#ifdef WIN32
#include <windows.h>
#endif
#include <stdio.h>
#include <stdlib.h>
#include <memory.h>
#include "SDL.h"
#include "SDL_thread.h"
#include <time.h>
#include <GL/gl.h>
#include <GL/glu.h>
#include <GL/glut.h>

SDL_Thread *worker_thread;
enum { GO, STOP } thread_control;
SDL_mutex *mutex;
short freq[512];
SDL_Surface *screen;

static int worker_func(void *data);
static void init_thread();
static void cleanup_thread();
static void change_size(int w, int h);

void render()
{
    int h;

	SDL_mutexP(mutex);
	h = freq[0];
	SDL_mutexV(mutex);	

	SDL_SetVideoMode(480,320,32,SDL_OPENGL);	//?
	change_size(screen->w, screen->h);
	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

	//glColor3f(color1,color2,color3);
	static float rotation = 0;
	float height, color1,color2,color3;
	height=h/1024.0;
	color1=h/512.0;
	color2=h/2048.0;
	color3=h/1024.0;

	glRotatef(rotation++,0,0,1);

	glBegin(GL_POLYGON);
		glColor3f(color3,0.0f,color1);
		glVertex3f(-0.5f,-0.5f,0.0f);

		glColor3f(color2,0.0f,0.0f);
		glVertex3f(0.5f,-0.5f,0.0f);

		glColor3f(0.0f,0.0f,color3);
		glVertex3f(0.5f,height,0.0f);

		glColor3f(color1,color2,color3);
		glVertex3f(-0.5f,height,0.0f);
	glEnd();
	
	SDL_GL_SwapBuffers();

	rotation+=1.0f;
	if(rotation>359) rotation=1.0f;

	printf("\bR");
}

int worker_func(void *data)
{
	//return 0;
	while (thread_control == GO) {
		int bucket;
		
    	SDL_mutexP(mutex);
	    for (bucket = 0 ; bucket <512; bucket++)
	    {
		 srand(time(NULL));
		 int n,m;
		 m=rand();
		 n=(m%512)+1;
		 freq[bucket]=n;
	    }
	    SDL_mutexV(mutex);

		printf("\bW");

		SDL_Delay(0.1f);
	}

	return 0;
}

static void init_thread()
{
	printf("mutex : Initializing\n");
	thread_control = GO;
	mutex = SDL_CreateMutex();
	memset(freq, 0, sizeof(short) * 2 * 256);
    worker_thread = SDL_CreateThread (worker_func, NULL);
}

static void cleanup_thread()
{
	printf("mutex : Cleanup entered\n");
	thread_control = STOP;
	SDL_WaitThread(worker_thread, NULL);
	SDL_DestroyMutex(mutex);
	printf("mutex : Cleanup completed\n");
}

void change_size(int w, int h)
{
	int h2 = h;
	if ( !h2 ) h2 = 1;

	GLfloat fAspect = (GLfloat)w / (GLfloat)h2;

	glViewport(0, 0, w, h2);

    gluLookAt(0,0,5,0,0,0,0,1,0);
	glLoadIdentity();
}

void setup_gl()
{
	change_size(screen->w, screen->h);

	glEnable(GL_DEPTH_TEST);
	//glDepthFunc(GL_LESS);

	glShadeModel(GL_SMOOTH);

	glEnable(GL_CULL_FACE);
	glCullFace(GL_BACK);
	glFrontFace(GL_CW);
	
	glClearColor(.0f, .0f, .0f, 1.0f);
}

int main(int argc, char **argv)
{
	//sdl-init
	SDL_Init(SDL_INIT_VIDEO );

	//create-sdl-surface
	screen = 
		SDL_SetVideoMode(640, 480, 32, SDL_GL_DOUBLEBUFFER | SDL_OPENGL);
	SDL_WM_SetCaption("Expo?", "Expo?");

	//gl-init
	init_thread();
	setup_gl();

	//eventloop
	SDL_Event evt;
	int is_done = 0, n ;
	while (!is_done) {
		n = SDL_PollEvent(&evt);
		if (n)
		{
			switch ( evt.type ) {
				case SDL_QUIT:
					is_done = 1;
					break;
				case SDL_VIDEORESIZE:
					change_size(evt.resize.w,evt.resize.h);
					break;
				default:
					break;
			}
		}
		render();
		SDL_Delay(0.1f);
	}

	//quit
	cleanup_thread();
	SDL_Quit();

	return 0;
}