Enhance XCUI demo text editing and host bridge

editor/src/Platform/D3D12WindowRenderer.h

@@ -182,7 +182,8 @@ public:
     void Render(
         UI::ImGuiBackendBridge& imguiBackend,
         const float clearColor[4],
-        const RenderCallback& beforeUiRender = {}) {
+        const RenderCallback& beforeUiRender = {},
+        const RenderCallback& afterUiRender = {}) {
         auto* d3d12Queue = GetD3D12CommandQueue();
         auto* d3d12CommandList = GetD3D12CommandList();
         if (m_swapChain == nullptr ||
@@ -222,6 +223,11 @@ public:
         d3d12CommandList->SetDescriptorHeaps(1, descriptorHeaps);
         imguiBackend.RenderDrawData(d3d12CommandList->GetCommandList());
 
+        if (afterUiRender) {
+            d3d12CommandList->SetRenderTargets(1, &renderTargetView, nullptr);
+            afterUiRender(GetRenderContext(), renderSurface);
+        }
+
         d3d12CommandList->TransitionBarrier(
             renderTargetView,
             RHI::ResourceStates::RenderTarget,

editor/src/UI/ImGuiBackendBridge.h

@@ -7,8 +7,10 @@
 #include <d3d12.h>
 #include <dxgi1_6.h>
 #include <XCEngine/RHI/D3D12/D3D12Device.h>
+#include <XCEngine/RHI/D3D12/D3D12ResourceView.h>
 #include <XCEngine/RHI/D3D12/D3D12Texture.h>
 #include <XCEngine/RHI/RHIDevice.h>
+#include <XCEngine/RHI/RHIResourceView.h>
 #include <XCEngine/RHI/RHITexture.h>
 #include <imgui.h>
 #include <imgui_impl_dx12.h>
@@ -168,6 +170,63 @@ public:
         return true;
     }
 
+    bool CreateTextureDescriptor(
+        ::XCEngine::RHI::RHIDevice* device,
+        ::XCEngine::RHI::RHIResourceView* shaderResourceView,
+        D3D12_CPU_DESCRIPTOR_HANDLE* outCpuHandle,
+        D3D12_GPU_DESCRIPTOR_HANDLE* outGpuHandle,
+        ImTextureID* outTextureId) {
+        if (device == nullptr ||
+            shaderResourceView == nullptr ||
+            outCpuHandle == nullptr ||
+            outGpuHandle == nullptr ||
+            outTextureId == nullptr) {
+            return false;
+        }
+
+        *outCpuHandle = {};
+        *outGpuHandle = {};
+        *outTextureId = {};
+
+        auto* nativeDevice = dynamic_cast<::XCEngine::RHI::D3D12Device*>(device);
+        auto* nativeView = dynamic_cast<::XCEngine::RHI::D3D12ResourceView*>(shaderResourceView);
+        if (nativeDevice == nullptr ||
+            nativeView == nullptr ||
+            !nativeView->IsValid() ||
+            nativeView->GetViewType() != ::XCEngine::RHI::ResourceViewType::ShaderResource) {
+            return false;
+        }
+
+        if (m_srvHeap == nullptr ||
+            m_srvDescriptorSize == 0 ||
+            m_srvUsage.empty() ||
+            std::find(m_srvUsage.begin(), m_srvUsage.end(), false) == m_srvUsage.end()) {
+            return false;
+        }
+
+        const D3D12_CPU_DESCRIPTOR_HANDLE sourceCpuHandle = nativeView->GetCPUHandle();
+        if (sourceCpuHandle.ptr == 0) {
+            return false;
+        }
+
+        AllocateTextureDescriptor(outCpuHandle, outGpuHandle);
+        if (outCpuHandle->ptr == 0 || outGpuHandle->ptr == 0) {
+            *outCpuHandle = {};
+            *outGpuHandle = {};
+            return false;
+        }
+
+        // ImGui samples from its own shader-visible heap, so copy the existing SRV into an ImGui-owned slot.
+        nativeDevice->GetDevice()->CopyDescriptorsSimple(
+            1,
+            *outCpuHandle,
+            sourceCpuHandle,
+            D3D12_DESCRIPTOR_HEAP_TYPE_CBV_SRV_UAV);
+
+        *outTextureId = static_cast<ImTextureID>(outGpuHandle->ptr);
+        return true;
+    }
+
     void FreeTextureDescriptor(
         D3D12_CPU_DESCRIPTOR_HANDLE cpuHandle,
         D3D12_GPU_DESCRIPTOR_HANDLE gpuHandle) {