(svn r20661) -Codechange: implement the "decide colour" callback for objects

src/newgrf_callbacks.h

@@ -265,7 +265,7 @@ enum CallbackID {
 	CBID_OBJECT_ANIMATION_SPEED          = 0x15A, // 8 bit callback, not implemented
 
 	/** Called to determine the colour of a town building. */
-	CBID_OBJECT_COLOUR                   = 0x15B, // 15 bit callback, not implemented
+	CBID_OBJECT_COLOUR                   = 0x15B, // 15 bit callback
 
 	/** Called to determine more text in the fund object window */
 	CBID_OBJECT_FUND_MORE_TEXT           = 0x15C, // 15 bit callback, not implemented

src/object_cmd.cpp

@@ -75,6 +75,11 @@ void BuildObject(ObjectType type, TileIndex tile, CompanyID owner, Town *town)
 	/* If the object wants only one colour, then give it that colour. */
 	if ((spec->flags & OBJECT_FLAG_2CC_COLOUR) == 0) o->colour &= 0xF;
 
+	if (HasBit(spec->callback_mask, CBM_OBJ_COLOUR)) {
+		uint16 res = GetObjectCallback(CBID_OBJECT_COLOUR, o->colour, 0, spec, o, tile);
+		if (res != CALLBACK_FAILED) o->colour = GB(res, 0, 8);
+	}
+
 	assert(o->town != NULL);
 
 	TILE_AREA_LOOP(t, ta) {