/*
 *	Modeles Numeriques de Terrain
 *
 */

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

#include   "../floatimg.h"

int		verbosity;

/* ------------------------------------------------------------------- */
/*
 *		First try
 */
int brotche_mnt_style(FloatImg *src, FloatImg *dst)
{
int		x, y;
int		offset;
float		z1, z2, z3, z4;
float		a, b, c;
float		pente;

fprintf(stderr, ">>> %s ( %p %p )\n", __func__, src, dst);

#define W    (src->width)
#define DX   1.0
#define DY   1.0

for (y=0; y<(src->height-1); y++) {
	for (x=0; x<(src->width-1); x++) {
		offset = (y * src->width) + x;
		z1 = src->R[offset];
		z2 = src->R[offset+1];
		z3 = src->R[offset+W];
		z4 = src->R[offset+W+1];

		a = ( z1 + z2 + z3 + z4) / 4.0;
		b = (-z1 + z2 - z3 + z4) / 2.0 / DX;
		c = (-z1 - z2 + z3 + z4) / 2.0 / DY;

		pente = atanf(sqrt(b*b + c*c));

		dst->R[offset] = 0;
		if (pente < 0.0) dst->G[offset] = pente;
		else		 dst->B[offset] = pente;


		}
	}

return 0;
}
/* ------------------------------------------------------------------- */
int main(int argc, char *argv[])
{
FloatImg	src, dst;
char		*infile, *outfile;
int		foo;

if (3 != argc) {
	fprintf(stderr, "%s need 2 args : infile & outfile\n", argv[0]);
	fimg_print_version(0);
	exit(1);
	}

infile = argv[1];	outfile = argv[2];

fprintf(stderr,"--- working on %s\n", infile);

foo = fimg_create_from_dump(infile, &src);
if (foo) {
	fprintf(stderr, "err %d loading image '%s'\n", foo, infile);
	exit(1);
	}

foo = fimg_clone(&src, &dst, 0);
if (foo) {
	fprintf(stderr, "err %d cloning image\n", foo);
	exit(1);
	}

foo = brotche_mnt_style(&src, &dst);
if (foo) {
	fprintf(stderr, "something weird happen %d\n", foo);
	exit(1);
	}

foo = fimg_export_picture(&dst, outfile, 0);
if (foo) {
	fprintf(stderr, "err %d exporting to %s\n", foo, outfile);
	exit(1);
	}

return 0;
}
/* ------------------------------------------------------------------- */