View Full Version : drifting

02-24-2008, 10:34 PM

I'm developing a cgm viewer and editor, strictly for 2D CAD use. The problem I'm encountering is drifting towards the right of the primatives along the x axis while the app draws a rubber band zoom rectangle. The text however doesn't drift. I am using lists. The environment is c# .NET. I do not have a lingering translate of the the matrix that draws the primatives, so I am at a loss as to why I'm experiencing this problem.

Has anyone else experienced this kind of problem and what was done to remedy it?

02-25-2008, 12:02 AM
Maybe you just forgot to load the identity matrix before your matrix operations so that the matrix transform gets accumulated each time the screen is refreshed...


02-25-2008, 09:19 AM
I seem to recall something like that happening once.

As I recall, I was using bilinear interpolation and ping-pong rendering. Since texture coordinates are never exact, I was grabbing a little bit of the black beyond one edge with each render, and that was being propagated forward through the ping-pong process, until eventually my entire texture was black.

02-26-2008, 08:29 AM
call me psychic, but I don't think that's this guys problem.

02-26-2008, 08:51 PM
You're right the identity matrix wasn't being loaded


02-27-2008, 03:13 AM
Told ya, lindley. Teach you to over-estimate people.