Use Skia's mapMScalars() for mapping homogeneous points.

Skia provides a point mapping method, so we don't need to roll
our own.  This deletes some unnecessary code and with any luck compiles
to faster code.

NOTRY=true
BUG=none

Review URL: https://chromiumcodereview.appspot.com/21161004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@214719 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 23 insertions, 62 deletions

diff --git a/cc/base/math_util.cc b/cc/base/math_util.cc
index 5443956..39a183e 100644
--- a/cc/base/math_util.cc
+++ b/cc/base/math_util.cc
@@ -29,63 +29,24 @@ static HomogeneousCoordinate ProjectHomogeneousPoint(
   // 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.matrix().getDouble(2, 2))
+  if (!transform.matrix().get(2, 2))
     return HomogeneousCoordinate(0.0, 0.0, 0.0, 1.0);
 
-  double x = p.x();
-  double y = p.y();
-  double z = -(transform.matrix().getDouble(2, 0) * x +
-               transform.matrix().getDouble(2, 1) * y +
-               transform.matrix().getDouble(2, 3)) /
-             transform.matrix().getDouble(2, 2);
-  // implicit definition of w = 1;
-
-  double out_x = x * transform.matrix().getDouble(0, 0) +
-                 y * transform.matrix().getDouble(0, 1) +
-                 z * transform.matrix().getDouble(0, 2) +
-                 transform.matrix().getDouble(0, 3);
-  double out_y = x * transform.matrix().getDouble(1, 0) +
-                 y * transform.matrix().getDouble(1, 1) +
-                 z * transform.matrix().getDouble(1, 2) +
-                 transform.matrix().getDouble(1, 3);
-  double out_z = x * transform.matrix().getDouble(2, 0) +
-                 y * transform.matrix().getDouble(2, 1) +
-                 z * transform.matrix().getDouble(2, 2) +
-                 transform.matrix().getDouble(2, 3);
-  double out_w = x * transform.matrix().getDouble(3, 0) +
-                 y * transform.matrix().getDouble(3, 1) +
-                 z * transform.matrix().getDouble(3, 2) +
-                 transform.matrix().getDouble(3, 3);
-
-  return HomogeneousCoordinate(out_x, out_y, out_z, out_w);
+  SkMScalar z = -(transform.matrix().get(2, 0) * p.x() +
+             transform.matrix().get(2, 1) * p.y() +
+             transform.matrix().get(2, 3)) /
+             transform.matrix().get(2, 2);
+  HomogeneousCoordinate result(p.x(), p.y(), z, 1.0);
+  transform.matrix().mapMScalars(result.vec, result.vec);
+  return result;
 }
 
 static HomogeneousCoordinate MapHomogeneousPoint(
     const gfx::Transform& transform,
     const gfx::Point3F& p) {
-  double x = p.x();
-  double y = p.y();
-  double z = p.z();
-  // implicit definition of w = 1;
-
-  double out_x = x * transform.matrix().getDouble(0, 0) +
-                 y * transform.matrix().getDouble(0, 1) +
-                 z * transform.matrix().getDouble(0, 2) +
-                 transform.matrix().getDouble(0, 3);
-  double out_y = x * transform.matrix().getDouble(1, 0) +
-                 y * transform.matrix().getDouble(1, 1) +
-                 z * transform.matrix().getDouble(1, 2) +
-                 transform.matrix().getDouble(1, 3);
-  double out_z = x * transform.matrix().getDouble(2, 0) +
-                 y * transform.matrix().getDouble(2, 1) +
-                 z * transform.matrix().getDouble(2, 2) +
-                 transform.matrix().getDouble(2, 3);
-  double out_w = x * transform.matrix().getDouble(3, 0) +
-                 y * transform.matrix().getDouble(3, 1) +
-                 z * transform.matrix().getDouble(3, 2) +
-                 transform.matrix().getDouble(3, 3);
-
-  return HomogeneousCoordinate(out_x, out_y, out_z, out_w);
+  HomogeneousCoordinate result(p.x(), p.y(), p.z(), 1.0);
+  transform.matrix().mapMScalars(result.vec, result.vec);
+  return result;
 }
 
 static HomogeneousCoordinate ComputeClippedPointForEdge(
@@ -106,18 +67,18 @@ static HomogeneousCoordinate ComputeClippedPointForEdge(
 
