Need a way to detect if a valid GPU device is available from Python

Other Development Topics Python API
#1

Blender allows the user to select “GPU Compute” as the rendering device even if the computer has no valid GPU device. It simply Greys out the drop down menu:

image

To a Python script, it then looks like a GPU compute device is in use:

image

Cycles will silently default to the CPU if the user selects GPU but doesn’t have one, but I don’t know how to detect this from a script.

I need a way to check from my Python script if an actual valid GPU device will be used for rendering or not.

Can anyone help?

#2

If you look at the UI code that draws those dropdown boxes you will see that it calls a function named show_device_active(context). The method code itself looks like this:

def show_device_active(context):
    cscene = context.scene.cycles
    if cscene.device != 'GPU':
        return True
    return context.preferences.addons[__package__].preferences.has_active_device()

The relevant part is the last line. You can replicate this in an own Add-on or script by calling context.preferences.addons[__package__].preferences.has_active_device()

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#3

Hi

I actually tried that already, but context.preferences.addons[__package__].preferences.has_active_device() seemed to always return False, even on my computer with an Nvidia GPU (note I had to change __package__ to "cycles" in that code.

I probably made a mistake. I will revisit it.

Thanks for the help.

#4

Yes this does work. I must have made some other error when I first tried it.

Many thanks for the help

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