wtfgl.cpp

#include <SDL2/SDL.h>
#include <SDL2/SDL_image.h>
#include <GL/glew.h>

const char *vertexShaderSource = "#version 330 core\n"
    "layout (location = 0) in vec3 aPos;\n"
    "void main()\n"
    "{\n"
    "   gl_Position = vec4(aPos.x, aPos.y, aPos.z, 1.0);\n"
    "}\0";
const char *fragmentShaderSource = "#version 330 core\n"
    "out vec4 FragColor;\n"
    "void main()\n"
    "{\n"
    "   FragColor = vec4(1.0f, 0.5f, 0.2f, 1.0f);\n"
    "}\n\0";

int main()
{
    SDL_Init(SDL_INIT_VIDEO || SDL_INIT_TIMER);
    IMG_Init(IMG_INIT_PNG);
    SDL_Window *win = SDL_CreateWindow("Untitled",SDL_WINDOWPOS_CENTERED,SDL_WINDOWPOS_CENTERED,640,480,SDL_WINDOW_OPENGL);
    int quit = false;
    SDL_Event event;

    SDL_GLContext context = SDL_GL_CreateContext(win);
	  SDL_Renderer *render = SDL_CreateRenderer(win, -1, 0);
    glewExperimental = GL_TRUE;
    glewInit();
    //glViewport(0, 0, 640,480);
    //glEnable(GL_TEXTURE_2D);

    GLuint vertexShader;
    vertexShader = glCreateShader(GL_VERTEX_SHADER);
    glShaderSource(vertexShader, 1, &vertexShaderSource, NULL);
    glCompileShader(vertexShader);

    GLuint fragmentShader;
    fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);
    glShaderSource(fragmentShader, 1, &fragmentShaderSource, NULL);
    glCompileShader(fragmentShader);

    GLuint shaderProgram;
    shaderProgram = glCreateProgram();
    glAttachShader(shaderProgram, vertexShader);
    glAttachShader(shaderProgram, fragmentShader);
    glLinkProgram(shaderProgram);
    glDeleteShader(vertexShader);
    glDeleteShader(fragmentShader);
    
    GLfloat vertices[] = {
    -0.5f, -0.5f, 0.0f,
     0.5f, -0.5f, 0.0f,
     0.0f,  0.5f, 0.0f
    };

    GLuint VBO;
    glGenBuffers(1, &VBO);
    GLuint VAO;
    glGenVertexArrays(1, &VAO);
    glBindVertexArray(VAO);
    glBindBuffer(GL_ARRAY_BUFFER, VBO);
    glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(GLfloat), (GLvoid*)0);
    glEnableVertexAttribArray(0);
    glBindBuffer(GL_ARRAY_BUFFER, 0); 
    glBindVertexArray(0);

    while(quit == false)
    {
        glClearColor(0.1,0.1,0.4,0);
        glClear(GL_COLOR_BUFFER_BIT);   
        glUseProgram(shaderProgram);
        glBindVertexArray(VAO);
        glDrawArrays(GL_TRIANGLES, 0, 3);
        glBindVertexArray(0);
        SDL_GL_SwapWindow(win);

        while(SDL_PollEvent(&event))
        {
            switch(event.type)
            {
            case SDL_QUIT:
                quit = true;
                break;
            default:
                break;
            }
        }
        SDL_Delay(40);
    }
    return 0;
}