right", event->type, event->gbutton.which, event->key.key);
+    obj->ax = obj->basechar->ax;
     AKGL_BITMASK_DEL(obj->state, (AKGL_ACTOR_STATE_FACE_ALL | AKGL_ACTOR_STATE_MOVING_ALL));
     AKGL_BITMASK_ADD(obj->state, (AKGL_ACTOR_STATE_MOVING_RIGHT | AKGL_ACTOR_STATE_FACE_RIGHT));
     //SDL_Log("new target actor state: %b", obj->state);
@@ -302,6 +323,8 @@ 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->ax = 0;
+    obj->ex = 0;
     obj->tx = 0;
     obj->vx = 0;
     AKGL_BITMASK_DEL(obj->state, AKGL_ACTOR_STATE_MOVING_RIGHT);
@@ -315,6 +338,7 @@ akerr_ErrorContext AKERR_NOIGNORE *akgl_Actor_cmhf_up_on(akgl_Actor *obj, SDL_Ev
     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) moves actor up", event->type, event->gbutton.which, event->key.key);	
+    obj->ay = -(obj->basechar->ay);
     AKGL_BITMASK_DEL(obj->state, (AKGL_ACTOR_STATE_FACE_ALL | AKGL_ACTOR_STATE_MOVING_ALL));
     AKGL_BITMASK_ADD(obj->state, (AKGL_ACTOR_STATE_FACE_UP | AKGL_ACTOR_STATE_MOVING_UP));
     //SDL_Log("new target actor state: %b", obj->state);
@@ -327,6 +351,8 @@ 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->ay = 0;
+    obj->ey = 0;
     obj->ty = 0;
     obj->vy = 0;
     AKGL_BITMASK_DEL(obj->state, AKGL_ACTOR_STATE_MOVING_UP);
@@ -340,6 +366,7 @@ akerr_ErrorContext AKERR_NOIGNORE *akgl_Actor_cmhf_down_on(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) moves actor down", event->type, event->gbutton.which, event->key.key);
+    obj->ay = obj->basechar->ay;
     AKGL_BITMASK_DEL(obj->state, (AKGL_ACTOR_STATE_FACE_ALL | AKGL_ACTOR_STATE_MOVING_ALL));
     AKGL_BITMASK_ADD(obj->state, (AKGL_ACTOR_STATE_MOVING_DOWN | AKGL_ACTOR_STATE_FACE_DOWN));
     //SDL_Log("new target actor state: %b", obj->state);
@@ -353,6 +380,8 @@ akerr_ErrorContext AKERR_NOIGNORE *akgl_Actor_cmhf_down_off(akgl_Actor *obj, SDL
     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->ey = 0;
+    obj->ay = 0;
     obj->vy = 0;
     AKGL_BITMASK_DEL(obj->state, AKGL_ACTOR_STATE_MOVING_DOWN);
     //SDL_Log("new target actor state: %b", obj->state);

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.sdl_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.sdl_renderer, &rect);
+            SDL_RenderFillRect(renderer->sdl_renderer, &rect);
         }
     }
 }

src/game.c

@@ -19,17 +19,22 @@
 #include <akgl/SDL_GameControllerDB.h>
 
 SDL_Window *window = NULL;
-akgl_RenderBackend renderer;
+
-akgl_PhysicsBackend physics;
+// Currently active objects
-akgl_Frame ball;
+akgl_RenderBackend *renderer;
-akgl_Frame paddle1;
+akgl_PhysicsBackend *physics;
-akgl_Frame paddle2;
+SDL_FRect *camera;
-akgl_Frame table;
+akgl_Tilemap *gamemap;
-akgl_Tilemap gamemap;
+
+// Default objects
+akgl_RenderBackend _akgl_renderer;
+akgl_PhysicsBackend _akgl_physics;
+SDL_FRect _akgl_camera;
+akgl_Tilemap _akgl_gamemap;
+
 MIX_Audio *bgm = NULL;
 MIX_Mixer *akgl_mixer = NULL;
 MIX_Track *akgl_tracks[AKGL_GAME_AUDIO_MAX_TRACKS];
-SDL_FRect camera;
 akgl_Game game;
 
 void akgl_game_lowfps(void)
@@ -45,31 +50,26 @@ akerr_ErrorContext AKERR_NOIGNORE *akgl_game_init()
     
