ANGLE: Allow Windows Phone to communicate swap region

eglPostSubBufferNV is used to communicate the size of the window, as
otherwise there is no way for the renderer to know if the last frame was
rendered in landscape or portrait, causing rendering glitches when the
orientation changes. The rotation flags are utilized in a few additional
places now to fix some corner cases where the rotation was not applied.

This patch should be squashed into "ANGLE-Improve-Windows-Phone-Support"
during the next ANGLE rebase.

Task-number: QTBUG-44333
Task-number: QTBUG-43502
Change-Id: Iec37f7531854184819c30c87eab82d96d56ff133
Reviewed-by: Oliver Wolff <oliver.wolff@theqtcompany.com>

4 files changed, 24 insertions, 13 deletions

diff --git a/src/3rdparty/angle/src/libANGLE/renderer/d3d/SurfaceD3D.cpp b/src/3rdparty/angle/src/libANGLE/renderer/d3d/SurfaceD3D.cpp
index 4fde295443..4a87488014 100644
--- a/src/3rdparty/angle/src/libANGLE/renderer/d3d/SurfaceD3D.cpp
+++ b/src/3rdparty/angle/src/libANGLE/renderer/d3d/SurfaceD3D.cpp
@@ -189,6 +189,7 @@ egl::Error SurfaceD3D::swapRect(EGLint x, EGLint y, EGLint width, EGLint height)
         return egl::Error(EGL_SUCCESS);
     }
 
+#if !defined(ANGLE_ENABLE_WINDOWS_STORE) || (defined(ANGLE_ENABLE_WINDOWS_STORE) && WINAPI_FAMILY == WINAPI_FAMILY_PC_APP) // Qt WP: eglPostSubBufferNV comes here
     if (x + width > mWidth)
     {
         width = mWidth - x;
@@ -198,6 +199,7 @@ egl::Error SurfaceD3D::swapRect(EGLint x, EGLint y, EGLint width, EGLint height)
     {
         height = mHeight - y;
     }
+#endif
 
     if (width == 0 || height == 0)
     {
diff --git a/src/3rdparty/angle/src/libANGLE/renderer/d3d/d3d11/SwapChain11.cpp b/src/3rdparty/angle/src/libANGLE/renderer/d3d/d3d11/SwapChain11.cpp
index 298f3ccbd2..dc539cf66e 100644
--- a/src/3rdparty/angle/src/libANGLE/renderer/d3d/d3d11/SwapChain11.cpp
+++ b/src/3rdparty/angle/src/libANGLE/renderer/d3d/d3d11/SwapChain11.cpp
@@ -552,18 +552,18 @@ EGLint SwapChain11::swapRect(EGLint x, EGLint y, EGLint width, EGLint height)
 
     d3d11::PositionTexCoordVertex *vertices = static_cast<d3d11::PositionTexCoordVertex*>(mappedResource.pData);
 
+#if defined(ANGLE_ENABLE_WINDOWS_STORE) && (WINAPI_FAMILY == WINAPI_FAMILY_PHONE_APP)
     // Create a quad in homogeneous coordinates
-    float x1 = (x / float(mWidth)) * 2.0f - 1.0f;
-    float y1 = (y / float(mHeight)) * 2.0f - 1.0f;
-    float x2 = ((x + width) / float(mWidth)) * 2.0f - 1.0f;
-    float y2 = ((y + height) / float(mHeight)) * 2.0f - 1.0f;
+    float x1 = -1.0f;
+    float y1 = -1.0f;
+    float x2 = 1.0f;
+    float y2 = 1.0f;
 
-#if defined(ANGLE_ENABLE_WINDOWS_STORE) && (WINAPI_FAMILY == WINAPI_FAMILY_PHONE_APP)
     const float dim = std::max(mWidth, mHeight);
-    float u1 = x / dim;
-    float v1 = y / dim;
-    float u2 = (x + width) / dim;
-    float v2 = (y + height) / dim;
+    float u1 = 0;
+    float v1 = 0;
+    float u2 = float(width) / dim;
+    float v2 = float(height) / dim;
 
