Hi,
I'm rendering a skybox by drawing 5 quads (front, back, left, right, top). This is Direct3D9.
This works when rendering to the backbuffer, as usual.
However, when I render a video, very strange problems occur. It looks as if one additional triangle is inserted.
Rendering a video from my application involves reloading the device and rendering to a rendertarget without presenting.
What I found out so far:
* the entire triangle has texture coordinates (0,0), and definitely belongs to the Skybox (same texture, same pixel shader)
* the triangle appears even if I just render one quad of the skybox. In that case, the triangle appears exactly opposite the quad. For example, if I render the "back" quad only, then the triangle appears in the front.
* The problem is sporadic - sometimes it just works, sometimes it doesn't.
* The debug runtime shows no problems, except an unrelated "Warning - device that was created without D3DCREATE_MULTITHREADED was accessed from a different thread". UPDATE: I solved that, and it made no difference. The skybox artifact still appears.
Does anybody have an idea what's wrong here?