Fix issues with ALLOW_TEARING

gfx-rs · Jun 25, 2022 · ec54fae · ec54fae
1 parent f49e4e3
commit ec54fae
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Showing 3 changed files with 26 additions and 18 deletions.
diff --git a/wgpu-hal/src/dx12/adapter.rs b/wgpu-hal/src/dx12/adapter.rs
@@ -426,19 +426,8 @@ impl crate::Adapter<super::Api> for super::Adapter {
         };
 
         let mut present_modes = vec![wgt::PresentMode::Mailbox, wgt::PresentMode::Fifo];
-        #[allow(trivial_casts)]
-        if let Some(factory5) = surface.factory.as_factory5() {
-            let mut allow_tearing: minwindef::BOOL = minwindef::FALSE;
-            let hr = factory5.CheckFeatureSupport(
-                dxgi1_5::DXGI_FEATURE_PRESENT_ALLOW_TEARING,
-                &mut allow_tearing as *mut _ as *mut _,
-                mem::size_of::<minwindef::BOOL>() as _,
-            );
-
-            match hr.into_result() {
-                Err(err) => log::warn!("Unable to check for tearing support: {}", err),
-                Ok(()) => present_modes.push(wgt::PresentMode::Immediate),
-            }
+        if surface.supports_allow_tearing {
+            present_mode.push(wgt::PresentMode::Immediate);
         }
 
         Some(crate::SurfaceCapabilities {

diff --git a/wgpu-hal/src/dx12/instance.rs b/wgpu-hal/src/dx12/instance.rs
@@ -50,10 +50,27 @@ impl crate::Instance<super::Api> for super::Instance {
         &self,
         has_handle: &impl raw_window_handle::HasRawWindowHandle,
     ) -> Result<super::Surface, crate::InstanceError> {
+        let mut supports_allow_tearing = false;
+        #[allow(trivial_casts)]
+        if let Some(factory5) = self.factory.as_factory5() {
+            let mut allow_tearing: minwindef::BOOL = minwindef::FALSE;
+            let hr = factory5.CheckFeatureSupport(
+                dxgi1_5::DXGI_FEATURE_PRESENT_ALLOW_TEARING,
+                &mut allow_tearing as *mut _ as *mut _,
+                mem::size_of::<minwindef::BOOL>() as _,
+            );
+
+            match hr.into_result() {
+                Err(err) => log::warn!("Unable to check for tearing support: {}", err),
+                Ok(()) => supports_allow_tearing = true,
+            }
+        }
+
         match has_handle.raw_window_handle() {
             raw_window_handle::RawWindowHandle::Win32(handle) => Ok(super::Surface {
                 factory: self.factory,
                 target: SurfaceTarget::WndHandle(handle.hwnd as *mut _),
+                supports_allow_tearing,
                 swap_chain: None,
             }),
             _ => Err(crate::InstanceError),

diff --git a/wgpu-hal/src/dx12/mod.rs b/wgpu-hal/src/dx12/mod.rs
@@ -128,6 +128,7 @@ enum SurfaceTarget {
 pub struct Surface {
     factory: native::DxgiFactory,
     target: SurfaceTarget,
+    supports_allow_tearing: bool,
     swap_chain: Option<SwapChain>,
 }
 
@@ -554,11 +555,11 @@ impl crate::Surface<Api> for Surface {
         config: &crate::SurfaceConfiguration,
     ) -> Result<(), crate::SurfaceError> {
         let mut flags = dxgi::DXGI_SWAP_CHAIN_FLAG_FRAME_LATENCY_WAITABLE_OBJECT;
-        match config.present_mode {
-            wgt::PresentMode::Immediate => {
-                flags |= dxgi::DXGI_SWAP_CHAIN_FLAG_ALLOW_TEARING;
-            }
-            _ => {}
+        // We always set ALLOW_TEARING on the swapchain no matter
+        // what kind of swapchain we want because ResizeBuffers
+        // cannot change if ALLOW_TEARING is applied to the swapchain.
+        if self.supports_allow_tearing {
+            flags |= dxgi::DXGI_SWAP_CHAIN_FLAG_ALLOW_TEARING;
         }
 
         let non_srgb_format = auxil::dxgi::conv::map_texture_format_nosrgb(config.format);
@@ -769,6 +770,7 @@ impl crate::Queue<Api> for Queue {
         sc.acquired_count -= 1;
 
         let (interval, flags) = match sc.present_mode {
+            // We only allow immediate if ALLOW_TEARING is valid.
             wgt::PresentMode::Immediate => (0, dxgi::DXGI_PRESENT_ALLOW_TEARING),
             wgt::PresentMode::Mailbox => (0, 0),
             wgt::PresentMode::Fifo => (1, 0),