Index: src/viewport.cpp
===================================================================
--- src/viewport.cpp	(revision 10160)
+++ src/viewport.cpp	(working copy)
@@ -89,6 +89,9 @@
 	int32 ymin;
 	int32 xmax;
 	int32 ymax;
+
+	int32 prec;	/* index while sorting */
+
 	ChildScreenSpriteToDraw *child;
 	byte unk16;
 	byte zmin;
@@ -1104,61 +1107,42 @@
 
 static void ViewportSortParentSprites(ParentSpriteToDraw *psd[])
 {
-	while (*psd != NULL) {
-		ParentSpriteToDraw* ps = *psd;
+//printf("sort\n");
+	for (int i=0;psd[i]!=NULL;i++) {
+//		printf("%d %d %d %d %d %d %d %d\n",i++,ps->xmin,ps->xmax,ps->ymin,ps->ymax,ps->zmin,ps->zmax,ps->zmin+ps->zmax);
+		psd[i]->prec =(psd[i]->xmin+psd[i]->xmax)+(psd[i]->ymin+psd[i]->ymax)+(psd[i]->zmin+psd[i]->zmax);
+	}
 
-		if (!(ps->unk16 & 1)) {
-			ParentSpriteToDraw** psd2 = psd;
-
-			ps->unk16 |= 1;
-
-			while (*++psd2 != NULL) {
-				ParentSpriteToDraw* ps2 = *psd2;
-				ParentSpriteToDraw** psd3;
-
-				if (ps2->unk16 & 1) continue;
-
-				/* Decide which comparator to use, based on whether the bounding
-				 * boxes overlap
-				 */
-				if (ps->xmax > ps2->xmin && ps->xmin < ps2->xmax && // overlap in X?
-						ps->ymax > ps2->ymin && ps->ymin < ps2->ymax && // overlap in Y?
-						ps->zmax > ps2->zmin && ps->zmin < ps2->zmax) { // overlap in Z?
-					/* Use X+Y+Z as the sorting order, so sprites closer to the bottom of
-					 * the screen and with higher Z elevation, are drawn in front.
-					 * Here X,Y,Z are the coordinates of the "center of mass" of the sprite,
-					 * i.e. X=(left+right)/2, etc.
-					 * However, since we only care about order, don't actually divide / 2
-					 */
-					if (ps->xmin + ps->xmax + ps->ymin + ps->ymax + ps->zmin + ps->zmax <=
-							ps2->xmin + ps2->xmax + ps2->ymin + ps2->ymax + ps2->zmin + ps2->zmax) {
-						continue;
-					}
-				} else {
-					if (ps->xmax < ps2->xmin ||
-							ps->ymax < ps2->ymin ||
-							ps->zmax < ps2->zmin || (
-								ps->xmin < ps2->xmax &&
-								ps->ymin < ps2->ymax &&
-								ps->zmin < ps2->zmax
-							)) {
-						continue;
-					}
-				}
-
-				/* Swap the two sprites ps and ps2 using bubble-sort algorithm. */
-				psd3 = psd;
-				do {
-					ParentSpriteToDraw* temp = *psd3;
-					*psd3 = ps2;
-					ps2 = temp;
-
-					psd3++;
-				} while (psd3 <= psd2);
+	for ( int i = 0 ; psd[i] != NULL ; i++ ) {
+		int pmin;
+		int jmin;
+		for ( int j = i ; psd[j] != NULL ; j++ ) {
+			ParentSpriteToDraw* ps = psd[j];
+			int prec=0;
+			for ( int k = j+1 ; psd[k] != NULL ; k++ ) {
+				ParentSpriteToDraw* ps2 = psd[k];
+				const Sprite* spr = GetSprite(ps->image & SPRITE_MASK);
+				const Sprite* spr2 = GetSprite(ps2->image & SPRITE_MASK);
+				if (
+					RemapCoords(ps->xmin,ps->ymin,ps->zmin).x+spr->x_offs <= RemapCoords(ps2->xmin,ps2->ymin,ps2->zmin).x+spr2->x_offs+spr2->width &&
+					RemapCoords(ps->xmin,ps->ymin,ps->zmin).x+spr->x_offs+spr->width >= RemapCoords(ps2->xmin,ps2->ymin,ps2->zmin).x+spr2->x_offs &&
+					RemapCoords(ps->xmin,ps->ymin,ps->zmin).y+spr->y_offs <= RemapCoords(ps2->xmin,ps2->ymin,ps2->zmin).y+spr2->y_offs+spr2->height &&
+					RemapCoords(ps->xmin,ps->ymin,ps->zmin).y+spr->y_offs+spr->height >= RemapCoords(ps2->xmin,ps2->ymin,ps2->zmin).y+spr2->y_offs
+				)
+				if (ps->zmin > ps2->zmax || ( ps->zmax >= ps2->zmin && ps->prec > ps2->prec ) ) prec++;
 			}
-		} else {
-			psd++;
+			if ( ( j == i ) || ( pmin > prec ) ) {
+				pmin = prec;
+				jmin = j;
+			}
 		}
+		if ( jmin != i ) {
+			ParentSpriteToDraw* swap = psd[i];
+			psd[i] = psd[jmin];
+			psd[jmin] = swap;
+		}
+//		printf("ss %d %d\n",pmin,jmin);
+//		printf("%d %d %d %d %d %d\n",psd[i]->xmin,psd[i]->xmax,psd[i]->ymin,psd[i]->ymax,psd[i]->zmin,psd[i]->zmax);
 	}
 }