BTILE_DIRS=wall floor tunnel underground
BTILE_SRC=$(shell find $(patsubst %, $(VPATH)/bitmap/%, $(BTILE_DIRS)) -name "*.png")
BTILE_DIRS=wall floor tunnel underground
BTILE_SRC=$(shell find $(patsubst %, $(VPATH)/bitmap/%, $(BTILE_DIRS)) -name "*.png")