     int i = 0;
     PREPARE_ERROR(e);
-    ATTEMPT {
+    strncpy((char *)&game.libversion, AKGL_VERSION, 32);
-	strncpy((char *)&game.libversion, AKGL_VERSION, 32);
+    game.gameStartTime = SDL_GetTicksNS();
-	game.gameStartTime = SDL_GetTicksNS();
+    game.lastIterTime = game.gameStartTime;
-	game.lastIterTime = game.gameStartTime;
+    game.lastFPSTime = game.gameStartTime;
-	game.lastFPSTime = game.gameStartTime;
+    game.lowfpsfunc = &akgl_game_lowfps;
-	game.lowfpsfunc = &akgl_game_lowfps;
+    game.statelock = SDL_CreateMutex();
-	game.statelock = SDL_CreateMutex();
+    FAIL_ZERO_RETURN(e, game.statelock, AKGL_ERR_SDL, "%s", SDL_GetError());
-	FAIL_ZERO_RETURN(e, game.statelock, AKGL_ERR_SDL, "%s", SDL_GetError());
+    PASS(e, akgl_game_state_lock());
-	CATCH(e, akgl_game_state_lock());
+    FAIL_ZERO_RETURN(e, strlen((char *)&game.name), AKERR_NULLPOINTER, "Must provide game name");
-	FAIL_ZERO_BREAK(e, strlen((char *)&game.name), AKERR_NULLPOINTER, "Must provide game name");
+    FAIL_ZERO_RETURN(e, strlen((char *)&game.version), AKERR_NULLPOINTER, "Must provide game version");
-	FAIL_ZERO_BREAK(e, strlen((char *)&game.version), AKERR_NULLPOINTER, "Must provide game version");
+    FAIL_ZERO_RETURN(e, strlen((char *)&game.uri), AKERR_NULLPOINTER, "Must provide game uri");
-	FAIL_ZERO_BREAK(e, strlen((char *)&game.uri), AKERR_NULLPOINTER, "Must provide game uri");
+    PASS(e, akgl_heap_init());
-	CATCH(e, akgl_heap_init());
+    PASS(e, akgl_registry_init_actor());
-	CATCH(e, akgl_registry_init_actor());
+    PASS(e, akgl_registry_init_sprite());
-	CATCH(e, akgl_registry_init_sprite());
+    PASS(e, akgl_registry_init_spritesheet());
-	CATCH(e, akgl_registry_init_spritesheet());
+    PASS(e, akgl_registry_init_character());
-	CATCH(e, akgl_registry_init_character());
+    PASS(e, akgl_registry_init_font());
-	CATCH(e, akgl_registry_init_font());
+    PASS(e, akgl_registry_init_music());
-	CATCH(e, akgl_registry_init_music());
+    PASS(e, akgl_registry_init_properties());
-	CATCH(e, akgl_registry_init_properties());
+    PASS(e, akgl_registry_init_actor_state_strings());
-	CATCH(e, akgl_registry_init_actor_state_strings());
-    } CLEANUP {
-	//IGNORE(akgl_game_state_unlock());
-    } PROCESS(e) {
-    } FINISH(e, true)
 	  
     SDL_SetAppMetadata(game.name, game.version, game.uri);
 
@@ -113,6 +113,12 @@ akerr_ErrorContext AKERR_NOIGNORE *akgl_game_init()
 	AKGL_ERR_SDL,
 	"Couldn't initialize front engine: %s",
 	SDL_GetError());
+
+    camera = &_akgl_camera;
+    renderer = &_akgl_renderer;
+    physics = &_akgl_physics;
+    gamemap = &_akgl_gamemap;
+    
     PASS(e, akgl_game_state_unlock());
     SUCCEED_RETURN(e);
 }
@@ -432,15 +438,15 @@ akerr_ErrorContext AKERR_NOIGNORE *akgl_game_update(akgl_Iterator *opflags)
 		continue;
 	    }
 	    if ( AKGL_BITMASK_HAS(opflags->flags, AKGL_ITERATOR_OP_TILEMAPSCALE) ) {
-		PASS(e, akgl_tilemap_scale_actor(&gamemap, actor));
+		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, physics->simulate(physics, NULL));
-    PASS(e, renderer.draw_world(&renderer, NULL));
+    PASS(e, renderer->draw_world(renderer, NULL));
     PASS(e, akgl_game_state_unlock());
     SUCCEED_RETURN(e);
 }

src/json_helpers.c

@@ -52,6 +52,17 @@ akerr_ErrorContext *akgl_get_json_number_value(json_t *obj, char *key, float *de
   SUCCEED_RETURN(errctx);
 }
 
