IDeviceContextGL: added PurgeCaches parameter to UpdateCurrentGLContext method

Author: TheMostDiligent

Graphics/GraphicsEngineOpenGL/include/DeviceContextGLImpl.hpp

@@ -293,7 +293,7 @@ class DeviceContextGLImpl final : public DeviceContextBase<EngineGLImplTraits>
     virtual void DILIGENT_CALL_TYPE BindSparseResourceMemory(const BindSparseResourceMemoryAttribs& Attribs) override final;
 
     /// Implementation of IDeviceContextGL::UpdateCurrentGLContext().
-    virtual bool DILIGENT_CALL_TYPE UpdateCurrentGLContext() override final;
+    virtual bool DILIGENT_CALL_TYPE UpdateCurrentGLContext(bool PurgeCaches) override final;
 
     GLContextState& GetContextState() { return m_ContextState; }
 

Graphics/GraphicsEngineOpenGL/include/RenderDeviceGLImpl.hpp

@@ -197,6 +197,8 @@ class RenderDeviceGLImpl : public RenderDeviceBase<EngineGLImplTraits>
     void      OnDestroyPSO(PipelineStateGLImpl& PSO);
     void      OnDestroyBuffer(BufferGLImpl& Buffer);
 
+    void PurgeContextCaches(GLContext::NativeGLContextType Context);
+
     GLProgramCache& GetProgramCache() { return m_ProgramCache; }
 
     size_t GetCommandQueueCount() const { return 1; }

Graphics/GraphicsEngineOpenGL/interface/DeviceContextGL.h

@@ -1,5 +1,5 @@
 /*
- *  Copyright 2019-2023 Diligent Graphics LLC
+ *  Copyright 2019-2024 Diligent Graphics LLC
  *  Copyright 2015-2019 Egor Yusov
  *
  *  Licensed under the Apache License, Version 2.0 (the "License");
@@ -56,10 +56,16 @@ DILIGENT_BEGIN_INTERFACE(IDeviceContextGL, IDeviceContext)
 
     /// If an application uses multiple GL contexts, this method must be called before any
     /// other command to let the engine update active context every time when control flow
-    /// is passed over from the main application
+    /// is passed over from the main application.
     ///
-    /// \return false if there is no active GL context, and true otherwise
-    VIRTUAL bool METHOD(UpdateCurrentGLContext)(THIS) PURE;
+    /// \param[in] PurgeCaches - Whether to purge context caches (e.g. VAO, FBO) before
+    ///                          updating the active context. An application should set this
+    ///                          flag to true if the last active context will not be used anymore
+    ///                          (e.g. it was destroyed) to avoid memory leaks.
+    /// 
+    /// \return     false if there is no active GL context, and true otherwise.
+    VIRTUAL bool METHOD(UpdateCurrentGLContext)(THIS_
+                                                bool PurgeCaches DEFAULT_INITIALIZER(false)) PURE;
 
     /// Sets the swap in the device context. The swap chain is used by the device context
     /// to obtain the default FBO handle.
@@ -74,8 +80,8 @@ DILIGENT_END_INTERFACE
 
 // clang-format off
 
-#    define IDeviceContextGL_UpdateCurrentGLContext(This) CALL_IFACE_METHOD(DeviceContextGL, UpdateCurrentGLContext, This)
-#    define IDeviceContextGL_SetSwapChain(This, ...)      CALL_IFACE_METHOD(DeviceContextGL, SetSwapChain,           This, __VA_ARGS__)
+#    define IDeviceContextGL_UpdateCurrentGLContext(This, ...) CALL_IFACE_METHOD(DeviceContextGL, UpdateCurrentGLContext, This, __VA_ARGS__)
+#    define IDeviceContextGL_SetSwapChain(This, ...)           CALL_IFACE_METHOD(DeviceContextGL, SetSwapChain,           This, __VA_ARGS__)
 
 // clang-format on
 

Graphics/GraphicsEngineOpenGL/src/DeviceContextGLImpl.cpp

@@ -408,9 +408,8 @@ void DeviceContextGLImpl::CommitRenderTargets()
                       "Depth buffer of the default framebuffer can only be bound with the default framebuffer's color buffer "
                       "and cannot be combined with any other render target in OpenGL backend.");
 
