Revert "Update SkLightingShader to support rotation"

This reverts commit 45b59ed6e4e231814dbdb9f707b3d2a7ee50de84.

TBR=herb@google.com

Review URL: https://codereview.chromium.org/1304673002

7 files changed, 146 insertions, 518 deletions

diff --git a/src/core/SkLight.h b/src/core/SkLight.h
deleted file mode 100644
index 4a6e149c76..0000000000
--- a/src/core/SkLight.h
+++ /dev/null
@@ -1,56 +0,0 @@
-
-/*
- * Copyright 2015 Google Inc.
- *
- * Use of this source code is governed by a BSD-style license that can be
- * found in the LICENSE file.
- */
-
-#ifndef SkLight_DEFINED
-#define SkLight_DEFINED
-
-#include "SkPoint3.h"
-
-class SK_API SkLight {
-public:
-    enum LightType {
-        kAmbient_LightType,       // only 'fColor' is used
-        kDirectional_LightType
-    };
-
-    SkLight() : fType(kAmbient_LightType) {
-        fColor.set(0.0f, 0.0f, 0.0f);
-        fDirection.set(0.0f, 0.0f, 1.0f);
-    }
-
-    SkLight(const SkColor3f& color)
-        : fType(kAmbient_LightType)
-        , fColor(color) {
-        fDirection.set(0.0f, 0.0f, 1.0f);
-    }
-
-    SkLight(const SkColor3f& color, const SkVector3& dir)
-        : fType(kDirectional_LightType)
-        , fColor(color)
-        , fDirection(dir) {
-        if (!fDirection.normalize()) {
-            fDirection.set(0.0f, 0.0f, 1.0f);
-        }
-    }
-
-    LightType type() const { return fType; }
-    const SkColor3f& color() const { return fColor; }
-    const SkVector3& dir() const { 
-        SkASSERT(kAmbient_LightType != fType);
-        return fDirection; 
-    }
-
-private:
-    LightType   fType;
-    SkColor3f   fColor;           // linear (unpremul) color. Range is 0..1 in each channel.
-    SkVector3   fDirection;       // direction towards the light (+Z is out of the screen).
-                                  // If degenerate, it will be replaced with (0, 0, 1).
-};
-
-
-#endif
diff --git a/src/core/SkPoint3.h b/src/core/SkPoint3.h
deleted file mode 100644
index af24a8df58..0000000000
--- a/src/core/SkPoint3.h
+++ /dev/null
@@ -1,124 +0,0 @@
-/*
- * Copyright 2015 Google Inc.
- *
- * Use of this source code is governed by a BSD-style license that can be
- * found in the LICENSE file.
- */
-
-#ifndef SkPoint3_DEFINED
-#define SkPoint3_DEFINED
-
-#include "SkScalar.h"
-
-struct SK_API SkPoint3 {
-    SkScalar fX, fY, fZ;
-
-    static SkPoint3 Make(SkScalar x, SkScalar y, SkScalar z) {
-        SkPoint3 pt;
-        pt.set(x, y, z);
-        return pt;
-    }
-
-    SkScalar x() const { return fX; }
-    SkScalar y() const { return fY; }
-    SkScalar z() const { return fZ; }
-
-    void set(SkScalar x, SkScalar y, SkScalar z) { fX = x; fY = y; fZ = z; }
-
-    friend bool operator==(const SkPoint3& a, const SkPoint3& b) {
-        return a.fX == b.fX && a.fY == b.fY && a.fZ == b.fZ;
-    }
-
-    friend bool operator!=(const SkPoint3& a, const SkPoint3& b) {
-        return !(a == b);
-    }
-
-    /** Returns the Euclidian distance from (0,0,0) to (x,y,z)
-    */
-    static SkScalar Length(SkScalar x, SkScalar y, SkScalar z);
-
-    /** Return the Euclidian distance from (0,0,0) to the point
-    */
-    SkScalar length() const { return SkPoint3::Length(fX, fY, fZ); }
-
-    /** Set the point (vector) to be unit-length in the same direction as it
-        already points.  If the point has a degenerate length (i.e., nearly 0)
-        then set it to (0,0,0) and return false; otherwise return true.
-    */
-    bool normalize();
-
-    /** Return a new point whose X, Y and Z coordinates are scaled.
-    */
-    SkPoint3 makeScale(SkScalar scale) const {
-        SkPoint3 p;
-        p.set(scale * fX, scale * fY, scale * fZ);
-        return p;
-    }
-
-    /** Scale the point's coordinates by scale.
-    */
-    void scale(SkScalar value) { 
-        fX *= value;
-        fY *= value;
-        fZ *= value;
-    }
-
-    /** Return a new point whose X, Y and Z coordinates are the negative of the
-        original point's
-    */
-    SkPoint3 operator-() const {
-        SkPoint3 neg;
-        neg.fX = -fX;
-        neg.fY = -fY;
-        neg.fZ = -fZ;
-        return neg;
-    }
-
-    /** Returns a new point whose coordinates are the difference between
-        a and b (i.e., a - b)
-    */
-    friend SkPoint3 operator-(const SkPoint3& a, const SkPoint3& b) {
-        SkPoint3 v;
-        v.set(a.fX - b.fX, a.fY - b.fY, a.fZ - b.fZ);
-        return v;
-    }
-
-    /** Returns a new point whose coordinates are the sum of a and b (a + b)
-    */
-    friend SkPoint3 operator+(const SkPoint3& a, const SkPoint3& b) {
-        SkPoint3 v;
-        v.set(a.fX + b.fX, a.fY + b.fY, a.fZ + b.fZ);
-        return v;
-    }
-
-    /** Add v's coordinates to the point's
-    */
-    void operator+=(const SkPoint3& v) {
-        fX += v.fX;
-        fY += v.fY;
-        fZ += v.fZ;
-    }
-
-    /** Subtract v's coordinates from the point's
-    */
-    void operator-=(const SkPoint3& v) {
-        fX -= v.fX;
-        fY -= v.fY;
-        fZ -= v.fZ;
-    }
-
-    /** Returns the dot product of a and b, treating them as 3D vectors
-    */
-    static SkScalar DotProduct(const SkPoint3& a, const SkPoint3& b) {
-        return a.fX * b.fX + a.fY * b.fY + a.fZ * b.fZ;
-    }
-
-    SkScalar dot(const SkPoint3& vec) const {
-        return DotProduct(*this, vec);
-    }
-};
-
-typedef SkPoint3 SkVector3;
-typedef SkPoint3 SkColor3f;
-
-#endif
diff --git a/src/core/SkLightingShader.cpp b/src/effects/SkLightingShader.cpp
index ce5c0ddb25..d441d9ba9f 100644
--- a/src/core/SkLightingShader.cpp
+++ b/src/effects/SkLightingShader.cpp
@@ -12,7 +12,6 @@
 #include "SkErrorInternals.h"
 #include "SkLightingShader.h"
 #include "SkMathPriv.h"
-#include "SkPoint3.h"
 #include "SkReadBuffer.h"
 #include "SkWriteBuffer.h"
 