+akerr_ErrorContext AKERR_NOIGNORE *akgl_get_json_double_value(json_t *obj, char *key, double *dest)
+{
+  PREPARE_ERROR(errctx);
+  FAIL_ZERO_RETURN(errctx, obj, AKERR_NULLPOINTER, "NULL pointer reference");
+  json_t *value = json_object_get(obj, key);
+  FAIL_ZERO_RETURN(errctx, value, AKERR_KEY, "Key %s not found in object", key);
+  FAIL_ZERO_RETURN(errctx, (json_is_number(value)), AKERR_TYPE, "Key %s in object has incorrect type", key);
+  *dest = json_number_value(value);
+  SUCCEED_RETURN(errctx);
+}
+
 akerr_ErrorContext *akgl_get_json_string_value(json_t *obj, char *key, akgl_String **dest)
 {
   json_t *value = NULL;
@@ -129,3 +140,26 @@ akerr_ErrorContext *akgl_get_json_array_index_string(json_t *array, int index, a
   strncpy((char *)&(*dest)->data, json_string_value(value), AKGL_MAX_STRING_LENGTH);
   SUCCEED_RETURN(errctx);
 }
+
+akerr_ErrorContext AKERR_NOIGNORE *akgl_get_json_with_default(akerr_ErrorContext *err, void *defval, void *dest, uint32_t defsize)
+{
+    PREPARE_ERROR(e);
+    if ( err == NULL ) {
+	SUCCEED_RETURN(e);
+    }
+    int docopy = 0;
+    
+    FAIL_ZERO_RETURN(e, err, AKERR_NULLPOINTER, "err");
+    FAIL_ZERO_RETURN(e, defval, AKERR_NULLPOINTER, "defval");
+    FAIL_ZERO_RETURN(e, dest, AKERR_NULLPOINTER, "dest");
+		     
+    ATTEMPT {
+    } CLEANUP {
+    } PROCESS(err) {
+    } HANDLE_GROUP(err, AKERR_KEY) {
+    } HANDLE_GROUP(err, AKERR_INDEX) {
+	memcpy(dest, defval, defsize);
+    } FINISH(err, true);
+    
+    SUCCEED_RETURN(e);
+}

src/physics.c

@@ -1,3 +1,4 @@
+#include <math.h>
 #include <akstdlib.h>
 #include <akgl/physics.h>
 #include <akgl/actor.h>
@@ -41,28 +42,29 @@ akerr_ErrorContext AKERR_NOIGNORE *akgl_physics_init_null(akgl_PhysicsBackend *s
 }
 
 
-akerr_ErrorContext AKERR_NOIGNORE *akgl_physics_ss_gravity(akgl_PhysicsBackend *self, akgl_Actor *actor, float32_t dt)
+akerr_ErrorContext AKERR_NOIGNORE *akgl_physics_arcade_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)
+    if ( self->gravity_x != 0 ) {
-    actor->gx -= (self->gravity_x * dt);
+	// Assume the X origin is - (screen left)
-    // Assume Y origin is + (down screen)
+	actor->ex -= (self->gravity_x * dt);
-    actor->gy += (self->gravity_y * dt);
+    }
-    // Assume Z origin is - (behind the camera)
+    if ( self->gravity_y != 0 ) {
-    actor->gz -= (self->gravity_z * dt);
+	// Assume Y origin is + (down screen)
-
+	actor->ey += (self->gravity_y * dt);
-    // Counteract velocity with atmospheric drag
+    }
-    actor->gx += actor->vx * self->drag_x * dt;
+    if ( self->gravity_z != 0 ) {
-    actor->gy -= actor->vy * self->drag_y * dt;
+	// Assume Z origin is - (behind the camera)
-    actor->gz += actor->vz * self->drag_z * dt;
+	actor->ez -= (self->gravity_z * dt);
+    }
     
     SUCCEED_RETURN(e);
 }
 
-akerr_ErrorContext AKERR_NOIGNORE *akgl_physics_ss_collide(akgl_PhysicsBackend *self, akgl_Actor *a1, akgl_Actor *a2)
+akerr_ErrorContext AKERR_NOIGNORE *akgl_physics_arcade_collide(akgl_PhysicsBackend *self, akgl_Actor *a1, akgl_Actor *a2)
 {
     PREPARE_ERROR(e);
     FAIL_ZERO_RETURN(e, self, AKERR_NULLPOINTER, "self");
@@ -70,37 +72,27 @@ akerr_ErrorContext AKERR_NOIGNORE *akgl_physics_ss_collide(akgl_PhysicsBackend *
     SUCCEED_RETURN(e);
 }
 
-akerr_ErrorContext AKERR_NOIGNORE *akgl_physics_ss_move(struct akgl_PhysicsBackend *self, akgl_Actor *actor, float32_t dt)
+akerr_ErrorContext AKERR_NOIGNORE *akgl_physics_arcade_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->x += (-actor->vx * dt) + (actor->gx * dt);
+    actor->y += actor->vy * dt;
-    }
+    actor->z += actor->vz * 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)
+akerr_ErrorContext AKERR_NOIGNORE *akgl_physics_init_arcade(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->gravity = akgl_physics_arcade_gravity;
-    self->collide = akgl_physics_ss_collide;
+    self->collide = akgl_physics_arcade_collide;
-    self->move = akgl_physics_ss_move;
+    self->move = akgl_physics_arcade_move;
     self->simulate = akgl_physics_simulate;
 