-        auto        CurrentNativeGLContext = m_ContextState.GetCurrentGLContext();
-        auto&       FBOCache               = m_pDevice->GetFBOCache(CurrentNativeGLContext);
-        const auto& FBO                    = FBOCache.GetFBO(NumRenderTargets, pBoundRTVs, m_pBoundDepthStencil, m_ContextState);
+        auto&       FBOCache = m_pDevice->GetFBOCache(m_ContextState.GetCurrentGLContext());
+        const auto& FBO      = FBOCache.GetFBO(NumRenderTargets, pBoundRTVs, m_pBoundDepthStencil, m_ContextState);
         // Even though the write mask only applies to writes to a framebuffer, the mask state is NOT
         // Framebuffer state. So it is NOT part of a Framebuffer Object or the Default Framebuffer.
         // Binding a new framebuffer will NOT affect the mask.
@@ -771,11 +770,10 @@ void DeviceContextGLImpl::PrepareForDraw(DRAW_FLAGS Flags, bool IsIndexed, GLenu
     DvpValidateCommittedShaderResources();
 #endif
 
-    const auto  CurrNativeGLContext = m_pDevice->m_GLContext.GetCurrentNativeGLContext();
-    const auto& PipelineDesc        = m_pPipelineState->GetGraphicsPipelineDesc();
+    const auto& PipelineDesc = m_pPipelineState->GetGraphicsPipelineDesc();
     if (!m_ContextState.IsValidVAOBound())
     {
-        auto& VaoCache     = m_pDevice->GetVAOCache(CurrNativeGLContext);
+        auto& VaoCache     = m_pDevice->GetVAOCache(m_ContextState.GetCurrentGLContext());
         auto* pIndexBuffer = IsIndexed ? m_pIndexBuffer.RawPtr() : nullptr;
         if (PipelineDesc.InputLayout.NumElements > 0 || pIndexBuffer != nullptr)
         {
@@ -1655,8 +1653,13 @@ void DeviceContextGLImpl::EndQuery(IQuery* pQuery)
     }
 }
 
-bool DeviceContextGLImpl::UpdateCurrentGLContext()
+bool DeviceContextGLImpl::UpdateCurrentGLContext(bool PurgeCaches)
 {
+    if (PurgeCaches)
+    {
+        m_pDevice->PurgeContextCaches(m_ContextState.GetCurrentGLContext());
+    }
+
     auto NativeGLContext = m_pDevice->m_GLContext.GetCurrentNativeGLContext();
     if (NativeGLContext == NULL)
         return false;
@@ -1905,8 +1908,7 @@ void DeviceContextGLImpl::ResolveTextureSubresource(ITexture*
     const auto& SrcTexDesc = pSrcTexGl->GetDesc();
     //const auto& DstTexDesc = pDstTexGl->GetDesc();
 
-    auto  CurrentNativeGLContext = m_ContextState.GetCurrentGLContext();
-    auto& FBOCache               = m_pDevice->GetFBOCache(CurrentNativeGLContext);
+    auto& FBOCache = m_pDevice->GetFBOCache(m_ContextState.GetCurrentGLContext());
 
     GLuint SrcFBOHandle = 0;
     {

Graphics/GraphicsEngineOpenGL/src/RenderDeviceGLImpl.cpp

@@ -1682,6 +1682,19 @@ void RenderDeviceGLImpl::OnDestroyBuffer(BufferGLImpl& Buffer)
         VAOCacheIt.second.OnDestroyBuffer(Buffer);
 }
 
+
+void RenderDeviceGLImpl::PurgeContextCaches(GLContext::NativeGLContextType Context)
+{
+    {
+        Threading::SpinLockGuard FBOCacheGuard{m_FBOCacheLock};
+        m_FBOCache.erase(Context);
+    }
+    {
+        Threading::SpinLockGuard VAOCacheGuard{m_VAOCacheLock};
+        m_VAOCache.erase(Context);
+    }
+}
+
 void RenderDeviceGLImpl::IdleGPU()
 {
     glFinish();

Tests/IncludeTest/GraphicsEngineOpenGL/DeviceContextGLH_test.c

@@ -29,7 +29,7 @@
 
 void TestDeviceContextGL_CInterface(IDeviceContextGL* pCtxGL)
 {
-    bool res = IDeviceContextGL_UpdateCurrentGLContext(pCtxGL);
+    bool res = IDeviceContextGL_UpdateCurrentGLContext(pCtxGL, true);
     (void)res;
     IDeviceContextGL_SetSwapChain(pCtxGL, (struct ISwapChainGL*)NULL);
 }