Camera Data Node for Cycles (Blender)

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)

[brechtvl, 2011-12-02 14:25:33]

http://codereview.appspot.com/5437112/diff/1/intern/cycles/kernel/svm/svm_cam...
File intern/cycles/kernel/svm/svm_camera.h (right):

http://codereview.appspot.com/5437112/diff/1/intern/cycles/kernel/svm/svm_cam...
intern/cycles/kernel/svm/svm_camera.h:29: zdepth = abs(vector[2]);
this should be changed to fabsf(vector.z)

http://codereview.appspot.com/5437112/diff/1/intern/cycles/kernel/svm/svm_cam...
intern/cycles/kernel/svm/svm_camera.h:30: distance = sqrt(dot(vector,vector));
this can be replaced by len(vector)

http://codereview.appspot.com/5437112/diff/1/intern/cycles/kernel/svm/svm_cam...
intern/cycles/kernel/svm/svm_camera.h:33: stack_store_float3(stack, out_vector,
vector);
this should be normalize(vector), maybe that makes it the same?

sd->I would be the same for a perspective camera on the first hit, but not for
further bounces, so it shouldn't be used.

[dfelinto, 2011-12-02 19:42:51]

final patch: addressed all the points from Brecht + removed fabs and implemented
OSL. good to go?

[dfelinto, 2011-12-02 19:46:15]

final set of comments, waiting for your 'go'

http://codereview.appspot.com/5437112/diff/1/intern/cycles/kernel/svm/svm_cam...
File intern/cycles/kernel/svm/svm_camera.h (right):

http://codereview.appspot.com/5437112/diff/1/intern/cycles/kernel/svm/svm_cam...
intern/cycles/kernel/svm/svm_camera.h:29: zdepth = abs(vector[2]);
with cycles z we don't even need abs/fabsf I believe. Not it's depth = vector.z;
and fyi: abs was the reason for the banding, with fabs the z was smooth;
On 2011/12/02 14:25:33, brechtvl wrote:
> this should be changed to fabsf(vector.z)

http://codereview.appspot.com/5437112/diff/1/intern/cycles/kernel/svm/svm_cam...
intern/cycles/kernel/svm/svm_camera.h:33: stack_store_float3(stack, out_vector,
vector);
the final version is with cycles Z (not blender). it makes more sense indeed. no
wonder blender had to abs(z).

On 2011/12/02 14:25:33, brechtvl wrote:
> this should be normalize(vector), maybe that makes it the same?
> 
> sd->I would be the same for a perspective camera on the first hit, but not for
> further bounces, so it shouldn't be used.

[brechtvl, 2011-12-02 19:56:21]

LGTM :)