--- a/engine.c	Tue Oct 04 19:52:26 2005 +0000
+++ b/engine.c	Tue Oct 04 20:38:26 2005 +0000
@@ -580,7 +580,7 @@
 			spriteset--;
 	}
 
-	r = (in_motion ? rsg->loaded[spriteset] : rsg->loading[spriteset]) + direction;
+	r = (in_motion ? rsg->loaded[spriteset]->g.result.result : rsg->loading[spriteset]->g.result.result) + direction;
 	return r;
 }
 

--- a/newgrf.c	Tue Oct 04 19:52:26 2005 +0000
+++ b/newgrf.c	Tue Oct 04 20:38:26 2005 +0000
@@ -1228,6 +1228,21 @@
 	return group;
 }
 
+/**
+ * Creates a spritegroup representing a sprite number result.
+ * @param value The sprite number.
+ * @param sprites The number of sprites per set.
+ * @return A spritegroup representing the sprite number result.
+ */
+SpriteGroup *NewResultSpriteGroup(uint16 value, byte sprites)
+{
+	SpriteGroup *group = calloc(1, sizeof(*group));
+	group->type = SGT_RESULT;
+	group->g.result.result = value;
+	group->g.result.sprites = sprites;
+	return group;
+}
+
 /* Action 0x01 */
 static void NewSpriteSet(byte *buf, int len)
 {
@@ -1421,15 +1436,18 @@
 		for (i = 0; i < rg->num_groups; i++) {
 			uint16 groupid = grf_load_word(&buf);
 
-			if (groupid & 0x8000 || groupid >= _cur_grffile->spritegroups_count) {
+			if (HASBIT(groupid, 15)) {
+				rg->groups[i] = NewCallBackResultSpriteGroup(groupid);
+			} else if (groupid >= _cur_grffile->spritegroups_count) {
 				/* This doesn't exist for us. */
 				i--;
 				rg->num_groups--;
 				continue;
+			} else {
+				/* XXX: If multiple surreal sets attach a surreal
+				 * set this way, we are in trouble. */
+				rg->groups[i] = _cur_grffile->spritegroups[groupid];
 			}
-			/* XXX: If multiple surreal sets attach a surreal
-			 * set this way, we are in trouble. */
-			rg->groups[i] = _cur_grffile->spritegroups[groupid];
 		}
 
 		_cur_grffile->spritegroups[setid] = group;
@@ -1476,14 +1494,22 @@
 
 	for (i = 0; i < numloaded; i++) {
 		uint16 spriteset_id = grf_load_word(&loaded_ptr);
-		rg->loaded[i] = _cur_grffile->spriteset_start + spriteset_id * _cur_grffile->spriteset_numents;
-		DEBUG(grf, 8) ("NewSpriteGroup: + rg->loaded[%i]  = %u (subset %u)", i, rg->loaded[i], spriteset_id);
+		if (HASBIT(spriteset_id, 15)) {
+			rg->loaded[i] = NewCallBackResultSpriteGroup(spriteset_id);
+		} else {
+			rg->loaded[i] = NewResultSpriteGroup(_cur_grffile->spriteset_start + spriteset_id * _cur_grffile->spriteset_numents, rg->sprites_per_set);
+		}
+		DEBUG(grf, 8) ("NewSpriteGroup: + rg->loaded[%i]  = %u (subset %u)", i, rg->loaded[i]->g.result.result, spriteset_id);
 	}
 
 	for (i = 0; i < numloading; i++) {
 		uint16 spriteset_id = grf_load_word(&loading_ptr);
-		rg->loading[i] = _cur_grffile->spriteset_start + spriteset_id * _cur_grffile->spriteset_numents;
-		DEBUG(grf, 8) ("NewSpriteGroup: + rg->loading[%i] = %u (subset %u)", i, rg->loading[i], spriteset_id);
+		if (HASBIT(spriteset_id, 15)) {
+			rg->loading[i] = NewCallBackResultSpriteGroup(spriteset_id);
+		} else {
+			rg->loading[i] = NewResultSpriteGroup(_cur_grffile->spriteset_start + spriteset_id * _cur_grffile->spriteset_numents, rg->sprites_per_set);
+		}
+		DEBUG(grf, 8) ("NewSpriteGroup: + rg->loading[%i] = %u (subset %u)", i, rg->loading[i]->g.result.result, spriteset_id);
 	}
 
 	_cur_grffile->spritegroups[setid] = group;

--- a/sprite.h	Tue Oct 04 19:52:26 2005 +0000
+++ b/sprite.h	Tue Oct 04 20:38:26 2005 +0000
@@ -44,9 +44,9 @@
 	// of da stuff.
 
 	byte loaded_count;
-	uint16 loaded[16]; // sprite ids
+	SpriteGroup *loaded[16]; // sprite ids
 	byte loading_count;
-	uint16 loading[16]; // sprite ids
+	SpriteGroup *loading[16]; // sprite ids
 } RealSpriteGroup;
 
 /* Shared by deterministic and random groups. */
@@ -114,11 +114,17 @@
 	uint16 result;
 } CallbackResultSpriteGroup;
 
+typedef struct ResultSpriteGroup {
+	uint16 result;
+	byte sprites;
+} ResultSpriteGroup;
+
 typedef enum SpriteGroupType {
 	SGT_REAL,
 	SGT_DETERMINISTIC,
 	SGT_RANDOMIZED,
 	SGT_CALLBACK,
+	SGT_RESULT,
 } SpriteGroupType;
 
 struct SpriteGroup {
@@ -129,6 +135,7 @@
 		DeterministicSpriteGroup determ;
 		RandomizedSpriteGroup random;
 		CallbackResultSpriteGroup callback;
+		ResultSpriteGroup result;
 	} g;
 };
 

--- a/station_cmd.c	Tue Oct 04 19:52:26 2005 +0000
+++ b/station_cmd.c	Tue Oct 04 20:38:26 2005 +0000
@@ -1349,9 +1349,9 @@
 	const RealSpriteGroup *rsg = ResolveStationSpriteGroup(spec->spritegroup[ctype], st);
 
 	if (rsg->sprites_per_set != 0) {
-		if (rsg->loading_count != 0) return rsg->loading[0];
-
-		if (rsg->loaded_count != 0) return rsg->loaded[0];
+		if (rsg->loading_count != 0) return rsg->loading[0]->g.result.result;
+
+		if (rsg->loaded_count != 0) return rsg->loaded[0]->g.result.result;
 	}
 
 	error("Custom station 0x%08x::0x%02x has no sprites associated.",