Added distance attenuation and diffuse shading to PointLights

src/utils/SkShadowPaintFilterCanvas.cpp

 /*
  * Copyright 2016 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkPathEffect.h"
 #include "SkShadowPaintFilterCanvas.h"
 
@@ skipping 33 matching lines @@
 
         *paint->writable() = newPaint;
     }
 
     return true;
 }
 
 SkISize SkShadowPaintFilterCanvas::ComputeDepthMapSize(const SkLights::Light& light, int maxDepth,
                                                        int width, int height) {
     SkASSERT(light.type() != SkLights::Light::kAmbient_LightType);
+    if (light.type() != SkLights::Light::kDirectional_LightType) {
+        return SkISize::Make(width *2 , height * 2);
+    }
+
     int dMapWidth = SkMin32(maxDepth * fabs(light.dir().fX) + width,
                             width * 2);
     int dMapHeight = SkMin32(maxDepth * fabs(light.dir().fY) + height,
                              height * 2);
     return SkISize::Make(dMapWidth, dMapHeight);
 }
 
 void SkShadowPaintFilterCanvas::setShadowParams(const SkShadowParams &params) {
     fShadowParams = params;
 }
 
 void SkShadowPaintFilterCanvas::onDrawPicture(const SkPicture *picture, const SkMatrix *matrix,
                                               const SkPaint *paint) {
     SkTCopyOnFirstWrite<SkPaint> filteredPaint(paint);
     if (this->onFilter(&filteredPaint, kPicture_Type)) {
         SkCanvas::onDrawPicture(picture, matrix, filteredPaint);
     }
 }
 
 void SkShadowPaintFilterCanvas::updateMatrix() {
     this->save();
 
     //  It is up to the user to set the 0th light in fLights to
     //  the light the want to render the depth map with.
-    if (this->fLights->light(0).type() != SkLights::Light::kAmbient_LightType) {
+    if (this->fLights->light(0).type() == SkLights::Light::kDirectional_LightType) {
         const SkVector3& lightDir = this->fLights->light(0).dir();
         SkScalar x = lightDir.fX * this->getZ();
         SkScalar y = lightDir.fY * this->getZ();
 
         this->translate(x, y);
     }
 }
 
 void SkShadowPaintFilterCanvas::onDrawPaint(const SkPaint &paint) {
     this->updateMatrix();
@@ skipping 150 matching lines @@
 }
 
 void SkShadowPaintFilterCanvas::onDrawTextBlob(const SkTextBlob *blob, SkScalar x, SkScalar y,
                                                const SkPaint &paint) {
     this->updateMatrix();
     this->INHERITED::onDrawTextBlob(blob, x, y, paint);
     this->restore();
 }
 
 #endif