#include <u.h>#include <libc.h>#include <libg.h>#include <layer.h> voidtexture(Bitmap *db, Rectangle r, Bitmap *t, Fcode c){	Layer *dl, *cover; 	dl = (Layer*)db;	if(dl->cache==0){    Easy:		_texture(db, r, t, c);		return;	}	if(rectclip(&r, dl->clipr) == 0)		return;	if(dl->vis==Visible)		/*		 * Look for a Bitmap we can write on instead of a Layer.		 * r is known to fit within dl->clipr.  As long as we have		 * only Visible covering layers, we know that r will		 * therefore fit within their cliprs and no more clipping		 * is required.		 */		for(cover=dl->cover->layer; ; cover=cover->cover->layer){			if(cover->cache == 0){				db = cover;				goto Easy;			}			if(cover->vis != Visible)				break;		}	/*	 * Either dl or one of the covering layers is not Visible.	 * Do the operation in the cache and restore as necessary.	 * If dl is Visible, r is contained within cover->clipr and	 * the cache must be restored from the cover; otherwise the	 * cache is up to date but the restoration of the screen may	 * require clipping.	 */	cover = dl->cover->layer;	if(dl->vis == Visible)		bitblt(dl->cache, r.min, cover, r, S);	_texture(dl->cache, r, t, c);	if(dl->vis == Visible)		bitblt(cover, r.min, dl->cache, r, S);	else if(dl->vis==Obscured){		if(rectclip(&r, cover->clipr))			layerop(lupdate, r, dl, (void *)0);	}} void_texture(Bitmap *d, Rectangle r, Bitmap *s, Fcode f){	uchar *buf; 	buf = bneed(23);	buf[0] = 't';	BPSHORT(buf+1, d->id);	BPLONG(buf+3, r.min.x);	BPLONG(buf+7, r.min.y);	BPLONG(buf+11, r.max.x);	BPLONG(buf+15, r.max.y);	BPSHORT(buf+19, s->id);	BPSHORT(buf+21, f);}