-SIMPLE_DIRS=roach_management
-SIMPLE_SVGS=$(shell find $(patsubst %, $(VPATH)/%, $(SIMPLE_DIRS)) -name "*.svg")
-SIMPLE_PNGS=$(patsubst $(VPATH)/%.svg, %.png, $(SIMPLE_SVGS))
+TILE_DIRS=roach serum vehicle_tiles
+TILE_SVGS=$(shell find $(patsubst %, $(VPATH)/vector/%, $(TILE_DIRS)) -name "*.svg")
+TILE_PNGS=$(patsubst $(VPATH)/vector/%.svg, %.png, $(TILE_SVGS))
+
+# Bitmap tiles
+
+BTILE_DIRS=wall floor tunnel underground
+BTILE_SRC=$(shell find $(patsubst %, $(VPATH)/bitmap/%, $(BTILE_DIRS)) -name "*.png")
+BTILE_PNGS=$(patsubst $(VPATH)/bitmap/%, bunker/%, $(BTILE_SRC))
+
+# Vector images to rasterize without resizing
+
+SIMPLE_DIRS=roach_management vehicles
+SIMPLE_SVGS=$(shell find $(patsubst %, $(VPATH)/vector/%, $(SIMPLE_DIRS)) -name "*.svg")
+SIMPLE_PNGS=$(patsubst $(VPATH)/vector/%.svg, %.png, $(SIMPLE_SVGS))
+
+# Aggregate cockroach sprites