[Bf-codereview] Camera Data Node for Cycles (Blender) (issue 5437112)

[dfelinto at gmail.com]

Reviewers: bf-codereview_blender.org, brechtvl,

Description:
My second cycles node, working partially:

View Distance:
------------
it's working fine. The formula [ distance = sqrt(dot(vector,vector)); ]
is the conversion to pure c/opencl of Blender's normalize_v3 function.

View Z Depth:
-----------
It works but it's 'banded' (expected I guess).
Also the Z doesn't seem to change if I change the camera clip start and
clip end. I thought Z was calculated between this range. That would
boost the resolution a bit.

View Vector:
----------
the result is always different than Blender Render. However the vector
seems to be fine given that I use it to calculate the Z and the
distance. So it may need a little tweak.

Also I thought that sd->I would be the view vector, but it doesn't seem
so.

OSL:
----
I didn't build the OSL shader because there is no way I can test it, and
no way I will get it right without testing it ;)

SVM ERROR in OSX:
----------------
If I try GPU rendering in my ATI OSX complains of tons of warnings (not
related to this patch), and that abs doesn't not match any of the
available overloads (although abs is part of OpenCL1.1)

Please review this at http://codereview.appspot.com/5437112/

Affected files:
   intern/cycles/app/cycles_xml.cpp
   intern/cycles/blender/blender_shader.cpp
   intern/cycles/kernel/CMakeLists.txt
   intern/cycles/kernel/osl/nodes/CMakeLists.txt
   intern/cycles/kernel/osl/nodes/node_camera.osl
   intern/cycles/kernel/svm/svm.h
   intern/cycles/kernel/svm/svm_camera.h
   intern/cycles/kernel/svm/svm_types.h
   intern/cycles/render/nodes.cpp
   intern/cycles/render/nodes.h
   source/blender/nodes/shader/nodes/node_shader_camera.c