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Re: OpengGL color / material properties
September 07, 2013 05:16PM
Hi Travis,

Right! The motivation for the enumerated "well-known" surfaces is exactly illustrated by procedural bump maps - some programs might want to use procedural bump maps and program the grit pattern in-shader or pass a shader function to POV-Ray; other programs might simply want to create a bump map texture with a pre-generated pattern and use it.

The lego logo on stud tops would be well-handled via an explicit bump-map texture; I would recommend tangent-space normal maps, e.g.

http://www.blender.org/development/release-logs/blender-236/normal-maps/

Put the red and green (X and Y in tangent-space) vectors into the red and green channels of an RGB png; leave the blue channel defined as reserved for future expansion. The shader can reconstruct the blue channel from the red and green using the pythagorean theorem.

(Saving channels can be useful later for displacement information, etc. Or the program can use a 2-channel texture and save VRAM. There are also dedicated compressed texture formats for normal maps that compress two channels instead of 3 or 4.)

cheers
Ben
SubjectAuthorViewsPosted
OpengGL color / material properties Roland Melkert552August 25, 2013 12:45PM
Re: OpengGL color / material properties Ben Supnik254August 25, 2013 03:33PM
Re: OpengGL color / material properties Roland Melkert238August 25, 2013 04:27PM
Re: OpengGL color / material properties Travis Cobbs280August 26, 2013 01:12PM
Re: OpengGL color / material properties Roland Melkert304August 26, 2013 03:59PM
Re: OpengGL color / material properties Roland Melkert271September 03, 2013 09:47AM
Re: OpengGL color / material properties Travis Cobbs295September 03, 2013 12:26PM
Re: OpengGL color / material properties Roland Melkert284September 04, 2013 11:45AM
Re: OpengGL color / material properties Ben Supnik305September 03, 2013 01:07PM
Re: OpengGL color / material properties Roland Melkert260September 04, 2013 11:49AM
Re: OpengGL color / material properties Ben Supnik288September 04, 2013 07:02PM
Re: OpengGL color / material properties Roland Melkert281September 05, 2013 09:32AM
Re: OpengGL color / material properties Steffen265September 05, 2013 02:08PM
Re: OpengGL color / material properties Ben Supnik219September 05, 2013 07:33PM
Re: OpengGL color / material properties Travis Cobbs201September 06, 2013 09:52AM
Re: OpengGL color / material properties Steffen217September 06, 2013 12:26PM
Re: OpengGL color / material properties Steffen205September 06, 2013 12:27PM
Re: OpengGL color / material properties Travis Cobbs270September 06, 2013 01:07PM
Re: OpengGL color / material properties Ben Supnik245September 06, 2013 02:14PM
Re: OpengGL color / material properties Travis Cobbs301September 06, 2013 02:46PM
Re: OpengGL color / material properties Ben Supnik293September 06, 2013 05:04PM
Re: OpengGL color / material properties Travis Cobbs294September 06, 2013 07:30PM
Re: OpengGL color / material properties Ben Supnik391September 07, 2013 05:16PM
Re: OpengGL color / material properties Allen Smith289September 05, 2013 10:03AM



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