diff --git a/planet/Graphics.ocg/AmbientShader.glsl b/planet/Graphics.ocg/AmbientShader.glsl
index d50456ada..3fe12fc1b 100644
--- a/planet/Graphics.ocg/AmbientShader.glsl
+++ b/planet/Graphics.ocg/AmbientShader.glsl
@@ -7,6 +7,8 @@ uniform sampler2D ambientTex;
 uniform mat3x2 ambientTransform;
 uniform float ambientBrightness;
 #endif
+//uniform float cullMode; // 0 if backface culling is enabled, 1 if it is disabled
+// Already declared in LightShader.glsl
 
 slice(texture+6)
 {
@@ -33,6 +35,6 @@ slice(light+1)
 #else
 	// For objects, ambient brightness is coming from the front
 	vec3 ambientDir = vec3(0.0, 0.0, 1.0);
-	light = mix(light, max(dot(normal, ambientDir), 0.0), ambient);
+	light = mix(light, max(max(dot(normal, ambientDir), 0.0), cullMode * max(dot(-normal, ambientDir), 0.0)), ambient);
 #endif
 }
diff --git a/planet/Graphics.ocg/LightShader.glsl b/planet/Graphics.ocg/LightShader.glsl
index 8d0305fec..b783fa521 100644
--- a/planet/Graphics.ocg/LightShader.glsl
+++ b/planet/Graphics.ocg/LightShader.glsl
@@ -56,9 +56,9 @@ slice(texture+5)
 
 slice(light)
 {
-	float light = 2.0 * lightBright * max(max(dot(normal, lightDir), 0.0), cullMode * max(dot(vec3(-normal.xy, normal.z), lightDir), 0.0));
+	float light = 2.0 * lightBright * max(max(dot(normal, lightDir), 0.0), cullMode * max(dot(-normal, lightDir), 0.0));
 #ifdef HAVE_2PX
-	float light2 = 2.0 * lightBright * max(max(dot(normal2, lightDir), 0.0), cullMode * max(dot(vec3(-normal2.xy, normal2.z), lightDir), 0.0));
+	float light2 = 2.0 * lightBright * max(max(dot(normal2, lightDir), 0.0), cullMode * max(dot(-normal2, lightDir), 0.0));
 #endif
 }