From 26131368ecc2e16dfb4965b9165632ee3ca4f1d9 Mon Sep 17 00:00:00 2001
From: ztenghui <ztenghui@google.com>
Date: Mon, 1 Sep 2014 17:19:51 -0700
Subject: Fix the (0,0) vector case for extra vertices computation

TODO: Figure out why we have collided vertices from input polygon.

b/17340792

Change-Id: I6636ff957ef17514bd11cf290ccc0a2c302aca0b
---
 libs/hwui/AmbientShadow.cpp | 4 ++++
 1 file changed, 4 insertions(+)

(limited to 'libs/hwui/AmbientShadow.cpp')

diff --git a/libs/hwui/AmbientShadow.cpp b/libs/hwui/AmbientShadow.cpp
index 7834ef85c750..4873479fdf17 100644
--- a/libs/hwui/AmbientShadow.cpp
+++ b/libs/hwui/AmbientShadow.cpp
@@ -93,6 +93,10 @@ inline float getTransformedAlphaFromFactoredZ(float factoredZ) {
 
 inline int getExtraVertexNumber(const Vector2& vector1, const Vector2& vector2,
         float divisor) {
+    // When there is no distance difference, there is no need for extra vertices.
+    if (vector1.lengthSquared() == 0 || vector2.lengthSquared() == 0) {
+        return 0;
+    }
     // The formula is :
     // extraNumber = floor(acos(dot(n1, n2)) / (M_PI / EXTRA_VERTEX_PER_PI))
     // The value ranges for each step are:
-- 
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