Added Z scale when X and Y scale to spot lights and point lights

src/effects/SkLightingImageFilter.cpp

 /*
  * Copyright 2012 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkLightingImageFilter.h"
 #include "SkBitmap.h"
 #include "SkColorPriv.h"
@@ skipping 623 matching lines @@
         if (other.type() != kPoint_LightType) {
             return false;
         }
         const SkPointLight& o = static_cast<const SkPointLight&>(other);
         return INHERITED::isEqual(other) &&
                fLocation == o.fLocation;
     }
     virtual SkLight* transform(const SkMatrix& matrix) const {
         SkPoint location2 = SkPoint::Make(fLocation.fX, fLocation.fY);
         matrix.mapPoints(&location2, 1);
-        SkPoint3 location(location2.fX, location2.fY, fLocation.fZ);
+        // Use X scale and Y scale on Z and average the result
+        SkPoint locationZ = SkPoint::Make(fLocation.fZ, fLocation.fZ);
+        matrix.mapVectors(&locationZ, 1);
+        SkPoint3 location(location2.fX, location2.fY, SkScalarAve(locationZ.fX, locationZ.fY));
         return new SkPointLight(location, color());
     }
 
     SkPointLight(SkReadBuffer& buffer) : INHERITED(buffer) {
         fLocation = readPoint3(buffer);
     }
 
 protected:
     SkPointLight(const SkPoint3& location, const SkPoint3& color)
      : INHERITED(color), fLocation(location) {}
@@ skipping 20 matching lines @@
        fS.normalize();
        fCosOuterConeAngle = SkScalarCos(SkDegreesToRadians(cutoffAngle));
        const SkScalar antiAliasThreshold = 0.016f;
        fCosInnerConeAngle = fCosOuterConeAngle + antiAliasThreshold;
        fConeScale = SkScalarInvert(antiAliasThreshold);
     }
 
     virtual SkLight* transform(const SkMatrix& matrix) const {
         SkPoint location2 = SkPoint::Make(fLocation.fX, fLocation.fY);
         matrix.mapPoints(&location2, 1);
-        SkPoint3 location(location2.fX, location2.fY, fLocation.fZ);
+        // Use X scale and Y scale on Z and average the result
+        SkPoint locationZ = SkPoint::Make(fLocation.fZ, fLocation.fZ);
+        matrix.mapVectors(&locationZ, 1);
+        SkPoint3 location(location2.fX, location2.fY, SkScalarAve(locationZ.fX, locationZ.fY));
         SkPoint target2 = SkPoint::Make(fTarget.fX, fTarget.fY);
         matrix.mapPoints(&target2, 1);
-        SkPoint3 target(target2.fX, target2.fY, fTarget.fZ);
-        return new SkSpotLight(location, target, fSpecularExponent, fCosOuterConeAngle, fCosInnerConeAngle, fConeScale, fS, color());
+        SkPoint targetZ = SkPoint::Make(fTarget.fZ, fTarget.fZ);
+        matrix.mapVectors(&targetZ, 1);
+        SkPoint3 target(target2.fX, target2.fY, SkScalarAve(targetZ.fX, targetZ.fY));
+        SkPoint3 s = target - location;
+        s.normalize();
+        return new SkSpotLight(location, target, fSpecularExponent, fCosOuterConeAngle, fCosInnerConeAngle, fConeScale, s, color());
     }
 
     SkPoint3 surfaceToLight(int x, int y, int z, SkScalar surfaceScale) const {
         SkPoint3 direction(fLocation.fX - SkIntToScalar(x),
                            fLocation.fY - SkIntToScalar(y),
                            fLocation.fZ - SkScalarMul(SkIntToScalar(z), surfaceScale));
         direction.normalize();
         return direction;
     };
     SkPoint3 lightColor(const SkPoint3& surfaceToLight) const {
@@ skipping 908 matching lines @@
 
     builder->fsCodeAppendf("%s(%s)", fLightColorFunc.c_str(), surfaceToLight);
 }
 
 #endif
 
 SK_DEFINE_FLATTENABLE_REGISTRAR_GROUP_START(SkLightingImageFilter)
     SK_DEFINE_FLATTENABLE_REGISTRAR_ENTRY(SkDiffuseLightingImageFilter)
     SK_DEFINE_FLATTENABLE_REGISTRAR_ENTRY(SkSpecularLightingImageFilter)
 SK_DEFINE_FLATTENABLE_REGISTRAR_GROUP_END