add blank material files

valve/pbr/halflife.wad/+BUTTON1/+BUTTON1.mat

@@ -0,0 +1,16 @@
+
+{
+"for" "+0BUTTON1"
+//"basecolor_map" "+0BUTTON1.png"
+//"normal_map" "+0BUTTON1_normal.png"
+//"metal_map" "+0BUTTON1_metal.png"
+//"roughness_map" "+0BUTTON1_roughness.png"
+}
+
+{
+"for" "+ABUTTON1"
+//"basecolor_map" "+ABUTTON1.png"
+//"normal_map" "+ABUTTON1_normal.png"
+//"metal_map" "+ABUTTON1_metal.png"
+//"roughness_map" "+ABUTTON1_roughness.png"
+}