One of the issues with J3D 1.2.1 was that you could not do an add and a subtract in one pass. So for example bump mapping you often want to lighten one part and darken another part. So what we would do is use a lighter material and then apply a "darken" multiply, where a value of 1 would leave it "brighter", a value of 0.8 would leave it "normal" (as if I had not applied the material brighten) and 0.6 would leave it shadowed. The reason we did this was that multitexturing could only multiply.
So when I spoke of limitations I was refering to your comment that only one register combiner is used. I was wondering what types of things we could do with one register combiner, versus the types of techniques which would require more than one. Dave Yazel -----Original Message----- From: Joachim Diepstraten [mailto:[EMAIL PROTECTED]] Sent: Friday, December 21, 2001 10:18 AM To: [EMAIL PROTECTED] Subject: Re: [JAVA3D] Question concerning Dot3 Texturecombiner Hi Yazel > Could you explain this using small words :) I don't have experience with > combiners, so a brief explanation would be helpful in understanding what it Depends on which combiners you're speaking? Register-combiners in OpenGL/Nvidia/Ati-ext or Texturecombiners in Java3D. I think Java3D uses register combiners for the texture combine modes at least for the dot3 I would assume. (or multipass if they're not available? I think someone from SUN should drop a comment here?). Well register-combiners on modern graphic hardware (like the Geforce-series) can be used to calculate effects or other things on pixel (or better say texel) level. Dot3 bump mapping is a good example for using texture combiners. PS1.1 (DirectX 8/8.1) or Nvidia OpenGL Pixelshader-extension are nothing more than 8 register combines with some little extra things. You can combine different stages of texture hardware (multitextures) but it's also possible to use a limit number of other sources (like a constant light vector, view vector). This means instead of simply placing and rendering two or more textures on a object you could actually calculate interactions between those two or more textures or between other "global" constants. At the moment register combines only allow dot product calculation, multipy, add and subtract operations (don't know about PS1.2,1.3,1.4 which ATI Radeon8500 supports) > does and what the limitation of this implementation are. Limitations where? EOF, J.D. -- Explore SRT with the help of Java3D (http://wwwvis.informatik.uni-stuttgart.de/relativity/minkowski) (http://www.antiflash.net/java3d/relativity (mirror) =========================================================================== To unsubscribe, send email to [EMAIL PROTECTED] and include in the body of the message "signoff JAVA3D-INTEREST". For general help, send email to [EMAIL PROTECTED] and include in the body of the message "help". =========================================================================== To unsubscribe, send email to [EMAIL PROTECTED] and include in the body of the message "signoff JAVA3D-INTEREST". For general help, send email to [EMAIL PROTECTED] and include in the body of the message "help".
