commit c9691d57787e43ad26ac6edb3880d25365c4a43e
author Lucas Dupin <dupin@google.com> Thu Sep 26 13:46:04 2019 -0700
committer Lucas Dupin <dupin@google.com> Thu Sep 26 13:50:36 2019 -0700
tree c5a9d0063912583e325e49062f5d819ef8ac2a14
parent b1fef3f70dde5e6310dca8333c4defe1723ac701

Fix rounded corner scission clipping

In cases where the corner radius is too big, the middle section that's
rendered without blending might have negative size, causing drawing
artifacts.

Test: manual, by slowing down app launch animation
Fixes: 141612402
Change-Id: I901e6b77791207360d06dea30496b7cbb65041c4

libs/renderengine/gl/GLESRenderEngine.cpp

diff --git a/libs/renderengine/gl/GLESRenderEngine.cpp b/libs/renderengine/gl/GLESRenderEngine.cpp
index dd4c55d..f39f066 100644
--- a/libs/renderengine/gl/GLESRenderEngine.cpp
+++ b/libs/renderengine/gl/GLESRenderEngine.cpp
@@ -827,11 +827,14 @@
     drawMesh(mesh);
 
     // The middle part of the layer can turn off blending.
-    const Rect middleRect(bounds.left, bounds.top + radius, bounds.right, bounds.bottom - radius);
-    setScissor(middleRect);
-    mState.cornerRadius = 0.0;
-    disableBlending();
-    drawMesh(mesh);
+    if (topRect.bottom < bottomRect.top) {
+        const Rect middleRect(bounds.left, bounds.top + radius, bounds.right,
+                              bounds.bottom - radius);
+        setScissor(middleRect);
+        mState.cornerRadius = 0.0;
+        disableBlending();
+        drawMesh(mesh);
+    }
     disableScissor();
 }