     ATTEMPT {
@@ -150,6 +142,9 @@ akerr_ErrorContext AKERR_NOIGNORE *akgl_physics_simulate(akgl_PhysicsBackend *se
 	}
 	if ( actor->parent != NULL ) {
 	    // Children don't move independently of their parents, they just have an offset
+	    actor->x = actor->parent->x + actor->vx;
+	    actor->y = actor->parent->y + actor->vy;
+	    actor->z = actor->parent->z + actor->vz;
 	    continue;
 	} else if ( actor->basechar == NULL ) {
 	    continue;
@@ -159,28 +154,58 @@ akerr_ErrorContext AKERR_NOIGNORE *akgl_physics_simulate(akgl_PhysicsBackend *se
 		continue;
 	    }
 	}
+	
+	// thrust is a function of acceleration on a given axis
 	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;
+	    actor->tx += actor->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;
+	    actor->ty += actor->ay * dt;
 	}
+
 	// velocity equals thrust unless thrust exceeds max speed
-	if ( actor->tx > actor->basechar->sx ) {
+	if ( fabsf(actor->tx) > fabsf(actor->sx) ) {
-	    actor->vx = actor->basechar->sx;
+	    if ( actor->tx < 0 ) {
-	} else {
+		actor->tx = -actor->sx;		
-	    actor->vx = actor->tx;
+	    } else {
+		actor->tx = actor->sx;
+	    }
 	}
-	if ( actor->ty > actor->basechar->sy ) {
+	if ( fabsf(actor->ty) > fabsf(actor->sy) ) {
-	    actor->vy = actor->basechar->sy;
+	    if ( actor->ty < 0 ) {
-	} else {
+		actor->ty = -actor->sy;
-	    actor->vy = actor->ty;
+	    } else {
+		actor->ty = actor->sy;
+	    }
+	}
+	if ( fabsf(actor->tz) > fabsf(actor->sz) ) {
+	    if ( actor->tz < 0 ) {
+		actor->tz = -actor->sz;
+	    } else {
+		actor->tz = actor->sz;
+	    }
 	}
 	ATTEMPT {
 	    CATCH(e, actor->movementlogicfunc(actor, dt));
 	    PASS(e, self->gravity(self, actor, dt));
+
+	    // Counteract velocity with atmospheric drag
+	    if ( self->drag_x != 0 ) {
+		actor->ex -= actor->ex * self->drag_x * dt;
+	    }
+	    if ( self->drag_y != 0 ) {
+		actor->ey -= actor->ey * self->drag_y * dt;
+	    }
+	    if ( self->drag_z != 0 ) {
+		actor->ez -= actor->ez * self->drag_z * dt;
+	    }
+
+	    actor->vx = actor->ex + actor->tx;
+	    actor->vy = actor->ey + actor->ty;
+	    actor->vz = actor->ez + actor->tz;
+
 	    PASS(e, self->move(self, actor, dt)); 
 	} CLEANUP {
 	} PROCESS(e) {
@@ -191,3 +216,21 @@ akerr_ErrorContext AKERR_NOIGNORE *akgl_physics_simulate(akgl_PhysicsBackend *se
     self->gravity_time = curtime; 
     SUCCEED_RETURN(e);
 }
+
+akerr_ErrorContext AKERR_NOIGNORE *akgl_physics_factory(akgl_PhysicsBackend *self, akgl_String *type)
+{
+    uint32_t hashval;
+    PREPARE_ERROR(e);
+    FAIL_ZERO_RETURN(e, self, AKERR_NULLPOINTER, "self");
+    FAIL_ZERO_RETURN(e, type, AKERR_NULLPOINTER, "type");
+    
+    if ( strncmp(type->data, "null", 4) == 0) {
+	PASS(e, akgl_physics_init_null(self));
+	SUCCEED_RETURN(e);
+    }
+    if ( strncmp(type->data, "arcade", 6) == 0) {
+	PASS(e, akgl_physics_init_arcade(self));
+	SUCCEED_RETURN(e);
+    }
+    FAIL_RETURN(e, AKERR_KEY, "Invalid physics engine %s", type->data);
+}

src/renderer.c

@@ -33,10 +33,10 @@ akerr_ErrorContext AKERR_NOIGNORE *akgl_render_init2d(akgl_RenderBackend *self)
 	"Couldn't create window/renderer: %s",
 	SDL_GetError());
     
