/*	$Id: chaleurgraphe.c,v 1.1 2008/03/20 12:30:23 minh Exp $	*/

/*-
 * Copyright (c) 2008 Nhat Minh Lê
 *
 * Permission is hereby granted, free of charge, to any person
 * obtaining a copy of this software and associated documentation
 * files (the "Software"), to deal in the Software without
 * restriction, including without limitation the rights to use, copy,
 * modify, merge, publish, distribute, sublicense, and/or sell copies
 * of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */


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

#include <SDL/SDL.h>


struct color {
	unsigned red: 8;
	unsigned green: 8;
	unsigned blue: 8;
};

static SDL_Surface *screen, *canvas;
static unsigned int width, height;
static double maxval;
static struct color basecolor = { 255, 0, 0 };



/* Utilities */

static void
error(const char *fmt, ...)
{
	va_list ap;

	fprintf(stderr, "error: ");

	va_start(ap, fmt);
	vfprintf(stderr, fmt, ap);
	va_end(ap);

	fprintf(stderr, "\n");

	exit(EXIT_FAILURE);
}

static void *
xmalloc(size_t n)
{
	void *p;
	if ((p = malloc(n)) == NULL)
		error(0, "out of memory");
	return p;
}



/* Rendering */

static Uint32
gradtosdlpix(SDL_Surface *s, struct color *c, double val)
{
	val /= maxval;
	return SDL_MapRGB(s->format,
			  c->red * val, c->green * val, c->blue * val);
}

static void
update(void)
{
	if (SDL_BlitSurface(canvas, NULL, screen, NULL) != 0)
		error("unable to blit canvas to screen");
	SDL_UpdateRect(screen, 0, 0, 0, 0);
}

static void
initrend(void)
{
	SDL_Init(SDL_INIT_VIDEO | SDL_INIT_TIMER);

	if ((screen = SDL_SetVideoMode(width, height,
				       24, SDL_SWSURFACE)) == NULL)
		error("unable to create SDL screen surface");
	if ((canvas = SDL_CreateRGBSurface(SDL_SWSURFACE, width, height,
					   32, 0, 0, 0, 0)) == NULL)
		error("unable to create SDL canvas surface");
}

static void
finirend(void)
{
	SDL_FreeSurface(canvas);
	SDL_Quit();
}



/* Loader */

static int
readdata(FILE *fp)
{
	Uint32 *pixs;
	double v;
	unsigned int i, msize;
	int r;

	r = 0;
	if (SDL_LockSurface(canvas) != 0)
		error("unable to lock canvas");

	fscanf(fp, " #%*[^\n]");

	pixs = canvas->pixels;
	for (i = 0, msize = width*height; i < msize; ++i) {
		if (fscanf(fp, "%lf", &v) < 1) {
			r = 1;
			break;
		}
		pixs[i] = gradtosdlpix(canvas, &basecolor, v);
	}

	SDL_UnlockSurface(canvas);
	return r;
}



/* Main program */

int
main(int argc, char *argv[])
{
	if (fscanf(stdin, "%u %u %lf", &width, &height, &maxval) < 2)
		error("syntax error in matrix declaration");

	initrend();
	atexit(finirend);

	while (readdata(stdin) == 0) {
		update();
		SDL_Delay(100);
	}

	return 0;
}