@@ -41,33 +40,24 @@
 class SK_API SkLightingShaderImpl : public SkShader {
 public:
 
-    /** Create a new lighting shader that uses the provided normal map and
-        lights to light the diffuse bitmap.
-        @param diffuse    the diffuse bitmap
-        @param normal     the normal map
-        @param lights     the lights applied to the normal map
-        @param invNormRotation rotation applied to the normal map's normals
-        @param diffLocalM the local matrix for the diffuse coordinates
-        @param normLocalM the local matrix for the normal coordinates
+    /** Create a new lighting shader that use the provided normal map, light
+        and ambient color to light the diffuse bitmap.
+        @param diffuse the diffuse bitmap
+        @param normal  the normal map
+        @param light   the light applied to the normal map
+        @param ambient the linear (unpremul) ambient light color
     */
     SkLightingShaderImpl(const SkBitmap& diffuse, const SkBitmap& normal,
-                         const SkLightingShader::Lights* lights,
-                         const SkVector& invNormRotation,
-                         const SkMatrix* diffLocalM, const SkMatrix* normLocalM) 
-        : INHERITED(diffLocalM)
+                         const SkLightingShader::Light& light,
+                         const SkColor3f& ambient, const SkMatrix* localMatrix) 
+        : INHERITED(localMatrix)
         , fDiffuseMap(diffuse)
         , fNormalMap(normal)
-        , fLights(SkRef(lights))
-        , fInvNormRotation(invNormRotation) {
-
-        if (normLocalM) {
-            fNormLocalMatrix = *normLocalM;
-        } else {
-            fNormLocalMatrix.reset();
+        , fLight(light)
+        , fAmbientColor(ambient) {
+        if (!fLight.fDirection.normalize()) {
+            fLight.fDirection = SkPoint3::Make(0.0f, 0.0f, 1.0f);
         }
-        // Pre-cache so future calls to fNormLocalMatrix.getType() are threadsafe.
-        (void)fNormLocalMatrix.getType();
-
     }
 
     bool isOpaque() const override;
@@ -104,16 +94,12 @@ public:
 protected:
     void flatten(SkWriteBuffer&) const override;
     Context* onCreateContext(const ContextRec&, void*) const override;
-    bool computeNormTotalInverse(const ContextRec& rec, SkMatrix* normTotalInverse) const;
 
 private:
-    SkBitmap  fDiffuseMap;
-    SkBitmap  fNormalMap;
-
-    SkAutoTUnref<const SkLightingShader::Lights>   fLights;
-
-    SkMatrix  fNormLocalMatrix;
-    SkVector  fInvNormRotation;
+    SkBitmap                fDiffuseMap;
+    SkBitmap                fNormalMap;
+    SkLightingShader::Light fLight;
+    SkColor3f               fAmbientColor;  // linear (unpremul) color. Range is 0..1/channel.
 
     friend class SkLightingShader;
 