-    camera.x = 0;
+    camera->x = 0;
-    camera.y = 0;
+    camera->y = 0;
-    camera.w = screenwidth;
+    camera->w = screenwidth;
-    camera.h = screenheight;
+    camera->h = screenheight;
 
     self->shutdown = &akgl_render_2d_shutdown;
     self->frame_start = &akgl_render_2d_frame_start;
@@ -117,8 +117,8 @@ akerr_ErrorContext AKERR_NOIGNORE *akgl_render_2d_draw_world(akgl_RenderBackend
 	PASS(e, aksl_memset((void *)opflags, 0x00, sizeof(akgl_Iterator)));
     }
     for ( int i = 0; i < AKGL_TILEMAP_MAX_LAYERS ; i++ ) {
-	if ( i < gamemap.numlayers ) {
+	if ( i < gamemap->numlayers ) {
-	    PASS(e, akgl_tilemap_draw((akgl_Tilemap *)&gamemap, &camera, i));
+	    PASS(e, akgl_tilemap_draw(gamemap, camera, i));
 	}
 	for ( int j = 0; j < AKGL_MAX_HEAP_ACTOR ; j++ ) {
 	    actor = &HEAP_ACTOR[j];

src/sprite.c

@@ -174,7 +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.sdl_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/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.sdl_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);
-    PASS(errctx, renderer.draw_texture(&renderer, texture, NULL, &dest, 0, NULL, SDL_FLIP_NONE));
+    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

@@ -64,14 +64,10 @@ akerr_ErrorContext *akgl_get_json_properties_string(json_t *obj, char *key, akgl
     PREPARE_ERROR(errctx);
     json_t *property;
     
-    ATTEMPT {
+    PASS(errctx, akgl_get_json_tilemap_property(obj, key, "string", &property));
-	CATCH(errctx, akgl_get_json_tilemap_property(obj, key, "string", &property));
+    PASS(errctx, akgl_heap_next_string(dest));
-	CATCH(errctx, akgl_heap_next_string(dest));
+    PASS(errctx, akgl_string_initialize(*dest, NULL));
-	CATCH(errctx, akgl_string_initialize(*dest, NULL));
+    PASS(errctx, akgl_get_json_string_value(property, "value", dest));
-	CATCH(errctx, akgl_get_json_string_value(property, "value", dest));
-    } CLEANUP {
-    } PROCESS(errctx) {
-    } FINISH(errctx, true);
     
     SUCCEED_RETURN(errctx);
 }
@@ -80,12 +76,8 @@ akerr_ErrorContext *akgl_get_json_properties_integer(json_t *obj, char *key, int
 {
     PREPARE_ERROR(errctx);
     json_t *property = NULL;
-    ATTEMPT {
+    PASS(errctx, akgl_get_json_tilemap_property(obj, key, "int", &property));
-	CATCH(errctx, akgl_get_json_tilemap_property(obj, key, "int", &property));
+    PASS(errctx, akgl_get_json_integer_value(property, "value", dest));
-	CATCH(errctx, akgl_get_json_integer_value(property, "value", dest));
-    } CLEANUP {
-    } PROCESS(errctx) {
-    } FINISH(errctx, true);
     
     SUCCEED_RETURN(errctx);
 }
@@ -94,12 +86,8 @@ akerr_ErrorContext *akgl_get_json_properties_number(json_t *obj, char *key, floa
 {
     PREPARE_ERROR(errctx);
     json_t *property = NULL;
-    ATTEMPT {
+    PASS(errctx, akgl_get_json_tilemap_property(obj, key, "number", &property));
-	CATCH(errctx, akgl_get_json_tilemap_property(obj, key, "number", &property));
+    PASS(errctx, akgl_get_json_number_value(property, "value", dest));
-	CATCH(errctx, akgl_get_json_number_value(property, "value", dest));
-    } CLEANUP {
-    } PROCESS(errctx) {
-    } FINISH(errctx, true);
     
     SUCCEED_RETURN(errctx);
 }
@@ -108,12 +96,18 @@ akerr_ErrorContext *akgl_get_json_properties_float(json_t *obj, char *key, float
 {
     PREPARE_ERROR(errctx);
     json_t *property = NULL;
-    ATTEMPT {
+    PASS(errctx, akgl_get_json_tilemap_property(obj, key, "float", &property));
-	CATCH(errctx, akgl_get_json_tilemap_property(obj, key, "float", &property));
+    PASS(errctx, akgl_get_json_number_value(property, "value", dest));
-	CATCH(errctx, akgl_get_json_number_value(property, "value", dest));
+    
-    } CLEANUP {
+    SUCCEED_RETURN(errctx);
-    } PROCESS(errctx) {
+}
-    } FINISH(errctx, true);
+
+akerr_ErrorContext *akgl_get_json_properties_double(json_t *obj, char *key, double *dest)
+{
+    PREPARE_ERROR(errctx);
+    json_t *property = NULL;
+    PASS(errctx, akgl_get_json_tilemap_property(obj, key, "float", &property));
+    PASS(errctx, akgl_get_json_double_value(property, "value", dest));
     
