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Draw: implement the BASIC 7.0 graphics verbs

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GRAPHIC, COLOR, DRAW, BOX, CIRCLE, PAINT, SCALE, SSHAPE, GSHAPE and LOCATE, all
against the akbasic_GraphicsBackend record rather than akgl_draw_* directly, so
src/runtime_graphics.c includes no SDL and the whole group is testable in a build
with no SDL on the machine.

The reference lists every one of these as unimplemented, so the semantics come
from Commodore BASIC 7.0 rather than from a port, and four places where a modern
renderer cannot do what a C128 did are recorded in TODO.md section 5 rather than
silently substituted:

- CIRCLE is drawn as a polygon of inc-degree segments and akgl_draw_circle is
  deliberately unused. 7.0's CIRCLE takes two radii, an arc range and a rotation,
  so the primitive could serve only the fully-defaulted call, and a shape that
  changed character depending on whether the radii happened to be equal would be
  worse than one uniformly a polygon.
- SSHAPE puts a SHAPE:<n> handle in the string variable rather than the pixels,
  because a value's string is a fixed 256 bytes and a region is a device surface.
  GSHAPE refuses a string without that prefix instead of parsing whatever digits
  it finds and pasting an unrelated slot.
- BOX fills on a negative angle; 7.0 puts the fill flag after the rotation, which
  would make a filled box a seventh argument.
- GRAPHIC stores its mode and honours only the one consequence that means
  anything here -- mode 0 is text -- while still refusing an out-of-range mode,
  since that is a typo worth catching.

PAINT surfaces the flood fill's AKERR_OUTOFBOUNDS as an error rather than
success. The device gives up when its span stack runs out having filled *part* of
the region, and a program that cannot tell that happened cannot recover from it.
Note the shape of that handler: HANDLE sets handled = true on the context, so a
FAIL_RETURN from inside the HANDLE block hands the caller something already
marked handled, whose FINISH_LOGIC then declines to pass it up and releases it --
the error disappears and PAINT reports success. Flag inside the block, raise
after FINISH.

COLOR, LOCATE and SCALE need no device on purpose, so a program can set itself up
before a host has lent it a renderer.

Adds a second golden corpus under tests/language/. The corpus in
deps/basicinterpret is a submodule and nothing here may add files to it, but
goal 2's new verbs still need the .bas/.txt half of their coverage. Registered
under local_ so a failure names which corpus it came from. What it can cover is
limited -- these verbs draw rather than print -- so the behaviour that reaches a
device is asserted against tests/mockdevice.h instead.

