MorphTarget: adjusting normals and tangents in visualizer

Author: gildor2

MeshInstance/SkelMeshInstance.cpp

@@ -1444,11 +1444,26 @@ bool CSkelMeshInstance::BuildMorphVerts()
 	// Copy unmodified vertices
 	memcpy(MorphedVerts, Lod.Verts, Lod.NumVerts * sizeof(CSkelMeshVertex));
 
-	// Apply delta
+	// Apply deltas
 	for (const CMorphVertex& Delta : Deltas)
 	{
 		CSkelMeshVertex& V = MorphedVerts[Delta.VertexIndex];
+		// Morph position
 		VectorAdd(V.Position, Delta.PositionDelta, V.Position);
+		// Morph normal
+		CVec3 Normal;
+		int8 W = V.Normal.GetW();
+		Unpack(Normal, V.Normal);
+		VectorAdd(Normal, Delta.NormalDelta, Normal);
+		Pack(V.Normal, Normal);
+		V.Normal.SetW(W);
+		// Adjust tangent vector to make basis orthonormal
+		CVec3 Tangent;
+		Unpack(Tangent, V.Tangent);
+		float shift = dot(Normal, Tangent); // it will be zero if vertices are perpendicular
+		VectorMA(Tangent, -shift, Normal);  // shift alongside the normal to make vertices perpendicular again
+		Tangent.NormalizeFast();            // ensure result is normalized
+		Pack(V.Tangent, Tangent);
 	}
 
 	return true;

readme.txt

@@ -98,7 +98,7 @@ keyboard shortcuts by pressing 'H' (Help) key. Here's the list of some shortcuts
   Shift+Up/Down    change scene FOV
   Ctrl+L           switch lighting modes
   Ctrl+Q           toggle visualization of debug information (text, 3D axis etc)
-  Ctrl+G           toggle OpenGL 2.0 / OpenGL 1.1 renderer
+  Ctrl+G           toggle between OpenGL 2.0 (using shaders) and OpenGL 1.1 (no shaders)
   Esc              exit from the umodel
 
 You may attach the AnimSet to the SkeletalMesh object using Ctrl+A key. Animation
@@ -212,6 +212,10 @@ detex
 
 Changes
 ~~~~~~~
+15.10.2019
+- loading and visualizing of UE3 and UE4 MorphTargets; switching between morphs is done with Ctrl+[ and Ctrl+]
+  keys
+
 13.10.2019
 - added full vertex color support (loading, viewing, exporting)