     SUCCEED_RETURN(errctx);
 }
@@ -152,7 +146,7 @@ akerr_ErrorContext *akgl_tilemap_load_tilesets_each(json_t *tileset, akgl_Tilema
     } PROCESS(e) {
     } FINISH(e, true);
     
-    dest->tilesets[tsidx].texture = IMG_LoadTexture(renderer.sdl_renderer, (char *)&dest->tilesets[tsidx].imagefilename);
+    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);
@@ -297,41 +291,36 @@ akerr_ErrorContext *akgl_tilemap_load_layer_objects(akgl_Tilemap *dest, json_t *
     FAIL_ZERO_RETURN(errctx, dest, AKERR_NULLPOINTER, "NULL destination tilemap reference");
     FAIL_ZERO_RETURN(errctx, root, AKERR_NULLPOINTER, "NULL tilemap root reference");
 
-    ATTEMPT {
+    PASS(errctx, akgl_get_json_array_value(root, "objects", &layerdata));
-	CATCH(errctx, akgl_get_json_array_value(root, "objects", &layerdata));
+    len = json_array_size((json_t *)layerdata);
-	len = json_array_size((json_t *)layerdata);
+    curlayer = &dest->layers[layerid];
-	curlayer = &dest->layers[layerid];
+    for ( j = 0; j < len; j++ ) {
-	for ( j = 0; j < len; j++ ) {
+	PASS(errctx, akgl_get_json_array_index_object((json_t *)layerdata, j, &layerdatavalue));
-	    CATCH(errctx, akgl_get_json_array_index_object((json_t *)layerdata, j, &layerdatavalue));
+	curobj = &curlayer->objects[j];
-	    curobj = &curlayer->objects[j];
+	PASS(errctx, akgl_get_json_string_value((json_t *)layerdatavalue, "name", &tmpstr));
-	    CATCH(errctx, akgl_get_json_string_value((json_t *)layerdatavalue, "name", &tmpstr));
+	strncpy((char *)curobj->name, tmpstr->data, AKGL_ACTOR_MAX_NAME_LENGTH);
-	    strncpy((char *)curobj->name, tmpstr->data, AKGL_ACTOR_MAX_NAME_LENGTH);
+	PASS(errctx, akgl_heap_release_string(tmpstr));
-	    CATCH(errctx, akgl_heap_release_string(tmpstr));
+	PASS(errctx, akgl_get_json_number_value((json_t *)layerdatavalue, "x", &curobj->x));
-	    CATCH(errctx, akgl_get_json_number_value((json_t *)layerdatavalue, "x", &curobj->x));
+	PASS(errctx, akgl_get_json_number_value((json_t *)layerdatavalue, "y", &curobj->y));
-	    CATCH(errctx, akgl_get_json_number_value((json_t *)layerdatavalue, "y", &curobj->y));
+	PASS(errctx, akgl_get_json_boolean_value((json_t *)layerdatavalue, "visible", &curobj->visible));
-		CATCH(errctx, akgl_get_json_boolean_value((json_t *)layerdatavalue, "visible", &curobj->visible));
 	
-	    CATCH(errctx, akgl_get_json_string_value((json_t *)layerdatavalue, "type", &tmpstr));
+	PASS(errctx, akgl_get_json_string_value((json_t *)layerdatavalue, "type", &tmpstr));
-	    if ( strcmp(tmpstr->data, "actor") == 0 ) {
+	if ( strcmp(tmpstr->data, "actor") == 0 ) {
-		CATCH(errctx, akgl_tilemap_load_layer_object_actor(curobj, layerdatavalue, layerid, dirname));
+	    PASS(errctx, akgl_tilemap_load_layer_object_actor(curobj, layerdatavalue, layerid, dirname));
-	    } else if ( strcmp(tmpstr->data, "perspective") == 0 ) {
+	} else if ( strcmp(tmpstr->data, "perspective") == 0 ) {
-		curobj->visible = false;
+	    curobj->visible = false;
-		if ( strcmp((char *)curobj->name, "p_foreground") == 0 ) {
+	    if ( strcmp((char *)curobj->name, "p_foreground") == 0 ) {
-		    dest->p_foreground_y = curobj->y;
+		dest->p_foreground_y = curobj->y;
-		    CATCH(errctx, akgl_get_json_integer_value((json_t *)layerdatavalue, "height", &dest->p_foreground_h));
+		PASS(errctx, akgl_get_json_integer_value((json_t *)layerdatavalue, "height", &dest->p_foreground_h));
-		    CATCH(errctx, akgl_get_json_properties_float((json_t *)layerdatavalue, "scale", &dest->p_foreground_scale));
+		PASS(errctx, akgl_get_json_properties_float((json_t *)layerdatavalue, "scale", &dest->p_foreground_scale));
-		} else if ( strcmp((char *)curobj->name, "p_vanishing") == 0 ) {
+	    } else if ( strcmp((char *)curobj->name, "p_vanishing") == 0 ) {
-		    dest->p_vanishing_y = curobj->y;
+		dest->p_vanishing_y = curobj->y;
-		    CATCH(errctx, akgl_get_json_integer_value((json_t *)layerdatavalue, "height", &dest->p_vanishing_h));
+		PASS(errctx, akgl_get_json_integer_value((json_t *)layerdatavalue, "height", &dest->p_vanishing_h));
-		    CATCH(errctx, akgl_get_json_properties_float((json_t *)layerdatavalue, "scale", &dest->p_vanishing_scale));
+		PASS(errctx, akgl_get_json_properties_float((json_t *)layerdatavalue, "scale", &dest->p_vanishing_scale));
-		}	
 	    }	
-		
-	    layerdatavalue = NULL;
 	}	
-    } CLEANUP {
+	layerdatavalue = NULL;
-    } PROCESS(errctx) {
+    }
-    } FINISH(errctx, true);
   
