xwayland: Refactor glamor EGL init

Glamor requires at least big GL 2.1 or GLES2, therefore Xwayland tries
to initialize first GL and then GLES2 if that fails.

It does that all in one single function which makes the code slightly
complicated, move the initialization of big-GL and GLES2 to separate
functions to help with readability of the code.

Signed-off-by: Olivier Fourdan <ofourdan@redhat.com>
Reviewed-by: Michel Dänzer <mdaenzer@redhat.com>
Reviewed-by: Tony Lindgren <tony@atomide.com>

1 files changed, 89 insertions, 60 deletions

diff --git a/hw/xwayland/xwayland-glamor-gbm.c b/hw/xwayland/xwayland-glamor-gbm.c
index f5718b80b..d1bda91c5 100644
--- a/hw/xwayland/xwayland-glamor-gbm.c
+++ b/hw/xwayland/xwayland-glamor-gbm.c
@@ -924,11 +924,30 @@ xwl_glamor_gbm_has_wl_interfaces(struct xwl_screen *xwl_screen)
 }
 
 static Bool
-xwl_glamor_gbm_init_egl(struct xwl_screen *xwl_screen)
+xwl_glamor_try_to_make_context_current(struct xwl_screen *xwl_screen)
+{
+    if (xwl_screen->egl_context == EGL_NO_CONTEXT)
+        return FALSE;
+
+    return eglMakeCurrent(xwl_screen->egl_display, EGL_NO_SURFACE,
+                          EGL_NO_SURFACE, xwl_screen->egl_context);
+}
+
+static void
+xwl_glamor_maybe_destroy_context(struct xwl_screen *xwl_screen)
+{
+    if (xwl_screen->egl_context == EGL_NO_CONTEXT)
+        return;
+
+   eglMakeCurrent(xwl_screen->egl_display, EGL_NO_SURFACE,
+                  EGL_NO_SURFACE, EGL_NO_CONTEXT);
+   eglDestroyContext(xwl_screen->egl_display, xwl_screen->egl_context);
+   xwl_screen->egl_context = EGL_NO_CONTEXT;
+}
+
+static Bool
+xwl_glamor_try_big_gl_api(struct xwl_screen *xwl_screen)
 {
-    struct xwl_gbm_private *xwl_gbm = xwl_gbm_get(xwl_screen);
-    EGLint major, minor;
-    Bool egl_initialized = FALSE;
     static const EGLint config_attribs_core[] = {
         EGL_CONTEXT_OPENGL_PROFILE_MASK_KHR,
         EGL_CONTEXT_OPENGL_CORE_PROFILE_BIT_KHR,
@@ -938,6 +957,68 @@ xwl_glamor_gbm_init_egl(struct xwl_screen *xwl_screen)
         GLAMOR_GL_CORE_VER_MINOR,
         EGL_NONE
     };
+    int gl_version;
+
+    eglBindAPI(EGL_OPENGL_API);
+
+    xwl_screen->egl_context =
+        eglCreateContext(xwl_screen->egl_display, NULL,
+                         EGL_NO_CONTEXT, config_attribs_core);
+
+    if (xwl_screen->egl_context == EGL_NO_CONTEXT)
+        xwl_screen->egl_context =
+            eglCreateContext(xwl_screen->egl_display, NULL,
+                             EGL_NO_CONTEXT, NULL);
+
+    if (!xwl_glamor_try_to_make_context_current(xwl_screen)) {
+        ErrorF("Failed to make EGL context current with GL\n");
+        xwl_glamor_maybe_destroy_context(xwl_screen);
+        return FALSE;
+    }
+
+    /* glamor needs at least GL 2.1, if the GL version is less than 2.1,
+     * drop the context we created, it's useless.
+     */
+    gl_version = epoxy_gl_version();
+    if (gl_version < 21) {
+        ErrorF("Supported GL version is not sufficient (required 21, found %i)\n",
+               gl_version);
+        xwl_glamor_maybe_destroy_context(xwl_screen);
+        return FALSE;
+    }
+
+    return TRUE;
+}
+
+static Bool
+xwl_glamor_try_gles_api(struct xwl_screen *xwl_screen)
+{
+    const EGLint gles_attribs[] = {
+        EGL_CONTEXT_CLIENT_VERSION,
+        2,
+        EGL_NONE,
+    };
+
+    eglBindAPI(EGL_OPENGL_ES_API);
+
+    xwl_screen->egl_context = eglCreateContext(xwl_screen->egl_display, NULL,
+                                               EGL_NO_CONTEXT, gles_attribs);
+
+    if (!xwl_glamor_try_to_make_context_current(xwl_screen)) {
+        ErrorF("Failed to make EGL context current with GLES2\n");
+        xwl_glamor_maybe_destroy_context(xwl_screen);
+        return FALSE;
+    }
+
+    return TRUE;
+}
+
+static Bool
+xwl_glamor_gbm_init_egl(struct xwl_screen *xwl_screen)
+{
+    struct xwl_gbm_private *xwl_gbm = xwl_gbm_get(xwl_screen);
+    EGLint major, minor;
+    Bool egl_initialized = FALSE;
     const GLubyte *renderer;
 
