cube example

Trying out snippet from http://chroma.bitbucket.org/render.html

Usage:

chroma-
cd ~/e/chroma/test
./cube.py

Controls on macbook pro

• rotate camera around object: one finger drag around
• rotate camera: control + one finger drag
• zoom: two finger drag in/out
• pan: shift + one finger drag
• some function key bindings are obscured by OSX system ones brightness/volume etc..

Issues

Needs nvcc in PATH

Initially got a giant stack trace in ipython ending:

ExecError: error invoking 'nvcc --preprocess --use_fast_math -I/usr/local/env/chroma_env/src/chroma/chroma/cuda -arch sm_30 -m64 -I/usr/local/env/chroma_env/lib/python2.7/site-packages/pycuda/cuda /var/folders/qm/1p5gh0x94l3b0xqc8dpr9    yn40000gn/T/tmpx1J3Va.cu --compiler-options -P': [Errno 2] No such file or directory

This was fixed by adding “cuda-” to “chroma-” environment setup providing access to nvcc via PATH. Perhaps that should be in VIRTUAL_ENV/env.d ?

CUDA Compilation Warnings

Succeeds to pull up a window containing a 3D cube that can interact with, but gives warnings:

(chroma_env)delta:test blyth$ ./cube.py
/usr/local/env/chroma_env/lib/python2.7/site-packages/pycuda/characterize.py:40: UserWarning: The CUDA compiler succeeded, but said the following:
kernel.cu(45): warning: variable "NCHILD_MASK" was declared but never referenced
kernel.cu(45): warning: variable "NCHILD_MASK" was declared but never referenced
...  % (preamble, type_name), no_extern_c=True)
/usr/local/env/chroma_env/src/chroma/chroma/gpu/tools.py:32: UserWarning: The CUDA compiler succeeded, but said the following:
kernel.cu(198): warning: integer conversion resulted in a change of sign
kernel.cu(198): warning: integer conversion resulted in a change of sign
... no_extern_c=True)

Warnings only show up on first run, presumably the compilation is cached somewhere:

(chroma_env)delta:test blyth$ ./cube.py

Initial Crash, no device

Initially crashed when run from macports ipython, with:

In [1]: import chroma
In [2]: chroma.view(chroma.make.cube(100))
Merging 24 nodes to 8 parents
Merging 8 nodes to 2 parents
Merging 2 nodes to 1 parent
Process Camera-1:
Traceback (most recent call last):
  File "/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/multiprocessing/process.py", line 258, in _bootstrap
    self.run()
  File "/usr/local/env/chroma_env/src/chroma/chroma/camera.py", line 629, in run
    self.init_gpu()
  File "/usr/local/env/chroma_env/src/chroma/chroma/camera.py", line 82, in init_gpu
    self.context = gpu.create_cuda_context(self.device_id)
  File "/usr/local/env/chroma_env/src/chroma/chroma/gpu/tools.py", line 129, in create_cuda_context
    cuda.init()
RuntimeError: cuInit failed: no device

Perhaps this is first access timeout or somesuch ?

Working

Subsequently is working using either:

(chroma_env)delta:test blyth$ ipython
WARNING: Attempting to work in a virtualenv. If you encounter problems, please install IPython inside the virtualenv.
Python 2.7.6 (default, Nov 18 2013, 15:12:51)
Type "copyright", "credits" or "license" for more information.

IPython 1.1.0 -- An enhanced Interactive Python.
?         -> Introduction and overview of IPython's features.
%quickref -> Quick reference.
help      -> Python's own help system.
object?   -> Details about 'object', use 'object??' for extra details.

In [1]: import chroma

In [2]: chroma.view(chroma.make.cube(100))

OR:

In [1]: run cube.py