     SUCCEED_RETURN(errctx);
 }
@@ -389,7 +378,7 @@ akerr_ErrorContext *akgl_tilemap_load_layer_image(akgl_Tilemap *dest, json_t *ro
 	    );
 	RESTORE_GCC_WARNINGS
 	
-	dest->layers[layerid].texture = IMG_LoadTexture(renderer.sdl_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;
@@ -451,6 +440,88 @@ akerr_ErrorContext *akgl_tilemap_load_layers(akgl_Tilemap *dest, json_t *root, a
     SUCCEED_RETURN(errctx);
 }
 
+akerr_ErrorContext *akgl_tilemap_load_physics(akgl_Tilemap *dest, json_t *root)
+{
+    PREPARE_ERROR(e);
+    json_t *props = NULL;
+    akgl_String *tmpval = NULL;
+    double defzero = 0.0;
+    
+    ATTEMPT {
+	CATCH(e, akgl_heap_next_string(&tmpval));
+	CATCH(e, akgl_get_json_array_value((json_t *)root, "properties", &props));
+    } CLEANUP {
+	IGNORE(akgl_heap_release_string(tmpval));
+    } PROCESS(e) {
+    } HANDLE(e, AKERR_KEY) {
+	// Map has no properties, do nothing
+	SDL_Log("Map has no properties");
+	SUCCEED_RETURN(e);
+    } FINISH(e, true);
+
+    ATTEMPT {
+	CATCH(e, akgl_heap_next_string(&tmpval));
+	CATCH(e, akgl_get_json_properties_string(
+		  root,
+		  "physics.model",
+		  &tmpval
+		  )
+	    );
+	PASS(e, akgl_physics_factory(&dest->physics, tmpval));
+	dest->use_own_physics = true;
+	
+	CATCH(e, akgl_get_json_with_default(
+		  akgl_get_json_properties_double(
+		      root, "physics.gravity.x", &dest->physics.gravity_x
+		      ),
+		  (void *)&defzero,
+		  (void *)&dest->physics.gravity_x,
+		  sizeof(double)));
+	CATCH(e, akgl_get_json_with_default(
+		  akgl_get_json_properties_double(
+		      root, "physics.gravity.y", &dest->physics.gravity_y
+		      ),
+		  (void *)&defzero,
+		  (void *)&dest->physics.gravity_y,
+		  sizeof(double)));
+	CATCH(e, akgl_get_json_with_default(
+		  akgl_get_json_properties_double(
+		      root, "physics.gravity.z", &dest->physics.gravity_z
+		      ),
+		  (void *)&defzero,
+		  (void *)&dest->physics.gravity_z,
+		  sizeof(double)));
+	CATCH(e, akgl_get_json_with_default(
+		  akgl_get_json_properties_double(
+		      root, "physics.drag.x", &dest->physics.drag_x
+		      ),
+		  (void *)&defzero,
+		  (void *)&dest->physics.drag_x,
+		  sizeof(double)));
+	CATCH(e, akgl_get_json_with_default(
+		  akgl_get_json_properties_double(
+		      root, "physics.drag.y", &dest->physics.drag_y
+		      ),
+		  (void *)&defzero,
+		  (void *)&dest->physics.drag_y,
+		  sizeof(double)));
+	CATCH(e, akgl_get_json_with_default(
+		  akgl_get_json_properties_double(
+		      root, "physics.drag.z", &dest->physics.drag_z
+		      ),
+		  (void *)&defzero,
+		  (void *)&dest->physics.drag_z,
+		  sizeof(double)));
+    } CLEANUP {
+	IGNORE(akgl_heap_release_string(tmpval));
+    } PROCESS(e) {
+    } HANDLE(e, AKERR_KEY) {
+	SDL_Log("Map uses game physics");
+    } FINISH(e, true);
+    
+    SUCCEED_RETURN(e);
+}
+
 akerr_ErrorContext *akgl_tilemap_load(char *fname, akgl_Tilemap *dest)
 {
     PREPARE_ERROR(errctx);
@@ -484,6 +555,7 @@ akerr_ErrorContext *akgl_tilemap_load(char *fname, akgl_Tilemap *dest)
 	    error.line,
 	    error.text
 	    );
+	CATCH(errctx, akgl_tilemap_load_physics(dest, json));
 	CATCH(errctx, akgl_get_json_integer_value((json_t *)json, "tileheight", &dest->tileheight));
 	CATCH(errctx, akgl_get_json_integer_value((json_t *)json, "tilewidth", &dest->tilewidth));
 	CATCH(errctx, akgl_get_json_integer_value((json_t *)json, "height", &dest->height));
@@ -573,7 +645,7 @@ akerr_ErrorContext *akgl_tilemap_draw(akgl_Tilemap *map, SDL_FRect *viewport, in
 	src.h = map->layers[layeridx].height;	
 	dest.w = map->layers[layeridx].width;
 	dest.h = map->layers[layeridx].height;
-	PASS(errctx, renderer.draw_texture(&renderer, map->layers[layeridx].texture, &src, &dest, 0, NULL, SDL_FLIP_NONE));
+	PASS(errctx, renderer->draw_texture(renderer, map->layers[layeridx].texture, &src, &dest, 0, NULL, SDL_FLIP_NONE));
 	SUCCEED_RETURN(errctx);
     }
     
