Re: [AD] DGA 2.0 driver completed

["Bertrand Coconnier" <bcoconni@xxxxxxxxxx>]

From: Michael Bukin <M.A.Bukin@xxxxxxxxxx>
Sent: Tuesday, September 26, 2000 3:32 AM

> In polygon3d[_f] it might add only one edge (or no edges at all?),
> then it will try to "close the double-linked list", which might not
> work correctly, and I don't know what would happen in drawing code.

You're right! When no edges at all were added to the list, the edge->prev
and edge->next were updated to a wrong value when closing the double-linked
list. Here is a patch where I have added a test to consider the "no edges
case" the right way. I think (but I don't want to be too optimistic :-) the
bug is now fixed.
IMHO the case where only one edge is added to the list was yet considered
the right way. Anyway I can barely imagine when such a situation can occur.

BTW, I have added another bug fix to this patch. The POLYTYPE_FLAT mode drew
one pixel too much every scanline. This bug has been posted six months ago
by Christian Schüler. The patch makes the flat mode to draw one pixel
less...

Anyway, feedback on this patch is welcome. Please let me know whether it
works fine or not.

Bertrand.

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