- Revision
- 116332
- Author
- shawnsi...@chromium.org
- Date
- 2012-05-07 11:48:06 -0700 (Mon, 07 May 2012)
Log Message
[chromium] CCMathUtil projectPoint needs to avoid divide-by-zero
https://bugs.webkit.org/show_bug.cgi?id=85560
Reviewed by Adrienne Walker.
Source/WebCore:
Unit test added: CCMathUtilTest.cpp - verifyProjectionOfPerpendicularPlane
Unit test updated/renamed: CCLayerTreeHostCommonTest.cpp - verifyVisibleRectFor3dPerspectiveWhenClippedByW
The divide-by-zero occurs in an innocuous case where the layers
are probably invisible anyway. However, producing Infs and NaNs
could cause values to be used when un-intended, so its appropriate
to handle the divide-by-zero correctly.
* platform/graphics/chromium/cc/CCMathUtil.cpp:
(WebCore::projectPoint):
Source/WebKit/chromium:
* tests/CCLayerTreeHostCommonTest.cpp:
(WebKitTests::TEST):
* tests/CCMathUtilTest.cpp:
(WebCore::TEST):
(WebCore):
Modified Paths
Diff
Modified: trunk/Source/WebCore/ChangeLog (116331 => 116332)
--- trunk/Source/WebCore/ChangeLog 2012-05-07 18:41:08 UTC (rev 116331)
+++ trunk/Source/WebCore/ChangeLog 2012-05-07 18:48:06 UTC (rev 116332)
@@ -1,3 +1,21 @@
+2012-05-07 Shawn Singh <shawnsi...@chromium.org>
+
+ [chromium] CCMathUtil projectPoint needs to avoid divide-by-zero
+ https://bugs.webkit.org/show_bug.cgi?id=85560
+
+ Reviewed by Adrienne Walker.
+
+ Unit test added: CCMathUtilTest.cpp - verifyProjectionOfPerpendicularPlane
+ Unit test updated/renamed: CCLayerTreeHostCommonTest.cpp - verifyVisibleRectFor3dPerspectiveWhenClippedByW
+
+ The divide-by-zero occurs in an innocuous case where the layers
+ are probably invisible anyway. However, producing Infs and NaNs
+ could cause values to be used when un-intended, so its appropriate
+ to handle the divide-by-zero correctly.
+
+ * platform/graphics/chromium/cc/CCMathUtil.cpp:
+ (WebCore::projectPoint):
+
2012-05-07 Pravin D <pravind....@gmail.com>
Wrong positioning due to wrong width calculation wrt width:0
Modified: trunk/Source/WebCore/platform/graphics/chromium/cc/CCMathUtil.cpp (116331 => 116332)
--- trunk/Source/WebCore/platform/graphics/chromium/cc/CCMathUtil.cpp 2012-05-07 18:41:08 UTC (rev 116331)
+++ trunk/Source/WebCore/platform/graphics/chromium/cc/CCMathUtil.cpp 2012-05-07 18:48:06 UTC (rev 116332)
@@ -66,6 +66,13 @@
static HomogeneousCoordinate projectPoint(const TransformationMatrix& transform, const FloatPoint& p)
{
+ // In this case, the layer we are trying to project onto is perpendicular to ray
+ // (point p and z-axis direction) that we are trying to project. This happens when the
+ // layer is rotated so that it is infinitesimally thin, or when it is co-planar with
+ // the camera origin -- i.e. when the layer is invisible anyway.
+ if (!transform.m33())
+ return HomogeneousCoordinate(0, 0, 0, 1);
+
double x = p.x();
double y = p.y();
double z = -(transform.m13() * x + transform.m23() * y + transform.m43()) / transform.m33();
Modified: trunk/Source/WebKit/chromium/ChangeLog (116331 => 116332)
--- trunk/Source/WebKit/chromium/ChangeLog 2012-05-07 18:41:08 UTC (rev 116331)
+++ trunk/Source/WebKit/chromium/ChangeLog 2012-05-07 18:48:06 UTC (rev 116332)
@@ -1,3 +1,16 @@
+2012-05-07 Shawn Singh <shawnsi...@chromium.org>
+
+ [chromium] CCMathUtil projectPoint needs to avoid divide-by-zero
+ https://bugs.webkit.org/show_bug.cgi?id=85560
+
+ Reviewed by Adrienne Walker.
