Merge pull request #496 from emersion/headless-backend

Headless backend

1 files changed, 146 insertions, 0 deletions

diff --git a/backend/headless/output.c b/backend/headless/output.c
new file mode 100644
index 00000000..9c4ba35e
--- /dev/null
+++ b/backend/headless/output.c
@@ -0,0 +1,146 @@
+#include <stdlib.h>
+#include <EGL/egl.h>
+#include <EGL/eglext.h>
+#include <GLES2/gl2.h>
+#include <wlr/interfaces/wlr_output.h>
+#include <wlr/util/log.h>
+#include "backend/headless.h"
+
+static EGLSurface egl_create_surface(struct wlr_egl *egl, unsigned int width,
+		unsigned int height) {
+	EGLint attribs[] = {EGL_WIDTH, width, EGL_HEIGHT, height, EGL_NONE};
+
+	EGLSurface surf = eglCreatePbufferSurface(egl->display, egl->config, attribs);
+	if (surf == EGL_NO_SURFACE) {
+		wlr_log(L_ERROR, "Failed to create EGL surface: %s", egl_error());
+		return EGL_NO_SURFACE;
+	}
+	return surf;
+}
+
+static bool output_set_custom_mode(struct wlr_output *wlr_output, int32_t width,
+		int32_t height, int32_t refresh) {
+	struct wlr_headless_output *output =
+		(struct wlr_headless_output *)wlr_output;
+	struct wlr_headless_backend *backend = output->backend;
+
+	if (output->egl_surface) {
+		eglDestroySurface(backend->egl.display, output->egl_surface);
+	}
+
+	output->egl_surface = egl_create_surface(&backend->egl, width, height);
+	if (output->egl_surface == EGL_NO_SURFACE) {
+		wlr_log(L_ERROR, "Failed to recreate EGL surface");
+		wlr_output_destroy(wlr_output);
+		return false;
+	}
+
+	output->frame_delay = 1000000 / refresh;
+
+	wlr_output_update_custom_mode(&output->wlr_output, width, height, refresh);
+	return true;
+}
+
+static void output_transform(struct wlr_output *wlr_output,
+		enum wl_output_transform transform) {
+	struct wlr_headless_output *output =
+		(struct wlr_headless_output *)wlr_output;
+	output->wlr_output.transform = transform;
+}
+
+static void output_make_current(struct wlr_output *wlr_output) {
+	struct wlr_headless_output *output =
+		(struct wlr_headless_output *)wlr_output;
+	if (!eglMakeCurrent(output->backend->egl.display,
+		output->egl_surface, output->egl_surface,
+		output->backend->egl.context)) {
+		wlr_log(L_ERROR, "eglMakeCurrent failed: %s", egl_error());
+	}
+}
+
+static void output_swap_buffers(struct wlr_output *wlr_output) {
+	// No-op
+}
+
+static void output_destroy(struct wlr_output *wlr_output) {
+	struct wlr_headless_output *output =
+		(struct wlr_headless_output *)wlr_output;
+	wl_signal_emit(&output->backend->backend.events.output_remove,
+		&output->wlr_output);
+
+	wl_list_remove(&output->link);
+
+	eglDestroySurface(output->backend->egl.display, output->egl_surface);
+	free(output);
+}
+
+static const struct wlr_output_impl output_impl = {
+	.set_custom_mode = output_set_custom_mode,
+	.transform = output_transform,
+	.destroy = output_destroy,
+	.make_current = output_make_current,
+	.swap_buffers = output_swap_buffers,
+};
+
+static int signal_frame(void *data) {
+	struct wlr_headless_output *output = data;
+	wl_signal_emit(&output->wlr_output.events.frame, &output->wlr_output);
+	wl_event_source_timer_update(output->frame_timer, output->frame_delay);
+	return 0;
+}
+
+struct wlr_output *wlr_headless_add_output(struct wlr_backend *wlr_backend,
+		unsigned int width, unsigned int height) {
+	struct wlr_headless_backend *backend =
+		(struct wlr_headless_backend *)wlr_backend;
+
+	struct wlr_headless_output *output =
+		calloc(1, sizeof(struct wlr_headless_output));
+	if (output == NULL) {
+		wlr_log(L_ERROR, "Failed to allocate wlr_headless_output");
+		return NULL;
+	}
+	output->backend = backend;
+	wlr_output_init(&output->wlr_output, &backend->backend, &output_impl);
+	struct wlr_output *wlr_output = &output->wlr_output;
+
+	output->egl_surface = egl_create_surface(&backend->egl, width, height);
+	if (output->egl_surface == EGL_NO_SURFACE) {
+		wlr_log(L_ERROR, "Failed to create EGL surface");
+		goto error;
+	}
+
+	output_set_custom_mode(wlr_output, width, height, 60*1000);
+	strncpy(wlr_output->make, "headless", sizeof(wlr_output->make));
+	strncpy(wlr_output->model, "headless", sizeof(wlr_output->model));
+	snprintf(wlr_output->name, sizeof(wlr_output->name), "HEADLESS-%d",
+		wl_list_length(&backend->outputs) + 1);
+
+	if (!eglMakeCurrent(output->backend->egl.display,
+			output->egl_surface, output->egl_surface,
+			output->backend->egl.context)) {
+		wlr_log(L_ERROR, "eglMakeCurrent failed: %s", egl_error());
+		goto error;
+	}
+
+	glViewport(0, 0, wlr_output->width, wlr_output->height);
+	glClearColor(1.0, 1.0, 1.0, 1.0);
+	glClear(GL_COLOR_BUFFER_BIT);
+
+	struct wl_event_loop *ev = wl_display_get_event_loop(backend->display);
+	output->frame_timer = wl_event_loop_add_timer(ev, signal_frame, output);
+
+	wl_list_insert(&backend->outputs, &output->link);
+
+	if (backend->started) {
+		wl_event_source_timer_update(output->frame_timer, output->frame_delay);
+		wlr_output_create_global(wlr_output, backend->display);
+		wl_signal_emit(&backend->backend.events.output_add, wlr_output);
+	}
+
+	return wlr_output;
+
+error:
+	wlr_output_destroy(&output->wlr_output);
+	return NULL;
+}