Vulkan: Improve viewport and scissor for pre-rotation

src/libANGLE/renderer/vulkan/ContextVk.cpp

@@ -270,7 +270,7 @@ SurfaceRotationType DetermineSurfaceRotation(gl::Framebuffer *framebuffer,
                 return SurfaceRotationType::Rotated180Degrees;
             case VK_SURFACE_TRANSFORM_ROTATE_270_BIT_KHR:
                 // Rotate gl_Position 270 degrees:
-                return SurfaceRotationType::Rotated180Degrees;
+                return SurfaceRotationType::Rotated270Degrees;
             default:
                 UNREACHABLE();
                 return SurfaceRotationType::Identity;
@@ -283,6 +283,50 @@ SurfaceRotationType DetermineSurfaceRotation(gl::Framebuffer *framebuffer,
     }
 }
 
+void RotateRectangle(const SurfaceRotationType rotation,
+                     const bool flipY,
+                     const int framebufferWidth,
+                     const int framebufferHeight,
+                     const gl::Rectangle &incoming,
+                     gl::Rectangle *outgoing)
+{
+    // GLES's y-axis points up; Vulkan's points down.
+    switch (rotation)
+    {
+        case SurfaceRotationType::Identity:
+            // Do not rotate gl_Position (surface matches the device's orientation):
+            outgoing->x     = incoming.x;
+            outgoing->y     = flipY ? framebufferHeight - incoming.y - incoming.height : incoming.y;
+            outgoing->width = incoming.width;
+            outgoing->height = incoming.height;
+            break;
+        case SurfaceRotationType::Rotated90Degrees:
+            // Rotate gl_Position 90 degrees:
+            outgoing->x      = incoming.y;
+            outgoing->y      = flipY ? incoming.x : framebufferWidth - incoming.x - incoming.width;
+            outgoing->width  = incoming.height;
+            outgoing->height = incoming.width;
+            break;
+        case SurfaceRotationType::Rotated180Degrees:
+            // Rotate gl_Position 180 degrees:
+            outgoing->x     = framebufferWidth - incoming.x - incoming.width;
+            outgoing->y     = flipY ? incoming.y : framebufferHeight - incoming.y - incoming.height;
+            outgoing->width = incoming.width;
+            outgoing->height = incoming.height;
+            break;
+        case SurfaceRotationType::Rotated270Degrees:
+            // Rotate gl_Position 270 degrees:
+            outgoing->x      = framebufferHeight - incoming.y - incoming.height;
+            outgoing->y      = flipY ? framebufferWidth - incoming.x - incoming.width : incoming.x;
+            outgoing->width  = incoming.height;
+            outgoing->height = incoming.width;
+            break;
+        default:
+            UNREACHABLE();
+            break;
+    }
+}
+
 // Should not generate a copy with modern C++.
 EventName GetTraceEventName(const char *title, uint32_t counter)
 {
@@ -2507,11 +2551,22 @@ bool ContextVk::isRotatedAspectRatioForDrawFBO() const
 {
     return IsRotatedAspectRatio(mCurrentRotationDrawFramebuffer);
 }
+
 bool ContextVk::isRotatedAspectRatioForReadFBO() const
 {
     return IsRotatedAspectRatio(mCurrentRotationReadFramebuffer);
 }
 
+SurfaceRotationType ContextVk::getRotationDrawFramebuffer() const
+{
+    return mCurrentRotationDrawFramebuffer;
+}
+
+SurfaceRotationType ContextVk::getRotationReadFramebuffer() const
+{
+    return mCurrentRotationReadFramebuffer;
+}
+
 void ContextVk::updateColorMask(const gl::BlendState &blendState)
 {
     mClearColorMask =
@@ -2579,21 +2634,17 @@ void ContextVk::updateViewport(FramebufferVk *framebufferVk,
         correctedHeight = viewportBoundsRangeHigh - correctedY;
     }
 
