Add support for OpenCL CPU

[erwincoumans]

Currently, some of the OpenCL kernels don't run on OpenCL CPU, due to certain workgroup size assumptions. It needs to be fixed.

[wolfviking0]

Hi, I am trying to play with bullet3 but my GPU (HD 4000) doesn't work with bullet. Do you have any news about the support of CPU ??

[erwincoumans]

Even if we can make it work on OpenCL CPU or HD4000, it will be slow and not practical and just a theoretical thing, possibly useful for a benchmark tool.

You better get a 7970 or GTX 280/290, it will fly...

[wolfviking0]

:( Too bad, I understand, Not sure I can add something like that inside my Mac mini ;)

But thanks for the quick response.

[erwincoumans]

The latest trunk version can handle OpenCL CPU on some platforms (only tested on Windows 7/8 with Intel OpenCL CPU). You need to use some flags: --cl_platform=x --allow_opencl_cpu --use_large_batches --use_uniform_grid
The performance is not as bad as I expected, but a high-end GPU outperforms it.

[erwincoumans]

There hasn't been any active OpenCL development in years, let's close this.