// Framework
// (c) 2003 Luke Philpot.

#define BUFFER_OFFSET(i) ((char *)NULL + (i))

#define win32 // comment out for non win32

#ifdef win32
#define WIN32_LEAN_AND_MEAN
#include <windows.h>
#endif

#include <SDL/SDL.h>
#include <GL/gl.h>
#include <GL/glu.h>
#include "glext.h"

GLfloat data[] = { -1.0f, 1.0f, 0.0f,
				 -1.0f, -1.0f, 0.0f,
				 1.0f, -1.0f, 0.0f };

GLuint buffer = 0;

PFNGLBINDBUFFERARBPROC glBindBufferARB = NULL;
PFNGLGENBUFFERSARBPROC glGenBuffersARB = NULL;
PFNGLBUFFERDATAARBPROC glBufferDataARB = NULL;

/*
===========
main
===========
*/

#ifdef win32
int WINAPI WinMain(HINSTANCE hInst, HINSTANCE hPrev, LPSTR lpCmdLine, int nshow)
#else
int main(void)
#endif

{
	SDL_Event e; // for input
        
	// init window

	SDL_Init(SDL_INIT_VIDEO);
	SDL_SetVideoMode(640, 480, 32, 2);

	// set up OpenGL
	glMatrixMode(GL_PROJECTION);					
	glLoadIdentity();

	gluPerspective(45, (float) 640 / (float) 480, 1, 512);

	glBindBufferARB = (PFNGLBINDBUFFERARBPROC)
	wglGetProcAddress("glBindBufferARB");
	glGenBuffersARB = (PFNGLGENBUFFERSARBPROC)
	wglGetProcAddress("glGenBuffersARB");
	glBufferDataARB = (PFNGLBUFFERDATAARBPROC)
	wglGetProcAddress("glBufferDataARB");

	// enable depth testing
	glEnable(GL_DEPTH_TEST);
	glDepthFunc(GL_LEQUAL);

	glEnableClientState(GL_VERTEX_ARRAY);

	glClearColor(0.5f, 0.5f, 1.0f, 1.0f);

	glGenBuffersARB(1, &buffer);
	glBindBufferARB(GL_ARRAY_BUFFER_ARB, 0);
	glBufferDataARB(GL_ARRAY_BUFFER_ARB, sizeof(data), data, GL_STATIC_DRAW_ARB);


	while (!SDL_PollEvent(&e) || e.type !=2) // check whether esc has been pressed
	{
		glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
		glMatrixMode(GL_MODELVIEW);
		glLoadIdentity();

		glTranslatef(0, 0, -3);

		glBindBufferARB(GL_ARRAY_BUFFER_ARB, buffer);
		
		glVertexPointer(3, GL_FLOAT, 0, 0);
		
		glDrawArrays(GL_TRIANGLE_STRIP, 0, 3);

		SDL_GL_SwapBuffers();

	}

	return 0;
}