Dynamically detect D3D12 feature level

src/graphics/d3d12.rs

@@ -10,7 +10,7 @@ use openxr as xr;
 use wgpu::Instance;
 use wgpu_hal::{Adapter as HalAdapter, Instance as HalInstance};
 use winapi::shared::dxgiformat::{self, DXGI_FORMAT};
-use winapi::um::d3dcommon;
+use winapi::um::{d3d12 as winapi_d3d12, d3dcommon};
 
 use crate::input::XrInput;
 use crate::resources::{
@@ -82,16 +82,7 @@ pub fn initialize_xr_graphics(
 
  let blend_mode = xr_instance.enumerate_environment_blend_modes(xr_system_id, VIEW_TYPE)?[0];
 
- // wgpu hardcodes this, so we'll hardcode it here too
- let d3d_target_version: u32 = d3dcommon::D3D_FEATURE_LEVEL_11_0;
-
  let reqs = xr_instance.graphics_requirements::<xr::D3D12>(xr_system_id)?;
- if (d3d_target_version) < (reqs.min_feature_level as u32) {
- panic!(
- "OpenXR runtime requires D3D12 feature level >= {}",
- reqs.min_feature_level
- );
- }
 
  let instance_descriptor = &wgpu_hal::InstanceDescriptor {
  name: option_env!("CARGO_BIN_NAME").unwrap_or("bevy"),
@@ -140,6 +131,15 @@ pub fn initialize_xr_graphics(
  .open(wgpu_features, &wgpu_limits)?
  };
 
+ let device_supported_feature_level: d3d12::FeatureLevel = get_device_feature_level(wgpu_open_device.device.raw_device());
+
+ if (device_supported_feature_level as u32) < (reqs.min_feature_level as u32) {
+ panic!(
+ "OpenXR runtime requires D3D12 feature level >= {}",
+ reqs.min_feature_level
+ );
+ }
+
  let (session, frame_wait, frame_stream) = unsafe {
  xr_instance.create_session::<xr::D3D12>(
  xr_system_id,
@@ -291,6 +291,36 @@ pub fn initialize_xr_graphics(
  ))
 }
 
+// Extracted from https://github.com/gfx-rs/wgpu/blob/1161a22f4fbb4fc204eb06f2ac4243f83e0e980d/wgpu-hal/src/dx12/adapter.rs#L73-L94
+// license: MIT OR Apache-2.0
+fn get_device_feature_level(device: &d3d12::ComPtr<winapi_d3d12::ID3D12Device>) -> d3d12::FeatureLevel {
+ // Detect the highest supported feature level.
+ let d3d_feature_level = [
+ d3d12::FeatureLevel::L12_1,
+ d3d12::FeatureLevel::L12_0,
+ d3d12::FeatureLevel::L11_1,
+ d3d12::FeatureLevel::L11_0,
+ ];
+ type FeatureLevelsInfo = winapi_d3d12::D3D12_FEATURE_DATA_FEATURE_LEVELS; 
+ let mut device_levels: FeatureLevelsInfo =
+ unsafe { std::mem::zeroed() };
+ device_levels.NumFeatureLevels = d3d_feature_level.len() as u32;
+ device_levels.pFeatureLevelsRequested = d3d_feature_level.as_ptr().cast();
+ unsafe {
+ device.CheckFeatureSupport(
+ winapi_d3d12::D3D12_FEATURE_FEATURE_LEVELS,
+ (&mut device_levels as *mut FeatureLevelsInfo).cast(),
+ std::mem::size_of::<FeatureLevelsInfo>() as _,
+ )
+ };
+ // This cast should never fail because we only requested feature levels that are already in the enum.
+ let max_feature_level =
+ d3d12::FeatureLevel::try_from(device_levels.MaxSupportedFeatureLevel)
+ .expect("Unexpected feature level");
+ max_feature_level
+}
+
+
 fn wgpu_to_d3d12(format: wgpu::TextureFormat) -> Option<DXGI_FORMAT> {
  // Copied wholesale from:
  // https://github.com/gfx-rs/wgpu/blob/a7defb723f856d946d6d220e9897d20dbb7b8f61/wgpu-hal/src/auxil/dxgi/conv.rs#L4-L84