add blank material files

valve/pbr/halflife.wad/+BUTTON3/+BUTTON3.mat

@@ -0,0 +1,16 @@
+
+{
+"for" "+0BUTTON3"
+//"basecolor_map" "+0BUTTON3.png"
+//"normal_map" "+0BUTTON3_normal.png"
+//"metal_map" "+0BUTTON3_metal.png"
+//"roughness_map" "+0BUTTON3_roughness.png"
+}
+
+{
+"for" "+ABUTTON3"
+//"basecolor_map" "+ABUTTON3.png"
+//"normal_map" "+ABUTTON3_normal.png"
+//"metal_map" "+ABUTTON3_metal.png"
+//"roughness_map" "+ABUTTON3_roughness.png"
+}