[PATCH weston 07/11] gl-renderer: Always setup gl-renderer

[Armin Krezović]

Currently, the gl-renderer setup is being done on per-output
basis. This isn't desirable when trying to make weston run
with zero outputs.

When there are no outputs present, there is no EGLContext or
EGLCurrent available, and trying to use an EGL extension will
result in a crash.

The problem is solved by creating a dummy surface at startup,
either by using EGL_KHR_surfaceless_context or PbufferSurface
to setup a context, and creating an EGLContext and EGLCurrent
with the help of dummy surface.

When an output gets plugged in, its configuration will replace
dummy buffer usage as the setup will be run again.

Signed-off-by: Armin Krezović <krezovic.armin at gmail.com>
---
 src/gl-renderer.c | 32 ++++++++++++++++++++++++++++++++
 1 file changed, 32 insertions(+)

diff --git a/src/gl-renderer.c b/src/gl-renderer.c
index 23c0cd7..7e2a787 100644
--- a/src/gl-renderer.c
+++ b/src/gl-renderer.c
@@ -175,6 +175,8 @@ struct gl_renderer {
 	EGLContext egl_context;
 	EGLConfig egl_config;
 
+	EGLSurface dummy_surface;
+
 	struct wl_array vertices;
 	struct wl_array vtxcnt;
 
@@ -201,6 +203,8 @@ struct gl_renderer {
 
 	int has_configless_context;
 
+	int has_surfaceless_context;
+
 	int has_dmabuf_import;
 	struct wl_list dmabuf_images;
 
@@ -2654,6 +2658,8 @@ gl_renderer_destroy(struct weston_compositor *ec)
 	wl_list_for_each_safe(image, next, &gr->dmabuf_images, link)
 		dmabuf_image_destroy(image);
 
+	eglDestroySurface(gr->egl_display, gr->dummy_surface);
+
 	eglTerminate(gr->egl_display);
 	eglReleaseThread();
 
@@ -2765,6 +2771,9 @@ gl_renderer_setup_egl_extensions(struct weston_compositor *ec)
 		gr->has_configless_context = 1;
 #endif
 
+	if (check_extension(extensions, "EGL_KHR_surfaceless_context"))
+		gr->has_surfaceless_context = 1;
+
 #ifdef EGL_EXT_image_dma_buf_import
 	if (check_extension(extensions, "EGL_EXT_image_dma_buf_import"))
 		gr->has_dmabuf_import = 1;
@@ -2881,6 +2890,12 @@ gl_renderer_create(struct weston_compositor *ec, EGLenum platform,
 	EGLint major, minor;
 	int supports = 0;
 
+	const EGLint pbuffer_attribs[] = {
+		EGL_WIDTH, 10,
+		EGL_HEIGHT, 10,
+		EGL_NONE
+	};
+
 	if (platform) {
 		supports = gl_renderer_supports(
 			ec, platform_to_extension(platform));
@@ -2956,6 +2971,23 @@ gl_renderer_create(struct weston_compositor *ec, EGLenum platform,
 	if (gr->has_dmabuf_import)
 		gr->base.import_dmabuf = gl_renderer_import_dmabuf;
 
+	if (gr->has_surfaceless_context) {
+		weston_log("EGL_KHR_surfaceless_context available\n");
+		gr->dummy_surface = EGL_NO_SURFACE;
+	} else {
+		weston_log("EGL_KHR_surfaceless_context unavailable "
+			   "trying PbufferSurface\n");
+		gr->dummy_surface = eglCreatePbufferSurface(gr->egl_display,
+							    gr->egl_config,
+							    pbuffer_attribs);
+		if (gr->dummy_surface == EGL_NO_SURFACE) {
+			weston_log("failed to create dummy pbuffer\n");
+			goto fail_terminate;
+		}
+	}
+
+	gl_renderer_setup(ec, gr->dummy_surface);
+
 	wl_display_add_shm_format(ec->wl_display, WL_SHM_FORMAT_RGB565);
 
 	wl_signal_init(&gr->destroy_signal);
-- 
2.9.0