Bug 1245242 - Normalize to unit vector for DOMMatrix.rotateAxisAngleSelf. r=roc

dom/base/DOMMatrix.cpp

@@ -552,22 +552,10 @@ DOMMatrix::RotateAxisAngleSelf(double aX, double aY,
   }
 
   aAngle *= radPerDegree;
-  // sin(aAngle / 2) * cos(aAngle / 2)
-  double sc = sin(aAngle) / 2;
-  // pow(sin(aAngle / 2), 2)
-  double sq = (1 - cos(aAngle)) / 2;
 
   Ensure3DMatrix();
   gfx::Matrix4x4 m;
-  m._11 = 1 - 2 * (aY * aY + aZ * aZ) * sq;
-  m._12 = 2 * (aX * aY * sq + aZ * sc);
-  m._13 = 2 * (aX * aZ * sq - aY * sc);
-  m._21 = 2 * (aX * aY * sq - aZ * sc);
-  m._22 = 1 - 2 * (aX * aX + aZ * aZ) * sq;
-  m._23 = 2 * (aY * aZ * sq + aX * sc);
-  m._31 = 2 * (aX * aZ * sq + aY * sc);
-  m._32 = 2 * (aY * aZ * sq - aX * sc);
-  m._33 = 1 - 2 * (aX * aX + aY * aY) * sq;
+  m.SetRotateAxisAngle(aX, aY, aZ, aAngle);
 
   *mMatrix3D = m * *mMatrix3D;
 

dom/tests/mochitest/general/test_WebKitCSSMatrix.html

@@ -323,4 +323,14 @@ test(function() {
   assert_throws("SyntaxError", function() { new WebKitCSSMatrix("initial"); }, "initial is not a valid constructor argument.")
   assert_throws("SyntaxError", function() { new WebKitCSSMatrix("inherit"); }, "inherit is not a valid constructor arugment.")
 }, "Test invalid constructor arguments.");
+
+test(function() {
+  var m1 = new WebKitCSSMatrix();
+  m1 = m1.rotateAxisAngle(0, 0, 1, 45);
+
+  var m2 = new WebKitCSSMatrix();
+  m2 = m2.rotateAxisAngle(0, 0, 3, 45);
+
+  assert_true(RoughCompareMatrix(m1, m2), "rotateAxisAngle should normalize vector to unit vector.");
+}, "Test normalization of vector for rotateAxisAngle");
 </script>

gfx/2d/Matrix.h

@@ -1433,6 +1433,48 @@ public:
     _24 = -sinTheta * temp + cosTheta * _24;
   }
 
+  // Sets this matrix to a rotation matrix about a
+  // vector [x,y,z] by angle theta. The vector is normalized
+  // to a unit vector.
+  // https://www.w3.org/TR/css3-3d-transforms/#Rotate3dDefined
+  void SetRotateAxisAngle(double aX, double aY, double aZ, double aTheta)
+  {
+    Point3D vector(aX, aY, aZ);
+    if (!vector.Length()) {
+      return;
+    }
+    vector.Normalize();
+
+    double x = vector.x;
+    double y = vector.y;
+    double z = vector.z;
+
+    double cosTheta = FlushToZero(cos(aTheta));
+    double sinTheta = FlushToZero(sin(aTheta));
+
+    // sin(aTheta / 2) * cos(aTheta / 2)
+    double sc = sinTheta / 2;
+    // pow(sin(aTheta / 2), 2)
+    double sq = (1 - cosTheta) / 2;
+
+    _11 = 1 - 2 * (y * y + z * z) * sq;
+    _12 = 2 * (x * y * sq + z * sc);
+    _13 = 2 * (x * z * sq - y * sc);
+    _14 = 0.0f;
+    _21 = 2 * (x * y * sq - z * sc);
+    _22 = 1 - 2 * (x * x + z * z) * sq;
+    _23 = 2 * (y * z * sq + x * sc);
+    _24 = 0.0f;
+    _31 = 2 * (x * z * sq + y * sc);
+    _32 = 2 * (y * z * sq - x * sc);
+    _33 = 1 - 2 * (x * x + y * y) * sq;
+    _34 = 0.0f;
+    _41 = 0.0f;
+    _42 = 0.0f;
+    _43 = 0.0f;
+    _44 = 1.0f;
+  }
+
   void Perspective(float aDepth)
   {
     MOZ_ASSERT(aDepth > 0.0f, "Perspective must be positive!");

layout/style/nsStyleTransformMatrix.cpp

@@ -134,17 +134,6 @@ TransformReferenceBox::Init(const nsSize& aDimensions)
   mIsCached = true;
 }
 
