(svn r12844) -Fix: the industry tick trigger should only be triggered once every 256 ticks, not every tick... Also bail out of the triggers a little earlier if you know they are not going to happen anyway.

src/newgrf_industrytiles.cpp

@@ -417,6 +417,8 @@ static void DoTriggerIndustryTile(TileIndex tile, IndustryTileTrigger trigger, I
 	IndustryGfx gfx = GetIndustryGfx(tile);
 	const IndustryTileSpec *itspec = GetIndustryTileSpec(gfx);
 
+	if (itspec->grf_prop.spritegroup == NULL) return;
+
 	NewIndustryTileResolver(&object, gfx, tile, ind);
 
 	object.callback = CBID_RANDOM_TRIGGER;