[dxgi] Implement and use GetWindowClientSize fuction

This new function provides a cleaner way to retrieve a
window's client size and can be used outside the swap
chain functions.

src/dxgi/dxgi_monitor.cpp

@@ -127,5 +127,20 @@ namespace dxvk {
     
     return status == DISP_CHANGE_SUCCESSFUL ? S_OK : DXGI_ERROR_NOT_CURRENTLY_AVAILABLE;;
   }
+  
+  
+  void GetWindowClientSize(
+          HWND                    hWnd,
+          UINT*                   pWidth,
+          UINT*                   pHeight) {
+    RECT rect = { };
+    ::GetClientRect(hWnd, &rect);
+    
+    if (pWidth)
+      *pWidth = rect.right - rect.left;
+    
+    if (pHeight)
+      *pHeight = rect.bottom - rect.top;
+  }
 
 }

src/dxgi/dxgi_monitor.h

@@ -85,5 +85,17 @@ namespace dxvk {
   HRESULT SetMonitorDisplayMode(
           HMONITOR                hMonitor,
     const DXGI_MODE_DESC*         pMode);
+  
+  /**
+   * \brief Queries window client size
+   * 
+   * \param [in] hWnd Window to query
+   * \param [out] pWidth Client width
+   * \param [out] pHeight Client height
+   */
+  void GetWindowClientSize(
+          HWND                    hWnd,
+          UINT*                   pWidth,
+          UINT*                   pHeight);
 
 }

src/dxgi/dxgi_swapchain.cpp

@@ -24,10 +24,9 @@ namespace dxvk {
     
     // Adjust initial back buffer size. If zero, these
     // shall be set to the current window size.
-    const VkExtent2D windowSize = GetWindowSize();
-    
-    if (m_desc.Width  == 0) m_desc.Width  = windowSize.width;
-    if (m_desc.Height == 0) m_desc.Height = windowSize.height;
+    GetWindowClientSize(m_window,
+      m_desc.Width  ? nullptr : &m_desc.Width,
+      m_desc.Height ? nullptr : &m_desc.Height);
     
     // Create presenter, which also serves as an interface to the device
     if (FAILED(CreatePresenter(pDevice, &m_presenter)))
@@ -287,11 +286,13 @@ namespace dxvk {
     if (!IsWindow(m_window))
       return DXGI_ERROR_INVALID_CALL;
     
-    const VkExtent2D windowSize = GetWindowSize();
-    
     std::lock_guard<std::mutex> lock(m_lockBuffer);
-    m_desc.Width  = Width  != 0 ? Width  : windowSize.width;
-    m_desc.Height = Height != 0 ? Height : windowSize.height;
+    m_desc.Width  = Width;
+    m_desc.Height = Height;
+    
+    GetWindowClientSize(m_window,
+      m_desc.Width  ? nullptr : &m_desc.Width,
+      m_desc.Height ? nullptr : &m_desc.Height);
     
     if (BufferCount != 0)
       m_desc.BufferCount = BufferCount;
@@ -491,19 +492,6 @@ namespace dxvk {
   }
 
 
-  VkExtent2D DxgiSwapChain::GetWindowSize() const {
-    RECT windowRect;
-    
-    if (!::GetClientRect(m_window, &windowRect))
-      windowRect = RECT();
-    
-    VkExtent2D result;
-    result.width  = windowRect.right;
-    result.height = windowRect.bottom;
-    return result;
-  }
-  
-  
   HRESULT DxgiSwapChain::EnterFullscreenMode(IDXGIOutput* pTarget) {
     Com<IDXGIOutput> output = static_cast<DxgiOutput*>(pTarget);
 

src/dxgi/dxgi_swapchain.h

@@ -183,8 +183,6 @@ namespace dxvk {
     HMONITOR                        m_monitor;
     WindowState                     m_windowState;
     
-    VkExtent2D GetWindowSize() const;
-    
     HRESULT EnterFullscreenMode(
             IDXGIOutput             *pTarget);