#include <math.h>
#include "typedefs.h"
#include "funcdefs.h"
#include "globalvar.h"

int shade(t_3d *pos, t_3d *ray, t_3d *nrm, t_object *obj, t_color *color)
{
	int lnum;
	double k, bright, spec, diffuse;
	t_surface *surf;
	t_3d refl, ltray;

	/* Compute ambient light */
	surf = &surface[obj->surfnum];
	color->r += surf->ar;
	color->g += surf->ag;
	color->b += surf->ab;

	/* Calculate reflected ray */
	k = -2.0 * dotp(ray, nrm);
	refl.x = k * nrm->x + ray->x;
	refl.y = k * nrm->y + ray->y;
	refl.z = k * nrm->z + ray->z;

	for (lnum = 0; lnum < nlight; lnum++) {
		lightray(lnum, pos, &ltray); /* Get ray to light */

		/* Compute diffuse light */
		diffuse = dotp(nrm, &ltray);
		if (diffuse > 0) { /* point of intersection faces light */
			bright = brightness(obj->id, lnum, pos, &ltray);
			diffuse *= bright;
			color->r += surf->dr * diffuse;
			color->g += surf->dg * diffuse;
			color->b += surf->db * diffuse;

			/* Compute specular component */
			spec = dotp(&refl, &ltray);
			if (spec > 0) {
				spec = bright * pow(spec, surf->coef);
				color->r += surf->sr * spec;
				color->g += surf->sg * spec;
				color->b += surf->sb * spec;
			}
		}
	}

	return 0;
}