Add a way to retrieve the EGL display

CHANGELOG.md

@@ -3,6 +3,7 @@
 - Added NetBSD support.
 - **Breaking:** Removed `new_shared` function from `Context` and `GlWindow`, in favor of `new`.
 - Added `build` method to `ContextBuilder`.
+- Added `get_egl_display` method to `GlContextExt` trait and its implementation for platforms.
 - Removed minimum supported Rust version guarantee.
 
 # Version 0.19.0 (2018-11-09)

src/api/android/mod.rs

@@ -165,4 +165,9 @@ impl Context {
     pub unsafe fn raw_handle(&self) -> egl::ffi::EGLContext {
         self.0.egl_context.raw_handle()
     }
+
+    #[inline]
+    pub unsafe fn get_egl_display(&self) -> egl::ffi::EGLDisplay {
+        self.0.egl_context.get_egl_display()
+    }
 }

src/api/egl/ffi.rs

@@ -4,6 +4,7 @@
 extern crate winapi;
 
 pub use self::egl::types::EGLContext;
+pub use self::egl::types::EGLDisplay;
 
 use libc;
 

src/api/egl/mod.rs

@@ -335,6 +335,11 @@ impl Context {
         self.context
     }
 
+    #[inline]
+    pub unsafe fn get_egl_display(&self) -> ffi::egl::types::EGLDisplay {
+        self.display
+    }
+
     // Handle Android Life Cycle.
     // Android has started the activity or sent it to foreground.
     // Create a new surface and attach it to the recreated ANativeWindow.

src/api/ios/mod.rs

@@ -396,4 +396,9 @@ impl GlContextExt for Context {
     unsafe fn raw_handle(&self) -> Self::Handle {
         self.eagl_context as *mut c_void
     }
+
+    #[inline]
+    unsafe fn get_egl_display(&self) -> Option<*const c_void> {
+        None
+    }
 }

src/os/android.rs

@@ -7,11 +7,18 @@ pub use api::egl::ffi::EGLContext;
 use Context;
 use os::GlContextExt;
 
+use std::os::raw;
+
 impl GlContextExt for Context {
     type Handle = EGLContext;
 
     #[inline]
     unsafe fn raw_handle(&self) -> Self::Handle {
         self.context.raw_handle()
     }
+
+    #[inline]
+    unsafe fn get_egl_display(&self) -> Option<*const raw::c_void> {
+        Some(self.context.get_egl_display())
+    }
 }

src/os/macos.rs

@@ -17,4 +17,9 @@ impl GlContextExt for Context {
     unsafe fn raw_handle(&self) -> Self::Handle {
         self.context.raw_handle()
     }
+
+    #[inline]
+    unsafe fn get_egl_display(&self) -> Option<*const c_void> {
+        None
+    }
 }

src/os/mod.rs

@@ -15,11 +15,20 @@ pub mod macos;
 pub mod unix;
 pub mod windows;
 
+use std::os::raw;
+
 /// Platform-specific extensions for OpenGL contexts.
 pub trait GlContextExt {
     /// Raw context handle.
     type Handle;
 
     /// Returns the raw context handle.
     unsafe fn raw_handle(&self) -> Self::Handle;
+
+    /// Returns a pointer to the `EGLDisplay` object of EGL that is used by this context.
+    ///
+    /// Return `None` if the context doesn't use EGL.
+    //
+    // The pointer will become invalid when the glutin `GlContext` is destroyed.
+    unsafe fn get_egl_display(&self) -> Option<*const raw::c_void>;
 }

src/os/unix.rs

@@ -14,11 +14,18 @@ pub use winit::os::unix::WindowExt;
 use Context;
 use os::GlContextExt;
 
+use std::os::raw;
+
 impl GlContextExt for Context {
     type Handle = RawHandle;
 
