Vulkan: Remove the flipViewportY feature

include/platform/FeaturesVk.h

@@ -41,22 +41,6 @@ struct FeaturesVk : FeatureSetBase
                                "Enable provoking vertex mode via VK_EXT_provoking_vertex extension",
                                &members};
 
-    // Flips the viewport to render upside-down. This has the effect to render the same way as
-    // OpenGL. If this feature gets enabled, we enable the KHR_MAINTENANCE_1 extension to allow
-    // negative viewports. We inverse rendering to the backbuffer by reversing the height of the
-    // viewport and increasing Y by the height. So if the viewport was (0,0,width,height), it
-    // becomes (0, height, width, -height). Unfortunately, when we start doing this, we also need
-    // to adjust a lot of places since the rendering now happens upside-down. Affected places so
-    // far:
-    // -readPixels
-    // -copyTexImage
-    // -framebuffer blit
-    // -generating mipmaps
-    // -Point sprites tests
-    // -texStorage
-    Feature flipViewportY = {"flip_viewport_y", FeatureCategory::VulkanFeatures,
-                             "Flips the viewport to render upside-down", &members};
-
     // Add an extra copy region when using vkCmdCopyBuffer as the Windows Intel driver seems
     // to have a bug where the last region is ignored.
     Feature extraCopyBufferRegion = {

src/libANGLE/renderer/vulkan/ContextVk.cpp

@@ -3146,11 +3146,10 @@ angle::Result ContextVk::onMakeCurrent(const gl::Context *context)
 {
     mRenderer->reloadVolkIfNeeded();
 
-    // Flip viewports if FeaturesVk::flipViewportY is enabled and the user did not request that
-    // the surface is flipped.
+    // Flip viewports if the user did not request that the surface is flipped.
     egl::Surface *drawSurface = context->getCurrentDrawSurface();
     mFlipYForCurrentSurface =
-        drawSurface != nullptr && mRenderer->getFeatures().flipViewportY.enabled &&
+        drawSurface != nullptr &&
         !IsMaskFlagSet(drawSurface->getOrientation(), EGL_SURFACE_ORIENTATION_INVERT_Y_ANGLE);
 
     if (drawSurface && drawSurface->getType() == EGL_WINDOW_BIT)
@@ -3181,16 +3180,29 @@ angle::Result ContextVk::onUnMakeCurrent(const gl::Context *context)
 
 void ContextVk::updateFlipViewportDrawFramebuffer(const gl::State &glState)
 {
+    // The default framebuffer (originating from the swapchain) is rendered upside-down due to the
+    // difference in the coordinate systems of Vulkan and GLES.  Rendering upside-down has the
+    // effect that rendering is done the same way as OpenGL.  The KHR_MAINTENANCE_1 extension is
+    // subsequently enabled to allow negative viewports.  We inverse rendering to the backbuffer by
+    // reversing the height of the viewport and increasing Y by the height.  So if the viewport was
+    // (0, 0, width, height), it becomes (0, height, width, -height).  Unfortunately, when we start
+    // doing this, we also need to adjust a number of places since the rendering now happens
+    // upside-down.  Affected places so far:
+    //
+    // - readPixels
+    // - copyTexImage
+    // - framebuffer blit
+    // - generating mipmaps
+    // - Point sprites tests
+    // - texStorage
     gl::Framebuffer *drawFramebuffer = glState.getDrawFramebuffer();
-    mFlipViewportForDrawFramebuffer =
-        drawFramebuffer->isDefault() && mRenderer->getFeatures().flipViewportY.enabled;
+    mFlipViewportForDrawFramebuffer  = drawFramebuffer->isDefault();
 }
 
 void ContextVk::updateFlipViewportReadFramebuffer(const gl::State &glState)
 {
     gl::Framebuffer *readFramebuffer = glState.getReadFramebuffer();
-    mFlipViewportForReadFramebuffer =
-        readFramebuffer->isDefault() && mRenderer->getFeatures().flipViewportY.enabled;
+    mFlipViewportForReadFramebuffer  = readFramebuffer->isDefault();
 }
 
 void ContextVk::updateSurfaceRotationDrawFramebuffer(const gl::State &glState)

src/libANGLE/renderer/vulkan/RendererVk.cpp

@@ -1144,12 +1144,12 @@ angle::Result RendererVk::initializeDevice(DisplayVk *displayVk, uint32_t queueF
         enabledDeviceExtensions.push_back(VK_KHR_BIND_MEMORY_2_EXTENSION_NAME);
     }
 
-    // Selectively enable KHR_MAINTENANCE1 to support viewport flipping.
-    if ((getFeatures().flipViewportY.enabled) &&
-        (mPhysicalDeviceProperties.apiVersion < VK_MAKE_VERSION(1, 1, 0)))
+    // Enable KHR_MAINTENANCE1 to support viewport flipping.
+    if (mPhysicalDeviceProperties.apiVersion < VK_MAKE_VERSION(1, 1, 0))
     {
         enabledDeviceExtensions.push_back(VK_KHR_MAINTENANCE1_EXTENSION_NAME);
     }
+
     if (getFeatures().supportsIncrementalPresent.enabled)
     {
         enabledDeviceExtensions.push_back(VK_KHR_INCREMENTAL_PRESENT_EXTENSION_NAME);
@@ -1660,14 +1660,6 @@ void RendererVk::initFeatures(DisplayVk *displayVk, const ExtensionNameList &dev
         ANGLE_FEATURE_CONDITION(&mFeatures, provokingVertex, true);
     }
 
-    // TODO(lucferron): Currently disabled on Intel only since many tests are failing and need
-    // investigation. http://anglebug.com/2728
-    ANGLE_FEATURE_CONDITION(
-        &mFeatures, flipViewportY,
-        !IsIntel(mPhysicalDeviceProperties.vendorID) &&
-                (mPhysicalDeviceProperties.apiVersion >= VK_MAKE_VERSION(1, 1, 0)) ||
-            ExtensionFound(VK_KHR_MAINTENANCE1_EXTENSION_NAME, deviceExtensionNames));
-
     // http://anglebug.com/2838
     ANGLE_FEATURE_CONDITION(&mFeatures, extraCopyBufferRegion, IsWindows() && isIntel);