Fix #35306: cycles normal mapping not working with flat shading.

1 files changed, 11 insertions, 6 deletions

diff --git a/intern/cycles/kernel/shaders/node_normal_map.osl b/intern/cycles/kernel/shaders/node_normal_map.osl
index 4428a12ac41..c3d6e7bd391 100644
--- a/intern/cycles/kernel/shaders/node_normal_map.osl
+++ b/intern/cycles/kernel/shaders/node_normal_map.osl
@@ -33,15 +33,17 @@ shader node_normal_map(
 		vector tangent;
 		vector ninterp;
 		float tangent_sign;
+		float is_smooth;
+
+		getattribute("geom:is_smooth", is_smooth);
+		if (!is_smooth)
+			ninterp = Ng;
 
 		// get _unnormalized_ interpolated normal and tangent
-		if (!getattribute(attr_name, tangent) ||
-		   !getattribute(attr_sign_name, tangent_sign) ||
-		   !getattribute("geom:N", ninterp))
+		if (getattribute(attr_name, tangent) &&
+		    getattribute(attr_sign_name, tangent_sign) &&
+		    (!is_smooth || getattribute("geom:N", ninterp)))
 		{
-			Normal = normal(0, 0, 0);
-		}
-		else {
 			// apply normal map
 			vector B = tangent_sign * cross(ninterp, tangent);
 			Normal = normalize(mcolor[0] * tangent + mcolor[1] * B + mcolor[2] * ninterp);
@@ -49,6 +51,9 @@ shader node_normal_map(
 			// transform to world space
 			Normal = normalize(transform("object", "world", Normal));
 		}
+		else {
+			Normal = normal(0, 0, 0);
+		}
 	}
 	else if (space == "Object")
 		Normal = normalize(transform("object", "world", vector(mcolor)));