65/65 ctest, clean under -Wall -Wextra, doxygen clean.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
This commit is contained in:
Andrew Kesterson
2026-07-31 08:17:48 -04:00
parent 9b9dd09c5a
commit 9d99d0a67e
15 changed files with 1264 additions and 0 deletions
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287
tests/graphics_verbs.c Normal file
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/**
* @file graphics_verbs.c
* @brief Tests the group G verbs against the recording mock backend.
*
* These verbs emit nothing a golden file can compare, so the assertions are on
* the call log: what reached the device, in what order, with what geometry and
* what color. Running a real BASIC line rather than calling the handler directly
* is deliberate -- it exercises the dispatch-table row and the parse handler as
* well, which is where an added verb is most likely to be wrong.
*/
#include <string.h>
#include <akbasic/error.h>
#include <akbasic/graphics.h>
#include <akbasic/runtime.h>
#include "harness.h"
#include "mockdevice.h"
#include "testutil.h"
/** @brief Bring up a runtime with the mock devices attached and a program loaded. */
static akerr_ErrorContext AKERR_NOIGNORE *run_program(const char *source)
{
PREPARE_ERROR(errctx);
PASS(errctx, harness_start(NULL));
mock_devices_init();
PASS(errctx, akbasic_runtime_set_devices(&HARNESS_RUNTIME, &MOCK_GRAPHICS,
&MOCK_AUDIO, &MOCK_INPUT));
PASS(errctx, akbasic_runtime_load(&HARNESS_RUNTIME, source));
PASS(errctx, akbasic_runtime_start(&HARNESS_RUNTIME, AKBASIC_MODE_RUN));
PASS(errctx, akbasic_runtime_run(&HARNESS_RUNTIME, 0));
SUCCEED_RETURN(errctx);
}
/** @brief The white of palette index 2, which most of these draw with. */
#define WHITE "#ffffff"
/** @brief The red of palette index 3. */
#define RED "#883932"
/**
* @brief A single DRAW coordinate pair plots a point; two or more draw a
* polyline; none at all plots wherever LOCATE left the cursor.
*/
static void test_draw(void)
{
TEST_REQUIRE_OK(run_program("10 DRAW 1, 10, 20\n"));
TEST_REQUIRE_STR(MOCK.log, "point 10.0,20.0 " WHITE "\n");
harness_stop();
TEST_REQUIRE_OK(run_program("10 DRAW 1, 0, 0 TO 10, 0 TO 10, 10\n"));
TEST_REQUIRE_STR(MOCK.log,
"line 0.0,0.0-10.0,0.0 " WHITE "\n"
"line 10.0,0.0-10.0,10.0 " WHITE "\n");
harness_stop();
/* LOCATE moves the pixel cursor; a bare DRAW plots it. */
TEST_REQUIRE_OK(run_program("10 LOCATE 33, 44\n20 DRAW 1\n"));
TEST_REQUIRE_STR(MOCK.log, "point 33.0,44.0 " WHITE "\n");
harness_stop();
/* An odd number of coordinates is a typo, not half a line. */
TEST_REQUIRE_OK(harness_start(NULL));
mock_devices_init();
TEST_REQUIRE_OK(akbasic_runtime_set_devices(&HARNESS_RUNTIME, &MOCK_GRAPHICS, NULL, NULL));
TEST_REQUIRE_OK(akbasic_runtime_load(&HARNESS_RUNTIME, "10 DRAW 1, 5\n"));
TEST_REQUIRE_OK(akbasic_runtime_start(&HARNESS_RUNTIME, AKBASIC_MODE_RUN));
TEST_REQUIRE_OK(akbasic_runtime_run(&HARNESS_RUNTIME, 0));
TEST_REQUIRE(strstr(HARNESS_OUTPUT, "X,Y pairs") != NULL,
"an odd coordinate count should be refused, got \"%s\"", HARNESS_OUTPUT);
harness_stop();
}
/** @brief COLOR rebinds a source, and every drawing verb follows the rebinding. */
static void test_color(void)
{
TEST_REQUIRE_OK(run_program("10 COLOR 1, 3\n20 DRAW 1, 1, 1\n"));
TEST_REQUIRE_STR(MOCK.log, "point 1.0,1.0 " RED "\n");
harness_stop();
/* Both arguments are range-checked, and BASIC counts colors from 1. */
TEST_REQUIRE_OK(run_program("10 COLOR 9, 3\n"));
TEST_REQUIRE(strstr(HARNESS_OUTPUT, "COLOR source 9") != NULL,
"an out-of-range source should be refused, got \"%s\"", HARNESS_OUTPUT);
harness_stop();
TEST_REQUIRE_OK(run_program("10 COLOR 1, 0\n"));
TEST_REQUIRE(strstr(HARNESS_OUTPUT, "COLOR 0") != NULL,
"color 0 should be refused, got \"%s\"", HARNESS_OUTPUT);
harness_stop();
}
/** @brief An unrotated BOX is a rectangle; a rotated one is four lines. */
static void test_box(void)
{
TEST_REQUIRE_OK(run_program("10 BOX 1, 0, 0, 10, 10\n"));
TEST_REQUIRE_STR(MOCK.log, "rect 0.0,0.0-10.0,10.0 " WHITE "\n");
harness_stop();
/*
* Rotated 90 degrees about its own center, a square lands back on itself --
* same four edges, walked from a different starting corner. That is the
