[Feat] (Diligent, EGL): route EGL window resize to Diligent swap chain

- Add renderer->ResizeSwapChain and override BackendObject_Diligent::ResizeEGLWindowSurface
- Update handoff; 16 Diligent tests pass

HANDOFF_DILIGENT.md

@@ -220,7 +220,7 @@ Notes:
 - User framebuffers now support texture color attachments, renderbuffer color readback, multiple simultaneous color targets, and depth/stencil texture or renderbuffer attachments.
 - Textures auto-sync `ITextureObject` → Diligent resources, including mip levels and sampler state; compressed textures and integer/3-channel formats that Diligent lacks are still skipped.
 - Global UBO (default-block `glUniform*`) and named application UBO blocks (through `glBindBufferBase`/`glUniformBlockBinding`) now upload and bind; SSBOs are still not fed from frontend buffer bindings.
-- Swapchain creation is now wired for native EGL window surfaces via `Diligent::ISwapChain`; `Present()` presents the active swap chain when present and otherwise flushes the offscreen target. Actual on-screen EGL presentation is still untested in this headless environment, and the X11 display/connection fields are not yet plumbed through `WindowHandle`. `SetSwapInterval` remains a no-op.
+- Swapchain creation and resize are wired for native EGL window surfaces via `Diligent::ISwapChain`; `Present()` presents the active swap chain when present and otherwise flushes the offscreen target. Actual on-screen EGL presentation is still untested in this headless environment, and the X11 display/connection fields are not yet plumbed through `WindowHandle`. `SetSwapInterval` remains a no-op.
 - No transform feedback / GPU-accelerated queries / non-color readback; fence sync and timer queries use CPU fallbacks.
 - Draw range, multi-draw, instanced-draw wrappers, clear-buffer, blit, read-pixels, CopyTexImage*, CopyImageSubData, GenerateMipmap, GetTexImage/GetTextureImage and indirect draws are now wired; buffer subdata paths still remain.
 - A last-PSO cache now avoids recreating the pipeline when program/render-state/topology/VAO layout is unchanged; texture/UBO resources are still rebound dynamically per draw.

MobileGL/MG_Backend/Diligent/BackendObject_Diligent.cpp

@@ -841,6 +841,17 @@ namespace MobileGL::MG_Backend::DiligentBackend {
         BackendObject::ReleaseEGLResources();
     }
 
+    Bool BackendObject_Diligent::ResizeEGLWindowSurface(EGLSurface surface, Uint32 width, Uint32 height) {
+        const std::lock_guard<std::recursive_mutex> lock(m_eglStateMutex);
+        if (!BackendObject::ResizeEGLWindowSurface(surface, width, height)) {
+            return false;
+        }
+        if (m_eglSurface == surface && m_pRenderer != nullptr) {
+            return m_pRenderer->ResizeSwapChain(width, height);
+        }
+        return true;
+    }
+
     const RendererInfo& BackendObject_Diligent::GetRendererInfo() const {
         return m_rendererInfo;
     }

MobileGL/MG_Backend/Diligent/BackendObject_Diligent.h

@@ -43,6 +43,7 @@ namespace MobileGL::MG_Backend::DiligentBackend {
         Bool InitCapabilities() override;
         Bool InitWindowSurface() override;
         Bool InitPbufferSurface(EGLint width, EGLint height) override;
+        Bool ResizeEGLWindowSurface(EGLSurface surface, Uint32 width, Uint32 height) override;
 
         const RendererInfo& GetRendererInfo() const override;
         String GetBackendAPIVersionString() const override;

MobileGL/MG_Backend/Diligent/Renderer/DiligentRenderer.cpp

@@ -420,6 +420,16 @@ void main()
         return true;
     }
 
+    Bool DiligentRenderer::ResizeSwapChain(Uint32 width, Uint32 height) {
+        if (m_pSwapChain == nullptr) {
+            return false;
+        }
+        m_pSwapChain->Resize(width > 0 ? width : 1, height > 0 ? height : 1);
+        m_width = width > 0 ? width : m_width;
+        m_height = height > 0 ? height : m_height;
+        return true;
+    }
+
     Bool DiligentRenderer::CreateOffscreenTargets() {
         ::Diligent::TextureDesc texDesc;
         texDesc.Name = "MobileGL Diligent offscreen color target";

MobileGL/MG_Backend/Diligent/Renderer/DiligentRenderer.h

@@ -64,6 +64,7 @@ namespace MobileGL::MG_Backend::DiligentBackend {
         // Creates a real Diligent swap chain for a native EGL window surface.
         Bool CreateSwapChain(::Diligent::IEngineFactoryVk* factory, const WindowHandle& handle,
                              Uint32 width, Uint32 height);
+        Bool ResizeSwapChain(Uint32 width, Uint32 height);
         // Creates a simple 2D RGBA8 texture from CPU data and makes it available
         // to state PSOs under the shader variable name "g_Texture".
         Bool CreateTestTexture(const void* data, Uint32 width, Uint32 height);