output, backend/drm: add wlr_output_export_dmabuf

backend/drm/drm.c

@@ -254,6 +254,26 @@ static uint32_t drm_connector_get_gamma_size(struct wlr_output *output) {
 	return 0;
 }
 
+static bool drm_connector_export_dmabuf(struct wlr_output *output,
+		struct wlr_dmabuf_buffer_attribs *attribs) {
+	struct wlr_drm_connector *conn = (struct wlr_drm_connector *)output;
+	struct wlr_drm_backend *drm = (struct wlr_drm_backend *)output->backend;
+
+	if (!drm->session->active) {
+		return false;
+	}
+
+	struct wlr_drm_crtc *crtc = conn->crtc;
+	if (!crtc) {
+		return false;
+	}
+	struct wlr_drm_plane *plane = crtc->primary;
+	struct wlr_drm_surface *surf = &plane->surf;
+
+	export_drm_bo(surf->back, attribs);
+	return true;
+}
+
 static void drm_connector_start_renderer(struct wlr_drm_connector *conn) {
 	if (conn->state != WLR_DRM_CONN_CONNECTED) {
 		return;
@@ -742,6 +762,7 @@ static const struct wlr_output_impl output_impl = {
 	.swap_buffers = drm_connector_swap_buffers,
 	.set_gamma = drm_connector_set_gamma,
 	.get_gamma_size = drm_connector_get_gamma_size,
+	.export_dmabuf = drm_connector_export_dmabuf,
 };
 
 bool wlr_output_is_drm(struct wlr_output *output) {

backend/drm/renderer.c

@@ -160,6 +160,19 @@ void post_drm_surface(struct wlr_drm_surface *surf) {
 	}
 }
 
+void export_drm_bo(struct gbm_bo *bo,
+		struct wlr_dmabuf_buffer_attribs *attribs) {
+	memset(attribs, 0, sizeof(struct wlr_dmabuf_buffer_attribs));
+	attribs->n_planes = 1;
+	attribs->width = gbm_bo_get_width(bo);
+	attribs->height = gbm_bo_get_height(bo);
+	attribs->format = gbm_bo_get_format(bo);
+	attribs->offset[0] = 0;
+	attribs->stride[0] = gbm_bo_get_stride_for_plane(bo, 0);
+	attribs->modifier[0] = DRM_FORMAT_MOD_LINEAR;
+	attribs->fd[0] = gbm_bo_get_fd(bo);
+}
+
 struct tex {
 	struct wlr_egl *egl;
 	EGLImageKHR img;
@@ -186,16 +199,8 @@ static struct wlr_texture *get_tex_for_bo(struct wlr_drm_renderer *renderer,
 		return NULL;
 	}
 
-	struct wlr_dmabuf_buffer_attribs attribs = {
-		.n_planes = 1,
-		.width = gbm_bo_get_width(bo),
-		.height = gbm_bo_get_height(bo),
-		.format = gbm_bo_get_format(bo),
-	};
-	attribs.offset[0] = 0;
-	attribs.stride[0] = gbm_bo_get_stride_for_plane(bo, 0);
-	attribs.modifier[0] = DRM_FORMAT_MOD_LINEAR;
-	attribs.fd[0] = gbm_bo_get_fd(bo);
+	struct wlr_dmabuf_buffer_attribs attribs;
+	export_drm_bo(bo, &attribs);
 
 	tex->tex = wlr_texture_from_dmabuf(renderer->wlr_rend, &attribs);
 	if (tex->tex == NULL) {

include/backend/drm/renderer.h

@@ -52,5 +52,7 @@ struct gbm_bo *get_drm_surface_front(struct wlr_drm_surface *surf);
 void post_drm_surface(struct wlr_drm_surface *surf);
 struct gbm_bo *copy_drm_surface_mgpu(struct wlr_drm_surface *dest,
 	struct gbm_bo *src);
+void export_drm_bo(struct gbm_bo *bo,
+	struct wlr_dmabuf_buffer_attribs *attribs);
 
 #endif

include/wlr/interfaces/wlr_output.h

@@ -23,6 +23,8 @@ struct wlr_output_impl {
 	void (*set_gamma)(struct wlr_output *output,
 		uint32_t size, uint16_t *r, uint16_t *g, uint16_t *b);
 	uint32_t (*get_gamma_size)(struct wlr_output *output);
+	bool (*export_dmabuf)(struct wlr_output *output,
+		struct wlr_dmabuf_buffer_attribs *attribs);
 };
 
 void wlr_output_init(struct wlr_output *output, struct wlr_backend *backend,

include/wlr/types/wlr_output.h

@@ -6,6 +6,7 @@
 #include <time.h>
 #include <wayland-server.h>
 #include <wayland-util.h>
+#include <wlr/types/wlr_linux_dmabuf.h>
 
 struct wlr_output_mode {
 	uint32_t flags; // enum wl_output_mode
@@ -162,6 +163,8 @@ void wlr_output_schedule_frame(struct wlr_output *output);
 void wlr_output_set_gamma(struct wlr_output *output,
 	uint32_t size, uint16_t *r, uint16_t *g, uint16_t *b);
 uint32_t wlr_output_get_gamma_size(struct wlr_output *output);
+bool wlr_output_export_dmabuf(struct wlr_output *output,
+	struct wlr_dmabuf_buffer_attribs *attribs);
 void wlr_output_set_fullscreen_surface(struct wlr_output *output,
 	struct wlr_surface *surface);
 struct wlr_output *wlr_output_from_resource(struct wl_resource *resource);

types/wlr_output.c

@@ -560,6 +560,14 @@ uint32_t wlr_output_get_gamma_size(struct wlr_output *output) {
 	return output->impl->get_gamma_size(output);
 }
 
+bool wlr_output_export_dmabuf(struct wlr_output *output,
+		struct wlr_dmabuf_buffer_attribs *attribs) {
+	if (!output->impl->export_dmabuf) {
+		return false;
+	}
+	return output->impl->export_dmabuf(output, attribs);
+}
+
 void wlr_output_update_needs_swap(struct wlr_output *output) {
 	output->needs_swap = true;
 	wlr_signal_emit_safe(&output->events.needs_swap, output);