Check Opengl version is 3.3+ before creating a GL context over a GL ES context (#5996)

* Retry with GLES if creating a GL context fails

* Cleaner GL context creation retry

Author: Rapdorian

CHANGELOG.md

@@ -49,6 +49,7 @@ Bottom level categories:
 
 #### General
 
+- If GL context creation fails retry with GLES. By @Rapdorian in [#5996](https://github.com/gfx-rs/wgpu/pull/5996)
 - Fix profiling with `tracy`. By @waywardmonkeys in [#5988](https://github.com/gfx-rs/wgpu/pull/5988)
 - As a workaround for [issue #4905](https://github.com/gfx-rs/wgpu/issues/4905), `wgpu-core` is undocumented unless `--cfg wgpu_core_doc` feature is enabled. By @kpreid in [#5987](https://github.com/gfx-rs/wgpu/pull/5987)
 - Bump MSRV for `d3d12`/`naga`/`wgpu-core`/`wgpu-hal`/`wgpu-types`' to 1.76. By @wumpf in [#6003](https://github.com/gfx-rs/wgpu/pull/6003)

wgpu-hal/src/gles/egl.rs

@@ -550,26 +550,25 @@ impl Inner {
         let supports_khr_context = display_extensions.contains("EGL_KHR_create_context");
 
         let mut context_attributes = vec![];
-        if supports_opengl {
-            context_attributes.push(khronos_egl::CONTEXT_MAJOR_VERSION);
-            context_attributes.push(3);
-            context_attributes.push(khronos_egl::CONTEXT_MINOR_VERSION);
-            context_attributes.push(3);
-            if force_gles_minor_version != wgt::Gles3MinorVersion::Automatic {
-                log::warn!("Ignoring specified GLES minor version as OpenGL is used");
-            }
-        } else {
-            context_attributes.push(khronos_egl::CONTEXT_MAJOR_VERSION);
-            context_attributes.push(3); // Request GLES 3.0 or higher
-            if force_gles_minor_version != wgt::Gles3MinorVersion::Automatic {
-                context_attributes.push(khronos_egl::CONTEXT_MINOR_VERSION);
-                context_attributes.push(match force_gles_minor_version {
-                    wgt::Gles3MinorVersion::Automatic => unreachable!(),
-                    wgt::Gles3MinorVersion::Version0 => 0,
-                    wgt::Gles3MinorVersion::Version1 => 1,
-                    wgt::Gles3MinorVersion::Version2 => 2,
-                });
-            }
+        let mut gl_context_attributes = vec![];
+        let mut gles_context_attributes = vec![];
+        gl_context_attributes.push(khronos_egl::CONTEXT_MAJOR_VERSION);
+        gl_context_attributes.push(3);
+        gl_context_attributes.push(khronos_egl::CONTEXT_MINOR_VERSION);
+        gl_context_attributes.push(3);
+        if supports_opengl && force_gles_minor_version != wgt::Gles3MinorVersion::Automatic {
+            log::warn!("Ignoring specified GLES minor version as OpenGL is used");
+        }
+        gles_context_attributes.push(khronos_egl::CONTEXT_MAJOR_VERSION);
+        gles_context_attributes.push(3); // Request GLES 3.0 or higher
+        if force_gles_minor_version != wgt::Gles3MinorVersion::Automatic {
+            gles_context_attributes.push(khronos_egl::CONTEXT_MINOR_VERSION);
+            gles_context_attributes.push(match force_gles_minor_version {
+                wgt::Gles3MinorVersion::Automatic => unreachable!(),
+                wgt::Gles3MinorVersion::Version0 => 0,
+                wgt::Gles3MinorVersion::Version1 => 1,
+                wgt::Gles3MinorVersion::Version2 => 2,
+            });
         }
         if flags.contains(wgt::InstanceFlags::DEBUG) {
             if version >= (1, 5) {
@@ -606,15 +605,31 @@ impl Inner {
             context_attributes.push(khr_context_flags);
         }
         context_attributes.push(khronos_egl::NONE);
-        let context = match egl.create_context(display, config, None, &context_attributes) {
-            Ok(context) => context,
-            Err(e) => {
-                return Err(crate::InstanceError::with_source(
-                    String::from("unable to create GLES 3.x context"),
-                    e,
-                ));
-            }
-        };
+
+        gl_context_attributes.extend(&context_attributes);
+        gles_context_attributes.extend(&context_attributes);
+
+        let context = if supports_opengl {
+            egl.create_context(display, config, None, &gl_context_attributes)
+                .or_else(|_| {
+                    egl.bind_api(khronos_egl::OPENGL_ES_API).unwrap();
+                    egl.create_context(display, config, None, &gles_context_attributes)
+                })
+                .map_err(|e| {
+                    crate::InstanceError::with_source(
+                        String::from("unable to create OpenGL or GLES 3.x context"),
+                        e,
+                    )
+                })
+        } else {
+            egl.create_context(display, config, None, &gles_context_attributes)
+                .map_err(|e| {
+                    crate::InstanceError::with_source(
+                        String::from("unable to create GLES 3.x context"),
+                        e,
+                    )
+                })
+        }?;
 
         // Testing if context can be binded without surface
         // and creating dummy pbuffer surface if not.