@blend_enable and windows 7

joshua goldberg's icon

hi all.

i'm porting an older patch to windows 7 for the first time and i'm having some trouble.

toggling blend_enable on the two videoplanes in the patch below makes them vanish. is there a known workaround to this?

max 5.1.2, windows 7, newest quicktime, running on a macbook pro in bootcamp with an nvidia card.

Max Patch
Copy patch and select New From Clipboard in Max.

many thanks in advance.

Joshua Kit Clayton's icon

First suggestion: disable depth testing in your jit.gl.videoplane objects.

As mentioned before, depth buffers are not necessarily up to our control on windows, as under many circustances, they are always created by the driver regardless of our request. Whenever you want to do transparent, composited videoplanes, I'd recommend @depth_enable 0

joshua goldberg's icon

both of the videoplanes in that example have @depth_enable 0 set. it's still not working. setting it explicitly on the render object still doesn't make it work. as soon as i set @blend_enable 1 on a videoplane, it vanishes.

joshua goldberg's icon

aha. thank you luke. it would appear that jit.dx.grab on windows 7 outputs a blank alpha channel instead of a white one. using a jit.op @op ~ pass pass pass after the jit.dx.grab solves the problem in this patch.

Joshua Kit Clayton's icon

Thanks for tracking down. We'll look at enforcing a white alpha in a future update.