Fix logic in egl Device::query_device

CHANGELOG.md

@@ -1,5 +1,7 @@
 # Unreleased
 
+- Fixed EGL's `Device::query_devices()` being too strict about required extensions
+
 # Version 0.32.0
 
 - **Breaking:** updated `raw-window-handle` dependency to `0.6`.

glutin/src/api/egl/device.rs

@@ -33,19 +33,24 @@ impl Device {
             None => return Err(ErrorKind::NotFound.into()),
         };
 
-        let no_display_extensions =
+        let client_extensions =
             CLIENT_EXTENSIONS.get_or_init(|| get_extensions(egl, egl::NO_DISPLAY));
 
-        // Querying devices requires EGL_EXT_device_enumeration and
-        // EGL_EXT_device_query.
+        // Querying devices requires EGL_EXT_device_enumeration or EGL_EXT_device_base.
         //
-        // Or we can check for the EGL_EXT_device_base extension since it contains both
-        // extensions.
-        if (!no_display_extensions.contains("EGL_EXT_device_enumeration")
-            && !no_display_extensions.contains("EGL_EXT_device_query"))
-            || !no_display_extensions.contains("EGL_EXT_device_base")
-        {
-            return Err(ErrorKind::NotSupported("EGL does not support EGL_EXT_device_base").into());
+        // The former depends on EGL_EXT_device_query, so also check that just in case.
+        if !client_extensions.contains("EGL_EXT_device_base") {
+            let query = client_extensions.contains("EGL_EXT_device_query");
+            let enumr = client_extensions.contains("EGL_EXT_device_enumeration");
+            if !(query & enumr) {
+                let msg = if !enumr {
+                    "Enumerating devices is not supported by the EGL instance"
+                } else {
+                    // this should not happen as device_enumeration depends on device_query
+                    "EGL_EXT_device_enumeration without EGL_EXT_device_query, buggy driver?"
+                };
+                return Err(ErrorKind::NotSupported(msg).into());
+            }
         }
 
         let mut device_count = 0;