@@ -133,32 +119,19 @@ private:
 
 class LightingFP : public GrFragmentProcessor {
 public:
-    LightingFP(GrProcessorDataManager* pdm, GrTexture* diffuse, GrTexture* normal,
-               const SkMatrix& diffMatrix, const SkMatrix& normMatrix,
-               const GrTextureParams& diffParams, const GrTextureParams& normParams,
-               const SkLightingShader::Lights* lights, const SkVector& invNormRotation)
-        : fDiffDeviceTransform(kLocal_GrCoordSet, diffMatrix, diffuse, diffParams.filterMode())
-        , fNormDeviceTransform(kLocal_GrCoordSet, normMatrix, normal, normParams.filterMode())
-        , fDiffuseTextureAccess(diffuse, diffParams)
-        , fNormalTextureAccess(normal, normParams)
-        , fInvNormRotation(invNormRotation) {
-        this->addCoordTransform(&fDiffDeviceTransform);
-        this->addCoordTransform(&fNormDeviceTransform);
+    LightingFP(GrTexture* diffuse, GrTexture* normal, const SkMatrix& matrix,
+               const SkVector3& lightDir, const SkColor3f& lightColor,
+               const SkColor3f& ambientColor)
+        : fDeviceTransform(kDevice_GrCoordSet, matrix)
+        , fDiffuseTextureAccess(diffuse)
+        , fNormalTextureAccess(normal)
+        , fLightDir(lightDir)
+        , fLightColor(lightColor)
+        , fAmbientColor(ambientColor) {
+        this->addCoordTransform(&fDeviceTransform);
         this->addTextureAccess(&fDiffuseTextureAccess);
         this->addTextureAccess(&fNormalTextureAccess);
 
-        // fuse all ambient lights into a single one
-        fAmbientColor.set(0.0f, 0.0f, 0.0f);
-        for (int i = 0; i < lights->numLights(); ++i) {
-            if (SkLight::kAmbient_LightType == lights->light(i).type()) {
-                fAmbientColor += lights->light(i).color();
-            } else {
-                // TODO: handle more than one of these
-                fLightColor = lights->light(i).color();
-                fLightDir = lights->light(i).dir();
-            }
-        }
-
         this->initClassID<LightingFP>();
     }
 
@@ -168,7 +141,6 @@ public:
             fLightDir.fX = 10000.0f;
             fLightColor.fX = 0.0f;
             fAmbientColor.fX = 0.0f;
-            fInvNormRotation.fX = 0.0f;
         }
 
         void emitCode(EmitArgs& args) override {
@@ -191,11 +163,6 @@ public:
                                                          kVec3f_GrSLType, kDefault_GrSLPrecision,
                                                          "AmbientColor", &ambientColorUniName);
 
-            const char* xformUniName = NULL;
-            fXformUni = args.fBuilder->addUniform(GrGLProgramBuilder::kFragment_Visibility,
-                                                  kVec2f_GrSLType, kDefault_GrSLPrecision,
-                                                  "Xform", &xformUniName);
-
             fpb->codeAppend("vec4 diffuseColor = ");
             fpb->appendTextureLookupAndModulate(args.fInputColor, args.fSamplers[0], 
                                                 args.fCoords[0].c_str(), 
@@ -204,20 +171,13 @@ public:
 
             fpb->codeAppend("vec4 normalColor = ");
             fpb->appendTextureLookup(args.fSamplers[1],
-                                     args.fCoords[1].c_str(), 
-                                     args.fCoords[1].getType());
+                                     args.fCoords[0].c_str(), 
+                                     args.fCoords[0].getType());
             fpb->codeAppend(";");
 
-            fpb->codeAppend("vec3 normal = normalColor.rgb - vec3(0.5);");
-
-            fpb->codeAppendf("mat3 m = mat3(%s.x, -%s.y, 0.0, %s.y, %s.x, 0.0, 0.0, 0.0, 1.0);",
-                             xformUniName, xformUniName, xformUniName, xformUniName);
-            
-            // TODO: inverse map the light direction vectors in the vertex shader rather than
-            // transforming all the normals here!
-            fpb->codeAppend("normal = normalize(m*normal);");
-
-            fpb->codeAppendf("float NdotL = clamp(dot(normal, %s), 0.0, 1.0);", lightDirUniName);
+            fpb->codeAppend("vec3 normal = normalize(normalColor.rgb - vec3(0.5));");
+            fpb->codeAppendf("vec3 lightDir = normalize(%s);", lightDirUniName);
+            fpb->codeAppend("float NdotL = dot(normal, lightDir);");
             // diffuse light
             fpb->codeAppendf("vec3 result = %s*diffuseColor.rgb*NdotL;", lightColorUniName);
             // ambient light
@@ -253,12 +213,6 @@ public:
                 pdman.set3fv(fAmbientColorUni, 1, &ambientColor.fX);
                 fAmbientColor = ambientColor;
             }
-
-            const SkVector& invNormRotation = lightingFP.invNormRotation();
-            if (invNormRotation != fInvNormRotation) {
-                pdman.set2fv(fXformUni, 1, &invNormRotation.fX);
-                fInvNormRotation = invNormRotation;
-            }
         }
 
     private:
@@ -270,9 +224,6 @@ public:
 
