fix clipping node issue (#20100)

Children are not correctly clipped.

Author: Mee-gu

cocos/2d/CCClippingNode.cpp

@@ -199,9 +199,10 @@ void ClippingNode::visit(Renderer *renderer, const Mat4 &parentTransform, uint32
     if (alphaThreshold < 1)
     {
         auto programState = new (std::nothrow) backend::ProgramState(positionTextureColor_vert, positionTextureColorAlphaTest_frag);
-        _stencil->setProgramState(programState);
         auto alphaLocation = programState->getUniformLocation("u_alpha_value");
         programState->setUniform(alphaLocation, &alphaThreshold, sizeof(alphaThreshold));
+        setProgramStateRecursively(_stencil, programState);
+
         CC_SAFE_RELEASE_NULL(programState);
     }
     _stencil->visit(renderer, _modelViewTransform, flags);
@@ -309,7 +310,13 @@ void ClippingNode::setStencil(Node *stencil)
     }
 
     if (_stencil != nullptr)
-        _originalStencilProgramState = _stencil->getProgramState();
+    {
+        _originalStencilProgramState[_stencil] = _stencil->getProgramState();
+        auto& children = _stencil->getChildren();
+        for (const auto &child : children) {
+            _originalStencilProgramState[child] = child->getProgramState();
+        }
+    }
 }
 
 bool ClippingNode::hasContent() const
@@ -328,7 +335,7 @@ void ClippingNode::setAlphaThreshold(float alphaThreshold)
     {
         // should reset program used by _stencil
         if (_stencil)
-            _stencil->setProgramState(_originalStencilProgramState);
+            restoreAllProgramStates();
     }
     _stencilStateManager->setAlphaThreshold(alphaThreshold);
 }
@@ -343,5 +350,26 @@ void ClippingNode::setInverted(bool inverted)
     _stencilStateManager->setInverted(inverted);
 }
 
+void ClippingNode::setProgramStateRecursively(Node* node, backend::ProgramState* programState)
+{
+    _originalStencilProgramState[node] = node->getProgramState();
+    node->setProgramState(programState);
+
+    auto& children = node->getChildren();
+    for (const auto &child : children) {
+        setProgramStateRecursively(child, programState);
+    }
+}
+
+void ClippingNode::restoreAllProgramStates()
+{
+    for (auto item : _originalStencilProgramState)
+    {
+        auto node = item.first;
+        auto programState = item.second;
+        node->setProgramState(programState);
+    }
+}
+
 
 NS_CC_END

cocos/2d/CCClippingNode.h

@@ -31,7 +31,7 @@
 #include "renderer/CCGroupCommand.h"
 #include "renderer/CCCustomCommand.h"
 #include "renderer/CCCallbackCommand.h"
-
+#include <unordered_map>
 NS_CC_BEGIN
 
 class StencilStateManager;
@@ -154,14 +154,17 @@ class CC_DLL ClippingNode : public Node
     virtual bool init(Node *stencil);
 
 protected:
+    void setProgramStateRecursively(Node* node, backend::ProgramState* programState);
+    void restoreAllProgramStates();
+
     Node* _stencil                              = nullptr;
     StencilStateManager* _stencilStateManager   = nullptr;
 
     GroupCommand _groupCommandStencil;
     GroupCommand _groupCommandChildren;
     CallbackCommand _afterDrawStencilCmd;
     CallbackCommand _afterVisitCmd;
-    backend::ProgramState* _originalStencilProgramState = nullptr;
+    std::unordered_map<Node*, backend::ProgramState*> _originalStencilProgramState;
 
 private:
     CC_DISALLOW_COPY_AND_ASSIGN(ClippingNode);