Fixed Particles restart after visibility has been set to off and on again

Make sure particles are processed during the same frame when visibility is set to on, in case they are still active from before and need to be restarted.

Fixed #33476

scene/3d/particles.cpp

@@ -331,6 +331,13 @@ void Particles::_notification(int p_what) {
 			set_process_internal(false);
 		}
 	}
+
+	if (p_what == NOTIFICATION_VISIBILITY_CHANGED) {
+		// make sure particles are updated before rendering occurs if they were active before
+		if (is_visible_in_tree() && !VS::get_singleton()->particles_is_inactive(particles)) {
+			VS::get_singleton()->particles_request_process(particles);
+		}
+	}
 }
 
 void Particles::_bind_methods() {

servers/visual/visual_server_raster.h

@@ -409,6 +409,8 @@ public:
 	BIND2(particles_set_process_material, RID, RID)
 	BIND2(particles_set_fixed_fps, RID, int)
 	BIND2(particles_set_fractional_delta, RID, bool)
+	BIND1R(bool, particles_is_inactive, RID)
+	BIND1(particles_request_process, RID)
 	BIND1(particles_restart, RID)
 
 	BIND2(particles_set_draw_order, RID, VS::ParticlesDrawOrder)

servers/visual/visual_server_wrap_mt.h

@@ -343,6 +343,8 @@ public:
 	FUNC2(particles_set_process_material, RID, RID)
 	FUNC2(particles_set_fixed_fps, RID, int)
 	FUNC2(particles_set_fractional_delta, RID, bool)
+	FUNC1R(bool, particles_is_inactive, RID)
+	FUNC1(particles_request_process, RID)
 	FUNC1(particles_restart, RID)
 
 	FUNC2(particles_set_draw_order, RID, VS::ParticlesDrawOrder)

servers/visual_server.cpp

@@ -1844,6 +1844,8 @@ void VisualServer::_bind_methods() {
 	ClassDB::bind_method(D_METHOD("particles_set_process_material", "particles", "material"), &VisualServer::particles_set_process_material);
 	ClassDB::bind_method(D_METHOD("particles_set_fixed_fps", "particles", "fps"), &VisualServer::particles_set_fixed_fps);
 	ClassDB::bind_method(D_METHOD("particles_set_fractional_delta", "particles", "enable"), &VisualServer::particles_set_fractional_delta);
+	ClassDB::bind_method(D_METHOD("particles_is_inactive", "particles"), &VisualServer::particles_is_inactive);
+	ClassDB::bind_method(D_METHOD("particles_request_process", "particles"), &VisualServer::particles_request_process);
 	ClassDB::bind_method(D_METHOD("particles_restart", "particles"), &VisualServer::particles_restart);
 	ClassDB::bind_method(D_METHOD("particles_set_draw_order", "particles", "order"), &VisualServer::particles_set_draw_order);
 	ClassDB::bind_method(D_METHOD("particles_set_draw_passes", "particles", "count"), &VisualServer::particles_set_draw_passes);

servers/visual_server.h

@@ -560,6 +560,8 @@ public:
 	virtual void particles_set_process_material(RID p_particles, RID p_material) = 0;
 	virtual void particles_set_fixed_fps(RID p_particles, int p_fps) = 0;
 	virtual void particles_set_fractional_delta(RID p_particles, bool p_enable) = 0;
+	virtual bool particles_is_inactive(RID p_particles) = 0;
+	virtual void particles_request_process(RID p_particles) = 0;
 	virtual void particles_restart(RID p_particles) = 0;
 
 	enum ParticlesDrawOrder {