Deferred shadows bug/limitation? or am i just doing it wrong?

Hiya,
I’m trying to use the deferred pcf shadows contribution (thanks catweasel!) and getting some weird shadows that shouldn’t be there.

The light is shining directly on the visible faces of the cubes, and so there shouldn’t be any shadow on them, but there is. It looks as if it’s the shadow from the cube behind it or something, even though the light is coming from the front.
The issue goes away if the camera is rotated beyond 45degrees or so, but I need it to be looking straight on at the objects for the patch.

Any ideas why this would be happening? is it already a known issue with that method of shadowing?

I’ve just gone and looked again at the contribution page and noticed specific reference to nvidia, could this issue be caused by using an ATI (7970) card?

hey try with the Rasterizer node, maybe its a culling problem.

:)

yeah i had tried that, i thought it kind of looked like the shadows needed culling even though the boxes themselves are rendered as desired. But the rasterizer didn’t help :(

Moving the light really far away seems to mitigate the problem, so I can work around it. Bizarrely, the bug comes back when the camera is rotated, the opposite of when the light is close, then rotating the camera fixes the issue.

The shadows are really sketchy/pixelly though, and I don’t know if that’s a result of moving the light far away, or whether it’s more of a backbuffer size or antialiasing issue.
How do you set the backbuffer size of minimized renderer in dx11 anyway?