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Kaesebrot

ray-tracing

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hi is it possible to code a (fast) ray-tracing engine for 3D-Games, or is it senseless to start ? I think with ray-tracing I can do some cool things, that´s why I want to do this.. Edited by - Kaesebrot on December 9, 2001 4:18:50 AM

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Guest Anonymous Poster
You can get a nice fast raytracer even on a "low-end" machine, but if you want to use it for games that is going to take a heftier system.

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Raytracing is incredibly slow. Your framerate would be in seconds (or minutes, depending on scene complexity) per frame instead of frames per second.

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Guest Anonymous Poster
I''ve seen realtime raytracing go as fast as 20-30 FPS on simple scebes, so it''s possible, but only for real simple games. Search the web for rtChess.

I wouldn''t try it for anything more complex than chess or pacman, though.

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Guest Anonymous Poster
The new Doom game is going to use some sort of ray tracing.

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Kaesebrot: I think you should pursue the idea of writing a ray tracer, real-time or not. It''s a great way to get acquainted with the mathematics of computer graphics in a very API- independent way.

As for real-time ray tracing, I''m not an expert, but from what I have seen, you will either need a super computer or you are going to need to sacrifice a lot. By sacrificing I mean dirty hacks and whole lot of preprocessing, and even then you won''t be able to do the fancy eye-popping stuff like depth of view, motion blur, soft shadows, diffuse materials, etc.

Good luck.

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Guest Anonymous Poster
quote:
Original post by Anonymous Poster
The new Doom game is going to use some sort of ray tracing.


probably just to pre-calculate light and shadow maps which will then be rendered/blended-in as a second pass on the geometry. i really doubt carmack''ll be doing any true ray tracing realtime.
pc hardware is still not even close to pulling it off high-res full screen with all the bells and whistles and tricks you get with modern lighting and texturing hardware.



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Guest Anonymous Poster
quote:
Original post by Anonymous Poster
[quote]Original post by Anonymous Poster
The new Doom game is going to use some sort of ray tracing.


probably just to pre-calculate light and shadow maps which will then be rendered/blended-in as a second pass on the geometry. i really doubt carmack''ll be doing any true ray tracing realtime.
pc hardware is still not even close to pulling it off high-res full screen with all the bells and whistles and tricks you get with modern lighting and texturing hardware.





I''m pretty sure the lighting is done in realtime. That''s one of the main features of the new Doom engine.

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Guest Anonymous Poster
quote:
Original post by Anonymous Poster
bleh, this fuck board messed up my quote!


i hear ya.

as far as lighting in realtime in the new doom engine..of course, id be very disappointed if it wasnt doing realtime lighting.
however, realtime lighting _does not_ assume ray tracing must be implemented.

and if you mean realtime shadowing as well..its still way cheaper to render a scene from your lights point of view and as you render your final image you transform your scenes pixels into the lights frame of reference do a little zbuffer value compare and adjust the color of that pixel accordlingly then to do the actual raytrace traverse of your scene data to see if a "light-ray" intersects anything, especially for large scene data sets most "next-gen" games have.


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quote:
Original post by Anonymous Poster
The new Doom game is going to use some sort of ray tracing.


No it doesnt. The new doom uses stencilled shadow volumes.

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0wn 0wn 0wn your goat
gently down the pw33n

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Guest Anonymous Poster
quote:
Original post by Maximus
No it doesnt. The new doom uses stencilled shadow volumes.
hm.. stencil buffered shadows are quite hardware intense. From where do you know thet doom is going to use it?

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It may be though, but take a look at it, it''s running at 30 fps on the highest high end machine with a GF3.. I think doing 2 or 3 stencil tests on the whole frame isn''t too though on a GF3... If they already do z-buffering so fast, optimizing a 8 bit compare shouldn''t be a problem.. (the only issue is that every pixel has to be touched)...

just my 2 cents,
cya,
Phil

Visit Rarebyte!
and no!, there are NO kangaroos in Austria (I got this questions a few times over in the states )

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