         SkColor3f fAmbientColor;
         GrGLProgramDataManager::UniformHandle fAmbientColorUni;
-
-        SkVector fInvNormRotation;
-        GrGLProgramDataManager::UniformHandle fXformUni;
     };
 
     void onGetGLProcessorKey(const GrGLSLCaps& caps, GrProcessorKeyBuilder* b) const override {
@@ -288,116 +239,106 @@ public:
     const SkVector3& lightDir() const { return fLightDir; }
     const SkColor3f& lightColor() const { return fLightColor; }
     const SkColor3f& ambientColor() const { return fAmbientColor; }
-    const SkVector& invNormRotation() const { return fInvNormRotation; }
 
 private:
     GrGLFragmentProcessor* onCreateGLInstance() const override { return SkNEW(LightingGLFP); }
 
     bool onIsEqual(const GrFragmentProcessor& proc) const override { 
         const LightingFP& lightingFP = proc.cast<LightingFP>();
-        return fDiffDeviceTransform == lightingFP.fDiffDeviceTransform &&
-               fNormDeviceTransform == lightingFP.fNormDeviceTransform &&
+        return fDeviceTransform == lightingFP.fDeviceTransform &&
                fDiffuseTextureAccess == lightingFP.fDiffuseTextureAccess &&
                fNormalTextureAccess == lightingFP.fNormalTextureAccess &&
                fLightDir == lightingFP.fLightDir &&
                fLightColor == lightingFP.fLightColor &&
-               fAmbientColor == lightingFP.fAmbientColor &&
-               fInvNormRotation == lightingFP.fInvNormRotation;
+               fAmbientColor == lightingFP.fAmbientColor;
     }
 
-    GrCoordTransform fDiffDeviceTransform;
-    GrCoordTransform fNormDeviceTransform;
+    GrCoordTransform fDeviceTransform;
     GrTextureAccess  fDiffuseTextureAccess;
     GrTextureAccess  fNormalTextureAccess;
     SkVector3        fLightDir;
     SkColor3f        fLightColor;
     SkColor3f        fAmbientColor;
-
-    SkVector         fInvNormRotation;
 };
 
 ////////////////////////////////////////////////////////////////////////////
 
-static bool make_mat(const SkBitmap& bm,
-                     const SkMatrix& localMatrix1,
-                     const SkMatrix* localMatrix2,
-                     SkMatrix* result) {
-    
-    result->setIDiv(bm.width(), bm.height());
+bool SkLightingShaderImpl::asFragmentProcessor(GrContext* context, const SkPaint& paint, 
+                                               const SkMatrix& viewM, const SkMatrix* localMatrix, 
+                                               GrColor* color, GrProcessorDataManager*,
+                                               GrFragmentProcessor** fp) const {
+    // we assume diffuse and normal maps have same width and height
+    // TODO: support different sizes
+    SkASSERT(fDiffuseMap.width() == fNormalMap.width() &&
+             fDiffuseMap.height() == fNormalMap.height());
+    SkMatrix matrix;
+    matrix.setIDiv(fDiffuseMap.width(), fDiffuseMap.height());
 
     SkMatrix lmInverse;
-    if (!localMatrix1.invert(&lmInverse)) {
+    if (!this->getLocalMatrix().invert(&lmInverse)) {
         return false;
     }
-    if (localMatrix2) {
+    if (localMatrix) {
         SkMatrix inv;
-        if (!localMatrix2->invert(&inv)) {
+        if (!localMatrix->invert(&inv)) {
             return false;
         }
         lmInverse.postConcat(inv);
     }
-    result->preConcat(lmInverse);
-
-    return true;
-}
-
-bool SkLightingShaderImpl::asFragmentProcessor(GrContext* context, const SkPaint& paint, 
-                                               const SkMatrix& viewM, const SkMatrix* localMatrix, 
-                                               GrColor* color, GrProcessorDataManager* pdm,
-                                               GrFragmentProcessor** fp) const {
-    // we assume diffuse and normal maps have same width and height
-    // TODO: support different sizes
-    SkASSERT(fDiffuseMap.width() == fNormalMap.width() &&
-             fDiffuseMap.height() == fNormalMap.height());
-    SkMatrix diffM, normM;
-    
-    if (!make_mat(fDiffuseMap, this->getLocalMatrix(), localMatrix, &diffM)) {
-        return false;    
+    matrix.preConcat(lmInverse);
+
+    // Must set wrap and filter on the sampler before requesting a texture. In two places below
+    // we check the matrix scale factors to determine how to interpret the filter quality setting.
+    // This completely ignores the complexity of the drawVertices case where explicit local coords
+    // are provided by the caller.
+    GrTextureParams::FilterMode textureFilterMode = GrTextureParams::kBilerp_FilterMode;
+    switch (paint.getFilterQuality()) {
+    case kNone_SkFilterQuality:
+        textureFilterMode = GrTextureParams::kNone_FilterMode;
+        break;
+    case kLow_SkFilterQuality:
+        textureFilterMode = GrTextureParams::kBilerp_FilterMode;
+        break;
+    case kMedium_SkFilterQuality:{                          
+        SkMatrix matrix;
+        matrix.setConcat(viewM, this->getLocalMatrix());
+        if (matrix.getMinScale() < SK_Scalar1) {
+            textureFilterMode = GrTextureParams::kMipMap_FilterMode;
+        } else {
+            // Don't trigger MIP level generation unnecessarily.
+            textureFilterMode = GrTextureParams::kBilerp_FilterMode;
+        }
+        break;
     }
+    case kHigh_SkFilterQuality:
+    default:
+        SkErrorInternals::SetError(kInvalidPaint_SkError,
+            "Sorry, I don't understand the filtering "
+            "mode you asked for.  Falling back to "
+            "MIPMaps.");
+        textureFilterMode = GrTextureParams::kMipMap_FilterMode;
+        break;
 
