Current status of EGL spec

Michel Danzer mdanzer at ati.com
Thu Aug 11 04:49:42 EST 2005


On Wed, 2005-08-10 at 08:17 -0600, Brian Paul wrote: 
> Jon Smirl wrote:
> 
> > 3) Should eglScreenPositionMESA(EGLDisplay dpy, EGLScreenMESA screen,
> > EGLint x, EGLint y) instead use EGLint *x, EGLint *y. That would allow
> > hardwar
> 
> You got chopped off there, but I think I know what you're getting at 
> (return the actual position in case 1-pixel positioning isn't supported).
> 
> First, OpenGL conventionally doesn't use in/out parameters like that. 
>   Second, how common is it that hardware can't support 1-pixel 
> positioning?  If it's not a common problem, I'd defer for a future 
> extension which would allow you to query the positioning granularity.

As mentioned by Jon, our current hardware can only position the CRTC
offset with a granularity of 8 bytes (i.e. 2-8 horizontal pixels).
Upcoming hardware will only support horizontal panning with a
granularity of four pixels (irrespective of depth).


-- 
Michel Danzer, Linux Software Engineering       \   Tel: +1 905-882-2600
ATI Technologies Inc., Markham, Ontario, Canada  \       Extension: 3550



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