RHI: Fix RenderTarget sub-class resources not cleanup

Author: halx99

axmol/base/Object.cpp

@@ -78,6 +78,8 @@ Object::~Object()
 #endif
 }
 
+void Object::dispose() {}
+
 void Object::retain()
 {
     AXASSERT(_referenceCount > 0, "reference count should be greater than 0");
@@ -91,6 +93,7 @@ void Object::release()
 
     if (_referenceCount == 0)
     {
+        dispose();
 #if defined(_AX_DEBUG) && (_AX_DEBUG > 0)
         auto poolManager = PoolManager::getInstance();
         if (!poolManager->getCurrentPool()->isClearing() && poolManager->isObjectInPools(this))

axmol/base/Object.h

@@ -134,6 +134,30 @@ class AX_DLL Object
      */
     Object();
 
+    /**
+     * @brief Virtual cleanup hook function called before object destruction (prior to ~Object()).
+     *
+     * This protected virtual method serves as a dedicated resource cleanup interface, designed to
+     * solve the C++ pitfall where calling virtual functions within a destructor fails to invoke
+     * subclass-specific implementations (polymorphism is disabled during destructor execution).
+     *
+     * Unlike destructors, this method is invoked while the object (including all subclass components)
+     * is still fully intact and its polymorphic behavior is fully functional. Subclasses can override
+     * this method to implement custom resource release logic (e.g., deallocating dynamic memory,
+     * closing file handles, releasing engine resources) that would otherwise be unsafe or ineffective
+     * if placed in a subclass destructor's virtual function call chain.
+     *
+     * @note This method is automatically invoked by Object::release() when the reference count
+     *       (_referenceCount) reaches 0, immediately before the object is deleted via `delete this`.
+     *       It is not intended to be called directly from external code (protected access control)
+     *       to avoid invalid resource cleanup or double-free issues.
+     * @note Subclasses overriding this method should ensure to call the base class implementation
+     *       (Object::dispose()) at the appropriate time to guarantee complete cleanup of the
+     *       inheritance hierarchy.
+     * @see Object::release() The method that triggers this cleanup hook when reference count is zero.
+     */
+    virtual void dispose();
+
 public:
     /**
      * Destructor

axmol/rhi/RenderTarget.cpp

@@ -27,7 +27,9 @@ THE SOFTWARE.
 namespace ax::rhi
 {
 
-RenderTarget::~RenderTarget()
+RenderTarget::~RenderTarget() {}
+
+void RenderTarget::dispose()
 {
     cleanupResources();
 }

axmol/rhi/RenderTarget.h

@@ -45,6 +45,9 @@ static constexpr uint32_t INITIAL_COLOR_CAPACITY = 4;
  */
 class RenderTarget : public ax::Object
 {
+protected:
+    void dispose() override;
+
 public:
     struct RenderBuffer
     {

axmol/rhi/d3d12/RenderTarget12.cpp

@@ -35,13 +35,11 @@ RenderTargetImpl::RenderTargetImpl(DriverImpl* driver, bool defaultRenderTarget)
         _dirtyFlags = TargetBufferFlags::ALL;
 }
 
-RenderTargetImpl::~RenderTargetImpl()
-{
-    _driver->waitForGPU();
-}
+RenderTargetImpl::~RenderTargetImpl() {}
 
 void RenderTargetImpl::cleanupResources()
 {
+    _driver->waitForGPU();
     // RTVs
     for (auto i = 0; i < _rtvsDescriptors.size(); ++i)
     {

axmol/rhi/vulkan/RenderTargetVK.cpp

@@ -39,13 +39,12 @@ RenderTargetImpl::RenderTargetImpl(DriverImpl* driver, bool defaultRenderTarget)
     _clearValues.reserve(_color.size() + 1);
 }
 
-RenderTargetImpl::~RenderTargetImpl()
-{
-    _driver->waitForGPU();
-}
+RenderTargetImpl::~RenderTargetImpl() {}
 
 void RenderTargetImpl::cleanupResources()
 {
+    _driver->waitForGPU();
+
     // Conservative: wait idle before destroying caches to avoid "in use" errors.
     for (auto& [_, pass] : _renderPassCache)
         _driver->destroyRenderPass(pass);