Merge pull request #45232 from Xrayez/doc-gpu-particles-visibility

Document GPU particles visibility rect/aabb behavior

doc/classes/GPUParticles2D.xml

@@ -71,7 +71,8 @@
 			Particle texture. If [code]null[/code], particles will be squares.
 		</member>
 		<member name="visibility_rect" type="Rect2" setter="set_visibility_rect" getter="get_visibility_rect" default="Rect2( -100, -100, 200, 200 )">
-			Editor visibility helper.
+			The [Rect2] that determines the node's region which needs to be visible on screen for the particle system to be active.
+			Grow the rect if particles suddenly appear/disappear when the node enters/exits the screen. The [Rect2] can be grown via code or with the [b]Particles → Generate Visibility Rect[/b] editor tool.
 		</member>
 	</members>
 	<constants>

doc/classes/GPUParticles3D.xml

@@ -123,7 +123,8 @@
 		<member name="sub_emitter" type="NodePath" setter="set_sub_emitter" getter="get_sub_emitter" default="NodePath(&quot;&quot;)">
 		</member>
 		<member name="visibility_aabb" type="AABB" setter="set_visibility_aabb" getter="get_visibility_aabb" default="AABB( -4, -4, -4, 8, 8, 8 )">
-			The [AABB] that determines the area of the world part of which needs to be visible on screen for the particle system to be active.
+			The [AABB] that determines the node's region which needs to be visible on screen for the particle system to be active.
+			Grow the box if particles suddenly appear/disappear when the node enters/exits the screen. The [AABB] can be grown via code or with the [b]Particles → Generate AABB[/b] editor tool.
 		</member>
 	</members>
 	<constants>