From f1c34cf4a2e6f152f98f2ba941a6f20cb0832b4b Mon Sep 17 00:00:00 2001
From: Fabrice Desclaux <fabrice.desclaux@cea.fr>
Date: Wed, 14 Dec 2022 11:08:17 +0100
Subject: [PATCH] Set dxgi latency to 1 frame

---
 sanzu/src/server_windows.rs | 33 +++++++++++++++++++++++++++++++++
 1 file changed, 33 insertions(+)

diff --git a/sanzu/src/server_windows.rs b/sanzu/src/server_windows.rs
index 036edf2..1720db9 100644
--- a/sanzu/src/server_windows.rs
+++ b/sanzu/src/server_windows.rs
@@ -332,6 +332,34 @@ fn d3d11_get_device_idxgidevice(device: &d3d11::ID3D11Device) -> Result<&dxgi::I
     unsafe { p_idxgidevice.as_ref() }.context("Null idxgiadapter")
 }
 
+fn d3d11_get_device_idxgidevice1(device: &d3d11::ID3D11Device) -> Result<&dxgi::IDXGIDevice1> {
+    /* GUID_ENTRY(0x77db970f,0x6276,0x48ba,0xba,0x28,0x07,0x01,0x43,0xb4,0x39,0x2c,IID_IDXGIDevice1) */
+    let riid_idxgidevice1 = GUID {
+        Data1: 0x77db970f,
+        Data2: 0x6276,
+        Data3: 0x48ba,
+        Data4: [0xba, 0x28, 0x07, 0x01, 0x43, 0xb4, 0x39, 0x2c],
+    };
+
+    let mut p_idxgidevice1: *mut c_void = null_mut();
+
+    let ret = unsafe {
+        device.QueryInterface(
+            &riid_idxgidevice1 as *const _,
+            &mut p_idxgidevice1 as *mut _,
+        )
+    };
+
+    if SUCCEEDED(ret) {
+        info!("Query interface success {:?}", p_idxgidevice1);
+    } else {
+        error!("Error in queryinterface");
+        return Err(anyhow!("Error in query interface idxgidevice1"));
+    }
+    let p_idxgidevice1: *mut dxgi::IDXGIDevice1 = unsafe { std::mem::transmute(p_idxgidevice1) };
+    unsafe { p_idxgidevice1.as_ref() }.context("Null idxgiadapter1")
+}
+
 fn d3d11_get_idxgidevice_idxgiadapter(
     idxgidevice: &dxgi::IDXGIDevice,
 ) -> Result<&dxgi::IDXGIAdapter> {
@@ -601,6 +629,11 @@ pub fn init_d3d11() -> Result<()> {
         let idxgidevice =
             d3d11_get_device_idxgidevice(d3d11_device).context("Cannot get idxgidevice")?;
 
+        if let Ok(idxgidevice1) = d3d11_get_device_idxgidevice1(d3d11_device) {
+            let ret = unsafe { idxgidevice1.SetMaximumFrameLatency(1) };
+            error!("Set max frame latency: {:x}", ret);
+        }
+
         let idxgiadapter =
             d3d11_get_idxgidevice_idxgiadapter(idxgidevice).context("Cannot get idxgiadapter")?;