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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 Melkert420August 25, 2013 12:45PM
Re: OpengGL color / material properties Ben Supnik192August 25, 2013 03:33PM
Re: OpengGL color / material properties Roland Melkert172August 25, 2013 04:27PM
Re: OpengGL color / material properties Travis Cobbs191August 26, 2013 01:12PM
Re: OpengGL color / material properties Roland Melkert230August 26, 2013 03:59PM
Re: OpengGL color / material properties Roland Melkert197September 03, 2013 09:47AM
Re: OpengGL color / material properties Travis Cobbs196September 03, 2013 12:26PM
Re: OpengGL color / material properties Roland Melkert193September 04, 2013 11:45AM
Re: OpengGL color / material properties Ben Supnik212September 03, 2013 01:07PM
Re: OpengGL color / material properties Roland Melkert194September 04, 2013 11:49AM
Re: OpengGL color / material properties Ben Supnik209September 04, 2013 07:02PM
Re: OpengGL color / material properties Roland Melkert177September 05, 2013 09:32AM
Re: OpengGL color / material properties Steffen197September 05, 2013 02:08PM
Re: OpengGL color / material properties Ben Supnik156September 05, 2013 07:33PM
Re: OpengGL color / material properties Travis Cobbs140September 06, 2013 09:52AM
Re: OpengGL color / material properties Steffen160September 06, 2013 12:26PM
Re: OpengGL color / material properties Steffen146September 06, 2013 12:27PM
Re: OpengGL color / material properties Travis Cobbs178September 06, 2013 01:07PM
Re: OpengGL color / material properties Ben Supnik182September 06, 2013 02:14PM
Re: OpengGL color / material properties Travis Cobbs231September 06, 2013 02:46PM
Re: OpengGL color / material properties Ben Supnik227September 06, 2013 05:04PM
Re: OpengGL color / material properties Travis Cobbs209September 06, 2013 07:30PM
Re: OpengGL color / material properties Ben Supnik266September 07, 2013 05:16PM
Re: OpengGL color / material properties Allen Smith194September 05, 2013 10:03AM



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