From d3a60e03c9f9ff5c8145c747552b4c85da7c4464 Mon Sep 17 00:00:00 2001
From: Victor Brekenfeld <github@drakulix.de>
Date: Mon, 18 May 2020 20:23:08 +0200
Subject: [PATCH] egl: differenciate display creation failures

---
 src/backend/egl/display.rs | 5 ++++-
 src/backend/egl/error.rs   | 7 +++++--
 2 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/src/backend/egl/display.rs b/src/backend/egl/display.rs
index e416299..aa273b4 100644
--- a/src/backend/egl/display.rs
+++ b/src/backend/egl/display.rs
@@ -97,8 +97,11 @@ impl<B: native::Backend, N: native::NativeDisplay<B>> EGLDisplay<B, N> {
                 |e: &str| dp_extensions.iter().any(|s| s == e),
                 log.clone(),
             )
-            .map_err(Error::DisplayNotSupported)?
+            .map_err(Error::DisplayCreationError)?
         };
+        if display == ffi::egl::NO_DISPLAY {
+            return Err(Error::DisplayNotSupported);
+        }
 
         let egl_version = {
             let mut major: MaybeUninit<ffi::egl::types::EGLint> = MaybeUninit::uninit();
diff --git a/src/backend/egl/error.rs b/src/backend/egl/error.rs
index cc4c24d..938fc19 100644
--- a/src/backend/egl/error.rs
+++ b/src/backend/egl/error.rs
@@ -15,9 +15,12 @@ pub enum Error {
     /// Backend does not match the context type
     #[error("The expected backend '{0:?}' does not match the runtime")]
     NonMatchingBackend(&'static str),
+    /// Display creation failed
+    #[error("Display creation failed with error: {0:}")]
+    DisplayCreationError(#[source] EGLError),
     /// Unable to obtain a valid EGL Display
-    #[error("Unable to obtain a valid EGL Display. Err: {0:}")]
-    DisplayNotSupported(#[source] EGLError),
+    #[error("Unable to obtain a valid EGL Display.")]
+    DisplayNotSupported,
     /// `eglInitialize` returned an error
     #[error("Failed to initialize EGL. Err: {0:}")]
     InitFailed(#[source] EGLError),