SDL OpenGL ES 2.0 >> C/C++
Fill Color
參考資訊:
1. docs
2. OpenGL_ES_2-0_ProgrammingGuide
3. learning-to-learn-opengl-es-2-0
OpenGL ES必須且只能有一個Vertex Shader和Fragment Shader,用來轉換點和顏色,這兩部份都是使用程式碼動態編譯方式,因此,使用字串方式傳入,目前只傳入程式框架,編譯後的Vertex Shader和Fragment Shader必須做Link才能使用,其實可以把OpenGL ES程式想像是在寫一個C語言程式的步驟,程式碼 > 編譯 > 連結 > 執行
main.c
#include <stdio.h> #include <stdlib.h> #include <SDL2/SDL.h> #include <GLES2/gl2.h> const char *vShaderSrc = "void main(void){}"; const char *fShaderSrc = "void main(void){}"; int main(int argc, char **argv) { SDL_Window *window = NULL; SDL_Renderer *render = NULL; SDL_GLContext context = {0}; SDL_Init(SDL_INIT_VIDEO); SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_ES); SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 2); SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 0); window = SDL_CreateWindow("main", 0, 0, 320, 240, SDL_WINDOW_OPENGL); render = SDL_CreateRenderer(window, -1, SDL_RENDERER_ACCELERATED | SDL_RENDERER_PRESENTVSYNC); context = SDL_GL_CreateContext(window); GLuint vShader = 0; GLuint fShader = 0; GLuint pObject = 0; vShader = glCreateShader(GL_VERTEX_SHADER); glShaderSource(vShader, 1, &vShaderSrc, NULL); glCompileShader(vShader); fShader = glCreateShader(GL_FRAGMENT_SHADER); glShaderSource(fShader, 1, &fShaderSrc, NULL); glCompileShader(fShader); pObject = glCreateProgram(); glAttachShader(pObject, vShader); glAttachShader(pObject, fShader); glLinkProgram(pObject); glUseProgram(pObject); glViewport(0, 0, 320, 240); glClearColor(1.0f, 0.0f, 0.0f, 1.0f); glClear(GL_COLOR_BUFFER_BIT); SDL_GL_SwapWindow(window); SDL_Delay(3000); SDL_DestroyWindow(window); SDL_DestroyRenderer(render); SDL_GL_DeleteContext(context); SDL_Quit(); return 0; }
完成