* assertion worth making, because it pins the rotation *origin*: rotating
* about the coordinate origin instead of the box's center would put the
* square somewhere else entirely, and rotating about a corner would tilt it.
*
* The -0.0 is real and harmless: cos(pi/2) is not exactly zero, so one
* coordinate lands on negative zero, which compares equal to zero everywhere
* it matters and only shows up because the mock prints it.
*/
TEST_REQUIRE_OK(run_program("10 BOX 1, 0, 0, 10, 10, 90\n"));
TEST_REQUIRE_STR(MOCK.log,
"line 10.0,-0.0-10.0,10.0 " WHITE "\n"
"line 10.0,10.0-0.0,10.0 " WHITE "\n"
"line 0.0,10.0-0.0,0.0 " WHITE "\n"
"line 0.0,0.0-10.0,-0.0 " WHITE "\n");
harness_stop();
}
/** @brief CIRCLE is a polygon of arc-increment segments, and closes. */
static void test_circle(void)
{
int segments = 0;
const char *cursor = NULL;
/* 360 degrees at 90 per segment is four lines, whatever the radius. */
TEST_REQUIRE_OK(run_program("10 CIRCLE 1, 50, 50, 10, 10, 0, 360, 0, 90\n"));
for ( cursor = MOCK.log; (cursor = strstr(cursor, "line ")) != NULL; cursor += 5 ) {
segments += 1;
}
TEST_REQUIRE_INT(segments, 4);
/* The first vertex is directly above the center, as BASIC 7.0 starts it. */
TEST_REQUIRE(strncmp(MOCK.log, "line 50.0,40.0-", 15) == 0,
"CIRCLE should start at the top of the circle, got \"%.30s\"", MOCK.log);
harness_stop();
/* A negative radius and a zero increment are both refusals, not loops. */
TEST_REQUIRE_OK(run_program("10 CIRCLE 1, 50, 50, -5\n"));
TEST_REQUIRE(strstr(HARNESS_OUTPUT, "radius") != NULL,
"a negative radius should be refused, got \"%s\"", HARNESS_OUTPUT);
harness_stop();
TEST_REQUIRE_OK(run_program("10 CIRCLE 1, 50, 50, 10, 10, 0, 360, 0, 0\n"));
TEST_REQUIRE(strstr(HARNESS_OUTPUT, "increment") != NULL,
"a zero arc increment should be refused, got \"%s\"", HARNESS_OUTPUT);
harness_stop();
}
/**
* @brief PAINT reports a partial fill rather than letting it pass as success.
*
* The device gives up when its span stack runs out, having filled some of the
* region. A program that cannot tell that happened has no way to recover, so the
* error is the feature.
*/
static void test_paint(void)
{
TEST_REQUIRE_OK(run_program("10 PAINT 1, 5, 5\n"));
TEST_REQUIRE_STR(MOCK.log, "paint 5,5 " WHITE "\n");
harness_stop();
TEST_REQUIRE_OK(harness_start(NULL));
mock_devices_init();
MOCK.paint_exhausts = true;
TEST_REQUIRE_OK(akbasic_runtime_set_devices(&HARNESS_RUNTIME, &MOCK_GRAPHICS, NULL, NULL));
TEST_REQUIRE_OK(akbasic_runtime_load(&HARNESS_RUNTIME, "10 PAINT 1, 5, 5\n"));
TEST_REQUIRE_OK(akbasic_runtime_start(&HARNESS_RUNTIME, AKBASIC_MODE_RUN));
TEST_REQUIRE_OK(akbasic_runtime_run(&HARNESS_RUNTIME, 0));
TEST_REQUIRE(strstr(HARNESS_OUTPUT, "only part of the region") != NULL,
"a partial fill should be reported, got \"%s\"", HARNESS_OUTPUT);
harness_stop();
}
/** @brief SCALE maps user coordinates onto the 320x200 space, and only then. */
static void test_scale(void)
{
/* Off by default: a coordinate passes through untouched. */
TEST_REQUIRE_OK(run_program("10 DRAW 1, 160, 100\n"));
TEST_REQUIRE_STR(MOCK.log, "point 160.0,100.0 " WHITE "\n");
harness_stop();
/* On, with the 7.0 default maxima: the middle of the user space is the
middle of the screen. */
TEST_REQUIRE_OK(run_program("10 SCALE 1\n20 DRAW 1, 1023, 1023\n"));
TEST_REQUIRE_STR(MOCK.log, "point 320.0,200.0 " WHITE "\n");
harness_stop();
TEST_REQUIRE_OK(run_program("10 SCALE 1, 640, 400\n20 DRAW 1, 320, 200\n"));
TEST_REQUIRE_STR(MOCK.log, "point 160.0,100.0 " WHITE "\n");
harness_stop();
TEST_REQUIRE_OK(run_program("10 SCALE 1, 0, 400\n"));
TEST_REQUIRE(strstr(HARNESS_OUTPUT, "positive") != NULL,
"a zero SCALE maximum should be refused, got \"%s\"", HARNESS_OUTPUT);
harness_stop();
}
/** @brief GRAPHIC records the mode, clears on request and refuses a bad mode. */
static void test_graphic(void)
{
TEST_REQUIRE_OK(run_program("10 GRAPHIC 1, 1\n"));
TEST_REQUIRE_STR(MOCK.log, "clear #000000\n");
TEST_REQUIRE_INT(HARNESS_RUNTIME.gfx.mode, 1);
harness_stop();
/* Without the clear argument nothing reaches the device. */
TEST_REQUIRE_OK(run_program("10 GRAPHIC 1\n"));