     #[inline]
     unsafe fn raw_handle(&self) -> Self::Handle {
         self.context.raw_handle()
     }
+
+    #[inline]
+    unsafe fn get_egl_display(&self) -> Option<*const raw::c_void> {
+        self.context.get_egl_display()
+    }
 }

src/os/windows.rs

@@ -6,6 +6,8 @@ pub use winit::os::windows::{DeviceIdExt, MonitorIdExt, WindowBuilderExt, Window
 pub use api::egl::ffi::EGLContext;
 pub use platform::RawHandle;
 
+use std::os::raw;
+
 use os::GlContextExt;
 use Context;
 
@@ -16,4 +18,9 @@ impl GlContextExt for Context {
     unsafe fn raw_handle(&self) -> Self::Handle {
         self.context.raw_handle()
     }
+
+    #[inline]
+    unsafe fn get_egl_display(&self) -> Option<*const raw::c_void> {
+        self.context.get_egl_display()
+    }
 }

src/platform/linux/mod.rs

@@ -12,6 +12,7 @@ mod wayland;
 mod x11;
 use api::osmesa;
 
+use std::os::raw;
 
 /// Context handles available on Unix-like platforms.
 #[derive(Clone, Debug)]
@@ -213,4 +214,17 @@ impl Context {
             Context::OsMesa(ref ctxt) => RawHandle::Egl(ctxt.raw_handle()),
         }
     }
+
+    #[inline]
+    pub unsafe fn get_egl_display(&self) -> Option<*const raw::c_void> {
+        match *self {
+            Context::WindowedX11(ref ctxt) | Context::HeadlessX11(_, ref ctxt) => {
+                ctxt.get_egl_display()
+            }
+            Context::WindowedWayland(ref ctxt) | Context::HeadlessWayland(_, ref ctxt) => {
+                ctxt.get_egl_display()
+            }
+            _ => None,
+        }
+    }
 }

src/platform/linux/wayland.rs

@@ -1,5 +1,6 @@
 use std::sync::Arc;
 use std::ffi::CString;
+use std::os::raw;
 use winit;
 use winit::os::unix::WindowExt;
 use {ContextError, CreationError, GlAttributes, PixelFormat, PixelFormatRequirements};
@@ -90,4 +91,9 @@ impl Context {
     pub unsafe fn raw_handle(&self) -> ffi::EGLContext {
         self.context.raw_handle()
     }
+
+    #[inline]
+    pub unsafe fn get_egl_display(&self) -> Option<*const raw::c_void> {
+        Some(self.context.get_egl_display())
+    }
 }

src/platform/linux/x11.rs

@@ -2,6 +2,7 @@ pub use winit::os::unix::x11::{XError, XNotSupported, XConnection};
 
 use std::{mem, ptr, fmt, error};
 use std::ffi::CString;
+use std::os::raw;
 use std::sync::Arc;
 
 use winit;
@@ -297,4 +298,12 @@ impl Context {
     pub unsafe fn raw_handle(&self) -> &GlContext {
         &self.context
     }
+
+    #[inline]
+    pub unsafe fn get_egl_display(&self) -> Option<*const raw::c_void> {
+        match self.context {
+            GlContext::Egl(ref ctxt) => Some(ctxt.get_egl_display()),
+            _ => None,
+        }
+    }
 }

src/platform/windows/context.rs

@@ -1,5 +1,6 @@
 #![cfg(target_os = "windows")]
 
+use std::os::raw;
 use std::ptr;
 
 use winapi::shared::windef::HWND;
@@ -187,4 +188,14 @@ impl Context {
             | Context::EglPbuffer(ref c) => RawHandle::Egl(c.raw_handle()),
         }
     }
+
+    #[inline]
+    pub unsafe fn get_egl_display(&self) -> Option<*const raw::c_void> {
+        match *self {
+            Context::Egl(ref c)
+            | Context::HiddenWindowEgl(_, ref c)
+            | Context::EglPbuffer(ref c) => Some(c.get_egl_display()),
+            _ => None,
+        }
+    }
 }