     const NativeWindow::RotationFlags flags = mNativeWindow.rotationFlags();
     const bool rotateL = flags == NativeWindow::RotateLeft;
@@ -573,6 +573,12 @@ EGLint SwapChain11::swapRect(EGLint x, EGLint y, EGLint width, EGLint height)
     d3d11::SetPositionTexCoordVertex(&vertices[2], x2, y1, rotateR ? u1 : u2, rotateL ? v2 : v1);
     d3d11::SetPositionTexCoordVertex(&vertices[3], x2, y2, rotateL ? u1 : u2, rotateR ? v1 : v2);
 #else
+    // Create a quad in homogeneous coordinates
+    float x1 = (x / float(mWidth)) * 2.0f - 1.0f;
+    float y1 = (y / float(mHeight)) * 2.0f - 1.0f;
+    float x2 = ((x + width) / float(mWidth)) * 2.0f - 1.0f;
+    float y2 = ((y + height) / float(mHeight)) * 2.0f - 1.0f;
+
     float u1 = x / float(mWidth);
     float v1 = y / float(mHeight);
     float u2 = (x + width) / float(mWidth);
@@ -613,8 +619,8 @@ EGLint SwapChain11::swapRect(EGLint x, EGLint y, EGLint width, EGLint height)
     viewport.TopLeftX = 0;
     viewport.TopLeftY = 0;
 #if defined(ANGLE_ENABLE_WINDOWS_STORE) && (WINAPI_FAMILY == WINAPI_FAMILY_PHONE_APP)
-    viewport.Width = (rotateL || rotateR) ? mHeight : mWidth;
-    viewport.Height = (rotateL || rotateR) ? mWidth : mHeight;
+    viewport.Width = (rotateL || rotateR) ? height : width;
+    viewport.Height = (rotateL || rotateR) ? width : height;
 #else
     viewport.Width = mWidth;
     viewport.Height = mHeight;
diff --git a/src/3rdparty/angle/src/libANGLE/renderer/d3d/d3d11/winrt/CoreWindowNativeWindow.cpp b/src/3rdparty/angle/src/libANGLE/renderer/d3d/d3d11/winrt/CoreWindowNativeWindow.cpp
index 350526c867..fa9a69c5a1 100644
--- a/src/3rdparty/angle/src/libANGLE/renderer/d3d/d3d11/winrt/CoreWindowNativeWindow.cpp
+++ b/src/3rdparty/angle/src/libANGLE/renderer/d3d/d3d11/winrt/CoreWindowNativeWindow.cpp
@@ -100,6 +100,7 @@ bool CoreWindowNativeWindow::registerForSizeChangeEvents()
     if (SUCCEEDED(result))
     {
         result = mDisplayInformation->add_OrientationChanged(orientationChangedHandler.Get(), &mOrientationChangedEventToken);
+        orientationChangedHandler->Invoke(mDisplayInformation.Get(), nullptr);
     }
 #endif
 
@@ -135,8 +136,8 @@ HRESULT CoreWindowNativeWindow::createSwapChain(ID3D11Device *device, DXGIFactor
     }
 
     DXGI_SWAP_CHAIN_DESC1 swapChainDesc = { 0 };
-    swapChainDesc.Width = width;
-    swapChainDesc.Height = height;
+    swapChainDesc.Width = mRotationFlags ? height : width;
+    swapChainDesc.Height = mRotationFlags ? width : height;
     swapChainDesc.Format = format;
     swapChainDesc.Stereo = FALSE;
     swapChainDesc.SampleDesc.Count = 1;
diff --git a/src/3rdparty/angle/src/libGLESv2/entry_points_egl_ext.cpp b/src/3rdparty/angle/src/libGLESv2/entry_points_egl_ext.cpp
index ded73dbb48..62f3ca1207 100644
--- a/src/3rdparty/angle/src/libGLESv2/entry_points_egl_ext.cpp
+++ b/src/3rdparty/angle/src/libGLESv2/entry_points_egl_ext.cpp
@@ -101,12 +101,14 @@ EGLBoolean EGLAPIENTRY PostSubBufferNV(EGLDisplay dpy, EGLSurface surface, EGLin
         return EGL_FALSE;
     }
 
+#if !defined(ANGLE_ENABLE_WINDOWS_STORE) || (defined(ANGLE_ENABLE_WINDOWS_STORE) && WINAPI_FAMILY == WINAPI_FAMILY_PC_APP) // Qt WP: Allow this entry point as a workaround
     if (!display->getExtensions().postSubBuffer)
     {
         // Spec is not clear about how this should be handled.
         SetGlobalError(Error(EGL_SUCCESS));
         return EGL_TRUE;
     }
+#endif
 
     error = eglSurface->postSubBuffer(x, y, width, height);
     if (error.isError())