-    if (!make_mat(fNormalMap, fNormLocalMatrix, localMatrix, &normM)) {
-        return false;
     }
 
-    bool doBicubic;
-    GrTextureParams::FilterMode diffFilterMode = GrSkFilterQualityToGrFilterMode(
-                                        SkTMin(paint.getFilterQuality(), kMedium_SkFilterQuality), 
-                                        viewM,
-                                        this->getLocalMatrix(),
-                                        &doBicubic); 
-    SkASSERT(!doBicubic);
-
-    GrTextureParams::FilterMode normFilterMode = GrSkFilterQualityToGrFilterMode(
-                                        SkTMin(paint.getFilterQuality(), kMedium_SkFilterQuality), 
-                                        viewM,
-                                        fNormLocalMatrix,
-                                        &doBicubic); 
-    SkASSERT(!doBicubic);
-
     // TODO: support other tile modes
-    GrTextureParams diffParams(kClamp_TileMode, diffFilterMode);
-    SkAutoTUnref<GrTexture> diffuseTexture(GrRefCachedBitmapTexture(context,
-                                                                    fDiffuseMap, &diffParams));
+    GrTextureParams params(kClamp_TileMode, textureFilterMode);
+    SkAutoTUnref<GrTexture> diffuseTexture(GrRefCachedBitmapTexture(context, fDiffuseMap, &params));
     if (!diffuseTexture) {
         SkErrorInternals::SetError(kInternalError_SkError,
             "Couldn't convert bitmap to texture.");
         return false;
     }
 
-    GrTextureParams normParams(kClamp_TileMode, normFilterMode);
-    SkAutoTUnref<GrTexture> normalTexture(GrRefCachedBitmapTexture(context,
-                                                                   fNormalMap, &normParams));
+    SkAutoTUnref<GrTexture> normalTexture(GrRefCachedBitmapTexture(context, fNormalMap, &params));
     if (!normalTexture) {
         SkErrorInternals::SetError(kInternalError_SkError,
             "Couldn't convert bitmap to texture.");
         return false;
     }
 
-
-    *fp = SkNEW_ARGS(LightingFP, (pdm, diffuseTexture, normalTexture,
-                                  diffM, normM, diffParams, normParams, fLights,
-                                  fInvNormRotation));
-
+    *fp = SkNEW_ARGS(LightingFP, (diffuseTexture, normalTexture, matrix,
+                                  fLight.fDirection, fLight.fColor, fAmbientColor));
     *color = GrColorPackA4(paint.getAlpha());
     return true;
 }
@@ -450,38 +391,27 @@ SkLightingShaderImpl::LightingShaderContext::~LightingShaderContext() {
     fNormalState->~SkBitmapProcState();
 }
 
-static inline SkPMColor convert(SkColor3f color, U8CPU a) {
-    if (color.fX <= 0.0f) {
-        color.fX = 0.0f;
-    } else if (color.fX >= 255.0f) {
-        color.fX = 255.0f;
-    } 
-
-    if (color.fY <= 0.0f) {
-        color.fY = 0.0f;
-    } else if (color.fY >= 255.0f) {
-        color.fY = 255.0f;
-    } 
-
-    if (color.fZ <= 0.0f) {
-        color.fZ = 0.0f;
-    } else if (color.fZ >= 255.0f) {
-        color.fZ = 255.0f;
-    } 
-
-    return SkPreMultiplyARGB(a, (int) color.fX,  (int) color.fY, (int) color.fZ);
+static inline int light(SkScalar light, int diff, SkScalar NdotL, SkScalar ambient) {
+    SkScalar color = light * diff * NdotL + 255 * ambient;
+    if (color <= 0.0f) {
+        return 0;
+    } else if (color >= 255.0f) {
+        return 255;
+    } else {
+        return (int) color;
+    }
 }
 
 // larger is better (fewer times we have to loop), but we shouldn't
-// take up too much stack-space (each one here costs 16 bytes)
+// take up too much stack-space (each could here costs 16 bytes)
 #define TMP_COUNT     16
 
 void SkLightingShaderImpl::LightingShaderContext::shadeSpan(int x, int y,
                                                             SkPMColor result[], int count) {
     const SkLightingShaderImpl& lightShader = static_cast<const SkLightingShaderImpl&>(fShader);
 
-    uint32_t  tmpColor[TMP_COUNT], tmpNormal[TMP_COUNT];
-    SkPMColor tmpColor2[2*TMP_COUNT], tmpNormal2[2*TMP_COUNT];
+    SkPMColor   tmpColor[TMP_COUNT], tmpColor2[TMP_COUNT];
+    SkPMColor   tmpNormal[TMP_COUNT], tmpNormal2[TMP_COUNT];
 
