print instead of panic

src/graphics.rs

@@ -162,7 +162,10 @@ impl GraphicsState{
 					height=height/4*4;
 					wgpu::TextureFormat::Bc7RgbaUnormSrgb
 				},
-				other=>panic!("unsupported format{:?}",other),
+				other=>{
+					println!("unsupported texture format{:?}",other);
+					return None;
+				},
 			};
 
 			let size=wgpu::Extent3d{