diff options
Diffstat (limited to 'main.c')
| -rw-r--r-- | main.c | 227 |
1 files changed, 227 insertions, 0 deletions
@@ -0,0 +1,227 @@ +#if _WIN32 +#include <SDL.h> +#else +#include <SDL2/SDL.h> +#endif +#include "base.h" +#include "math.c" +#include "arr.c" +#include "gl.c" +#include "time.c" +#include "util.c" + +typedef struct { + GLuint program; + struct timespec last_modified; + char vfilename[64], ffilename[64]; +} Shader; + +// pass NULL for filenames to reload the shader. +static void shader_load(Shader *shader, char const *vfilename, char const *ffilename) { + if (vfilename) + strbuf_cpy(shader->vfilename, vfilename); + if (ffilename) + strbuf_cpy(shader->ffilename, ffilename); + + shader->last_modified = timespec_max(time_last_modified(shader->vfilename), time_last_modified(shader->ffilename)); + FILE *vfp = fopen(shader->vfilename, "rb"); + FILE *ffp = fopen(shader->ffilename, "rb"); + + if (vfp) { + if (ffp) { + fseek(vfp, 0, SEEK_END); + size_t vsize = (size_t)ftell(vfp); + fseek(vfp, 0, SEEK_SET); + + fseek(ffp, 0, SEEK_END); + size_t fsize = (size_t)ftell(ffp); + fseek(ffp, 0, SEEK_SET); + + char *vcode = calloc(vsize + 1, 1); + char *fcode = calloc(fsize + 1, 1); + if (vcode && fcode) { + fread(vcode, 1, vsize, vfp); + fread(fcode, 1, fsize, ffp); + + GLuint program = gl_compile_and_link_shaders(vcode, fcode); + if (program) + shader->program = program; + } else print("Out of memory.\n"); + free(vcode); free(fcode); + } else { + print("Error loading shader: fragment shader file %s does not exist.\n", ffilename); + } + } else { + print("Error loading shader: vertex shader file %s does not exist.\n", vfilename); + } + + if (vfp) fclose(vfp); + if (ffp) fclose(ffp); +} + +static void shader_check_for_changes(Shader *shader) { + if (!timespec_eq(shader->last_modified, + timespec_max(time_last_modified(shader->vfilename), time_last_modified(shader->ffilename)))) { + GLuint prev_program = shader->program; + shader_load(shader, NULL, NULL); + if (shader->program != prev_program) + glDeleteProgram(prev_program); + } +} + +static void die(char const *fmt, ...) { + char buf[256] = {0}; + + va_list args; + va_start(args, fmt); + vsnprintf(buf, sizeof buf - 1, fmt, args); + va_end(args); + + // show a message box, and if that fails, print it + if (SDL_ShowSimpleMessageBox(SDL_MESSAGEBOX_ERROR, "Error", buf, NULL) < 0) { + print("%s\n", buf); + } + + exit(EXIT_FAILURE); +} + +#if DEBUG +static void APIENTRY gl_message_callback(GLenum source, GLenum type, unsigned int id, GLenum severity, + GLsizei length, const char *message, const void *userParam) { + (void)source; (void)type; (void)id; (void)length; (void)userParam; + if (severity == GL_DEBUG_SEVERITY_NOTIFICATION) return; + debug_println("Message from OpenGL: %s.", message); +} +#endif + +int main(void) { + if (SDL_Init(SDL_INIT_VIDEO) < 0) + die("%s", SDL_GetError()); + + SDL_Window *window = SDL_CreateWindow("shaders", SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, + 1280, 720, SDL_WINDOW_SHOWN|SDL_WINDOW_OPENGL|SDL_WINDOW_RESIZABLE); + if (!window) + die("%s", SDL_GetError()); + + gl_version_major = 4; + gl_version_minor = 3; + SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, gl_version_major); + SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, gl_version_minor); +#if DEBUG + SDL_GL_SetAttribute(SDL_GL_CONTEXT_FLAGS, SDL_GL_CONTEXT_DEBUG_FLAG); +#endif + SDL_GLContext *glctx = SDL_GL_CreateContext(window); + if (!glctx) { + debug_println("Couldn't get GL 4.3 context. Falling back to 2.0."); + gl_version_major = 2; + gl_version_minor = 0; + SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, gl_version_major); + SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, gl_version_minor); + SDL_GL_SetAttribute(SDL_GL_CONTEXT_FLAGS, 0); + glctx = SDL_GL_CreateContext(window); + if (!glctx) + die("%s", SDL_GetError()); + } + gl_get_procs(); + +#if DEBUG + if (gl_version_major * 100 + gl_version_minor >= 403) { + GLint flags = 0; + glGetIntegerv(GL_CONTEXT_FLAGS, &flags); + glEnable(GL_DEBUG_OUTPUT); + glEnable(GL_DEBUG_OUTPUT_SYNCHRONOUS); + if (flags & GL_CONTEXT_FLAG_DEBUG_BIT) { + // set up debug message callback + glDebugMessageCallback(gl_message_callback, NULL); + glDebugMessageControl(GL_DONT_CARE, GL_DONT_CARE, GL_DONT_CARE, 0, NULL, GL_TRUE); + } + } +#endif + + gl_geometry_init(); + + SDL_GL_SetSwapInterval(1); // vsync + + Shader shader = {0}; + shader_load(&shader, "1v.glsl", "1f.glsl"); + + GLuint vbo = 0; + glGenBuffers(1, &vbo); + GLuint vao = 0; + if (gl_version_major >= 3) + glGenVertexArrays(1, &vao); + + v2 buffer_data[] = { + // gl coordinates (v_render_pos) + {-1, -1}, + {+1, -1}, + {-1, +1}, + + {+1, -1}, + {+1, +1}, + {-1, +1}, + + // normalized coordinates (v_pos) + {0, 0}, + {1, 0}, + {0, 1}, + + {1, 0}, + {1, 1}, + {0, 1}, + }; + + if (vao) glBindVertexArray(vao); + glBindBuffer(GL_ARRAY_BUFFER, vbo); + glBufferData(GL_ARRAY_BUFFER, (GLsizeiptr)sizeof buffer_data, buffer_data, GL_STATIC_DRAW); + GLuint v_render_pos = gl_attrib_loc(shader.program, "v_render_pos"); + GLuint v_pos = gl_attrib_loc(shader.program, "v_pos"); + if (v_render_pos != (GLuint)-1) { + glVertexAttribPointer(v_render_pos, 2, GL_FLOAT, 0, sizeof(v2), NULL); + glEnableVertexAttribArray(v_render_pos); + } + if (v_pos != (GLuint)-1) { + glVertexAttribPointer(v_pos, 2, GL_FLOAT, 0, sizeof(v2), (void *)(6 * sizeof(v2))); + glEnableVertexAttribArray(v_pos); + } + + bool quit = false; + double start = time_get_seconds(); + while (!quit) { + SDL_Event event = {0}; + while (SDL_PollEvent(&event)) { + switch (event.type) { + case SDL_QUIT: + quit = true; + break; + } + } + + int window_width, window_height; + SDL_GetWindowSize(window, &window_width, &window_height); + + // set up GL + glEnable(GL_BLEND); + glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA); + glViewport(0, 0, (GLsizei)window_width, (GLsizei)window_height); + glClearColor(0, 0, 0, 1); + glClear(GL_COLOR_BUFFER_BIT); + + shader_check_for_changes(&shader); + + if (shader.program) { + if (vao) glBindVertexArray(vao); + glBindBuffer(GL_ARRAY_BUFFER, vbo); + glUseProgram(shader.program); + GLint u_time = gl_uniform_loc(shader.program, "u_time"); + if (u_time >= 0) + glUniform1f(u_time, (float)fmod(time_get_seconds() - start, 10000)); + glDrawArrays(GL_TRIANGLES, 0, 6); + } + + SDL_GL_SwapWindow(window); + } + + + return 0; +} |