     SkBitmapProcState::MatrixProc   diffMProc = fDiffuseState->getMatrixProc();
     SkBitmapProcState::SampleProc32 diffSProc = fDiffuseState->getSampleProc32();
@@ -489,19 +419,17 @@ void SkLightingShaderImpl::LightingShaderContext::shadeSpan(int x, int y,
     SkBitmapProcState::MatrixProc   normalMProc = fNormalState->getMatrixProc();
     SkBitmapProcState::SampleProc32 normalSProc = fNormalState->getSampleProc32();
 
-    int diffMax = fDiffuseState->maxCountForBufferSize(sizeof(tmpColor[0]) * TMP_COUNT);
-    int normMax = fNormalState->maxCountForBufferSize(sizeof(tmpNormal[0]) * TMP_COUNT);
-    int max = SkTMin(diffMax, normMax);
-
     SkASSERT(fDiffuseState->fPixmap.addr());
     SkASSERT(fNormalState->fPixmap.addr());
 
-    SkPoint3 norm, xformedNorm;
+    SkPoint3 norm;
+    SkScalar NdotL;
+    int r, g, b;
 
     do {
         int n = count;
-        if (n > max) {
-            n = max;
+        if (n > TMP_COUNT) {
+            n = TMP_COUNT;
         }
 
         diffMProc(*fDiffuseState, tmpColor, n, x, y);
@@ -517,34 +445,18 @@ void SkLightingShaderImpl::LightingShaderContext::shadeSpan(int x, int y,
                      SkIntToScalar(SkGetPackedB32(tmpNormal2[i]))-127.0f);
             norm.normalize();
 
-            xformedNorm.fX = lightShader.fInvNormRotation.fX * norm.fX +
-                             lightShader.fInvNormRotation.fY * norm.fY;
-            xformedNorm.fY = lightShader.fInvNormRotation.fX * norm.fX - 
-                             lightShader.fInvNormRotation.fY * norm.fY;
-            xformedNorm.fZ = norm.fZ;
-
             SkColor diffColor = SkUnPreMultiply::PMColorToColor(tmpColor2[i]);
+            NdotL = norm.dot(lightShader.fLight.fDirection);
 
-            SkColor3f accum = SkColor3f::Make(0.0f, 0.0f, 0.0f);
-            // This is all done in linear unpremul color space (each component 0..255.0f though)
-            for (int l = 0; l < lightShader.fLights->numLights(); ++l) {
-                const SkLight& light = lightShader.fLights->light(l);
-
-                if (SkLight::kAmbient_LightType == light.type()) {
-                    accum += light.color().makeScale(255.0f);
-                } else {
-                    SkScalar NdotL = xformedNorm.dot(light.dir());
-                    if (NdotL < 0.0f) {
-                        NdotL = 0.0f;
-                    }
-
-                    accum.fX += light.color().fX * SkColorGetR(diffColor) * NdotL;
-                    accum.fY += light.color().fY * SkColorGetG(diffColor) * NdotL;
-                    accum.fZ += light.color().fZ * SkColorGetB(diffColor) * NdotL;
-                }
-            }
+            // This is all done in linear unpremul color space
+            r = light(lightShader.fLight.fColor.fX, SkColorGetR(diffColor), NdotL, 
+                      lightShader.fAmbientColor.fX);
+            g = light(lightShader.fLight.fColor.fY, SkColorGetG(diffColor), NdotL, 
+                      lightShader.fAmbientColor.fY);
+            b = light(lightShader.fLight.fColor.fZ, SkColorGetB(diffColor), NdotL, 
+                      lightShader.fAmbientColor.fZ);
 
-            result[i] = convert(accum, SkColorGetA(diffColor));
+            result[i] = SkPreMultiplyARGB(SkColorGetA(diffColor), r, g, b);
         }
 
         result += n;
@@ -562,21 +474,8 @@ void SkLightingShaderImpl::toString(SkString* str) const {
 #endif
 
 SkFlattenable* SkLightingShaderImpl::CreateProc(SkReadBuffer& buf) {
-    SkMatrix diffLocalM;
-    bool hasDiffLocalM = buf.readBool();
-    if (hasDiffLocalM) {
-        buf.readMatrix(&diffLocalM);
-    } else {
-        diffLocalM.reset();
-    }
-
-    SkMatrix normLocalM;
-    bool hasNormLocalM = buf.readBool();
-    if (hasNormLocalM) {
-        buf.readMatrix(&normLocalM);
-    } else {
-        normLocalM.reset();
-    }
+    SkMatrix localMatrix;
+    buf.readMatrix(&localMatrix);
 
     SkBitmap diffuse;
     if (!buf.readBitmap(&diffuse)) {
@@ -590,84 +489,38 @@ SkFlattenable* SkLightingShaderImpl::CreateProc(SkReadBuffer& buf) {
     }
     normal.setImmutable();
 
