Fix pivot and animation in building LWS node graph.

When building the graph for an object, we always have:
ParentAttachNode -> PivotNode -> AttachNode -> MeshNode -> Meshes
PivotNode receives animations if any.
AttachNode receives the -pivotPos transform, as well as the child nodes,
MeshNode has no transformation and contains the meshes.
MeshNode and Meshes are already converted to RH by LWOLoader.
PivotNode and AttachNode are LH until they get converted to RH later and separately.
The pivot position, when not available in the LWS file is obtained from the LWO object, converted back from RH to LH.

code/LWSLoader.cpp

@@ -314,18 +314,62 @@ void LWSImporter::BuildGraph(aiNode* nd, LWS::NodeDesc& src, std::vector<Attachm
 {
 	// Setup a very cryptic name for the node, we want the user to be happy
 	SetupNodeName(nd,src);
+    aiNode* ndAnim = nd;
 
-	// If this is an object from an external file - get the scene and setup proper attachment tags
+	// If the node is an object
-	aiScene* obj = NULL;
+	if (src.type == LWS::NodeDesc::OBJECT) {
-	if (src.type == LWS::NodeDesc::OBJECT && src.path.length() ) {
+
-		obj = batch.GetImport(src.id);
+		// If the object is from an external file, get it
-		if (!obj) {
+		aiScene* obj = NULL;
-			DefaultLogger::get()->error("LWS: Failed to read external file " + src.path);
+        if (src.path.length() ) {
-		}
+            obj = batch.GetImport(src.id);
-		else {
+            if (!obj) {
-			attach.push_back(AttachmentInfo(obj,nd));
+                DefaultLogger::get()->error("LWS: Failed to read external file " + src.path);
-		}
+            }
-	}
+            else {
+                if (obj->mRootNode->mNumChildren == 1) {
+					
+                    //If the pivot is not set for this layer, get it from the external object
+                    if (!src.isPivotSet) {
+                        src.pivotPos.x = +obj->mRootNode->mTransformation.a4;
+                        src.pivotPos.y = +obj->mRootNode->mTransformation.b4;
+                        src.pivotPos.z = -obj->mRootNode->mTransformation.c4; //The sign is the RH to LH back conversion
+                    }
+					
+                    //Remove first node from obj (the old pivot), reset transform of second node (the mesh node)
+                    aiNode* newRootNode = obj->mRootNode->mChildren[0];
+                    free(obj->mRootNode->mChildren);
+                    free(obj->mRootNode);
+                    obj->mRootNode = newRootNode;
+                    obj->mRootNode->mTransformation.a4 = 0.0;
+                    obj->mRootNode->mTransformation.b4 = 0.0;
+                    obj->mRootNode->mTransformation.c4 = 0.0;
+                }
+            }
+        }
+		
+		//Setup the pivot node (also the animation node), the one we received
+        nd->mName = std::string("Pivot:") + nd->mName.data;
+		ndAnim = nd;
+		
+        //Add the attachment node to it
+        nd->mNumChildren = 1;
+        nd->mChildren = new aiNode*[1];
+        nd->mChildren[0] = new aiNode();
+        nd->mChildren[0]->mParent = nd;
+        nd->mChildren[0]->mTransformation.a4 = -src.pivotPos.x;
+        nd->mChildren[0]->mTransformation.b4 = -src.pivotPos.y;
+        nd->mChildren[0]->mTransformation.c4 = -src.pivotPos.z;
+		SetupNodeName(nd->mChildren[0], src);
+		
+		//Update the attachment node
+		nd = nd->mChildren[0];
+		
+        //Push attachment, if the object came from an external file
+        if (obj) {
+            attach.push_back(AttachmentInfo(obj,nd));
+        }
+    }
 
 	// If object is a light source - setup a corresponding ai structure
 	else if (src.type == LWS::NodeDesc::LIGHT) {
@@ -369,7 +413,7 @@ void LWSImporter::BuildGraph(aiNode* nd, LWS::NodeDesc& src, std::vector<Attachm
 
 	// Get the node transformation from the LWO key
 	LWO::AnimResolver resolver(src.channels,fps);
-	resolver.ExtractBindPose(nd->mTransformation);
+	resolver.ExtractBindPose(ndAnim->mTransformation);
 
 	// .. and construct animation channels
 	aiNodeAnim* anim = NULL;
@@ -378,44 +422,11 @@ void LWSImporter::BuildGraph(aiNode* nd, LWS::NodeDesc& src, std::vector<Attachm
 		resolver.SetAnimationRange(first,last);
 		resolver.ExtractAnimChannel(&anim,AI_LWO_ANIM_FLAG_SAMPLE_ANIMS|AI_LWO_ANIM_FLAG_START_AT_ZERO);
 		if (anim) {
-			anim->mNodeName = nd->mName;
+			anim->mNodeName = ndAnim->mName;
 			animOut.push_back(anim);
 		}
 	}
 
-	// process pivot point, if any
-	if (src.pivotPos != aiVector3D()) {
-		aiMatrix4x4 tmp;
-		aiMatrix4x4::Translation(-src.pivotPos,tmp);
-
-		if (anim) {
-		
-			// We have an animation channel for this node. Problem: to combine the pivot
-			// point with the node anims, we'd need to interpolate *all* keys, get 
-			// transformation matrices from them, apply the translation and decompose
-			// the resulting matrices again in order to reconstruct the keys. This 
-			// solution here is *much* easier ... we're just inserting an extra node
-			// in the hierarchy.
-			// Maybe the final optimization here will be done during postprocessing.
-
-			aiNode* pivot = new aiNode();
-			pivot->mName.length = sprintf( pivot->mName.data, "$Pivot_%s",nd->mName.data);
-			pivot->mTransformation = tmp;
-
-			pivot->mChildren = new aiNode*[pivot->mNumChildren = 1];
-			pivot->mChildren[0] = nd;
-
-			pivot->mParent = nd->mParent;
-			nd->mParent    = pivot;
-			
-			// swap children and hope the parents wont see a huge difference
-			pivot->mParent->mChildren[pivot->mParent->mNumChildren-1] = pivot;
-		}
-		else {
-			nd->mTransformation = tmp*nd->mTransformation;
-		}
-	}
-
 	// Add children
 	if (src.children.size()) {
 		nd->mChildren = new aiNode*[src.children.size()];
@@ -870,7 +881,7 @@ void LWSImporter::InternReadFile( const std::string& pFile, aiScene* pScene,
 
 	// .. ccw
 	FlipWindingOrderProcess flipper;
-	flipper.Execute(pScene);
+	flipper.Execute(master);
 
 	// OK ... finally build the output graph
 	SceneCombiner::MergeScenes(&pScene,master,attach,