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egl: Fallback if EGL_KHR_display_reference not supported
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libglvnd reports client extensions if at least one vendor supports them.
This might lead to display creation failure when a vendor library reports support but
fails to create a display for another reason (like when the nvidia egl implementation is installed but no nvidia card is available).
To work around this issue retry creation without EGL_KHR_display_reference.
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@Molytho
Molytho committed Oct 9, 2023
1 parent ecf0428 commit 49f9b96
Showing 1 changed file with 156 additions and 118 deletions.
274 changes: 156 additions & 118 deletions glutin/src/api/egl/display.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -203,7 +203,7 @@ impl Display {
/// and managed by other libraries. Use this function only when you're
/// bringing everything down.
pub unsafe fn terminate(self) {
if !CLIENT_EXTENSIONS.get().unwrap().contains("EGL_KHR_display_reference") {
if !self.inner.uses_display_reference() {
unsafe {
self.inner.egl.Terminate(*self.inner.raw);
}
Expand All @@ -217,50 +217,63 @@ impl Display {

let extensions = CLIENT_EXTENSIONS.get().unwrap();

let mut attrs = Vec::<EGLAttrib>::with_capacity(5);
let (platform, mut display) = match display {
#[cfg(wayland_platform)]
RawDisplayHandle::Wayland(handle)
if extensions.contains("EGL_KHR_platform_wayland") =>
{
(egl::PLATFORM_WAYLAND_KHR, handle.display)
},
#[cfg(x11_platform)]
RawDisplayHandle::Xlib(handle) if extensions.contains("EGL_KHR_platform_x11") => {
attrs.push(egl::PLATFORM_X11_SCREEN_KHR as EGLAttrib);
attrs.push(handle.screen as EGLAttrib);
(egl::PLATFORM_X11_KHR, handle.display)
},
RawDisplayHandle::Gbm(handle) if extensions.contains("EGL_KHR_platform_gbm") => {
(egl::PLATFORM_GBM_KHR, handle.gbm_device)
},
RawDisplayHandle::Android(_) if extensions.contains("EGL_KHR_platform_android") => {
(egl::PLATFORM_ANDROID_KHR, egl::DEFAULT_DISPLAY as *mut _)
},
_ => {
return Err(
ErrorKind::NotSupported("provided display handle is not supported").into()
)
},
};
let mut first_try = true;
loop {
let mut attrs = Vec::<EGLAttrib>::with_capacity(5);
let (platform, mut display) = match display {
#[cfg(wayland_platform)]
RawDisplayHandle::Wayland(handle)
if extensions.contains("EGL_KHR_platform_wayland") =>
{
(egl::PLATFORM_WAYLAND_KHR, handle.display)
},
#[cfg(x11_platform)]
RawDisplayHandle::Xlib(handle) if extensions.contains("EGL_KHR_platform_x11") => {
attrs.push(egl::PLATFORM_X11_SCREEN_KHR as EGLAttrib);
attrs.push(handle.screen as EGLAttrib);
(egl::PLATFORM_X11_KHR, handle.display)
},
RawDisplayHandle::Gbm(handle) if extensions.contains("EGL_KHR_platform_gbm") => {
(egl::PLATFORM_GBM_KHR, handle.gbm_device)
},
RawDisplayHandle::Android(_) if extensions.contains("EGL_KHR_platform_android") => {
(egl::PLATFORM_ANDROID_KHR, egl::DEFAULT_DISPLAY as *mut _)
},
_ => {
return Err(
ErrorKind::NotSupported("provided display handle is not supported").into()
)
},
};

if extensions.contains("EGL_KHR_display_reference") && first_try {
attrs.push(egl::TRACK_REFERENCES_KHR as _);
attrs.push(egl::TRUE as _);
} else {
first_try = false;
}

if extensions.contains("EGL_KHR_display_reference") {
attrs.push(egl::TRACK_REFERENCES_KHR as _);
attrs.push(egl::TRUE as _);
}
// Be explicit here.
if display.is_null() {
display = egl::DEFAULT_DISPLAY as *mut _;
}

// Be explicit here.
if display.is_null() {
display = egl::DEFAULT_DISPLAY as *mut _;
}
// Push `egl::NONE` to terminate the list.
attrs.push(egl::NONE as EGLAttrib);