     if (!xwl_gbm->fd_render_node && !xwl_gbm->drm_authenticated) {
@@ -964,60 +1045,12 @@ xwl_glamor_gbm_init_egl(struct xwl_screen *xwl_screen)
         goto error;
     }
 
-    eglBindAPI(EGL_OPENGL_API);
-
-    xwl_screen->egl_context = eglCreateContext(
-        xwl_screen->egl_display, NULL, EGL_NO_CONTEXT, config_attribs_core);
-    if (xwl_screen->egl_context == EGL_NO_CONTEXT) {
-        xwl_screen->egl_context = eglCreateContext(
-            xwl_screen->egl_display, NULL, EGL_NO_CONTEXT, NULL);
-    }
-
-    if (xwl_screen->egl_context != EGL_NO_CONTEXT &&
-        !eglMakeCurrent(xwl_screen->egl_display,
-                        EGL_NO_SURFACE, EGL_NO_SURFACE,
-                        xwl_screen->egl_context)) {
-        ErrorF("Failed to make EGL context current with GL\n");
+    if (!xwl_glamor_try_big_gl_api(xwl_screen) &&
+        !xwl_glamor_try_gles_api(xwl_screen)) {
+        ErrorF("Cannot use neither GL nor GLES2\n");
         goto error;
     }
 
-    /* glamor needs either big-GL 2.1 or GLES2. Note that we can't rely only
-     * on calling epoxy_gl_version() here if eglBindAPI(EGL_OPENGL_API) above
-     * failed. Calling epoxy_gl_version() here makes GLES only devices fail
-     * below
-     */
-    if (xwl_screen->egl_context == EGL_NO_CONTEXT || epoxy_gl_version() < 21) {
-        const EGLint gles_attribs[] = {
-            EGL_CONTEXT_CLIENT_VERSION,
-            2,
-            EGL_NONE,
-        };
-
-        if (xwl_screen->egl_context != EGL_NO_CONTEXT) {
-            /* Recreate the context with GLES2 instead */
-            eglMakeCurrent(xwl_screen->egl_display,EGL_NO_SURFACE,
-                           EGL_NO_SURFACE, EGL_NO_CONTEXT);
-            eglDestroyContext(xwl_screen->egl_display, xwl_screen->egl_context);
-        }
-
-        eglBindAPI(EGL_OPENGL_ES_API);
-        xwl_screen->egl_context = eglCreateContext(xwl_screen->egl_display,
-                                                   NULL, EGL_NO_CONTEXT,
-                                                   gles_attribs);
-
-        if (xwl_screen->egl_context == EGL_NO_CONTEXT) {
-            ErrorF("Failed to create EGL context with GLES2\n");
-            goto error;
-        }
-
-        if (!eglMakeCurrent(xwl_screen->egl_display,
-                            EGL_NO_SURFACE, EGL_NO_SURFACE,
-                            xwl_screen->egl_context)) {
-            ErrorF("Failed to make EGL context current with GLES2\n");
-            goto error;
-        }
-    }
-
     renderer = glGetString(GL_RENDERER);
     if (!renderer) {
         ErrorF("glGetString() returned NULL, your GL is broken\n");
@@ -1041,12 +1074,8 @@ xwl_glamor_gbm_init_egl(struct xwl_screen *xwl_screen)
 
     return TRUE;
 error:
-    if (xwl_screen->egl_context != EGL_NO_CONTEXT) {
-        eglDestroyContext(xwl_screen->egl_display, xwl_screen->egl_context);
-        xwl_screen->egl_context = EGL_NO_CONTEXT;
-    }
-
     if (xwl_screen->egl_display != EGL_NO_DISPLAY) {
+        xwl_glamor_maybe_destroy_context(xwl_screen);
         eglTerminate(xwl_screen->egl_display);
         xwl_screen->egl_display = EGL_NO_DISPLAY;
     }