GPU Acceleration docs

[J the Ninja]

http://www.luxrender.net/wiki/GPU

^I made some, since it seems we didn't have one until now.

[Abel]

That's a nice and clear read, great!

[paco]

Great work J!

[dougal2]

I added a link to the GPU page on the website: http://www.luxrender.net/en_GB/gpu_support

[B.Y.O.B.]

Very good, thanks!

[SATtva]

The only thing it lacks is the description of various advanced parameters like workgroup size and so on.

[J the Ninja]

The only thing it lacks is the description of various advanced parameters like workgroup size and so on.

That's because I don't understand them that well.

[rovitotv]

This is an excellent start to the GPU acceleration docs.

What it be OK if I added a sub-section to the trouble shooting section on required changes to a lux scene file. It took me a little time of digging this morning to get the syntax just right and I think a simple example would be terrific. Thanks for the feedback. Here is the example I suggest:

Code: Select all

# Main Scene File from LuxTime http://www.luxrender.net/forum/download/file.php?id=13825

# Renderer "sampler"  # original for CPU
Renderer "hybrid"     # changed for GPU


Sampler "metropolis"
   "float largemutationprob" [0.400000005960464]
   "bool usevariance" ["false"]

Accelerator "qbvh"

#SurfaceIntegrator "bidirectional" # original for CPU
#   "integer eyedepth" [48]    # original for CPU
#   "integer lightdepth" [48]  # original for CPU
SurfaceIntegrator "path"               # changed for GPU
   "string lightstrategy" ["one"] # changed for GPU




[Abel]

What it be OK if I added a sub-section to the trouble shooting section on required changes to a lux scene file.

So far J the ninja hasn't voiced any opinions against it so I'd say go for it.

Instead of the trouble shooting section, I'd just add a new section to the Using GPU Rendering part - maybe something with a title like "modifying old scene files manually"?

[MCMXC]

> "On a simple scene, or with a slow GPU, this overhead may be larger than the speedup from the GPU, resulting in a slower overal render speed."

I have a different configuration: a slow CPU (Intel Q9550) and a fast GPU (Radeon 6950 FLEX), but seems that it will results in a slow rendering too:(

I made some tests with the same picture in a HDRI light and different samplers: every test ran 2 hours. Here's the results...

Sampler Metropolis

GPU ON (143 s/p) http://img259.imageshack.us/img259/1181/metrocl143.jpg
GPU OFF (785 s/p) http://img401.imageshack.us/img401/5671/metro785.jpg

Sampler Lowdiscrepancy

GPU ON (557 s/p) http://img528.imageshack.us/img528/3034/lowcl557.jpg
GPU OFF (486 s/p) http://img857.imageshack.us/img857/8359/low486.jpg

Maybe later I'll try with just one Sun light to see if the results will differ...

One note: in the OpenCL pictures, the glass material is a little darker.