diff --git a/canvas/texture.go b/canvas/texture.go
index d529379..da1b900 100644
--- a/canvas/texture.go
+++ b/canvas/texture.go
@@ -95,6 +95,9 @@ func (this *Texture) Clip (bounds image.Rectangle) canvas.Texture {
 
 // AssertTexture checks if a given canvas.Texture is a texture from this package.
 func AssertTexture (unknown canvas.Texture) *Texture {
+	if unknown == nil {
+		return nil
+	}
 	if tx, ok := unknown.(*Texture); ok {
 		return tx
 	} else {