266 lines
7.4 KiB
C
266 lines
7.4 KiB
C
#include <stdio.h>
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#include <stdlib.h>
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#include <GL/glew.h>
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#include <SDL3/SDL.h>
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#include <SDL3/SDL_opengl.h>
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#include <SDL3/SDL_main.h> // only include this one in the source file with main()!
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#define INITIAL_FPS 60
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SDL_Window* window = NULL;
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SDL_GLContext glcontext = NULL;
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GLuint program;
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GLuint vbo;
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static double FPS = INITIAL_FPS;
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static double FrameTime = 1.0 / INITIAL_FPS;
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static double PerformancePeriod;
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static void panic ( const char *text ) __attribute__((noreturn));
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static double GetTime( void )
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{
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return PerformancePeriod * SDL_GetPerformanceCounter();
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}
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static void SetTitle ( SDL_Window *window )
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{
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char title[48] = {0};
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SDL_snprintf(title, sizeof(title), "Crude frame limiter @ %6.3f Hz", FPS);
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SDL_SetWindowTitle(window, title);
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}
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void panic ( const char *text )
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{
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//fprintf(stderr, "ERROR: %s. %s\n", text, SDL_GetError());
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SDL_LogCritical(SDL_LOG_CATEGORY_ASSERT, "%s. %s\n", text, SDL_GetError());
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SDL_GL_DestroyContext(glcontext);
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SDL_DestroyWindow(window);
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SDL_Quit();
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exit(1);
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}
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char *readFile ( const char *fileName )
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{
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SDL_IOStream *ioStream = SDL_IOFromFile(fileName, "rb");
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if (!ioStream) panic("SDL_IOFromfile");
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if (!SDL_SeekIO(ioStream, 0, SDL_IO_SEEK_END)) panic("SDL_SeekIO_END");
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long len = SDL_TellIO(ioStream);
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if (!len) panic("SDL_TellIO");
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if (!SDL_SeekIO(ioStream, 0, SDL_IO_SEEK_SET)) panic("SDL_SeekIO_SET");
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char *res = SDL_malloc(len + 1);
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if (!res) panic("SDL_malloc_RES");
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if (SDL_ReadIO(ioStream, res, len) != (size_t)len) panic("SDL_ReadIO");
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if (!SDL_CloseIO(ioStream)) panic("SDL_CloseIO");
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/* char *res = SDL_LoadFile_IO(ioStream, NULL, true); */
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/* if (!res) panic("SDL_LoadFile_IO"); */
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res[len] = 0;
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return res;
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}
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GLuint CreateShader ( const char *shaderFile, GLenum shaderType )
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{
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const char *strShaderType;
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if (shaderType == GL_VERTEX_SHADER) {
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strShaderType = "vertex";
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} else if (shaderType == GL_GEOMETRY_SHADER) {
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strShaderType = "geometry";
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} else if (shaderType == GL_FRAGMENT_SHADER) {
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strShaderType = "fragment";
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} else {
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SDL_LogCritical(SDL_LOG_CATEGORY_ASSERT, "Unrecognized shader type.\n");
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exit(1);
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}
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GLuint shader = glCreateShader(shaderType);
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if (!shader) {
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SDL_LogCritical(SDL_LOG_CATEGORY_ASSERT, "Error create shader type %s\n", strShaderType);
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exit(1);
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}
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GLchar *content = readFile(shaderFile);
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glShaderSource(shader, 1, (const GLchar **)&content, NULL);
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SDL_free(content);
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glCompileShader(shader);
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GLint status;
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glGetShaderiv(shader, GL_COMPILE_STATUS, &status);
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if (status == GL_FALSE) {
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GLint infoLen;
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glGetShaderiv(shader, GL_INFO_LOG_LENGTH, &infoLen);
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GLchar *info = SDL_malloc(sizeof(GLchar) * (infoLen + 1));
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glGetShaderInfoLog(shader, infoLen, NULL, info);
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SDL_LogCritical(SDL_LOG_CATEGORY_ASSERT, "Filed to compile %s shader:\n%s\n", strShaderType, info);
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exit(1);
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}
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return shader;
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}
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void CreateProgram ( GLuint *shaders, int len )
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{
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program = glCreateProgram();
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if (!program) {
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SDL_LogCritical(SDL_LOG_CATEGORY_ASSERT, "Can't to create shader program\n");
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exit(1);
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}
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for (int i = 0; i < len; i++) {
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glAttachShader(program, shaders[i]);
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}
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glLinkProgram(program);
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GLint status;
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glGetProgramiv(program, GL_LINK_STATUS, &status);
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if (status == GL_FALSE) {
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GLint infoLen;
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glGetProgramiv(program, GL_INFO_LOG_LENGTH, &infoLen);
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GLchar *info = SDL_malloc(sizeof(GLchar) * (infoLen + 1));
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glGetProgramInfoLog(program, infoLen, NULL, info);
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SDL_LogCritical(SDL_LOG_CATEGORY_ASSERT, "Link failed: %s\n", info);
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exit(1);
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}