+
+ * tests/CCLayerTreeHostCommonTest.cpp:
+ (WebKitTests::TEST):
+ * tests/CCMathUtilTest.cpp:
+ (WebCore::TEST):
+ (WebCore):
+
2012-05-07 Nat Duca <nd...@chromium.org>
Unreviewed, rolling out r115525.
Modified: trunk/Source/WebKit/chromium/tests/CCLayerTreeHostCommonTest.cpp (116331 => 116332)
--- trunk/Source/WebKit/chromium/tests/CCLayerTreeHostCommonTest.cpp 2012-05-07 18:41:08 UTC (rev 116331)
+++ trunk/Source/WebKit/chromium/tests/CCLayerTreeHostCommonTest.cpp 2012-05-07 18:48:06 UTC (rev 116332)
@@ -1172,7 +1172,7 @@
EXPECT_INT_RECT_EQ(expected, actual);
}
-TEST(CCLayerTreeHostCommonTest, verifyVisibleRectFor3dPerspectiveIsClipped)
+TEST(CCLayerTreeHostCommonTest, verifyVisibleRectFor3dPerspectiveWhenClippedByW)
{
// Test the calculateVisibleRect() function works correctly when projecting a surface
// onto a layer, but the layer is partially behind the camera (not just behind the
@@ -1190,7 +1190,7 @@
// center of the layer.
layerToSurfaceTransform.makeIdentity();
layerToSurfaceTransform.applyPerspective(1);
- layerToSurfaceTransform.translate3d(0, 0, 1);
+ layerToSurfaceTransform.translate3d(-1, 0, 1);
layerToSurfaceTransform.rotate3d(0, 45, 0);
// Sanity check that this transform does indeed cause w < 0 when applying the
@@ -1199,7 +1199,7 @@
CCMathUtil::mapQuad(layerToSurfaceTransform, FloatQuad(FloatRect(layerContentRect)), clipped);
ASSERT_TRUE(clipped);
- int expectedXPosition = -10;
+ int expectedXPosition = 0;
int expectedWidth = 10;
IntRect actual = CCLayerTreeHostCommon::calculateVisibleRect(targetSurfaceRect, layerContentRect, layerToSurfaceTransform);
EXPECT_EQ(expectedXPosition, actual.x());
Modified: trunk/Source/WebKit/chromium/tests/CCMathUtilTest.cpp (116331 => 116332)
--- trunk/Source/WebKit/chromium/tests/CCMathUtilTest.cpp 2012-05-07 18:41:08 UTC (rev 116331)
+++ trunk/Source/WebKit/chromium/tests/CCMathUtilTest.cpp 2012-05-07 18:48:06 UTC (rev 116332)
@@ -99,4 +99,21 @@
EXPECT_TRUE(layerSpaceToProjectionPlane.isBackFaceVisible());
}
+TEST(CCMathUtilTest, verifyProjectionOfPerpendicularPlane)
+{
+ // In this case, the m33() element of the transform becomes zero, which could cause a
+ // divide-by-zero when projecting points/quads.
+
+ TransformationMatrix transform;
+ transform.makeIdentity();
+ transform.setM33(0);
+
+ FloatRect rect = FloatRect(0, 0, 1, 1);
+ FloatRect projectedRect = CCMathUtil::projectClippedRect(transform, rect);
+
+ EXPECT_EQ(0, projectedRect.x());
+ EXPECT_EQ(0, projectedRect.y());
+ EXPECT_TRUE(projectedRect.isEmpty());
+}
+
} // namespace
