Add a --max-fps command-line argument to set a FPS limit

This allows limiting framerate on any project, which is useful to
reduce power usage and latency with certain setups (such as VRR displays).

This is particularly useful in projects that do not expose a setting to change
the FPS limit. While external FPS limiters can be used, they can be cumbersome
to set up and result in increased input lag compared to a built-in FPS limiter.

misc/dist/linux/godot.6

@@ -105,8 +105,11 @@ Show collisions shapes when running the scene.
 \fB\-\-debug\-navigation\fR
 Show navigation polygons when running the scene.
 .TP
+\fB\-\-max\-fps\fR <fps>
+Set a maximum number of frames per second rendered (can be used to limit power usage). A value of 0 results in unlimited framerate.
+.TP
 \fB\-\-frame\-delay\fR <ms>
-Simulate high CPU load (delay each frame by <ms> milliseconds).
+Simulate high CPU load (delay each frame by <ms> milliseconds). Do not use as a FPS limiter; use --max-fps instead.
 .TP
 \fB\-\-time\-scale\fR <scale>
 Force time scale (higher values are faster, 1.0 is normal speed).

misc/dist/shell/_godot.zsh-completion

@@ -69,6 +69,7 @@ _arguments \
   '--debug-collisions[show collision shapes when running the scene]' \
   '--debug-navigation[show navigation polygons when running the scene]' \
   '--debug-stringnames[print all StringName allocations to stdout when the engine quits]' \
+  '--frame-delay[set a maximum number of frames per second rendered (can be used to limit power usage), a value of 0 results in unlimited framerate]:maximum frames per seocnd' \
   '--frame-delay[simulate high CPU load (delay each frame by the given number of milliseconds)]:number of milliseconds' \
   '--time-scale[force time scale (higher values are faster, 1.0 is normal speed)]:time scale' \
   '--disable-vsync[disable vertical synchronization even if enabled in the project settings]' \

misc/dist/shell/godot.bash-completion

@@ -72,6 +72,7 @@ _complete_godot_options() {
 --debug-collisions
 --debug-navigation
 --debug-stringnames
+--max-fps
 --frame-delay
 --time-scale
 --disable-vsync

misc/dist/shell/godot.fish

@@ -89,6 +89,7 @@ complete -c godot -l remote-debug -d "Enable remote debugging"
 complete -c godot -l debug-collisions -d "Show collision shapes when running the scene"
 complete -c godot -l debug-navigation -d "Show navigation polygons when running the scene"
 complete -c godot -l debug-stringnames -d "Print all StringName allocations to stdout when the engine quits"
+complete -c godot -l max-fps -d "Set a maximum number of frames per second rendered (can be used to limit power usage), a value of 0 results in unlimited framerate" -x
 complete -c godot -l frame-delay -d "Simulate high CPU load (delay each frame by the given number of milliseconds)" -x
 complete -c godot -l time-scale -d "Force time scale (higher values are faster, 1.0 is normal speed)" -x
 complete -c godot -l disable-render-loop -d "Disable render loop so rendering only occurs when called explicitly from script"