Revert of Update feSpotLight to match spec

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 665 matching lines @@
 class GrGLLight;
 
 #endif
 
 };
 
 ///////////////////////////////////////////////////////////////////////////////
 
 class SkImageFilterLight : public SkRefCnt {
 public:
-
+    
 
     enum LightType {
         kDistant_LightType,
         kPoint_LightType,
         kSpot_LightType,
     };
     virtual LightType type() const = 0;
     const SkPoint3& color() const { return fColor; }
     virtual GrGLLight* createGLLight() const = 0;
     virtual bool isEqual(const SkImageFilterLight& other) const {
@@ skipping 116 matching lines @@
         const SkPointLight& o = static_cast<const SkPointLight&>(other);
         return INHERITED::isEqual(other) &&
                fLocation == o.fLocation;
     }
     SkImageFilterLight* transform(const SkMatrix& matrix) const override {
         SkPoint location2 = SkPoint::Make(fLocation.fX, fLocation.fY);
         matrix.mapPoints(&location2, 1);
         // 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 = SkPoint3::Make(location2.fX,
-                                           location2.fY,
+        SkPoint3 location = SkPoint3::Make(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)
@@ skipping 13 matching lines @@
 class SkSpotLight : public SkImageFilterLight {
 public:
     SkSpotLight(const SkPoint3& location,
                 const SkPoint3& target,
                 SkScalar specularExponent,
                 SkScalar cutoffAngle,
                 SkColor color)
      : INHERITED(color),
        fLocation(location),
        fTarget(target),
-       fSpecularExponent(specularExponent)
+       fSpecularExponent(SkScalarPin(specularExponent, kSpecularExponentMin, kSpecularExponentMax))
     {
        fS = target - location;
        fast_normalize(&fS);
        fCosOuterConeAngle = SkScalarCos(SkDegreesToRadians(cutoffAngle));
        const SkScalar antiAliasThreshold = 0.016f;
        fCosInnerConeAngle = fCosOuterConeAngle + antiAliasThreshold;
        fConeScale = SkScalarInvert(antiAliasThreshold);
     }
 
     SkImageFilterLight* transform(const SkMatrix& matrix) const override {
@@ skipping 109 matching lines @@
 
         const SkSpotLight& o = static_cast<const SkSpotLight&>(other);
         return INHERITED::isEqual(other) &&
                fLocation == o.fLocation &&
                fTarget == o.fTarget &&
                fSpecularExponent == o.fSpecularExponent &&
                fCosOuterConeAngle == o.fCosOuterConeAngle;
     }
 
 private:
+    static const SkScalar kSpecularExponentMin;
+    static const SkScalar kSpecularExponentMax;
+
     SkPoint3 fLocation;
     SkPoint3 fTarget;
     SkScalar fSpecularExponent;
     SkScalar fCosOuterConeAngle;
     SkScalar fCosInnerConeAngle;
     SkScalar fConeScale;
     SkPoint3 fS;
 
     typedef SkImageFilterLight INHERITED;
 };
 
+// According to the spec, the specular term should be in the range [1, 128] :
+// http://www.w3.org/TR/SVG/filters.html#feSpecularLightingSpecularExponentAttribute
+const SkScalar SkSpotLight::kSpecularExponentMin = 1.0f;
+const SkScalar SkSpotLight::kSpecularExponentMax = 128.0f;
+
 ///////////////////////////////////////////////////////////////////////////////
 
 void SkImageFilterLight::flattenLight(SkWriteBuffer& buffer) const {
     // Write type first, then baseclass, then subclass.
     buffer.writeInt(this->type());
     writePoint3(fColor, buffer);
     this->onFlattenLight(buffer);
 }
 
 /*static*/ SkImageFilterLight* SkImageFilterLight::UnflattenLight(SkReadBuffer& buffer) {
@@ skipping 972 matching lines @@
     SkString lightColorBody;
     lightColorBody.appendf("\tfloat cosAngle = -dot(surfaceToLight, %s);\n", s);
     lightColorBody.appendf("\tif (cosAngle < %s) {\n", cosOuter);
     lightColorBody.appendf("\t\treturn vec3(0);\n");
     lightColorBody.appendf("\t}\n");
     lightColorBody.appendf("\tfloat scale = pow(cosAngle, %s);\n", exponent);
     lightColorBody.appendf("\tif (cosAngle < %s) {\n", cosInner);
     lightColorBody.appendf("\t\treturn %s * scale * (cosAngle - %s) * %s;\n",
                            color, cosOuter, coneScale);
     lightColorBody.appendf("\t}\n");
-    lightColorBody.appendf("\treturn %s * scale;\n", color);
+    lightColorBody.appendf("\treturn %s;\n", color);
     GrGLFragmentBuilder* fsBuilder = builder->getFragmentShaderBuilder();
     fsBuilder->emitFunction(kVec3f_GrSLType,
                             "lightColor",
                             SK_ARRAY_COUNT(gLightColorArgs),
                             gLightColorArgs,
                             lightColorBody.c_str(),
                             &fLightColorFunc);
 
     fsBuilder->codeAppendf("%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