Graphics Performance

Thomas White taw at
Mon Apr 6 19:16:27 CEST 2009

On Sat, 4 Apr 2009 15:04:27 +0200
Rask Ingemann Lambertsen <rask at> wrote:

>    The Glamo doesn't have a vblank interrupt. Try to search the bug
> tracker, though, because there was a mention of an alternative means
> of getting double buffering to work.

Not having a vblank interrupt doesn't rule out double buffering in any
way.  It just means we may have to put up with tearing.

If we can make proper use of what Glamo can do, we can do back->front
buffer blitting with the 2D engine in a fast way - i.e. without
"draping", as it has been called.  That would possibly give us tearing,
since there's no nice way to synchronise our blits with vblank.

In addition, Glamo can do page flipping which should be synchronised
properly with the LCD (the datasheet claims "tearing free" operation).
Just the ticket for full-screen applications, but not great (read:
probably slow, but perhaps not - I haven't investigated properly yet)
for an X desktop with multiple windows.


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