Merge pull request #55667 from Calinou/doc-physics-ticks-per-rendered-frame

2 files changed, 7 insertions, 4 deletions

diff --git a/doc/classes/Engine.xml b/doc/classes/Engine.xml
index 9756b26dee..d0c4d28c55 100644
--- a/doc/classes/Engine.xml
+++ b/doc/classes/Engine.xml
@@ -187,7 +187,8 @@
 			[b]Note:[/b] For best results, when using a custom physics interpolation solution, the physics jitter fix should be disabled by setting [member physics_jitter_fix] to [code]0[/code].
 		</member>
 		<member name="physics_ticks_per_second" type="int" setter="set_physics_ticks_per_second" getter="get_physics_ticks_per_second" default="60">
-			The number of fixed iterations per second. This controls how often physics simulation and [method Node._physics_process] methods are run. This value should generally always be set to [code]60[/code] or above, as Godot doesn't interpolate the physics step. As a result, values lower than [code]60[/code] will look stuttery. This value can be increased to make input more reactive or work around tunneling issues, but keep in mind doing so will increase CPU usage. See also [member target_fps].
+			The number of fixed iterations per second. This controls how often physics simulation and [method Node._physics_process] methods are run. This value should generally always be set to [code]60[/code] or above, as Godot doesn't interpolate the physics step. As a result, values lower than [code]60[/code] will look stuttery. This value can be increased to make input more reactive or work around collision tunneling issues, but keep in mind doing so will increase CPU usage. See also [member target_fps] and [member ProjectSettings.physics/common/physics_ticks_per_second].
+			[b]Note:[/b] Only 8 physics ticks may be simulated per rendered frame at most. If more than 8 physics ticks have to be simulated per rendered frame to keep up with rendering, the game will appear to slow down (even if [code]delta[/code] is used consistently in physics calculations). Therefore, it is recommended not to increase [member physics_ticks_per_second] above 240. Otherwise, the game will slow down when the rendering framerate goes below 30 FPS.
 		</member>
 		<member name="print_error_messages" type="bool" setter="set_print_error_messages" getter="is_printing_error_messages" default="true">
 			If [code]false[/code], stops printing error and warning messages to the console and editor Output log. This can be used to hide error and warning messages during unit test suite runs. This property is equivalent to the [member ProjectSettings.application/run/disable_stderr] project setting.
@@ -195,7 +196,7 @@
 			[b]Note:[/b] This property does not impact the editor's Errors tab when running a project from the editor.
 		</member>
 		<member name="target_fps" type="int" setter="set_target_fps" getter="get_target_fps" default="0">
-			The desired frames per second. If the hardware cannot keep up, this setting may not be respected. A value of 0 means no limit. See also [member physics_ticks_per_second].
+			The desired frames per second. If the hardware cannot keep up, this setting may not be respected. A value of 0 means no limit. See also [member physics_ticks_per_second] and [member ProjectSettings.debug/settings/fps/force_fps].
 		</member>
 		<member name="time_scale" type="float" setter="set_time_scale" getter="get_time_scale" default="1.0">
 			Controls how fast or slow the in-game clock ticks versus the real life one. It defaults to 1.0. A value of 2.0 means the game moves twice as fast as real life, whilst a value of 0.5 means the game moves at half the regular speed.
diff --git a/doc/classes/ProjectSettings.xml b/doc/classes/ProjectSettings.xml
index e0371a6a4a..ce9f41410a 100644
--- a/doc/classes/ProjectSettings.xml
+++ b/doc/classes/ProjectSettings.xml
@@ -432,8 +432,9 @@
 		</member>
 		<member name="debug/settings/fps/force_fps" type="int" setter="" getter="" default="0">
 			Maximum number of frames per second allowed. The actual number of frames per second may still be below this value if the game is lagging.
-			If [member display/window/vsync/vsync_mode] is set to [code]Enabled[/code] or [code]Adaptive[/code], it takes precedence and the forced FPS number cannot exceed the monitor's refresh rate.
+			If [member display/window/vsync/vsync_mode] is set to [code]Enabled[/code] or [code]Adaptive[/code], it takes precedence and the forced FPS number cannot exceed the monitor's refresh rate. See also [member physics/common/physics_ticks_per_second].
 			This setting is therefore mostly relevant for lowering the maximum FPS below VSync, e.g. to perform non-real-time rendering of static frames, or test the project under lag conditions.
+			[b]Note:[/b] This property is only read when the project starts. To change the rendering FPS cap at runtime, set [member Engine.target_fps] instead.
 		</member>
 		<member name="debug/settings/gdscript/max_call_stack" type="int" setter="" getter="" default="1024">
 			Maximum call stack allowed for debugging GDScript.
@@ -1481,8 +1482,9 @@
 			[b]Note:[/b] This property is only read when the project starts. To change the physics FPS at runtime, set [member Engine.physics_jitter_fix] instead.
 		</member>
 		<member name="physics/common/physics_ticks_per_second" type="int" setter="" getter="" default="60">
-			The number of fixed iterations per second. This controls how often physics simulation and [method Node._physics_process] methods are run.
+			The number of fixed iterations per second. This controls how often physics simulation and [method Node._physics_process] methods are run. See also [member debug/settings/fps/force_fps].
 			[b]Note:[/b] This property is only read when the project starts. To change the physics FPS at runtime, set [member Engine.physics_ticks_per_second] instead.
+			[b]Note:[/b] Only 8 physics ticks may be simulated per rendered frame at most. If more than 8 physics ticks have to be simulated per rendered frame to keep up with rendering, the game will appear to slow down (even if [code]delta[/code] is used consistently in physics calculations). Therefore, it is recommended not to increase [member physics/common/physics_ticks_per_second] above 240. Otherwise, the game will slow down when the rendering framerate goes below 30 FPS.
 		</member>
 		<member name="rendering/2d/opengl/batching_send_null" type="int" setter="" getter="" default="0">
 		</member>