On 26/01/2012 04:41 PM, Saul Luizaga wrote:
> Invisible wrote:
>> Au contrare... Ever heard of displacement mapping? This is nothing other
>> than running a (simplistic) ray tracer as a pixel shader. Physically
>> correct dynamic reflections are already possible via ray tracing
>> (although you're still tracing stupid flat polygons rather than true
>> geometry). There have been tech demos of full ray tracers running on
>> standard GPU hardware.
>
> Yes, as I have mentioned, I have seen them too, impressive, but not yet
> in a commercial way and I doubt with 100% POV-Ray features &
> capabilities.

I think the main thing that makes POV-Ray look so damned good is that it 
doesn't use polygon meshes (it uses real curved geometry), and it 
doesn't use bitmap textures (it uses procedural texturing), and it 
doesn't fake the lighting equation quite as poorly as most game engines. 
(Although it's no unbiased renderer.)

> Never hear of displacement mapping.

Apparently the correct term is "relief mapping", not displacement mapping.

http://en.wikipedia.org/wiki/Relief_mapping_%28computer_graphics%29

> As you mention *some*
> raytracing is possible on *some* experimental GPUs;

My point is, this is *not* experimental hardware. Relief mapping can be 
done in commercial hardware. Accurate reflections can be done on 
commercial hardware. These features are in commercial games, today.

> what I meant was a
> 100% GPU implementation of POV-Ray giving at least 24fps at, lets say,
> 1360x768 resolution.

You're never going to get a 100% GPU implementation of "POV-Ray". 
Because "POV-Ray" is a piece of code that runs on a CPU. What you 
/might/ be able to do some day is implement the same algorithms on a 
GPU. More likely, you could move "most" of the work to the GPU; things 
like parsing the scene data and so forth will always be on the CPU.

I gather that procedural texturing is quite possible on a GPU. (But 
nobody uses it, for whatever reason.) Ray tracing is certainly possible. 
Realistic real-time lighting is possible. The big thing that I haven't 
seen done is non-polygon geometry. I don't know if it's currently 
feasible to do that on a GPU. I don't see why not...

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