PDA

View Full Version : glFeedbackBuffer consistency



blueskyday
02-04-2003, 07:05 AM
In the docs for glFeedbackBuffer it mentions that "Feedback occurs after polygon culling ... It can also occur after polygons with more than three edges are broken up into triangles, if the OpenGL implementation renders polygons by performing this decomposition."

Does anybody know how common it is across the different implementations/cards to render polys of more than three edges?

Any help would be greatly appereciated!

JustHanging
02-05-2003, 02:02 AM
Hi,

As far as I know, they all render polygons with more than three edges, and they all split them into triangles. The polygons must be convex though.

The way a polygon is turned into triangles may vary however, so be careful with those polygons, they'll propably cause problems. To get consistent results, split them yourself. It's easy, just replace the glBegin(GL_POLYGON) with glBegin(GL_TRIANGLE_FAN).

-Ilkka