added point light attenuations to raster

src/core/SkShadowShader.cpp

Index: src/core/SkShadowShader.cpp
diff --git a/src/core/SkShadowShader.cpp b/src/core/SkShadowShader.cpp
index 09d0bcaf5080c2822b3abd9dc4e7cb17bb1efaac..372a0faee6ff1e89ac4962b05d60e53cfc4ce0ee 100644
--- a/src/core/SkShadowShader.cpp
+++ b/src/core/SkShadowShader.cpp
@@ -765,8 +765,23 @@ void SkShadowShaderImpl::ShadowShaderContext::shadeSpan(int x, int y,
                     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;
                 }
             }