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Submitted by Simon Howes, posted on November 10, 2004




Image Description, by Simon Howes



We work for a CAE simulation company and have done some work for our next release adding support for pixel and vertex shaders. :) We used OpenGL Shader Language for this, as it seemed a better option than the proprietary CG/etc languages that are out there. It seems this is likely to stay around longer (who remembers Voodoo II) than the custom stuff vendors are putting out...

Top left: simple chrome effect. Top right: 3 point-light phong-shaded with cubic reflection map. It's amazing to see realtime phong rendering at 1600x1200 res, when you used to remember how long 3D studio DOS would take to render a scanline! :) The middle image is a fake-phong: which uses a specular map to lookup based on the surface normal: it runs really fast and sometimes looks even better than the real-phong! At the bottom is the X-ray shader (don't ask... maybe nostalgia, or maybe too much Syndicate Wars..)

Cons/Pros?

Man. Earlier ATI cards are pants! During our testing these were the suffering, with tiny instruction limits, lots of crashes and not a very friendly Shader Language Compiler. nVidia really kicks butt! Though, I can see why there is no option in the display properties to "render gouraud triangles as phong", as it's still just a little bit too slow for that yet (we get only about 3 frames per second on our most complex shaders: but then, these are HUGE programs.) It's amazing the computer power that is packed into a GPU in addition most of our models are around 20,000+ polies. The main taker of time is not Tris but pixels..

It was surprising to find out how many cards did support OpenGL 2.0 when we installed the latest reference drivers from nVidia and *cough* ATI. There's been no fanfar about it however: nothing on the webpages like when some redundant feature is added (ie full-page advert about a better cooling-fan and how this will make your life better.) Of course, the reason for this may be that both nVidia and ATI support is still not 100%... (no noise operator for nVidia, and no variables indexing arrays and poor compiler support for ATI!)


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Archive Notice: This thread is old and no longer active. It is here for reference purposes. This thread was created on an older version of the flipcode forums, before the site closed in 2005. Please keep that in mind as you view this thread, as many of the topics and opinions may be outdated.
 
tokjunior

November 10, 2004, 05:37 AM

Well, the reason the manufacturers aren't saying anything about GL2.0 is that the cards really are DX9-cards. DX9 includes a lot (everything?) GL2.0 has, plus a lot of other usefull stuff.
And i still think the only reason for running nVidia today is for early access to SM3.0, but ATI are bound to have a card like the X800, but with SM3.0-support out pretty soon, and that's what i'm waiting for.

 
lycium

November 10, 2004, 08:43 AM

hmm, "render gouraud triangles as phong" isn't really possible in general, since you'd need the normals. maybe quadratic gouraud instead...

about opengl 2, it's actually a superset of dx9 functionality (not the other way around, even though dx9 has api support for sh stuff etc) and that's why you won't find it on ati cards atm, they're designed directly from the dx9 spec i think.

you mention huge fragment programs, what are they doing?

anyway, your work sounds (and looks) very cool!

 
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