fix broken shader

git-svn-id: https://dng.biozentrum.unibas.ch/svn/openstructure/trunk@2720 5a81b35b-ba03-0410-adc8-b2c5c5119f08

modules/gfx/src/shader/fraglight_lf_vs.glsl

@@ -18,7 +18,7 @@ void main()
     // ambient occlusion and color terms
     ambient_color = gl_MultiTexCoord0;
   } else {
-    ambient_color.rgb = gl_Color;
+    ambient_color = gl_Color;
     ambient_color.a = 1.0;
   }
   gl_FrontColor=gl_Color;