SDL OpenGL ES 2.0 >> C/C++

Fill Triangle

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參考資訊：
1. docs
2. OpenGL_ES_2-0_ProgrammingGuide
3. learning-to-learn-opengl-es-2-0

Attribute是用來描述Vertex的頂點資料，此次範例使用到如下兩個Functions：
glVertexAttribPointer()：Set Vertex Attribute
glEnableVertexAttribArray()：Enable Vertex Attribute

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);
     
    GLfloat v[] = {
         0.0f,  0.5f, 0.0f,
        -0.5f, -0.5f, 0.0f,
         0.5f, -0.5f, 0.0f
    };

    glViewport(0, 0, 320, 240);
    glClear(GL_COLOR_BUFFER_BIT);
    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 0, v);
    glEnableVertexAttribArray(0);
    glDrawArrays(GL_TRIANGLES, 0, 3);

    SDL_GL_SwapWindow(window);
    SDL_Delay(3000);
 
    SDL_DestroyWindow(window);
    SDL_DestroyRenderer(render);
    SDL_GL_DeleteContext(context);
    SDL_Quit();
    return 0;
}

完成

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