diff --git a/platform/base_glsl.pk3dir/glsl/vertexlit_specular.glsl b/platform/base_glsl.pk3dir/glsl/vertexlit_specular.glsl
index c3d6da68..5fcbdaa2 100644
--- a/platform/base_glsl.pk3dir/glsl/vertexlit_specular.glsl
+++ b/platform/base_glsl.pk3dir/glsl/vertexlit_specular.glsl
@@ -124,7 +124,7 @@ varying mat3 invsurface;
 			discard;
 		}
 
-		light += (e_light_mul * lambert(norm, e_light_dir)) * 2.0f; /* directional light */
+		light = (e_light_mul * lambert(norm, e_light_dir)) * 2.0f; /* directional light */
 		light += (e_light_ambient * lambert(norm, reflect(norm, e_light_dir))) * 0.5f; /* reverse ambient */
 		light *= 2.0f;