   // Technically this is a special case of the following assertion, but its a
   // good idea to keep it an explicit sanity check here.
-  DCHECK_NE(h2.w, h1.w);
+  DCHECK_NE(h2.w(), h1.w());
   // Exactly one of h1 or h2 (but not both) must be on the negative side of the
   // w plane when this is called.
   DCHECK(h1.ShouldBeClipped() ^ h2.ShouldBeClipped());
 
-  double w = 0.00001;  // or any positive non-zero small epsilon
+  SkMScalar w = 0.00001;  // or any positive non-zero small epsilon
 
-  double t = (w - h1.w) / (h2.w - h1.w);
+  SkMScalar t = (w - h1.w()) / (h2.w() - h1.w());
 
-  double x = (1 - t) * h1.x + t * h2.x;
-  double y = (1 - t) * h1.y + t * h2.y;
-  double z = (1 - t) * h1.z + t * h2.z;
+  SkMScalar x = (1 - t) * h1.x() + t * h2.x();
+  SkMScalar y = (1 - t) * h1.y() + t * h2.y();
+  SkMScalar z = (1 - t) * h1.z() + t * h2.z();
 
   return HomogeneousCoordinate(x, y, z, w);
 }
@@ -400,7 +361,7 @@ gfx::PointF MathUtil::MapPoint(const gfx::Transform& transform,
                                bool* clipped) {
   HomogeneousCoordinate h = MapHomogeneousPoint(transform, gfx::Point3F(p));
 
-  if (h.w > 0) {
+  if (h.w() > 0) {
     *clipped = false;
     return h.CartesianPoint2d();
   }
@@ -409,7 +370,7 @@ gfx::PointF MathUtil::MapPoint(const gfx::Transform& transform,
   *clipped = true;
 
   // Avoid dividing by w if w == 0.
-  if (!h.w)
+  if (!h.w())
     return gfx::PointF();
 
   // This return value will be invalid because clipped == true, but (1) users of
@@ -424,7 +385,7 @@ gfx::Point3F MathUtil::MapPoint(const gfx::Transform& transform,
                                 bool* clipped) {
   HomogeneousCoordinate h = MapHomogeneousPoint(transform, p);
 
-  if (h.w > 0) {
+  if (h.w() > 0) {
     *clipped = false;
     return h.CartesianPoint3d();
   }
@@ -433,7 +394,7 @@ gfx::Point3F MathUtil::MapPoint(const gfx::Transform& transform,
   *clipped = true;
 
   // Avoid dividing by w if w == 0.
-  if (!h.w)
+  if (!h.w())
     return gfx::Point3F();
 
   // This return value will be invalid because clipped == true, but (1) users of
@@ -465,7 +426,7 @@ gfx::PointF MathUtil::ProjectPoint(const gfx::Transform& transform,
                                    bool* clipped) {
   HomogeneousCoordinate h = ProjectHomogeneousPoint(transform, p);
 
-  if (h.w > 0) {
+  if (h.w() > 0) {
     // The cartesian coordinates will be valid in this case.
     *clipped = false;
     return h.CartesianPoint2d();
@@ -475,7 +436,7 @@ gfx::PointF MathUtil::ProjectPoint(const gfx::Transform& transform,
   *clipped = true;
 
   // Avoid dividing by w if w == 0.
-  if (!h.w)
+  if (!h.w())
     return gfx::PointF();
 
   // This return value will be invalid because clipped == true, but (1) users of