Gfx backend for gpu-alloc

Usage example

use {
eyre::eyre,
gfx_backend_vulkan::Instance,
gfx_hal::{
adapter::{Gpu, PhysicalDevice as _},
queue::QueueFamily as _,
Features, Instance as _,
},
gpu_alloc::{Config, GpuAllocator, Request, UsageFlags},
gpu_alloc_gfx::{gfx_device_properties, GfxMemoryDevice},
};

fn main() -> eyre::Result<()> {
color_eyre::install()?;

let instance =
Instance::create("gpu_alloc-example", 1).map_err(|_| eyre!("Unsupported backend"))?;

let adapters = instance.enumerate_adapters();

let adapter = adapters
.iter()
.min_by_key(|a| {
use gfx_hal::adapter::DeviceType::*;
match a.info.device_type {
Other => 4,
IntegratedGpu => 1,
DiscreteGpu => 0,
VirtualGpu => 2,
Cpu => 3,
}
})
.ok_or_else(|| eyre!("No adapters found"))?;

let queue_family = adapter
.queue_families
.iter()
.min_by_key(|qf| {
use gfx_hal::queue::QueueType::*;
match qf.queue_type() {
General => 0,
Graphics => 1,
Compute => 3,
Transfer => 4,
}
})
.ok_or_else(|| eyre!("No queue families found"))?;

let props = gfx_device_properties(adapter);

let Gpu { device, .. } = unsafe {
adapter
.physical_device
.open(&[(queue_family, &[1.0])], Features::empty())
}?;

let config = Config::i_am_potato();

let mut allocator = GpuAllocator::new(config, props);

let mut block = unsafe {
allocator.alloc(
GfxMemoryDevice::wrap(&device),
Request {
size: 10,
align_mask: 1,
usage: UsageFlags::HOST_ACCESS,
memory_types: !0,
},
)
}?;

unsafe {
block.write_bytes(
GfxMemoryDevice::wrap(&device),
0,
&[0, 1, 2, 3, 4, 5, 6, 7, 8, 9],
)
}?;

unsafe { allocator.dealloc(GfxMemoryDevice::wrap(&device), block) }

Ok(())
}