compositor: Stop using EGL_KHR_surfaceless_gles2

The remaining use case was making our context current before we had any
output surfaces.  We can do that now using a dummy surface, so let's stop
relying on surfaceless.

src/compositor-drm.c

@@ -60,6 +60,9 @@ struct drm_compositor {
 	uint32_t connector_allocator;
 	struct tty *tty;
 
+	struct gbm_surface *dummy_surface;
+	EGLSurface dummy_egl_surface;
+
 	struct wl_list sprite_list;
 	int sprites_are_broken;
 
@@ -770,7 +773,7 @@ static int
 init_egl(struct drm_compositor *ec, struct udev_device *device)
 {
 	EGLint major, minor, n;
-	const char *extensions, *filename, *sysnum;
+	const char *filename, *sysnum;
 	int fd;
 	static const EGLint context_attribs[] = {
 		EGL_CONTEXT_CLIENT_VERSION, 2,
@@ -817,12 +820,6 @@ init_egl(struct drm_compositor *ec, struct udev_device *device)
 		return -1;
 	}
 
-	extensions = eglQueryString(ec->base.display, EGL_EXTENSIONS);
-	if (!strstr(extensions, "EGL_KHR_surfaceless_gles2")) {
-		fprintf(stderr, "EGL_KHR_surfaceless_gles2 not available\n");
-		return -1;
-	}
-
 	if (!eglBindAPI(EGL_OPENGL_ES_API)) {
 		fprintf(stderr, "failed to bind api EGL_OPENGL_ES_API\n");
 		return -1;
@@ -841,8 +838,24 @@ init_egl(struct drm_compositor *ec, struct udev_device *device)
 		return -1;
 	}
 
-	if (!eglMakeCurrent(ec->base.display, EGL_NO_SURFACE,
-			    EGL_NO_SURFACE, ec->base.context)) {
+	ec->dummy_surface = gbm_surface_create(ec->gbm, 10, 10,
+					       GBM_FORMAT_XRGB8888,
+					       GBM_BO_USE_RENDERING);
+	if (!ec->dummy_surface) {
+		fprintf(stderr, "failed to create dummy gbm surface\n");
+		return -1;
+	}
+
+	ec->dummy_egl_surface =
+		eglCreateWindowSurface(ec->base.display, ec->base.config,
+				       ec->dummy_surface, NULL);
+	if (ec->dummy_egl_surface == EGL_NO_SURFACE) {
+		fprintf(stderr, "failed to create egl surface\n");
+		return -1;
+	}
+
+	if (!eglMakeCurrent(ec->base.display, ec->dummy_egl_surface,
+			    ec->dummy_egl_surface, ec->base.context)) {
 		fprintf(stderr, "failed to make context current\n");
 		return -1;
 	}

src/compositor-wayland.c

@@ -45,6 +45,9 @@
 struct wayland_compositor {
 	struct weston_compositor	 base;
 
+	struct wl_egl_pixmap		*dummy_pixmap;
+	EGLSurface			 dummy_egl_surface;;
+
 	struct {
 		struct wl_display *display;
 		struct wl_compositor *compositor;
@@ -260,7 +263,6 @@ wayland_compositor_init_egl(struct wayland_compositor *c)
 {
 	EGLint major, minor;
 	EGLint n;
-	const char *extensions;
 	EGLint config_attribs[] = {
 		EGL_SURFACE_TYPE, EGL_WINDOW_BIT,
 		EGL_RED_SIZE, 1,
@@ -286,12 +288,6 @@ wayland_compositor_init_egl(struct wayland_compositor *c)
 		return -1;
 	}
 
-	extensions = eglQueryString(c->base.display, EGL_EXTENSIONS);
-	if (!strstr(extensions, "EGL_KHR_surfaceless_gles2")) {
-		fprintf(stderr, "EGL_KHR_surfaceless_gles2 not available\n");
-		return -1;
-	}
-
 	if (!eglBindAPI(EGL_OPENGL_ES_API)) {
 		fprintf(stderr, "failed to bind EGL_OPENGL_ES_API\n");
 		return -1;
@@ -309,8 +305,17 @@ wayland_compositor_init_egl(struct wayland_compositor *c)
 		return -1;
 	}
 
-	if (!eglMakeCurrent(c->base.display, EGL_NO_SURFACE,
-			    EGL_NO_SURFACE, c->base.context)) {
+	c->dummy_pixmap = wl_egl_pixmap_create(10, 10, 0);
+	if (!c->dummy_pixmap) {
+		fprintf(stderr, "failure to create dummy_pixmap\n");
+		return -1;
+	}
+
+	c->dummy_egl_surface =
+		eglCreatePixmapSurface(c->base.display, c->base.config,
+				       c->dummy_pixmap, NULL);
+	if (!eglMakeCurrent(c->base.display, c->dummy_egl_surface,
+			    c->dummy_egl_surface, c->base.context)) {
 		fprintf(stderr, "failed to make context current\n");
 		return -1;
 	}

src/compositor-x11.c

@@ -48,6 +48,8 @@
 struct x11_compositor {
 	struct weston_compositor	 base;
 
+	EGLSurface		 dummy_pbuffer;
+
 	Display			*dpy;
 	xcb_connection_t	*conn;
 	xcb_screen_t		*screen;
@@ -117,7 +119,6 @@ x11_compositor_init_egl(struct x11_compositor *c)
 {
 	EGLint major, minor;
 	EGLint n;
-	const char *extensions;
 	EGLint config_attribs[] = {
 		EGL_SURFACE_TYPE, EGL_WINDOW_BIT,
 		EGL_RED_SIZE, 1,
@@ -131,6 +132,12 @@ x11_compositor_init_egl(struct x11_compositor *c)
 		EGL_NONE
 	};
 
+	static const EGLint pbuffer_attribs[] = {
+		EGL_WIDTH, 10,
+		EGL_HEIGHT, 10,
+		EGL_NONE
+	};
+
 	c->base.display = eglGetDisplay(c->dpy);
 	if (c->base.display == NULL) {
 		fprintf(stderr, "failed to create display\n");
@@ -142,12 +149,6 @@ x11_compositor_init_egl(struct x11_compositor *c)
 		return -1;
 	}
 
-	extensions = eglQueryString(c->base.display, EGL_EXTENSIONS);
-	if (!strstr(extensions, "EGL_KHR_surfaceless_gles2")) {
-		fprintf(stderr, "EGL_KHR_surfaceless_gles2 not available\n");
-		return -1;
-	}
-
 	if (!eglBindAPI(EGL_OPENGL_ES_API)) {
 		fprintf(stderr, "failed to bind EGL_OPENGL_ES_API\n");
 		return -1;
@@ -165,6 +166,14 @@ x11_compositor_init_egl(struct x11_compositor *c)
 		return -1;
 	}
 
+	c->dummy_pbuffer = eglCreatePbufferSurface(c->base.display,
+						   c->base.config,
+						   pbuffer_attribs);
+	if (c->base.context == NULL) {
+		fprintf(stderr, "failed to create dummy pbuffer\n");
+		return -1;
+	}
+
 	if (!eglMakeCurrent(c->base.display, EGL_NO_SURFACE,
 			    EGL_NO_SURFACE, c->base.context)) {
 		fprintf(stderr, "failed to make context current\n");