Document _process() and _physics_process() delta behavior at low FPS

2024-07-22 21:54:08 +02:00
parent 4e5ed0bbfb
commit c15633139f
2 changed files with 7 additions and 1 deletions
@@ -78,6 +78,7 @@
 			<description>
 				Called each physics frame with the time since the last physics frame as argument ([param delta], in seconds). Equivalent to [method Node._physics_process].
 				If implemented, the method must return a boolean value. [code]true[/code] ends the main loop, while [code]false[/code] lets it proceed to the next frame.
+				[b]Note:[/b] [param delta] will be larger than expected if running at a framerate lower than [member Engine.physics_ticks_per_second] / [member Engine.max_physics_steps_per_frame] FPS. This is done to avoid "spiral of death" scenarios where performance would plummet due to an ever-increasing number of physics steps per frame. This behavior affects both [method _process] and [method _physics_process]. As a result, avoid using [param delta] for time measurements in real-world seconds. Use the [Time] singleton's methods for this purpose instead, such as [method Time.get_ticks_usec].
 			</description>
 		</method>
 		<method name="_process" qualifiers="virtual">
@@ -86,6 +87,7 @@
 			<description>
 				Called each process (idle) frame with the time since the last process frame as argument (in seconds). Equivalent to [method Node._process].
 				If implemented, the method must return a boolean value. [code]true[/code] ends the main loop, while [code]false[/code] lets it proceed to the next frame.
+				[b]Note:[/b] [param delta] will be larger than expected if running at a framerate lower than [member Engine.physics_ticks_per_second] / [member Engine.max_physics_steps_per_frame] FPS. This is done to avoid "spiral of death" scenarios where performance would plummet due to an ever-increasing number of physics steps per frame. This behavior affects both [method _process] and [method _physics_process]. As a result, avoid using [param delta] for time measurements in real-world seconds. Use the [Time] singleton's methods for this purpose instead, such as [method Time.get_ticks_usec].
 			</description>
 		</method>
 	</methods>