From e437c854cda9be1b4637e1bbae650c9618a69a11 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Michel=20D=C3=A4nzer?= <mdaenzer@redhat.com>
Date: Wed, 31 May 2023 15:57:11 +0200
Subject: [PATCH] cogl/egl: Add COGL_EGL_WINSYS_FEATURE_NO_CONFIG_CONTEXT

If the EGL_KHR_no_config_context extension is supported, pass
EGL_NO_CONFIG_KHR to eglCreateContext. This will allow binding the
context to surfaces created with different configs.

Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/3139>
---
 .../cogl-winsys-egl-feature-functions.h       |  6 ++++++
 cogl/cogl/winsys/cogl-winsys-egl-private.h    |  1 +
 cogl/cogl/winsys/cogl-winsys-egl.c            | 19 +++++++++++++++----
 3 files changed, 22 insertions(+), 4 deletions(-)

diff --git a/cogl/cogl/winsys/cogl-winsys-egl-feature-functions.h b/cogl/cogl/winsys/cogl-winsys-egl-feature-functions.h
index 494d5ea39..4b74e2088 100644
--- a/cogl/cogl/winsys/cogl-winsys-egl-feature-functions.h
+++ b/cogl/cogl/winsys/cogl-winsys-egl-feature-functions.h
@@ -99,6 +99,12 @@ COGL_WINSYS_FEATURE_BEGIN (create_context,
                            COGL_EGL_WINSYS_FEATURE_CREATE_CONTEXT)
 COGL_WINSYS_FEATURE_END ()
 
+COGL_WINSYS_FEATURE_BEGIN (no_config_context,
+                           "KHR\0",
+                           "no_config_context\0",
+                           COGL_EGL_WINSYS_FEATURE_NO_CONFIG_CONTEXT)
+COGL_WINSYS_FEATURE_END ()
+
 COGL_WINSYS_FEATURE_BEGIN (buffer_age,
                            "EXT\0",
                            "buffer_age\0",
diff --git a/cogl/cogl/winsys/cogl-winsys-egl-private.h b/cogl/cogl/winsys/cogl-winsys-egl-private.h
index 0c103e9c1..8b6f21406 100644
--- a/cogl/cogl/winsys/cogl-winsys-egl-private.h
+++ b/cogl/cogl/winsys/cogl-winsys-egl-private.h
@@ -101,6 +101,7 @@ typedef enum _CoglEGLWinsysFeature
   COGL_EGL_WINSYS_FEATURE_FENCE_SYNC                    = 1L << 5,
   COGL_EGL_WINSYS_FEATURE_SURFACELESS_CONTEXT           = 1L << 6,
   COGL_EGL_WINSYS_FEATURE_CONTEXT_PRIORITY              = 1L << 7,
+  COGL_EGL_WINSYS_FEATURE_NO_CONFIG_CONTEXT             = 1L << 8,
 } CoglEGLWinsysFeature;
 
 typedef struct _CoglRendererEGL
diff --git a/cogl/cogl/winsys/cogl-winsys-egl.c b/cogl/cogl/winsys/cogl-winsys-egl.c
index 5986fd1c9..26a3395fe 100644
--- a/cogl/cogl/winsys/cogl-winsys-egl.c
+++ b/cogl/cogl/winsys/cogl-winsys-egl.c
@@ -428,10 +428,21 @@ try_create_context (CoglDisplay *display,
 
   attribs[i++] = EGL_NONE;
 
-  egl_display->egl_context = eglCreateContext (edpy,
-                                               config,
-                                               EGL_NO_CONTEXT,
-                                               attribs);
+  if (egl_renderer->private_features &
+      COGL_EGL_WINSYS_FEATURE_NO_CONFIG_CONTEXT)
+    {
+      egl_display->egl_context = eglCreateContext (edpy,
+                                                   EGL_NO_CONFIG_KHR,
+                                                   EGL_NO_CONTEXT,
+                                                   attribs);
+    }
+  else
+    {
+      egl_display->egl_context = eglCreateContext (edpy,
+                                                   config,
+                                                   EGL_NO_CONTEXT,
+                                                   attribs);
+    }
 
   if (egl_display->egl_context == EGL_NO_CONTEXT)
     {