// Push `egl::NONE` to terminate the list.
attrs.push(egl::NONE as EGLAttrib);
let display =
unsafe { egl.GetPlatformDisplay(platform, display as *mut _, attrs.as_ptr()) };
let result = Self::check_display_error(display).map(EglDisplay::Khr);

let display =
unsafe { egl.GetPlatformDisplay(platform, display as *mut _, attrs.as_ptr()) };
// We can't check for the type of error here because for some reason it doesn't
// always report BadAttribute even though EGL_KHR_display_reference
// was the reason of the failure
if result.is_ok() || result.is_err() && !first_try {
return result;
}

Self::check_display_error(display).map(EglDisplay::Khr)
first_try = false;
}
}

fn get_platform_display_ext(egl: &Egl, display: RawDisplayHandle) -> Result<EglDisplay> {
Expand All @@ -270,72 +283,88 @@ impl Display {

let extensions = CLIENT_EXTENSIONS.get().unwrap();

let mut attrs = Vec::<EGLint>::with_capacity(5);
let mut legacy = false;
let (platform, mut display) = match display {
#[cfg(wayland_platform)]
RawDisplayHandle::Wayland(handle)
if extensions.contains("EGL_EXT_platform_wayland") =>
{
(egl::PLATFORM_WAYLAND_EXT, handle.display)
},
#[cfg(x11_platform)]
RawDisplayHandle::Xlib(handle) if extensions.contains("EGL_EXT_platform_x11") => {
attrs.push(egl::PLATFORM_X11_SCREEN_EXT as EGLint);
attrs.push(handle.screen as EGLint);
(egl::PLATFORM_X11_EXT, handle.display)
},
#[cfg(x11_platform)]
RawDisplayHandle::Xcb(handle)
if extensions.contains("EGL_MESA_platform_xcb")
|| extensions.contains("EGL_EXT_platform_xcb") =>
{
attrs.push(egl::PLATFORM_XCB_SCREEN_EXT as EGLint);
attrs.push(handle.screen as EGLint);
(egl::PLATFORM_XCB_EXT, handle.connection)
},
RawDisplayHandle::Gbm(handle) if extensions.contains("EGL_MESA_platform_gbm") => {
(egl::PLATFORM_GBM_MESA, handle.gbm_device)
},
RawDisplayHandle::Windows(..) if extensions.contains("EGL_ANGLE_platform_angle") => {
// Only CreateWindowSurface appears to work with Angle.
legacy = true;
(egl::PLATFORM_ANGLE_ANGLE, egl::DEFAULT_DISPLAY as *mut _)
},
_ => {
return Err(
ErrorKind::NotSupported("provided display handle is not supported").into()
)
},
};
let mut first_try = true;
loop {
let mut attrs = Vec::<EGLint>::with_capacity(5);
let mut legacy = false;
let (platform, mut display) = match display {
#[cfg(wayland_platform)]
RawDisplayHandle::Wayland(handle)
if extensions.contains("EGL_EXT_platform_wayland") =>
{
(egl::PLATFORM_WAYLAND_EXT, handle.display)
},
#[cfg(x11_platform)]
RawDisplayHandle::Xlib(handle) if extensions.contains("EGL_EXT_platform_x11") => {
attrs.push(egl::PLATFORM_X11_SCREEN_EXT as EGLint);
attrs.push(handle.screen as EGLint);
(egl::PLATFORM_X11_EXT, handle.display)
},
#[cfg(x11_platform)]
RawDisplayHandle::Xcb(handle)
if extensions.contains("EGL_MESA_platform_xcb")
|| extensions.contains("EGL_EXT_platform_xcb") =>
{
attrs.push(egl::PLATFORM_XCB_SCREEN_EXT as EGLint);
attrs.push(handle.screen as EGLint);
(egl::PLATFORM_XCB_EXT, handle.connection)
},
RawDisplayHandle::Gbm(handle) if extensions.contains("EGL_MESA_platform_gbm") => {
(egl::PLATFORM_GBM_MESA, handle.gbm_device)
},
RawDisplayHandle::Windows(..)
if extensions.contains("EGL_ANGLE_platform_angle") =>
{
// Only CreateWindowSurface appears to work with Angle.
legacy = true;
(egl::PLATFORM_ANGLE_ANGLE, egl::DEFAULT_DISPLAY as *mut _)
},
_ => {
return Err(
ErrorKind::NotSupported("provided display handle is not supported").into()
)
},
};

if extensions.contains("EGL_KHR_display_reference") && first_try {
attrs.push(egl::TRACK_REFERENCES_KHR as _);
attrs.push(egl::TRUE as _);
} else {
first_try = false;
}

if extensions.contains("EGL_KHR_display_reference") {
attrs.push(egl::TRACK_REFERENCES_KHR as _);
attrs.push(egl::TRUE as _);
}
// Be explicit here.
if display.is_null() {
display = egl::DEFAULT_DISPLAY as *mut _;
}

