[Bf-cycles] Tests with OpenCL - Cycles
Thomas Dinges
blender at dingto.org
Tue Jan 15 16:02:53 CET 2013
Hey everyone,
I played around a bit with OpenCL the past few days and want to share my
foundings here.
1) Nvidia GT 540M:
I compiled Blender with default settings, also for OpenCL. That means
only __KERNEL_SHADING__ and __MULTI_CLOSURE__ was enabled.
The compilation fails though: It does not like the "int segment = ~0"
default.
:26679:87: error: C does not support default arguments
int shader, int object, int prim, float u, float v, float t,
float time, int segment = ~0)
I compiled without hair support and removed the segment parameter to
workaround this issue.
I tested with color_ramp.blend (SVN test repository) and Mix and Add
Shaders do not work. Only the first closure input is passed through, the
second gets ignored.
It seems to be related to __MULTI_CLOSURE__. When I recompile the OpenCL
kernel without it, mix and add shaders work fine.
2) Intel Core i7 2630QM
I wanted to test OpenCL on my Sandy Bridge Intel CPU, but the CPU is not
recognized. I of course changed device_opencl.cpp and replaced all
CL_DEVICE_TYPE_ parameters to CL_DEVICE_TYPE_ALL.
The issue is in the way Cycles detects OpenCL platforms as far as I can
see that. LuxMark 2.0 recognized both devices (nvidia GPU and Intel CPU)
fine.
I could not get it up and running, although I found that changing the
"platform_ids[]" index from 0 to 1 in lines 757 and 762 in
device_opencl.cpp, at least brings up the device inside of the User
Preferences. (the nvidia card disappears then though from UserPrefs, yet
it will still render with the GPU).
3) Intel Core i5-3570 with HD 2500 GPU
Intels Ivy Bridge CPUs now also support OpenCL on the GPU, so I wanted
to test that. Both devides (CPU and GPU) show up fine in User
Preferences (after CL_DEVICE_TYPE_ALL tweak) but the kernel compile
crashes. It starts, but after some time Blender just closes. I could not
debug that further.
Thanks for reading this.
Brecht: Please don't see this as a real bug report, I know OpenCL
development is on hold but it's interesting to keep an eye on it and
maybe some information here is helpful.
All tests done on Windows 7 x64.
Best regards,
Thomas
--
Thomas Dinges
Blender Developer, Artist and Musician
www.dingto.org
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