Motion Blur for simple test scene

[wahn]

With the PBRT book there comes a simple test scene, which renders like this:

After checking in this scene (and the textures being used) we have to add step by step all missing features to render exactly the same image. The most important one should be motion blur.

[wahn]

We did not implement motion blur (yet), but commit 6738bfa brings us the InfiniteAreaLight (see issue #20 ), we need for this scene:

We also had to replace the sampler:

##Sampler "sobol" "integer pixelsamples" [1024]                                                                                             
Sampler "lowdiscrepancy" "integer pixelsamples" [1024]                                                                                      

[wahn]

There is a separate issue for implementing the SobolSampler (see issue #25) now. We should focus on the motion blur here ...

[wahn]

Since commit 798be88 we get at least some motion blur, but it does not match the C++ version (yet) ...

[wahn]

Commit 3e352cb does implement the motion blur correctly:

It does not match the C++ counterpart 100%:

differing pixels:	 34.129% (109212 of 320000)
average difference:	 12.739%
maximum difference:	 36.782%
Summary: Many pixels differ strongly.
== "anim-bluespheres.exr" and "pbrt_rust.exr" are different

Actually the three spheres (and the mirrored parts) are far too bright.

But I assume it's either related to the infinite light source or the materials. Anyway, I'm going to close this ticket, because it was about motion blur.