Next step: Is there a graphics card we can use? Or, rather, a “physical device”? Let us look for some:
let phys_devs = unsafe { instance.enumerate_physical_devices()? };
for p in phys_devs {
let props = unsafe { instance.get_physical_device_properties(p) };
dbg!(props);
}
That should give a list in the terminal, including the properties of the devices that we might wish to use. Of course, we now have to choose one. That could be the first one in this Vec. (That’s reasonable in tutorials. I would, however, recommend to check at least once by some dbg! whether it’s the right choice - or if there might be a different integrated graphics card in your computer that you had forgotten about. Another choice might be picking the one with the right name:
let (physical_device, physical_device_properties) = {
let mut chosen = None;
for p in phys_devs {
let properties = unsafe { instance.get_physical_device_properties(p) };
let name = String::from(
unsafe { std::ffi::CStr::from_ptr(properties.device_name.as_ptr()) }
.to_str()
.unwrap(),
);
if name == "GeForce GTX 760" {
chosen = Some((p, properties));
}
}
chosen.unwrap()
};
I guess that also tells what graphics card my computer contains… Needless to say, this way is not a good choice if you ever want to run the program on a different computer. For the moment, let’s pick any (the last listed) discrete GPU.
let (physical_device, physical_device_properties) = {
let mut chosen = None;
for p in phys_devs {
let properties = unsafe { instance.get_physical_device_properties(p) };
if properties.device_type == vk::PhysicalDeviceType::DISCRETE_GPU {
chosen = Some((p, properties));
}
}
chosen.unwrap()
};
Still, might not be optimal (it’s a way to exclude my laptop, for example), but is easy enough to adjust. Now that we have a physical device, we will need queue families on it.