-    int numLights = buf.readInt();
-
-    SkLightingShader::Lights::Builder builder;
-
-    for (int l = 0; l < numLights; ++l) {
-        bool isAmbient = buf.readBool();
-
-        SkColor3f color;
-        if (!buf.readScalarArray(&color.fX, 3)) {
-            return NULL;
-        }
-
-        if (isAmbient) {
-            builder.add(SkLight(color));
-        } else {
-            SkVector3 dir;
-            if (!buf.readScalarArray(&dir.fX, 3)) {
-                return NULL;
-            }
-            builder.add(SkLight(color, dir));        
-        }
+    SkLightingShader::Light light;
+    if (!buf.readScalarArray(&light.fDirection.fX, 3)) {
+        return NULL;
+    }
+    if (!buf.readScalarArray(&light.fColor.fX, 3)) {
+        return NULL;
     }
 
-    SkAutoTUnref<const SkLightingShader::Lights> lights(builder.finish());
+    SkColor3f ambient;
+    if (!buf.readScalarArray(&ambient.fX, 3)) {
+        return NULL;
+    }
 
-    return SkNEW_ARGS(SkLightingShaderImpl, (diffuse, normal, lights,
-                                             SkVector::Make(1.0f, 0.0f),
-                                             &diffLocalM, &normLocalM));
+    return SkNEW_ARGS(SkLightingShaderImpl, (diffuse, normal, light, ambient, &localMatrix));
 }
 
 void SkLightingShaderImpl::flatten(SkWriteBuffer& buf) const {
-    this->INHERITED::flatten(buf);
-
-    bool hasNormLocalM = !fNormLocalMatrix.isIdentity();
-    buf.writeBool(hasNormLocalM);
-    if (hasNormLocalM) {
-        buf.writeMatrix(fNormLocalMatrix);
-    }
+    buf.writeMatrix(this->getLocalMatrix());
 
     buf.writeBitmap(fDiffuseMap);
     buf.writeBitmap(fNormalMap);
-
-    buf.writeInt(fLights->numLights());
-    for (int l = 0; l < fLights->numLights(); ++l) {
-        const SkLight& light = fLights->light(l);
-
-        bool isAmbient = SkLight::kAmbient_LightType == light.type();
-
-        buf.writeBool(isAmbient);
-        buf.writeScalarArray(&light.color().fX, 3);
-        if (!isAmbient) {
-            buf.writeScalarArray(&light.dir().fX, 3);
-        }
-    }
-}
-
-bool SkLightingShaderImpl::computeNormTotalInverse(const ContextRec& rec,
-                                                   SkMatrix* normTotalInverse) const {
-    SkMatrix total;
-    total.setConcat(*rec.fMatrix, fNormLocalMatrix);
-
-    const SkMatrix* m = &total;
-    if (rec.fLocalMatrix) {
-        total.setConcat(*m, *rec.fLocalMatrix);
-        m = &total;
-    }
-    return m->invert(normTotalInverse);
+    buf.writeScalarArray(&fLight.fDirection.fX, 3);
+    buf.writeScalarArray(&fLight.fColor.fX, 3);
+    buf.writeScalarArray(&fAmbientColor.fX, 3);
 }
 
 SkShader::Context* SkLightingShaderImpl::onCreateContext(const ContextRec& rec,
                                                          void* storage) const {
 
-    SkMatrix diffTotalInv;
-    // computeTotalInverse was called in SkShader::createContext so we know it will succeed
-    SkAssertResult(this->computeTotalInverse(rec, &diffTotalInv));
-
-    SkMatrix normTotalInv;
-    if (!this->computeNormTotalInverse(rec, &normTotalInv)) {
+    SkMatrix totalInverse;
+    // Do this first, so we know the matrix can be inverted.
+    if (!this->computeTotalInverse(rec, &totalInverse)) {
         return NULL;
     }
 
@@ -678,7 +531,7 @@ SkShader::Context* SkLightingShaderImpl::onCreateContext(const ContextRec& rec,
     diffuseState->fTileModeX = SkShader::kClamp_TileMode;
     diffuseState->fTileModeY = SkShader::kClamp_TileMode;
     diffuseState->fOrigBitmap = fDiffuseMap;
-    if (!diffuseState->chooseProcs(diffTotalInv, *rec.fPaint)) {
+    if (!diffuseState->chooseProcs(totalInverse, *rec.fPaint)) {
         diffuseState->~SkBitmapProcState();
         return NULL;
     }
@@ -690,7 +543,7 @@ SkShader::Context* SkLightingShaderImpl::onCreateContext(const ContextRec& rec,
     normalState->fTileModeX = SkShader::kClamp_TileMode;
     normalState->fTileModeY = SkShader::kClamp_TileMode;
     normalState->fOrigBitmap = fNormalMap;
-    if (!normalState->chooseProcs(normTotalInv, *rec.fPaint)) {
+    if (!normalState->chooseProcs(totalInverse, *rec.fPaint)) {
         diffuseState->~SkBitmapProcState();
         normalState->~SkBitmapProcState();
         return NULL;
@@ -713,9 +566,9 @@ static bool bitmap_is_too_big(const SkBitmap& bm) {
 }
 
