fix: setAdditionalTransform support reference

Author: ricardoquesada

cocos/2d/CCNode.cpp

@@ -1788,15 +1788,25 @@ void Node::setAdditionalTransform(Mat4* additionalTransform)
     if (additionalTransform == nullptr)
     {
         _useAdditionalTransform = false;
+        _additionalTransform = Mat4::IDENTITY;
     }
     else
     {
+        // FIXME: Why "set" multiplies with the previous one.
+        // "set" should just replace the old one.
+        // in any case, we should add a new method called "concatAdditionalTransform"
         _additionalTransform = *additionalTransform;
         _useAdditionalTransform = true;
     }
     _transformUpdated = _transformDirty = _inverseDirty = true;
 }
 
+void Node::setAdditionalTransform(const Mat4& additionalTransform)
+{
+    _useAdditionalTransform = true;
+    _additionalTransform = additionalTransform;
+    _transformUpdated = _transformDirty = _inverseDirty = true;
+}
 
 AffineTransform Node::getParentToNodeAffineTransform() const
 {

cocos/2d/CCNode.h

@@ -1644,6 +1644,7 @@ class CC_DLL Node : public Ref
      * @param additionalTransform An additional transform matrix.
      */
     void setAdditionalTransform(Mat4* additionalTransform);
+    void setAdditionalTransform(const Mat4& additionalTransform);
     void setAdditionalTransform(const AffineTransform& additionalTransform);
 
     /// @} end of Coordinate Converters

cocos/2d/CCScene.cpp

@@ -201,9 +201,14 @@ void Scene::render(Renderer* renderer, const Mat4& eyeTransform)
             defaultCamera = Camera::_visitingCamera;
         }
 
-        Mat4 eyeCopy = camera->getNodeToParentTransform();
-        // eyeTransform is in "camera/view" coordinates. Convert it to "model" coordinates
-        camera->setNodeToParentTransform(eyeCopy * eyeTransform.getInversed());
+        // There are two ways to modify the "default camera" with the eye Transform:
+        // a) modify the "nodeToParentTransform" matrix
+        // b) modify the "additional transform" matrix
+        // both alternatives are correct, if the user manually modifies the camera with a camera->setPosition()
+        // then the "nodeToParent transform" will be lost.
+        // And it is important that the change is "permament", because the matrix might be used for calculate
+        // culling and other stuff.
+        camera->setAdditionalTransform(eyeTransform.getInversed());
 
         director->pushMatrix(MATRIX_STACK_TYPE::MATRIX_STACK_PROJECTION);
         director->loadMatrix(MATRIX_STACK_TYPE::MATRIX_STACK_PROJECTION, Camera::_visitingCamera->getViewProjectionMatrix());
@@ -224,7 +229,9 @@ void Scene::render(Renderer* renderer, const Mat4& eyeTransform)
 
         director->popMatrix(MATRIX_STACK_TYPE::MATRIX_STACK_PROJECTION);
 
-        camera->setNodeToParentTransform(eyeCopy);
+        // we shouldn't restore the transform matrix since it could be used
+        // from "update" or other parts of the game to calculate culling or something else.
+//        camera->setNodeToParentTransform(eyeCopy);
     }
 
 #if CC_USE_3D_PHYSICS && CC_ENABLE_BULLET_INTEGRATION