Weirdness with alpha

[madmark]

I have 2 systems that most places that has zero alpha displays a random solid color while other zero alpha areas display fine. (see pic http://www.wbiwork.com/lwbug.JPG)

Systems are both old ATI card based (9600 and 8500).

[LaDoncella]

that happened to me too some months ago:
there the topic (http://www.rtsoft.com/forums/showthread.php?t=1499)

there are two options:

1 - just use sprites instead of surfaces

or

2 - have lots of luck and try to update graphic card drivers


I wish it helps,
Alex

[madmark]

So sprites work differently from surfaces?

that's a huge change for the code...

[Seth]

Sprites use surfaces internally.

I think the best thing to do would be debug what sprites are doing differently and fix up the surface code to do the same so these older cards will work right.

Is it fixed when a power of 2-sized texture is used? If so, may be related to older video cards needing to have the entire texture (you can get the 'true' size if you dig into the surface properties) set to transparent alpha before using it.

Do any of the clanlib examples show the same problem? Might make it easier for someone else here with that card to debug.

[madmark]

Good suggestion Seth.

I wonder if there might be an option to zero the surface on creation before putting pixel data on it.