// Be explicit here.
if display.is_null() {
display = egl::DEFAULT_DISPLAY as *mut _;
}
// Push `egl::NONE` to terminate the list.
attrs.push(egl::NONE as EGLint);

// Push `egl::NONE` to terminate the list.
attrs.push(egl::NONE as EGLint);
let display =
unsafe { egl.GetPlatformDisplayEXT(platform, display as *mut _, attrs.as_ptr()) };

let display =
unsafe { egl.GetPlatformDisplayEXT(platform, display as *mut _, attrs.as_ptr()) };
let result = Self::check_display_error(display).map(|display| {
if legacy {
// NOTE: For angle we use the Legacy code path, as that uses CreateWindowSurface
// instead of CreatePlatformWindowSurface*. The latter somehow
// doesn't work, only the former does. But Angle's own example also use the
// former: https://github.com/google/angle/blob/main/util/EGLWindow.cpp#L424
EglDisplay::Legacy(display)
} else {
EglDisplay::Ext(display)
}
});

Self::check_display_error(display).map(|display| {
if legacy {
// NOTE: For angle we use the Legacy code path, as that uses CreateWindowSurface
// instead of CreatePlatformWindowSurface*. The latter somehow
// doesn't work, only the former does. But Angle's own example also use the
// former: https://github.com/google/angle/blob/main/util/EGLWindow.cpp#L424
EglDisplay::Legacy(display)
} else {
EglDisplay::Ext(display)
// We can't check for the type of error here because for some reason it doesn't
// always report BadAttribute even though EGL_KHR_display_reference
// was the reason of the failure
if result.is_ok() || result.is_err() && !first_try {
return result;
}
})

first_try = false;
}
}

fn get_display(egl: &Egl, display: RawDisplayHandle) -> Result<EglDisplay> {
Expand Down Expand Up @@ -525,6 +554,31 @@ pub(crate) struct DisplayInner {
pub(crate) _native_display: Option<NativeDisplay>,
}

impl DisplayInner {
fn uses_display_reference(&self) -> bool {
if !CLIENT_EXTENSIONS.get().unwrap().contains("EGL_KHR_display_reference") {
return false;
}

let mut track_references = MaybeUninit::<EGLAttrib>::uninit();
unsafe {
return match self.raw {
EglDisplay::Khr(khr) => self.egl.QueryDisplayAttribKHR(
khr,
egl::TRACK_REFERENCES_KHR as _,
track_references.as_mut_ptr(),
),
EglDisplay::Ext(ext) => self.egl.QueryDisplayAttribEXT(
ext,
egl::TRACK_REFERENCES_KHR as _,
track_references.as_mut_ptr(),
),
EglDisplay::Legacy(_) => egl::FALSE,
} == egl::TRUE;
}
}
}

impl fmt::Debug for DisplayInner {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.debug_struct("Display")
Expand All @@ -542,25 +596,9 @@ impl Drop for DisplayInner {
// reference count the display. If that is the case, glutin can
// terminate the display without worry for the instance being
// reused elsewhere.
if CLIENT_EXTENSIONS.get().unwrap().contains("EGL_KHR_display_reference") {
let mut track_references = MaybeUninit::<EGLAttrib>::uninit();
if self.uses_display_reference() {
unsafe {
if match self.raw {
EglDisplay::Khr(khr) => self.egl.QueryDisplayAttribKHR(
khr,
egl::TRACK_REFERENCES_KHR as _,
track_references.as_mut_ptr(),
),
EglDisplay::Ext(ext) => self.egl.QueryDisplayAttribEXT(
ext,
egl::TRACK_REFERENCES_KHR as _,
track_references.as_mut_ptr(),
),
EglDisplay::Legacy(_) => return,
} == egl::TRUE
{
self.egl.Terminate(*self.raw);
}
self.egl.Terminate(*self.raw);
}
}

Expand Down

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