Summary:
This fixes two small issues with blending.py:softmax_rgb_blend():
1) zfar and znear attributes are propagated from the camera settings instead of just using default settings of znear=1.0 and zfar=100.0
2) A check is added to prevent arithmetic overflow in softmax_rgb_blend()
This is a fix in response to https://github.com/facebookresearch/pytorch3d/issues/334
where meshes rendererd using a SoftPhongShader with faces_per_pixel=1 appear black. This only occurs when the scale of the mesh is large (vertex values > 100, where 100 is the default value of zfar). This fix allows the caller to increase the value of cameras.zfar to match the scale of her/his mesh.
Reviewed By: nikhilaravi
Differential Revision: D23517541
fbshipit-source-id: ab8631ce9e5f2149f140b67b13eff857771b8807
f8ea5906c0