src/c/sokol-graphics.c — sigil-graphics

1/*

2 * sokol-graphics.c - Sokol implementation for sigil-graphics

3 *

4 * Implements sokol_gfx and sokol_gp (and, on native, sokol_log), with GL

5 * entry points supplied by an external loader on both targets.

6 *

7 * NATIVE (default): SOKOL_GLCORE + SOKOL_EXTERNAL_GL_LOADER. The window and

8 * context are sigil-desktop's (GLFW); gl_native_loader.h fills sokol's GL

9 * function pointers through sigil_desktop_gl_get_proc_address. No system GL

10 * header, no libGL link.

11 *

12 * WEB (wasm32-wasi, __wasm__): SOKOL_GLES3 + SOKOL_EXTERNAL_GL_LOADER. sokol's

13 * gl* calls resolve to WASM imports in the "gl" module via gl_shim.h (shipped

14 * by sigil-wasm-gles3). There is no window package on web: the canvas, WebGL2

15 * context, and swapchain come from the sigil-wasm-gles3 JS bridge (see

16 * graphics.c's sig_gfx_* abstraction), and slog_func is provided here.

17 */

19/* sgp's per-draw uniform buffer: 128 floats (512 B). Must equal

20 * SIGIL_GFX_UNIFORM_BUFFER_SIZE / sizeof(float) in graphics.c, which

21 * mirrors the block on the CPU side and asserts nothing larger is pushed.

22 * sokol_gp's default is 8 floats (32 bytes), too small for even the

23 * auto-uniforms (u_time, u_resolution) plus one vec4; 64 floats (v0.10)

24 * held a handful of vec4s; 128 floats holds uniform arrays such as

25 * `vec4 palette[8]` beside them. Cost: sokol_gp keeps max_commands

26 * (16384) copies of the sgp_uniform struct in its pool, so the pool goes

27 * from 4.3 MB to 8.4 MB, allocated and zeroed once in sgp_setup; per draw

28 * under a custom shader it memcmps one 512 B struct. Default-pipeline

29 * draws (no shader bound) skip the uniform path entirely. */

30#define SGP_UNIFORM_CONTENT_SLOTS 128

32#if defined(__wasm__)

34/* Web (wasm32-wasi): sokol_gfx's GLES3 backend, with GL entry points supplied

35 * as WASM imports (SOKOL_EXTERNAL_GL_LOADER) rather than a native loader. These

36 * are self-configured here from the wasm target so a first-class `sigil build

37 * --config web` needs no -D flags; the #ifndef guards keep the older examples

38 * that still pass -DSOKOL_GLES3/-DSOKOL_EXTERNAL_GL_LOADER conflict-free. */

39#ifndef SOKOL_GLES3

40#define SOKOL_GLES3

41#endif

42#ifndef SOKOL_EXTERNAL_GL_LOADER

43#define SOKOL_EXTERNAL_GL_LOADER

44#endif

46/* Web: bind every gl* sokol calls as a WASM import in the "gl" module. Must be

47 * included before sokol_gfx.h so GL types/constants/prototypes are visible. */

48#include "gl_shim.h"

50#define SOKOL_IMPL

51/* Order matters: gfx before gp. No sokol_glue (no sokol_app on web). */

52#include "sokol_gfx.h"

53#include "sokol_gp.h"

55/* slog_func is compiled from sokol_log.h in the native branch below; on web

56 * that header is not compiled, so supply it here. Routes to stderr (wasi

57 * fd_write -> console) so sokol

58 * validation failures stay visible without any import beyond gl.* + wasi. */

59#include <stdio.h>

60#include <stdint.h>

61void slog_func(const char* tag, uint32_t log_level, uint32_t log_item_id,

62 const char* message_or_null, uint32_t line_nr,

63 const char* filename_or_null, void* user_data) {

64 (void)log_item_id; (void)user_data;

65 fprintf(stderr, "sokol[level=%u] %s:%u [%s] %s\n",

66 log_level,

67 filename_or_null ? filename_or_null : "?",

68 line_nr,

69 tag ? tag : "sokol",

70 message_or_null ? message_or_null : "");

71}

73#else

75/* Native: desktop GL core backend over sigil-desktop's window. GL comes in

76 * through the generated loader (gl_native_loader.h: sokol's own list of

77 * entry points, filled from sigil_desktop_gl_get_proc_address, which is

78 * GLFW's glfwGetProcAddress), so this file needs no system GL header and

79 * the package links no libGL; GLFW loads libGL/libEGL at run time. The

80 * loader is the same shape as the web build's gl_shim.h, hence

81 * SOKOL_EXTERNAL_GL_LOADER on both. */

82#ifndef SOKOL_GLCORE

83#define SOKOL_GLCORE

84#endif

85#ifndef SOKOL_EXTERNAL_GL_LOADER

86#define SOKOL_EXTERNAL_GL_LOADER

87#endif

89#include "gl_native_loader.h"

90#include "sigil-desktop.h"

92/* sokol_log's implementation lives here now (it was in sigil-app when the

93 * window was sokol_app); graphics.c declares slog_func through sokol_log.h. */

94#define SOKOL_IMPL

95#include "sokol_log.h"

97/* Order matters: gfx before gp. No sokol_glue: graphics.c builds the

98 * environment and swapchain from sigil-desktop's framebuffer size. */

99#include "sokol_gfx.h"

100#include "sokol_gp.h"

101

102/* Called by graphics.c before sg_setup, with the window's context current.

103 * Returns 0 when the core entry points are all present, else the count of

104 * missing ones (and sokol cannot run). */

105int sigil_graphics_load_gl(void)

106{

107 int missing = sigil_gl_load(sigil_desktop_gl_get_proc_address);

108 if (!sigil_gl_ready()) return missing > 0 ? missing : 1;

109 return 0;

110}

111

112#endif