gl4scafold.c

#include <stdio.h>
#include <SDL.h>
#include <SDL_image.h>
#include <GL/glew.h>
#include <glt.h>

#define TITLE  "OpenGL 4.0 Scaffold"
#define WIDTH  1024
#define HEIGHT  768 

int           running   = 1;
SDL_Window*   window    = NULL;
SDL_GLContext glcontext = NULL;

int open_window()
{
    int r = SDL_Init(SDL_INIT_VIDEO);
    if (r != 0)
    {
        printf("Failed to init SDL.");
        return -1;
    }
    
    window = SDL_CreateWindow(TITLE, SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, 
                              WIDTH, HEIGHT, SDL_WINDOW_OPENGL);
    if (window == NULL)
    {
        printf("Failed to open window.");
        return -2;
    }
    
    SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 4);
    SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 0);
    
    glcontext = SDL_GL_CreateContext(window);
    if (glcontext == NULL)
    {
        SDL_DestroyWindow(window);
        printf("Failed to create OpenGL context.");
        return -3;
    }
    
    glewExperimental = GL_TRUE;
    GLenum err = glewInit();
    if (GLEW_OK != err)
    {        
        SDL_GL_DeleteContext(window);
        SDL_DestroyWindow(window);
        printf("Failed to initialize GLEW.");
        return -4;
    }
    
    return 0;
}

int build_scene()
{
    
}

void pump_events()
{
    SDL_Event event;
    while (SDL_PollEvent(&event))
    {
        switch (event.type)
        {
            case SDL_QUIT:
                running = 0;
                break;
            default:
                // stfu
                break;
        }        
    }
}

void draw_scene()
{
    int w, h;
    SDL_GetWindowSize(window, &w, &h);

    glViewport(0, 0, w, h);        
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    
    // draw stuff here
    
    SDL_GL_SwapWindow(window);
}

void close_window()
{
    if (glcontext != NULL)
    {
        SDL_GL_DeleteContext(glcontext);
        glcontext = NULL;
    }

    if (window != NULL)
    {
        SDL_DestroyWindow(window);
        window = NULL;
    }
    
    free(window);
}

int main(int argc, char* argv[])
{
    int r = open_window();
    if (r < 0)
    {
        return r;
    }
    
    r = build_scene();
    if (r < 0)
    {   
        close_window();
        return r;
    }
    
    while (running)
    {
        pump_events();
        draw_scene();
    }
    
    close_window();
}