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}
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void CreateBuffer ( void )
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{
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float vertices[] = {
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-1.0f, -1.0f, 0.0f,
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1.0f, -1.0f, 0.0f,
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0.0f, 1.0f, 0.0f
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};
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glGenBuffers(1, &vbo);
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glBindBuffer(GL_ARRAY_BUFFER, vbo);
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glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
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}
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void ConfProg ( void )
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{
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CreateBuffer();
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GLuint shaders[] = {
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CreateShader("vertex.glsl", GL_VERTEX_SHADER),
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CreateShader("fragmet.glsl", GL_FRAGMENT_SHADER)
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};
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int len = sizeof(shaders) / sizeof(shaders[0]);
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CreateProgram(shaders, len);
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for (int i = 0; i < len; i++) {
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glDeleteShader(shaders[i]);
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}
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}
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int main( int argc, char* argv[] )
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{
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const int WIDTH = 640;
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const int HEIGHT = 480;
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int delay_threshold = 2;
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double sleep_time;
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double time_counter = 0;
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bool loopShouldStop = false;
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SDL_SetHint(SDL_HINT_RENDER_VSYNC, 0);
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if (!SDL_Init(SDL_INIT_VIDEO)) {
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panic("SDL_Init failed");
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}
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SDL_GL_SetAttribute(SDL_GL_RED_SIZE, 5);
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SDL_GL_SetAttribute(SDL_GL_GREEN_SIZE, 5);
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SDL_GL_SetAttribute(SDL_GL_BLUE_SIZE, 5);
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SDL_GL_SetAttribute(SDL_GL_DEPTH_SIZE, 16);
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SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1);
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PerformancePeriod = 1.0 / SDL_GetPerformanceFrequency();
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time_counter = GetTime();
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window = SDL_CreateWindow("Hello SDL", WIDTH, HEIGHT, SDL_WINDOW_OPENGL|SDL_WINDOW_RESIZABLE);
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if (!window) {
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panic("SDL_CreateWindow");
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}
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glcontext = SDL_GL_CreateContext(window);
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if (!glcontext) {
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panic("SDL_GL_CreateContext");
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}
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ConfProg();
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SetTitle(window);
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//if (!SDL_SetRenderVSync(renderer, 1))
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//{
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// panic("SDL_SetRenderVSync");
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//}
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SDL_HideCursor();
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int red = 0;
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int green = 0;
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int r, g, b;
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while (!loopShouldStop) {
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SDL_Event e;
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SDL_zero(e);
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while (SDL_PollEvent(&e)) {
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if (e.type == SDL_EVENT_QUIT)
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loopShouldStop = true;
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else if (e.type == SDL_EVENT_KEY_DOWN) {
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if (e.key.key == SDLK_X) {
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FPS -= 0.1;
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if (FPS < 1) {
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FPS = 1;
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}
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FrameTime = 1.0 / FPS;
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SetTitle(window);
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}
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else if (e.key.key == SDLK_C) {
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FPS += 0.1;
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FrameTime = 1.0 / FPS;
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SetTitle(window);
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}
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if (e.key.key == SDLK_ESCAPE)
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loopShouldStop = true;
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}
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}
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/* SDL_SetRenderDrawColor(renderer, red, green, 0, 255); */
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/* SDL_RenderClear(renderer); */
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glClearColor(0, 0, 0, 1);
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glClear(GL_COLOR_BUFFER_BIT);
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SDL_GL_SwapWindow(window);
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sleep_time = time_counter - GetTime();
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if (sleep_time * 1000 > delay_threshold) {
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Uint32 ms = (Uint32)(sleep_time * 1000) - delay_threshold;
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SDL_Delay(ms);
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if (time_counter < GetTime()) {
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delay_threshold++;
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SDL_Log("Slept too long. Increased threshold to %u ms.", delay_threshold);
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}
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}
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while (time_counter > GetTime()) {
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/* Waiting for the right moment. */
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}
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/* red = (red + 1) % 256; */
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/* green = (green + 1) % 64; */
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time_counter += FrameTime;
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}
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SDL_GL_GetAttribute(SDL_GL_RED_SIZE, &r);
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SDL_GL_GetAttribute(SDL_GL_GREEN_SIZE, &g);
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SDL_GL_GetAttribute(SDL_GL_BLUE_SIZE, &b);
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printf("Red size: %d, Green size: %d, Blue size: %d\n", r, g, b);
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SDL_DestroyWindow(window);
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SDL_GL_DestroyContext(glcontext);
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SDL_Quit();
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exit(0);
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}
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