From 4cab77094a0816900a7c06461cb1b9ffad679341 Mon Sep 17 00:00:00 2001 From: Hugo Locurcio Date: Thu, 8 Jun 2023 19:33:10 +0200 Subject: [PATCH] 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. --- doc/classes/ProjectSettings.xml | 1 + main/main.cpp | 18 +++++++++++++++++- misc/dist/linux/godot.6 | 5 ++++- misc/dist/shell/_godot.zsh-completion | 1 + misc/dist/shell/godot.bash-completion | 1 + misc/dist/shell/godot.fish | 1 + 6 files changed, 25 insertions(+), 2 deletions(-) diff --git a/doc/classes/ProjectSettings.xml b/doc/classes/ProjectSettings.xml index 02f001edc9ce..8746a1d8b4f2 100644 --- a/doc/classes/ProjectSettings.xml +++ b/doc/classes/ProjectSettings.xml @@ -345,6 +345,7 @@ If [member display/window/vsync/vsync_mode] is [code]Enabled[/code], on monitors with variable refresh rate enabled (G-Sync/FreeSync), using a FPS limit a few frames lower than the monitor's refresh rate will [url=https://blurbusters.com/howto-low-lag-vsync-on/]reduce input lag while avoiding tearing[/url]. If [member display/window/vsync/vsync_mode] is [code]Disabled[/code], limiting the FPS to a high value that can be consistently reached on the system can reduce input lag compared to an uncapped framerate. Since this works by ensuring the GPU load is lower than 100%, this latency reduction is only effective in GPU-bottlenecked scenarios, not CPU-bottlenecked scenarios. See also [member physics/common/physics_ticks_per_second]. + This setting can be overridden using the [code]--max-fps <fps;>[/code] command line argument (including with a value of [code]0[/code] for unlimited framerate). [b]Note:[/b] This property is only read when the project starts. To change the rendering FPS cap at runtime, set [member Engine.max_fps] instead. diff --git a/main/main.cpp b/main/main.cpp index 7e2741648da1..6f77169502c1 100644 --- a/main/main.cpp +++ b/main/main.cpp @@ -210,6 +210,7 @@ static bool debug_paths = false; static bool debug_navigation = false; static bool debug_avoidance = false; #endif +static int max_fps = -1; static int frame_delay = 0; static bool disable_render_loop = false; static int fixed_fps = -1; @@ -462,7 +463,8 @@ void Main::print_help(const char *p_binary) { OS::get_singleton()->print(" --debug-avoidance Show navigation avoidance debug visuals when running the scene.\n"); OS::get_singleton()->print(" --debug-stringnames Print all StringName allocations to stdout when the engine quits.\n"); #endif - OS::get_singleton()->print(" --frame-delay Simulate high CPU load (delay each frame by milliseconds).\n"); + OS::get_singleton()->print(" --max-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.\n"); + OS::get_singleton()->print(" --frame-delay Simulate high CPU load (delay each frame by milliseconds). Do not use as a FPS limiter; use --max-fps instead.\n"); OS::get_singleton()->print(" --time-scale Force time scale (higher values are faster, 1.0 is normal speed).\n"); OS::get_singleton()->print(" --disable-vsync Forces disabling of vertical synchronization, even if enabled in the project settings. Does not override driver-level V-Sync enforcement.\n"); OS::get_singleton()->print(" --disable-render-loop Disable render loop so rendering only occurs when called explicitly from script.\n"); @@ -1329,6 +1331,16 @@ Error Main::setup(const char *execpath, int argc, char *argv[], bool p_second_ph goto error; } + } else if (I->get() == "--max-fps") { // set maximum rendered FPS + + if (I->next()) { + max_fps = I->next()->get().to_int(); + N = I->next()->next(); + } else { + OS::get_singleton()->print("Missing maximum FPS argument, aborting.\n"); + goto error; + } + } else if (I->get() == "--frame-delay") { // force frame delay if (I->next()) { @@ -1961,6 +1973,10 @@ Error Main::setup(const char *execpath, int argc, char *argv[], bool p_second_ph OS::get_singleton()->set_environment("MVK_CONFIG_LOG_LEVEL", OS::get_singleton()->_verbose_stdout ? "3" : "1"); // 1 = Errors only, 3 = Info #endif + if (max_fps >= 0) { + Engine::get_singleton()->set_max_fps(max_fps); + } + if (frame_delay == 0) { frame_delay = GLOBAL_DEF(PropertyInfo(Variant::INT, "application/run/frame_delay_msec", PROPERTY_HINT_RANGE, "0,100,1,or_greater"), 0); } diff --git a/misc/dist/linux/godot.6 b/misc/dist/linux/godot.6 index 2481869d8a4d..a00a69299c3d 100644 --- a/misc/dist/linux/godot.6 +++ b/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 +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 -Simulate high CPU load (delay each frame by milliseconds). +Simulate high CPU load (delay each frame by milliseconds). Do not use as a FPS limiter; use --max-fps instead. .TP \fB\-\-time\-scale\fR Force time scale (higher values are faster, 1.0 is normal speed). diff --git a/misc/dist/shell/_godot.zsh-completion b/misc/dist/shell/_godot.zsh-completion index 89fe84016637..3b12fdbc22e9 100644 --- a/misc/dist/shell/_godot.zsh-completion +++ b/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]' \ diff --git a/misc/dist/shell/godot.bash-completion b/misc/dist/shell/godot.bash-completion index a7ce11e52410..ba4edc4f2553 100644 --- a/misc/dist/shell/godot.bash-completion +++ b/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 diff --git a/misc/dist/shell/godot.fish b/misc/dist/shell/godot.fish index ed58d8dcf6d6..bb4ff0b558a4 100644 --- a/misc/dist/shell/godot.fish +++ b/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"