-/* Force small values to zero.  We do this to avoid having sin(360deg)
- * evaluate to a tiny but nonzero value.
- */
-static double FlushToZero(double aVal)
-{
-  if (-FLT_EPSILON < aVal && aVal < FLT_EPSILON)
-    return 0.0f;
-  else
-    return aVal;
-}
-
 float
 ProcessTranslatePart(const nsCSSValue& aValue,
                      nsStyleContext* aContext,
@@ -543,50 +532,13 @@ ProcessRotate3D(Matrix4x4& aMatrix, const nsCSSValue::Array* aData)
 {
   NS_PRECONDITION(aData->Count() == 5, "Invalid array!");
 
-  /* We want our matrix to look like this:
-   * |       1 + (1-cos(angle))*(x*x-1)   -z*sin(angle)+(1-cos(angle))*x*y   y*sin(angle)+(1-cos(angle))*x*z   0 |
-   * |  z*sin(angle)+(1-cos(angle))*x*y         1 + (1-cos(angle))*(y*y-1)  -x*sin(angle)+(1-cos(angle))*y*z   0 |
-   * | -y*sin(angle)+(1-cos(angle))*x*z    x*sin(angle)+(1-cos(angle))*y*z        1 + (1-cos(angle))*(z*z-1)   0 |
-   * |                                0                                  0                                 0   1 |
-   * (see http://www.w3.org/TR/css3-3d-transforms/#transform-functions)
-   */
-
-  /* The current spec specifies a matrix that rotates in the wrong direction. For now we just negate
-   * the angle provided to get the correct rotation direction until the spec is updated.
-   * See bug 704468.
-   */
-  double theta = -aData->Item(4).GetAngleValueInRadians();
-  float cosTheta = FlushToZero(cos(theta));
-  float sinTheta = FlushToZero(sin(theta));
-
-  Point3D vector(aData->Item(1).GetFloatValue(),
-                 aData->Item(2).GetFloatValue(),
-                 aData->Item(3).GetFloatValue());
-
-  if (!vector.Length()) {
-    return;
-  }
-  vector.Normalize();
+  double theta = aData->Item(4).GetAngleValueInRadians();
+  float x = aData->Item(1).GetFloatValue();
+  float y = aData->Item(2).GetFloatValue();
+  float z = aData->Item(3).GetFloatValue();
 
   Matrix4x4 temp;
-
-  /* Create our matrix */
-  temp._11 = 1 + (1 - cosTheta) * (vector.x * vector.x - 1);
-  temp._12 = -vector.z * sinTheta + (1 - cosTheta) * vector.x * vector.y;
-  temp._13 = vector.y * sinTheta + (1 - cosTheta) * vector.x * vector.z;
-  temp._14 = 0.0f;
-  temp._21 = vector.z * sinTheta + (1 - cosTheta) * vector.x * vector.y;
-  temp._22 = 1 + (1 - cosTheta) * (vector.y * vector.y - 1);
-  temp._23 = -vector.x * sinTheta + (1 - cosTheta) * vector.y * vector.z;
-  temp._24 = 0.0f;
-  temp._31 = -vector.y * sinTheta + (1 - cosTheta) * vector.x * vector.z;
-  temp._32 = vector.x * sinTheta + (1 - cosTheta) * vector.y * vector.z;
-  temp._33 = 1 + (1 - cosTheta) * (vector.z * vector.z - 1);
-  temp._34 = 0.0f;
-  temp._41 = 0.0f;
-  temp._42 = 0.0f;
-  temp._43 = 0.0f;
-  temp._44 = 1.0f;
+  temp.SetRotateAxisAngle(x, y, z, theta);
 
   aMatrix = temp * aMatrix;
 }