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View Full Version : Accelerated Stippled Line Drawing



glfreak
03-16-2009, 09:32 AM
Is stippled line drawing (patterns) supported by the 3D accelerator? How does it work? Any document out there describes the inner working of 3D hardware?

Thanks.

Don't Disturb
03-16-2009, 10:29 AM
http://www.opengl.org/documentation/specs/man_pages/hardcopy/GL/html/gl/linestipple.html

glfreak
03-16-2009, 10:41 AM
I meant to say if this patterned line drawing is supported by hardware naively or the API layer has to setup the geometry to mimic stipples???? :)

Jackis
03-16-2009, 10:43 AM
glfreak
If you want some advanced stippling (with images, or with rectangular patterns), so you have to create quadstrip for each line-contour with integrated width, stored at each vertex, and do some vertex-shader trivial math to make stipples be zoom-independent.
[EDIT]
AFAIK, stippling is not HW-accelerated, but I can be wrong. Anyway, this built-in stippling is very weak, so I recommend to make it your-own.

Rob Barris
03-16-2009, 11:28 AM
Some generations of GPU have stipple hardware. The ones that don't would need to implement that functionality through the pixel shader probably.

Brolingstanz
03-16-2009, 01:03 PM
Incidentally there's a nice little Geforce/Quadro comparison over here (http://www.nvidia.com/object/quadro_geforce.html). Hardware support for all sorts of stuff like AA points/lines, logic ops, clip regions, clip planes, 2 sided lighting, quad buffer stereo, etc.