dmabuf: Limit rate to 30 FPS

include/dmabuf.h

@@ -50,6 +50,10 @@ struct dmabuf_capture {
 	struct zwlr_export_dmabuf_frame_v1* zwlr_frame;
 	struct dmabuf_frame frame;
 	uint64_t render_finish_time;
+	uint64_t start_time;
+
+	struct aml_timer* timer;
 };
 
 void dmabuf_capture_init(struct dmabuf_capture* self);
+void dmabuf_capture_destroy(struct dmabuf_capture* self);

src/dmabuf.c

@@ -29,8 +29,14 @@
 #include "render.h"
 #include "usdt.h"
 
+#define RATE_LIMIT 30.0
+#define MIN_PERIOD ((uint64_t)(1000.0 / RATE_LIMIT))
+
 #define PROCESSING_DURATION_LIMIT 16 /* ms */
 
+static int dmabuf_capture_start_now(struct frame_capture* fc,
+                                    enum frame_capture_options options);
+
 static void dmabuf_close_fds(struct dmabuf_capture* self)
 {
 	for (size_t i = 0; i < self->frame.n_planes; ++i)
@@ -43,6 +49,8 @@ static void dmabuf_capture_stop(struct frame_capture* fc)
 {
 	struct dmabuf_capture* self = (void*)fc;
 
+	aml_stop(aml_get_default(), self->timer);
+
 	fc->status = CAPTURE_STOPPED;
 
 	if (self->zwlr_frame) {
@@ -150,11 +158,41 @@ static void dmabuf_frame_cancel(void* data,
 	dmabuf_close_fds(self);
 }
 
+static void dmabuf__poll(void* obj)
+{
+	struct dmabuf_capture* self = aml_get_userdata(obj);
+	struct frame_capture* fc = (struct frame_capture*)self;
+
+	dmabuf_capture_start_now(fc, 0);
+}
+
 static int dmabuf_capture_start(struct frame_capture* fc,
                                 enum frame_capture_options options)
 {
 	struct dmabuf_capture* self = (void*)fc;
 
+	if (fc->status == CAPTURE_IN_PROGRESS)
+		return -1;
+
+	uint64_t now = gettime_ms();
+	uint64_t dt = now - self->start_time;
+
+	fc->status = CAPTURE_IN_PROGRESS;
+
+	if (dt < MIN_PERIOD) {
+		uint64_t time_left = MIN_PERIOD - dt;
+		aml_set_duration(self->timer, time_left);
+		return aml_start(aml_get_default(), self->timer);
+	}
+
+	return dmabuf_capture_start_now(fc, options);
+}
+
+static int dmabuf_capture_start_now(struct frame_capture* fc,
+                                    enum frame_capture_options options)
+{
+	struct dmabuf_capture* self = (void*)fc;
+
 	static const struct zwlr_export_dmabuf_frame_v1_listener
 	dmabuf_frame_listener = {
 		.frame = dmabuf_frame_start,
@@ -172,7 +210,7 @@ static int dmabuf_capture_start(struct frame_capture* fc,
 	if (!self->zwlr_frame)
 		return -1;
 
-	fc->status = CAPTURE_IN_PROGRESS;
+	self->start_time = gettime_ms();
 
 	zwlr_export_dmabuf_frame_v1_add_listener(self->zwlr_frame,
 			&dmabuf_frame_listener, self);
@@ -190,7 +228,16 @@ static void dmabuf_capture_render(struct frame_capture* fc,
 
 void dmabuf_capture_init(struct dmabuf_capture* self)
 {
+	self->timer = aml_timer_new(0, dmabuf__poll, self, NULL);
+	assert(self->timer);
+
 	self->fc.backend.start = dmabuf_capture_start;
 	self->fc.backend.stop = dmabuf_capture_stop;
 	self->fc.backend.render = dmabuf_capture_render;
 }
+
+void dmabuf_capture_destroy(struct dmabuf_capture* self)
+{
+	aml_stop(aml_get_default(), self->timer);
+	aml_unref(self->timer);
+}

src/main.c

@@ -885,7 +885,10 @@ int main(int argc, char* argv[])
 	nvnc_display_unref(self.nvnc_display);
 	nvnc_close(self.nvnc);
 	renderer_destroy(&self.renderer);
-	screencopy_destroy(&self.screencopy_backend);
+	if (self.screencopy_backend.manager)
+		screencopy_destroy(&self.screencopy_backend);
+	if (self.dmabuf_backend.manager)
+		dmabuf_capture_destroy(&self.dmabuf_backend);
 	wayvnc_destroy(&self);
 	aml_unref(aml);