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- From: Carson Brownlee <
>
- To:
- Subject: [Manta] Re: Re: Re: Re: Support for photon mapping
- Date: Wed, 29 Sep 2010 16:26:24 -0600
not elegantly. I believe I just had a flag and a static photon map in
the material which and then build on calls to shade. A better solution
would probably be to add the photon map to Scene and then implement the
photonmap build through a parallel callback but at the time I was just
getting something working.
Carson
On Wed, 2010-09-29 at 16:03 -0600, James Bigler wrote:
>
Carson, how did you do the precomputation step in manta?
>
>
Daniel, if you want a simple kd-tree build for photons, there's one
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you can poach from the progressivePhotonMapper sample in OptiX. It's
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a CPU based kd-tree build, so it should be fairly straightforward to
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adapt to your needs.
>
>
In the past, I've also used the code found in Wann Jensen's photon
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mapping book to do the photon kd-tree and lookup.
>
>
James
>
>
On Wed, Sep 29, 2010 at 3:32 PM, Carson Brownlee
>
<
>
>
wrote:
>
I implemented a very crude photon map in Manta a year ago for
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a project
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which kind of fizzled out. It was pretty simple to implement,
>
especially if you are familiar with Manta. I don't see it in
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my project
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directory so I might have accidentally deleted it though. I
>
think I
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just ended up making a custom material type and building the
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photon map
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as a pre-computation step using a flag that tells the material
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to bounce
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the ray and add it to a kdtree. If I remember correctly there
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is
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already a random sampling for the lights; I think I used that
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function
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to generate rays from the light sources. There is a BRDF
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class already.
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I think the main things were building my own basic kdtree for
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sample
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lookup (I don't think I was easily able to adapt the existing
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kd-tree
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for storing samples for k-nearest but I could be remembering
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that wrong
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or was just being lazy) and filtering.
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>
what is this engine for?
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>
Carson
>
>
>
On Wed, 2010-09-29 at 10:03 -0600, James Bigler wrote:
>
> I'm not sure how to get Manta to switch between different
>
Cameras, but
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> you might be able to implement the photon pass as a camera
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and
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> material set, build your photon map, and then use another
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camera and
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> material set for the gather pass.
>
>
>
> As an alternative to Manta, NVIDIA's OptiX
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> ( http://developer.nvidia.com/object/optix-home.html ) has a
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> progressive photon mapping sample:
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> (windows one click samples:
>
> http://developer.nvidia.com/object/optix-examples.html).
>
OptiX
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> requires a CUDA capable device, but it should work on
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> Windows/Linux/Mac. The SDK has precompiled binaries for
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each
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> platform.
>
>
>
> James
>
>
>
> On Wed, Sep 29, 2010 at 9:49 AM,
>
<
>
>
wrote:
>
>
>
> Hello,
>
>
>
> I am relatively new to ray tracing and it was
>
suggested that I
>
> consider Manta
>
> for my engine development. I have been impressed by
>
the
>
> architecture and
>
> features but was curious whether photon mapping (or
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other
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> forward ray tracing
>
> concepts) had been incorporated into the existing
>
Manta
>
> release. A post from
>
> March 17, 2010 suggests that forward ray tracing
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techniques
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> would still need to
>
> be developed. Is this accurate?
>
>
>
>
>
> Off the top of my head, Manta has a simple
>
(brute
>
> force) path tracer,
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> it can do soft shadows (outside of the path tracer
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as well),
>
> and also ambient
>
> occlusion. And of course if it doesn't have
>
something you can
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> add it. I am not
>
> aware of Manta currently having bidirectional path
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tracing,
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> metropolis light
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> transport, photon mapping, or any of the other fancy
>
GI stuff.
>
> Thiago
>
>
>
> Thank you,
>
> Daniel
>
>
>
>
>
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