made point lights linear attenuation; also fixed point light depth bug

samplecode/SampleShadowing.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 "SampleCode.h"
 #include "SkPictureRecorder.h"
 #include "SkShadowPaintFilterCanvas.h"
@@ skipping 148 matching lines @@
     SkView::Click* onFindClickHandler(SkScalar x, SkScalar y, unsigned modi) override {
         return new SkView::Click(this);
     }
 
     void updateLights(int x, int y) {
         SkLights::Builder builder;
         builder.add(SkLights::Light::MakePoint(SkColor3f::Make(1.0f, 1.0f, 1.0f),
                                                SkVector3::Make(x,
                                                                kHeight - y,
                                                                fLightDepth),
-                                               100000, true));
+                                               400, true));
         fLights = builder.finish();
     }
 
     void updateFromSelectedSlider() {
         SkScalar newValue = fSliders[fSelectedSliderID].fGeometry.fLeft *
                             fSliders[fSelectedSliderID].fScale +
                             fSliders[fSelectedSliderID].fOffset;
 
         switch (fSelectedSliderID) {
             case 0:
@@ skipping 112 matching lines @@
     sk_sp<SkLights> fLights;
 
     typedef SampleView INHERITED;
 };
 
 //////////////////////////////////////////////////////////////////////////////
 static SkView* MyFactory() { return new ShadowingView; }
 static SkViewRegister reg(MyFactory);
 
 #endif