added point light attenuations to raster

src/core/SkShadowShader.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 "SkCanvas.h"
 #include "SkReadBuffer.h"
 #include "SkShadowShader.h"
@@ skipping 747 matching lines @@
                             lightProb = SkMaxScalar((lightProb - bias) / (1.0f - bias), 0.0f);
                         } else {
                             lightProb = 0.0f;
                         }
                     }
 
                     // assume object normals are pointing straight up
                     totalLight.fX += light.dir().fZ * light.color().fX * lightProb;
                     totalLight.fY += light.dir().fZ * light.color().fY * lightProb;
                     totalLight.fZ += light.dir().fZ * light.color().fZ * lightProb;
-                } else {
-                    totalLight += light.color();
+

[robertphillips, 2016/08/31 13:44:27]

Maybe:

} else {
   SkASSERT(light.type() == SkLights::Light::kPoint_LightType);

?

[vjiaoblack, 2016/08/31 13:53:27]

Done.

+                } else if (light.type() == SkLights::Light::kPoint_LightType) {

[robertphillips, 2016/08/31 13:44:27]

Move this line out of the if-then block and share with the prior block ?

[vjiaoblack, 2016/08/31 13:53:27]

Done.

+                    int pvDepth = SkColorGetB(povDepthColor);
+
+                    SkVector3 fragToLight = SkVector3::Make(light.pos().fX - (x + i),

[robertphillips, 2016/08/31 13:44:27]

where's this 400 coming from?

[vjiaoblack, 2016/08/31 13:53:27]

Done.

+                                                            light.pos().fY - (400 - y),
+                                                            light.pos().fZ - pvDepth);
+
+                    SkScalar dist = fragToLight.length();
+                    SkScalar normalizedZ = fragToLight.fZ / dist;
+
+                    SkScalar attenuationValue = dist / light.intensity();

[jvanverth1, 2016/08/31 17:18:23]

This is the old lighting equation.

[vjiaoblack, 2016/08/31 17:58:28]

Done.

+                    attenuationValue = attenuationValue * attenuationValue + 1.0f;
+

[robertphillips, 2016/08/31 13:44:27]

// assume object normals are pointing straight up

[vjiaoblack, 2016/08/31 13:53:27]

Done.

+                    totalLight.fX += normalizedZ * light.color().fX / attenuationValue;

[jvanverth1, 2016/08/31 17:18:22]

If you precompute 1/attenuation and multiply by that, that should help perf.

[vjiaoblack, 2016/08/31 17:58:28]

Done.

+                    totalLight.fY += normalizedZ * light.color().fY / attenuationValue;
+                    totalLight.fZ += normalizedZ * light.color().fZ / attenuationValue;
                 }
             }
 
             SkColor3f totalColor = SkColor3f::Make(SkColorGetR(diffColor) * totalLight.fX,
                                                    SkColorGetG(diffColor) * totalLight.fY,
                                                    SkColorGetB(diffColor) * totalLight.fZ);
 
             result[i] = convert(totalColor, SkColorGetA(diffColor));
         }
 
@@ skipping 110 matching lines @@
 
 ///////////////////////////////////////////////////////////////////////////////
 
 SK_DEFINE_FLATTENABLE_REGISTRAR_GROUP_START(SkShadowShader)
     SK_DEFINE_FLATTENABLE_REGISTRAR_ENTRY(SkShadowShaderImpl)
 SK_DEFINE_FLATTENABLE_REGISTRAR_GROUP_END
 
 ///////////////////////////////////////////////////////////////////////////////
 
 #endif