sdl: Allow OpenGL ES context creation

Signed-off-by: NElie Tournier <elie.tournier@collabora.com>
Message-id: 20180413135842.21325-4-tournier.elie@gmail.com

[ kraxel: fix indent ]
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>

qemu-options.hx

@@ -1240,7 +1240,7 @@ ETEXI
 
 DEF("display", HAS_ARG, QEMU_OPTION_display,
     "-display sdl[,frame=on|off][,alt_grab=on|off][,ctrl_grab=on|off]\n"
-    "            [,window_close=on|off][,gl=on|off]\n"
+    "            [,window_close=on|off][,gl=on|core|es|off]\n"
     "-display gtk[,grab_on_hover=on|off][,gl=on|off]|\n"
     "-display vnc=<display>[,<optargs>]\n"
     "-display curses\n"

ui/sdl2-gl.c

@@ -140,12 +140,27 @@ QEMUGLContext sdl2_gl_create_context(DisplayChangeListener *dcl,
     SDL_GL_MakeCurrent(scon->real_window, scon->winctx);
 
     SDL_GL_SetAttribute(SDL_GL_SHARE_WITH_CURRENT_CONTEXT, 1);
-    SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK,
-                        SDL_GL_CONTEXT_PROFILE_CORE);
+    if (scon->opts->gl == DISPLAYGL_MODE_ON ||
+        scon->opts->gl == DISPLAYGL_MODE_CORE) {
+        SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK,
+                            SDL_GL_CONTEXT_PROFILE_CORE);
+    } else if (scon->opts->gl == DISPLAYGL_MODE_ES) {
+        SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK,
+                            SDL_GL_CONTEXT_PROFILE_ES);
+    }
     SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, params->major_ver);
     SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, params->minor_ver);
 
     ctx = SDL_GL_CreateContext(scon->real_window);
+
+    /* If SDL fail to create a GL context and we use the "on" flag,
+     * then try to fallback to GLES.
+     */
+    if (!ctx && scon->opts->gl == DISPLAYGL_MODE_ON) {
+        SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK,
+                            SDL_GL_CONTEXT_PROFILE_ES);
+        ctx = SDL_GL_CreateContext(scon->real_window);
+    }
     return (QEMUGLContext)ctx;
 }
 

vl.c

@@ -2144,6 +2144,10 @@ static void parse_display(const char *p)
                 dpy.has_gl = true;
                 if (strstart(opts, "on", &nextopt)) {
                     dpy.gl = DISPLAYGL_MODE_ON;
+                } else if (strstart(opts, "core", &nextopt)) {
+                    dpy.gl = DISPLAYGL_MODE_CORE;
+                } else if (strstart(opts, "es", &nextopt)) {
+                    dpy.gl = DISPLAYGL_MODE_ES;
                 } else if (strstart(opts, "off", &nextopt)) {
                     dpy.gl = DISPLAYGL_MODE_OFF;
                 } else {