#include <allegro.h>

#include "lighting.h"

/* Apply lighting and visibility effects to img, outputting to buf */
void combine_maps(BITMAP* light, BITMAP* vis, BITMAP* img, BITMAP* buf)
{
	unsigned char* bp;
	unsigned char* bp_end;
	unsigned char* lp;
	unsigned char* vp;
	unsigned char* ip;
	int y;
	
	for (y = 0; y < SCREEN_H; y++) {
		bp = buf->line[y];
		lp = light->line[y];
		vp = vis->line[y];
		ip = img->line[y];
		bp_end = bp + SCREEN_W * 4;
		while (bp < bp_end) {
			switch (*vp) {
			case 0: /* Blind */
				*(unsigned long*)bp = 0;	/* Black */
				break;
			case 1: /* Remembered */
				bp[0] = bp[1] = bp[2] = /* Desaturate & dim */
						(ip[0] + ip[1] + ip[2]) / 4;
				break;
			case 2: /* Visible */
#if 1
#define apply(i) (bp[i] = lp[i] < 192 ?				/* Test */ \
(ip[i] * lp[i]) / 192 :						/* Burn */ \
(ip[i] * (64 - (lp[i] - 192)) + 255 * (lp[i] - 192)) / 64)	/* Overbright */
				apply(0);
				apply(1);
				apply(2);
#undef apply
#else
				*(unsigned long*)bp = *(unsigned long*)ip;
#endif
			}
			bp += 4;/* 32bpp */
			lp += 4;/* 32bpp */
			vp += 1;/*  8bpp */
			ip += 4;/* 32bpp */
		}
	}
}