 SkShader* SkLightingShader::Create(const SkBitmap& diffuse, const SkBitmap& normal,
-                                   const Lights* lights,
-                                   const SkVector& invNormRotation,
-                                   const SkMatrix* diffLocalM, const SkMatrix* normLocalM) {
+                                   const SkLightingShader::Light& light,
+                                   const SkColor3f& ambient,
+                                   const SkMatrix* localMatrix) {
     if (diffuse.isNull() || bitmap_is_too_big(diffuse) ||
         normal.isNull() || bitmap_is_too_big(normal) ||
         diffuse.width() != normal.width() ||
@@ -723,10 +576,7 @@ SkShader* SkLightingShader::Create(const SkBitmap& diffuse, const SkBitmap& norm
         return nullptr;
     }
 
-    SkASSERT(SkScalarNearlyEqual(invNormRotation.lengthSqd(), SK_Scalar1));
-
-    return SkNEW_ARGS(SkLightingShaderImpl, (diffuse, normal, lights,
-                                             invNormRotation, diffLocalM, normLocalM));
+    return SkNEW_ARGS(SkLightingShaderImpl, (diffuse, normal, light, ambient, localMatrix));
 }
 
 ///////////////////////////////////////////////////////////////////////////////
diff --git a/src/core/SkLightingShader.h b/src/effects/SkLightingShader.h
index 499e358238..64d41a291e 100644
--- a/src/core/SkLightingShader.h
+++ b/src/effects/SkLightingShader.h
@@ -10,57 +10,15 @@
 #ifndef SkLightingShader_DEFINED
 #define SkLightingShader_DEFINED
 
-#include "SkFlattenable.h"
-#include "SkLight.h"
+#include "SkPoint3.h"
 #include "SkShader.h"
-#include "SkTDArray.h"
-
-class SkBitmap;
-class SkMatrix;
 
 class SK_API SkLightingShader {
 public:
-    class Lights  : public SkRefCnt {
-    public:
-        class Builder {
-        public:
-            Builder(const SkLight lights[], int numLights)
-                : fLights(SkNEW_ARGS(Lights, (lights, numLights))) {
-            }
-
-            Builder() : fLights(SkNEW(Lights)) { }
-    
-            // TODO: limit the number of lights here or just ignore those
-            // above some maximum?
-            void add(const SkLight& light) {
-                if (fLights) {
-                    *fLights->fLights.push() = light;
-                }
-            }
-
-            const Lights* finish() {
-                return fLights.detach();
-            }
-
-        private:
-            SkAutoTUnref<Lights> fLights;
-        };
-
-        int numLights() const {
-            return fLights.count();
-        }
-
-        const SkLight& light(int index) const {
-            return fLights[index];
-        }
-
-    private:
-        Lights() {}
-        Lights(const SkLight lights[], int numLights) : fLights(lights, numLights) {}
-
-        SkTDArray<SkLight> fLights;
-
-        typedef SkRefCnt INHERITED;
+    struct Light {
+        SkVector3   fDirection;       // direction towards the light (+Z is out of the screen).
+                                      // If degenerate, it will be replaced with (0, 0, 1).
+        SkColor3f   fColor;           // linear (unpremul) color. Range is 0..1 in each channel.
     };
 
     /** Returns a shader that lights the diffuse and normal maps with a single light.
@@ -92,8 +50,8 @@ public:
         (127, 127, 0).
     */
     static SkShader* Create(const SkBitmap& diffuse, const SkBitmap& normal,
-                            const Lights* lights, const SkVector& invNormRotation,
-                            const SkMatrix* diffLocalMatrix, const SkMatrix* normLocalMatrix);
+                            const SkLightingShader::Light& light, const SkColor3f& ambient,
+                            const SkMatrix* localMatrix);
 
     SK_DECLARE_FLATTENABLE_REGISTRAR_GROUP()
 };
diff --git a/src/core/SkPoint3.cpp b/src/effects/SkPoint3.cpp
index 3b5586b067..3b5586b067 100644
--- a/src/core/SkPoint3.cpp
+++ b/src/effects/SkPoint3.cpp
diff --git a/src/ports/SkGlobalInitialization_chromium.cpp b/src/ports/SkGlobalInitialization_chromium.cpp
index 04ca841e5f..3aecbd5471 100644
--- a/src/ports/SkGlobalInitialization_chromium.cpp
+++ b/src/ports/SkGlobalInitialization_chromium.cpp
@@ -41,7 +41,7 @@
 #include "SkLayerRasterizer.h"
 #include "SkLerpXfermode.h"
 #include "SkLightingImageFilter.h"
-#include "SkLightingShader.h"
+#include "../effects/SkLightingShader.h"
 #include "SkLocalMatrixShader.h"
 #include "SkLumaColorFilter.h"
 #include "SkMagnifierImageFilter.h"
diff --git a/src/ports/SkGlobalInitialization_default.cpp b/src/ports/SkGlobalInitialization_default.cpp
index 0d05c1dcb7..47b00b96f1 100644
--- a/src/ports/SkGlobalInitialization_default.cpp
+++ b/src/ports/SkGlobalInitialization_default.cpp
@@ -37,7 +37,7 @@
 #include "SkLayerRasterizer.h"
 #include "SkLerpXfermode.h"
 #include "SkLightingImageFilter.h"
-#include "SkLightingShader.h"
+#include "../effects/SkLightingShader.h"
 #include "SkLocalMatrixShader.h"
 #include "SkLumaColorFilter.h"
 #include "SkMagnifierImageFilter.h"