#include <allegro.h>
#include <stdlib.h>
#include "shadow.h"

/* Renders the whole scene to a bitmap */
/* TODO: consider internal and external color depths */
void render_lscene(BITMAP* b, lscene_t* s)
{
	/* Pixel rows */
	unsigned int** bpp;
	int y;
	/* Pixel columns */
	unsigned int* bp;
	int x;
	/* Layer stack */
	layer_t** l_begin = s->l;
	layer_t** k;
	layer_t** l;
	layer_t** l_end = l_begin + s->c;

#if INTERNAL_DEPTH == 32
#define GETPIXEL(l, x, y) _getpixel32((*(l))->img, (x), (y))
#define MASK_COLOR MASK_COLOR_32
#endif

	for (bpp = (unsigned int**)b->line, y = 0; y < SCREEN_HEIGHT; bpp++,
			y++) {
		for (bp = *bpp, x = 0; x < SCREEN_WIDTH; bp++, x++) {
			int c;
			/* Find which layer to draw */
			for (k = l_begin; k < l_end; k++) {
				c = GETPIXEL(k, x, y);
				if (c != MASK_COLOR) break;
			}
			/* Skip empty areas */
			if (k == l_end) {
				*bp = 0;
				continue;
			}
			/* Calculate shadows */
			for (l = l_begin; l < k; l++) {
#if 0
/* Uncomment for plain shadows */
				int o = ((*l)->z - (*k)->z) * 5;
				if (x < o || y < o) continue;
				if (GETPIXEL(l, x - o, y - o) !=
						MASK_COLOR) break;
#endif
#if 0
/* Uncomment for growing shadows */
				int o = ((*k)->z - (*l)->z);
				int xx = x + (x - 160) * (float)o / 20.0;
				int yy = y + (y - 100) * (float)o / 20.0;
				if (xx < 0 || xx > 319 || yy < 0 || yy > 199)
					continue;
				if (GETPIXEL(l, xx, yy) != MASK_COLOR) break;
#endif
#if 1
/* Uncomment for shrinking shadows */
				int o = ((*l)->z - (*k)->z);
				int xx = x + (x - 160) * (float)o / 20.0;
				int yy = y + (y - 100) * (float)o / 20.0;
				if (xx < 0 || xx > 319 || yy < 0 || yy > 199)
					continue;
				if (GETPIXEL(l, xx, yy) != MASK_COLOR) break;
#endif
			}
			if (l != k)+
				c = (((c >> 16) / 2) << 16) +
					((((c >> 8) & 0xff) / 2) << 8) +
					((c & 0xff) / 2);
			/* Plot! */
			*bp = c;
		}
	}
}