Tile seams on scrolling layer + point sampling

Hi,

I have a background made up of several 512x512 tiles and the layer they are on scroll horizontally only and have enabled the point sampling for that layer. I�ve run a few tests on machines running a mix of GPU�s such as nvidia 6155 mainboard combo, a gforce 8800gt card, and an ati firegl 7600 to check performance.

The only GPU I�m having problems with is the ATI firegl 7600 card. I know it�s not a consumer card that the typical gamer will want to use, but to satisfy my curiosity I was wondering if anyone else has similar issues with seams randomly showing every now and then with this category of card. These seams flicker for a split second and go away then later they may flicker, it�s consistent every time no matter how fast or slow the layer scrolls. I�ve tried different ATI drivers, enabled �reduce DVI frequency on high resolution displays� and enabled �Alternate DVI operational mode� but these seams always show whereas the other GPU's run perfectly fine seam free.

<img src="http://www.meisgood.com/images/avatar/tiles.jpg">

are they tiled background objects or sprites?

Tiled background objects

FireGL? sweet!

Wasn't there some issue with non power of two textures with tiled bg in the past.

The image you posted doesn't look square even, so I think you can assume thats whats happening here.

But each background tile image is 512x512 positioned next to each other in one long row and works on a range of other GPU's? I've tried it on newer ATI workstation card and it works without glitches. I guess it's just that model of card or the driver on the system is corrupt.

I wonder, is there away to detect what the GPU is in a system and deny or print a warning in the application window?

Anyway going to try it on a gforce and radeon card over the weekend which is more akin to what its targeted.

I wonder, is there away to detect what the GPU is in a system and deny or print a warning in the application window?

I'm afraid I can only answer this question. The system expression "Display Device" returns a string describing the graphics card (e.g. "ATI Radeon HD 2600 XT")

[EDIT] Was thinking if the vertices are somehow inaccurate. Do you by chance have an uneven number of TBs? If so, does using an even number of TBs change anything?

thanks for the info and suggestion. There are 10 tiles. I deleted all but 5, then 4, and flickering issue rears it's head each time. I'll do some more tests with different files.

Oops, sorry didn't read all the first post.

Still it looks a lot like the bug I was talking about, as it looks like the first row of pixels is not showing up.

Hmmm 512 is a pretty big size, perhaps you might try cutting it down a bit.