gdkglcontext-wayland: Fallback to GLES 2.0 after legacy failed

This lets the NGL backend be selected instead of the Cairo backend on
devices which expose both GL and GLES, but have better support of GLES.

Tested on a PinePhone.

diff --git a/gdk/wayland/gdkglcontext-wayland.c b/gdk/wayland/gdkglcontext-wayland.c
index 1667117e7f6346e7c26d8624a5ac781ea07bf1fa..9e2572f5bea387050816b576af76da10ff440767 100644 (file)
--- a/gdk/wayland/gdkglcontext-wayland.c
+++ b/gdk/wayland/gdkglcontext-wayland.c
@@ -126,14 +126,48 @@ gdk_wayland_gl_context_realize (GdkGLContext *context,
                                                   : EGL_NO_CONTEXT,
                           context_attribs);
 
+  /* If context creation failed without the ES bit, let's try again with it */
+  if (ctx == NULL)
+    {
+      i = 0;
+      context_attribs[i++] = EGL_CONTEXT_MAJOR_VERSION;
+      context_attribs[i++] = 2;
+      context_attribs[i++] = EGL_CONTEXT_MINOR_VERSION;
+      context_attribs[i++] = 0;
+      context_attribs[i++] = EGL_CONTEXT_FLAGS_KHR;
+      context_attribs[i++] = flags & ~EGL_CONTEXT_OPENGL_FORWARD_COMPATIBLE_BIT_KHR;
+      context_attribs[i++] = EGL_NONE;
+      g_assert (i < N_EGL_ATTRS);
+
+      eglBindAPI (EGL_OPENGL_ES_API);
+
+      legacy_bit = FALSE;
+      use_es = TRUE;
+
+      GDK_DISPLAY_NOTE (display, OPENGL,
+                g_message ("eglCreateContext failed, switching to OpenGL ES"));
+      ctx = eglCreateContext (display_wayland->egl_display,
+                              context_wayland->egl_config,
+                              share != NULL ? GDK_WAYLAND_GL_CONTEXT (share)->egl_context
+                                 : shared_data_context != NULL ? GDK_WAYLAND_GL_CONTEXT (shared_data_context)->egl_context
+                                    : EGL_NO_CONTEXT,
+                              context_attribs);
+    }
+
   /* If context creation failed without the legacy bit, let's try again with it */
-  if (ctx == NULL && !legacy_bit)
+  if (ctx == NULL)
     {
-      /* Ensure that re-ordering does not break the offsets */
-      g_assert (context_attribs[0] == EGL_CONTEXT_OPENGL_PROFILE_MASK_KHR);
-      context_attribs[1] = EGL_CONTEXT_OPENGL_COMPATIBILITY_PROFILE_BIT_KHR;
-      context_attribs[3] = 3;
-      context_attribs[5] = 0;
+      i = 0;
+      context_attribs[i++] = EGL_CONTEXT_OPENGL_PROFILE_MASK_KHR;
+      context_attribs[i++] = EGL_CONTEXT_OPENGL_COMPATIBILITY_PROFILE_BIT_KHR;
+      context_attribs[i++] = EGL_CONTEXT_MAJOR_VERSION;
+      context_attribs[i++] = 3;
+      context_attribs[i++] = EGL_CONTEXT_MINOR_VERSION;
+      context_attribs[i++] = 0;
+      context_attribs[i++] = EGL_CONTEXT_FLAGS_KHR;
+      context_attribs[i++] = flags & ~EGL_CONTEXT_OPENGL_FORWARD_COMPATIBLE_BIT_KHR;
+      context_attribs[i++] = EGL_NONE;
+      g_assert (i < N_EGL_ATTRS);
 
       eglBindAPI (EGL_OPENGL_API);