#if 0
#!/bin/sh

FILE=`echo $0 | sed "s/\.cp*$//"`
CC="gcc -std=c99 -Wall -pedantic"

if [ -z "$SDL_CONFIG" ]; then
	SDL_CONFIG="sdl-config"
fi

$CC `$SDL_CONFIG --cflags` $FILE.c -o $FILE `$SDL_CONFIG --libs` -lGL

exit
#endif

/* here the example file:
 * qmesh.txt, one single row
 * 0.0 1.0 0.0 -1.0 5.0 -1.0 5.0 1.0
 */

#include <stdio.h>
#include <stdlib.h>

#include "SDL.h"
#include "SDL_opengl.h"

typedef struct
{
	float x,
		  y;
} Point;

typedef struct
{
	float x,
		  y,
		  a,
		  l;
} Line;

typedef struct
{
	Point a,
		  b,
		  c,
		  d;
} Quad;

typedef struct
{
	int qCount;
	Quad quads[20];
} QMesh;

QMesh *loadQMesh(char *path)
{
	FILE *f;
	char buff[512];
	int i;
	Quad q;
	QMesh *m;

	if (!(f = fopen(path, "r")))
		return NULL;

	m = malloc(sizeof(QMesh));
	if (!m)
		return NULL;

	m->qCount = 0;

	while (!feof(f))
	{
		fgets(buff, 512, f);

		for (i = 0; buff[i]; i++)
			if (buff[i] == '\n')
				buff[i] = '\0';

		sscanf(buff, "%f %f %f %f %f %f %f %f",
				&q.a.x, &q.a.y,
				&q.b.x, &q.b.y,
				&q.c.x, &q.c.y,
				&q.d.x, &q.d.y);

		m->quads[m->qCount++] = q;
	}

	
	fclose(f);
	return m;
}

void drawLineMesh(Line *l, QMesh *m)
{
	int i;

	glPushMatrix();

	glTranslatef(l->x, l->y, 0.0);
	glRotatef(l->a, 0.0, 0.0, 1.0);
	
	glLineWidth(1.0);
	glColor3f(1.0, 1.0, 1.0);
	glBegin(GL_QUADS);
		for (i = 0; i < m->qCount; i++)
		{
			glVertex2f(m->quads[i].a.x, m->quads[i].a.y);
			glVertex2f(m->quads[i].b.x, m->quads[i].b.y);
			glVertex2f(m->quads[i].c.x, m->quads[i].c.y);
			glVertex2f(m->quads[i].d.x, m->quads[i].d.y);
		}
	glEnd();

	glLineWidth(2.0);
	glColor3f(1.0, 0.0, 0.0);
	glBegin(GL_LINES);
		glVertex2f(0.0, 0.0);
		glVertex2f(l->l, 0.0);
	glEnd();

	glTranslatef(l->l, 0.0, 0.0);
	
	glPopMatrix();
}

int main(int argc, char **argv)
{
	SDL_Event sdlEv;
	Uint32 sdlVideoFlags = SDL_OPENGL;
	Uint8 quit;

	/* Initialize */
	if (SDL_Init(SDL_INIT_VIDEO | SDL_INIT_AUDIO | SDL_INIT_EVENTTHREAD) < 0)
	{
		fprintf(stderr, "SDL_Init: %s\n", SDL_GetError());
		exit(EXIT_FAILURE);
	}
	atexit(SDL_Quit);

	/* Start graphic system with OGL */
	SDL_GL_SetAttribute(SDL_GL_RED_SIZE, 5);
	SDL_GL_SetAttribute(SDL_GL_GREEN_SIZE, 5);
	SDL_GL_SetAttribute(SDL_GL_BLUE_SIZE, 5);
	SDL_GL_SetAttribute(SDL_GL_DEPTH_SIZE, 5);
	SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1);

	if (!SDL_SetVideoMode(400, 400, 0, sdlVideoFlags))
	{
		fprintf(stderr, "SDL_SetVideoMode: %s\n", SDL_GetError());
		exit(EXIT_FAILURE);
	}

	glShadeModel(GL_SMOOTH);
	glViewport(0, 0, 400, 400);

	glMatrixMode(GL_PROJECTION);
	glOrtho(-10, 10, -10, 10, -1, 1);
	glMatrixMode(GL_MODELVIEW);

	/* Application Initialization */
	Line l;
	l.l = 6.0;
	l.a = 0.0;
	QMesh *m = loadQMesh("qmesh.txt");

	if (!m)
		exit(EXIT_FAILURE);

	SDL_EnableKeyRepeat(100, 50);

	/* Main loop */
	quit = 0;
	while (!quit)
	{
		while (SDL_PollEvent(&sdlEv))
			switch (sdlEv.type)
			{
				case SDL_QUIT:
					quit = 1;
					break;

				case SDL_KEYDOWN:
					switch (sdlEv.key.keysym.sym)
					{
						case SDLK_LEFT:
							l.a += 2.0;
							break;

						case SDLK_RIGHT:
							l.a -= 2.0;
							break;
						
						default:
							break;
					}

				default:
					break;
			}
		
		glClear(GL_COLOR_BUFFER_BIT);
		glLoadIdentity();

		drawLineMesh(&l, m);
		
		SDL_GL_SwapBuffers();
	}

	return EXIT_SUCCESS;
}