TEST_REQUIRE_STR(MOCK.log, "");
harness_stop();
/* GRAPHIC CLR drops the saved shapes and resets the whole state. */
TEST_REQUIRE_OK(run_program("10 COLOR 1, 3\n20 GRAPHIC 5\n"));
TEST_REQUIRE_STR(MOCK.log, "freeshapes\n");
TEST_REQUIRE_INT(HARNESS_RUNTIME.gfx.source[1], 2);
harness_stop();
TEST_REQUIRE_OK(run_program("10 GRAPHIC 9\n"));
TEST_REQUIRE(strstr(HARNESS_OUTPUT, "GRAPHIC mode 9") != NULL,
"an out-of-range mode should be refused, got \"%s\"", HARNESS_OUTPUT);
harness_stop();
}
/** @brief SSHAPE stores a handle a later GSHAPE can use, and only that. */
static void test_shapes(void)
{
TEST_REQUIRE_OK(run_program("10 SSHAPE A$, 0, 0, 8, 8\n20 GSHAPE A$, 32, 32\n"));
TEST_REQUIRE_STR(MOCK.log, "save 0,0-8,8 -> 0\npaste 0 at 32.0,32.0\n");
harness_stop();
/*
* The string is opaque but not magic: a string that did not come from SSHAPE
* has to be refused, or GSHAPE parses whatever digits it finds and pastes
* some unrelated slot.
*/
TEST_REQUIRE_OK(run_program("10 A$ = \"5\"\n20 GSHAPE A$, 0, 0\n"));
TEST_REQUIRE(strstr(HARNESS_OUTPUT, "did not come from SSHAPE") != NULL,
"a hand-written shape string should be refused, got \"%s\"", HARNESS_OUTPUT);
harness_stop();
/* A numeric variable is the wrong type for either verb. */
TEST_REQUIRE_OK(run_program("10 SSHAPE A#, 0, 0, 8, 8\n"));
TEST_REQUIRE(strstr(HARNESS_OUTPUT, "string variable") != NULL,
"SSHAPE into a number should be refused, got \"%s\"", HARNESS_OUTPUT);
harness_stop();
}
/**
* @brief Every verb that needs a device says so by name when it has none.
*
* This is the standalone driver's situation, so it is the common path. COLOR,
* LOCATE and SCALE are excluded on purpose: they only touch interpreter state
* and must keep working before a host has lent the script a renderer.
*/
static void test_no_device(void)
{
TEST_REQUIRE_OK(harness_start(NULL));
TEST_REQUIRE_OK(akbasic_runtime_load(&HARNESS_RUNTIME,
"10 COLOR 1, 3\n"
"20 LOCATE 5, 5\n"
"30 SCALE 1\n"
"40 DRAW 1, 1, 1\n"));
TEST_REQUIRE_OK(akbasic_runtime_start(&HARNESS_RUNTIME, AKBASIC_MODE_RUN));
TEST_REQUIRE_OK(akbasic_runtime_run(&HARNESS_RUNTIME, 0));
TEST_REQUIRE(strstr(HARNESS_OUTPUT, "DRAW needs a graphics device") != NULL,
"DRAW without a device should name itself, got \"%s\"", HARNESS_OUTPUT);
TEST_REQUIRE(strstr(HARNESS_OUTPUT, "COLOR") == NULL,
"COLOR should not need a device, got \"%s\"", HARNESS_OUTPUT);
TEST_REQUIRE_INT(HARNESS_RUNTIME.gfx.source[1], 3);
TEST_REQUIRE_FEQ(HARNESS_RUNTIME.gfx.x, 5.0);
TEST_REQUIRE(HARNESS_RUNTIME.gfx.scaling, "SCALE should not need a device");
harness_stop();
}
int main(void)
{
test_draw();
test_color();
test_box();
test_circle();
test_paint();
test_scale();
test_graphic();
test_shapes();
test_no_device();
return akbasic_test_failures;
}

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tests/language/graphics/argument_errors.bas Normal file
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10 REM A range check reported through the driver, end to end. The program stops
20 REM at the first error, so this file covers one; the rest of the checks are
30 REM asserted in tests/graphics_verbs.c against the recording backend.
40 PRINT "BEFORE"
50 SCALE 1, 0, 400
60 PRINT "UNREACHABLE"

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tests/language/graphics/argument_errors.txt Normal file
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BEFORE
? 50 : RUNTIME ERROR SCALE maxima must be positive

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tests/language/graphics/no_device.bas Normal file
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10 REM The standalone driver lends the script no graphics device.
20 REM COLOR, LOCATE and SCALE only touch interpreter state and must still work.
30 COLOR 1, 3
40 LOCATE 40, 50
50 SCALE 1, 640, 400
60 PRINT "STATE VERBS OK"
70 REM DRAW needs the device, and has to say which verb wanted it.
80 DRAW 1, 10, 10

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tests/language/graphics/no_device.txt Normal file
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STATE VERBS OK
? 80 : RUNTIME ERROR DRAW needs a graphics device and this runtime has none