-    gl::Box framebufferDimensions = framebufferVk->getState().getDimensions();
-    if (isRotatedAspectRatioForDrawFBO())
-    {
-        // The surface is rotated 90/270 degrees.  This changes the aspect ratio of the surface.
-        // Swap the width and height of the viewport we calculate, and the framebuffer height that
-        // we use to calculate it with.
-        // TODO(ianelliott): handle small viewport/scissor cases.  http://anglebug.com/4431
-        std::swap(correctedWidth, correctedHeight);
-        std::swap(framebufferDimensions.width, framebufferDimensions.height);
-    }
+    gl::Box fbDimensions = framebufferVk->getState().getDimensions();
     gl::Rectangle correctedRect =
         gl::Rectangle(correctedX, correctedY, correctedWidth, correctedHeight);
-
-    gl_vk::GetViewport(correctedRect, nearPlane, farPlane, invertViewport,
-                       framebufferDimensions.height, &vkViewport);
+    gl::Rectangle rotatedRect;
+    RotateRectangle(getRotationDrawFramebuffer(), false, fbDimensions.width, fbDimensions.height,
+                    correctedRect, &rotatedRect);
+    gl_vk::GetViewport(rotatedRect, nearPlane, farPlane, invertViewport,
+                       // If the surface is rotated 90/270 degrees, use the framebuffer's width
+                       // instead of the height for calculating the final viewport.
+                       isRotatedAspectRatioForDrawFBO() ? fbDimensions.width : fbDimensions.height,
+                       &vkViewport);
     mGraphicsPipelineDesc->updateViewport(&mGraphicsPipelineTransition, vkViewport);
     invalidateGraphicsDriverUniforms();
 }
@@ -2614,20 +2665,12 @@ angle::Result ContextVk::updateScissor(const gl::State &glState)
     gl::ClipRectangle(renderArea, glState.getViewport(), &viewportClippedRenderArea);
 
     gl::Rectangle scissoredArea = ClipRectToScissor(getState(), viewportClippedRenderArea, false);
-    if (isViewportFlipEnabledForDrawFBO())
-    {
-        scissoredArea.y = renderArea.height - scissoredArea.y - scissoredArea.height;
-    }
-    if (isRotatedAspectRatioForDrawFBO())
-    {
-        // The surface is rotated 90/270 degrees.  This changes the aspect ratio of the surface.
-        // Swap the width and height of the scissor we use.
-        // TODO(ianelliott): handle small viewport/scissor cases.  http://anglebug.com/4431
-        std::swap(scissoredArea.width, scissoredArea.height);
-    }
+    gl::Rectangle rotatedScissoredArea;
+    RotateRectangle(getRotationDrawFramebuffer(), isViewportFlipEnabledForDrawFBO(),
+                    renderArea.width, renderArea.height, scissoredArea, &rotatedScissoredArea);
 
     mGraphicsPipelineDesc->updateScissor(&mGraphicsPipelineTransition,
-                                         gl_vk::GetRect(scissoredArea));
+                                         gl_vk::GetRect(rotatedScissoredArea));
 
     // If the scissor has grown beyond the previous scissoredRenderArea, make sure the render pass
     // is restarted.  Otherwise, we can continue using the same renderpass area.
@@ -3088,7 +3131,7 @@ void ContextVk::updateSurfaceRotationDrawFramebuffer(const gl::State &glState)
 void ContextVk::updateSurfaceRotationReadFramebuffer(const gl::State &glState)
 {
     gl::Framebuffer *readFramebuffer = glState.getReadFramebuffer();
-    mCurrentRotationDrawFramebuffer =
+    mCurrentRotationReadFramebuffer =
         DetermineSurfaceRotation(readFramebuffer, mCurrentWindowSurface);
 }
 

src/libANGLE/renderer/vulkan/ContextVk.h

@@ -384,6 +384,8 @@ class ContextVk : public ContextImpl, public vk::Context
     // render area must be swapped.
     bool isRotatedAspectRatioForDrawFBO() const;
     bool isRotatedAspectRatioForReadFBO() const;
+    SurfaceRotationType getRotationDrawFramebuffer() const;
+    SurfaceRotationType getRotationReadFramebuffer() const;
 
     void invalidateProgramBindingHelper(const gl::State &glState);
     angle::Result invalidateProgramExecutableHelper(const gl::Context *context);