Blender Discussions

[fcgrreat]

Dear all, I have an external EGPU Vega64 with my MacBook Pro (with discrete graphics AMD560X).

in blender 2.8 ...If I try to render (or viewport rendering) only on my Vega 64, the view port remains transparent. no rendering at all.

If I enable the rendering both on my Vega64 and on my 560X it works fine, and both GPU works at 100%.

I'd like to exclude the discrete graphics from rendering in order not to warm too much my Mac.

Is this a bug or something intended?

best regards

[bsavery · Accepted solution]

Hey, good question.  The issue here is actually where the OpenGL viewport is being displayed.  For viewport rendering we send the viewport directly from RPR (rendering in OpenCL or Metal in this case) and then sends it directly to OpenGL for display.  If you're rendering on you eGPU and display is on the internal GPU for the viewport this gets weird.

If you look in the addon folder there is a file there called config.py.  You want to change the line in there:

use_gl_interop = True

set that to 
use_gl_interop = False

[fcgrreat]

Yes, that fixed the problem, in my humble opinion by default if I select only one GPU it should tweak automatically that parameter!

great work!

[bsavery]

It's hard to say really.  IF that one GPU selected is the OpenGL device or not is the question.  We have no way of detecting that though...

[fcgrreat]

It doesn't work anymore in blender 2.81 and RPR 2.1... it crashes instantly after switching to rendering viewport (OS X Catalina) 😞

[bsavery]

Thanks.  We have a fix.  If you want to edit a quick file to change it for now here's a workaround if you can edit a python file:

in engine/viewport_engine.py

line 590 should be something like

def _get_render_image(self): return self.rpr_context.get_image()

change that to
def _get_render_image(self):

   with self.render_lock:

      return self.rpr_context.get_image()

[j3s]

fix doesn't work ;(