@@ -628,7 +700,7 @@ akerr_ErrorContext *akgl_tilemap_draw(akgl_Tilemap *map, SDL_FRect *viewport, in
 		      dest.y,
 		      dest.w,
 		      dest.h);*/
-		    PASS(errctx, renderer.draw_texture(&renderer, map->tilesets[tilesetidx].texture, &src, &dest, 0, NULL, SDL_FLIP_NONE));
+		    PASS(errctx, renderer->draw_texture(renderer, map->tilesets[tilesetidx].texture, &src, &dest, 0, NULL, SDL_FLIP_NONE));
 		}
 	    }
 	    dest.x += map->tilewidth;
@@ -683,7 +755,7 @@ akerr_ErrorContext *akgl_tilemap_draw_tileset(akgl_Tilemap *map, int tilesetidx)
 	  dest.y,
 	  dest.w,
 	  dest.h);*/
-	PASS(errctx, renderer.draw_texture(&renderer, map->tilesets[tilesetidx].texture, &src, &dest, 0, NULL, SDL_FLIP_NONE));
+	PASS(errctx, renderer->draw_texture(renderer, map->tilesets[tilesetidx].texture, &src, &dest, 0, NULL, SDL_FLIP_NONE));
     }
     SUCCEED_RETURN(errctx);
 }

src/util.c

@@ -202,9 +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.sdl_renderer);
+	SDL_RenderClear(renderer->sdl_renderer);
-	CATCH(errctx, renderer.draw_texture(&renderer, t1, &src, &dest, 0, NULL, SDL_FLIP_NONE));
+	CATCH(errctx, renderer->draw_texture(renderer, t1, &src, &dest, 0, NULL, SDL_FLIP_NONE));
-	s1 = SDL_RenderReadPixels(renderer.sdl_renderer, &read);
+	s1 = SDL_RenderReadPixels(renderer->sdl_renderer, &read);
 	FAIL_ZERO_BREAK(errctx, s1, AKGL_ERR_SDL, "Failed to read pixels from renderer");
 	
 	if ( writeout != NULL ) {
@@ -218,10 +218,10 @@ akerr_ErrorContext *akgl_render_and_compare(SDL_Texture *t1, SDL_Texture *t2, in
 		SDL_GetError());
 	}
 	
-	SDL_RenderClear(renderer.sdl_renderer);
+	SDL_RenderClear(renderer->sdl_renderer);
 	
-	CATCH(errctx, renderer.draw_texture(&renderer, t1, &src, &dest, 0, NULL, SDL_FLIP_NONE));
+	CATCH(errctx, renderer->draw_texture(renderer, t1, &src, &dest, 0, NULL, SDL_FLIP_NONE));
-	s2 = SDL_RenderReadPixels(renderer.sdl_renderer, &read);
+	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));