#include <assert.h>
#include <gtk/gtk.h>

#include "render.h"
#include "image.h"

/* LBX images can have up to three palettes, with each superseding the last. */
struct lbx_colour palette_external[256];
struct lbx_colour palette_internal[256];
struct lbx_colour palette_override[256];

static void get_colour(unsigned char index, unsigned char out[static 4])
{
	struct lbx_colour *colour;

	if (palette_override[index].active)
		colour = palette_override + index;
	else if (palette_internal[index].active)
		colour = palette_internal + index;
	else if (palette_external[index].active)
		colour = palette_external + index;
	else
		colour = &(struct lbx_colour) { .red = 0xff, .blue = 0xff };

	out[0] = colour->red;
	out[1] = colour->green;
	out[2] = colour->blue;
	out[3] = -1; /* opaque */
}

int render_to_pixbuf(LBX_IMG *image, GdkPixbuf *pixbuf, unsigned frame)
{
	unsigned char **framedata, **framemask, *outbuf;
	struct lbx_imginfo info;
	unsigned stride;

	lbximg_getinfo(image, &info);
	assert(info.width  == gdk_pixbuf_get_width(pixbuf));
	assert(info.height == gdk_pixbuf_get_height(pixbuf));

	framedata = lbximg_getframe(image, frame);
	g_return_val_if_fail(framedata, -1);
	framemask = lbximg_getmask(image);

	outbuf = gdk_pixbuf_get_pixels(pixbuf);
	stride = gdk_pixbuf_get_rowstride(pixbuf);

	for (unsigned i = 0; i < info.height; i++) {
		unsigned char (*px)[4] = (void *)(outbuf + i*stride);

		for (unsigned j = 0; j < info.width; j++) {
			if (framemask[i][j])
				get_colour(framedata[i][j], px[j]);
			else
				px[j][3] = 0; /* transparent */
		}
	}

	return 0;
}