///////////////////////////////////////////////////////////////
// A SIMPLE SDL BASECODE BY BALDURK AT GLPROGRAMMING.COM
///////////////////////////////////////////////////////////////
// find us at glprogramming.com or on IRC at irc.enterthegame.com/#opengl
///////////////////////////////////////////////////////////////
// Last Modified: 19/05/04
///////////////////////////////////////////////////////////////
// SDL documentation here: http://sdldoc.csn.ul.ie/index.php
//
// OpenGL documentation here: http://www.opengl.org
//             and here: http://www.glprogramming.com/red
//             and here: http://www.glprogramming.com/blue
///////////////////////////////////////////////////////////////



// Necessary windows libraries and includes.
#ifdef _WIN32
    #pragma comment(lib, "glu32.lib")
    #pragma comment(lib, "opengl32.lib")
    #pragma comment(lib, "SDL.lib")
    #pragma comment(lib, "SDLmain.lib")    

    #include <windows.h>
#endif

// Includes for the OpenGL, GLU and SDL headers.
#include <GL/gl.h>
#include <GL/glu.h>
#include <SDL/SDL.h>

// An array to keep key-states.
bool keys[SDLK_LAST];
// The width, height and bitdepth
const int width = 800, height = 600, bitdepth = 32;

// A function to draw the scene. The parameter is the number of milliseconds passed
// since the previous frame.
// This is where you put your code that executes every frame.
void Draw(int TimePassed)
{
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    glLoadIdentity();
    glColor3f(1.0f, 1.0f, 1.0f);
}

// This function performs any Initialisation you need to do for your project before
// the program starts up
void Init()
{

}

// The Basecode below here.

int main(int argc, char **argv)
{
    // Initialise SDL, complain if we can't.
    if(SDL_InitSubSystem(SDL_INIT_VIDEO) < 0)
    {
        fprintf(stderr, "InitSubSystem() failed. SDL Error: %s\n", SDL_GetError());
        SDL_Quit();
        return -1;
    }

    // Get a surface.
    SDL_Surface *Surface = SDL_SetVideoMode(width, height, bitdepth, SDL_OPENGL);

    // Check the surface, complain if we didn't get it.
    if(!Surface)
    {
        fprintf(stderr, "SetVideoMode() Failed. SDL_Error: %s\n", SDL_GetError());
        SDL_Quit();
        return -1;
    }

    // Set up the GL viewport
    glViewport(0, 0, width, height);
    glMatrixMode(GL_PROJECTION);
    gluPerspective(45.0f, float(width)/float(height), 1.0f, 500.0f);
    glMatrixMode(GL_MODELVIEW);

    // Call the user defined Init function.
    Init();

    // initialise all the key stats to "up" initially
    for(int i=0; i < SDLK_LAST; i++) keys[i] = false;

    // initialise the time variables
    int TimePrev = SDL_GetTicks(), TimeCurrent, TimePassed;
    // main message pump
    while(1)
    {
        // Do the time-based movement calculations
        TimeCurrent = SDL_GetTicks();
        TimePassed  = TimeCurrent - TimePrev;

        // Call the user defined Draw function
        Draw(TimePassed);
        // Swap the front and back buffers
        SDL_GL_SwapBuffers();

        // Do the time-based movement calculations
        TimePrev = TimeCurrent;

        // Get an event
        SDL_Event Event;
        SDL_PollEvent(&Event);

        // Check its type.
        // If it's a quit-type event, break out of the SDL loop
        if((Event.type == SDL_KEYDOWN && Event.key.keysym.sym == SDLK_ESCAPE) ||
           Event.type == SDL_QUIT)
            break; // we get out of the while(1) like this.

        // If it's a keydown event, set the relevant key to true/down
        if(Event.type == SDL_KEYDOWN)
            keys[Event.key.keysym.sym] = true;

        // If it's a keyup event, set the relevant to false/up
        if(Event.type == SDL_KEYUP)
            keys[Event.key.keysym.sym] = false;
    }

    SDL_Quit();

    // Everything went fine.
    return 0;
}