diff --git a/main/main.cpp b/main/main.cpp index fa2668ccc5..f95003d546 100644 --- a/main/main.cpp +++ b/main/main.cpp @@ -2163,22 +2163,37 @@ bool Main::iteration() { if (fixed_fps != -1) return exit; - if (OS::get_singleton()->is_in_low_processor_usage_mode() || !OS::get_singleton()->can_draw()) - OS::get_singleton()->delay_usec(OS::get_singleton()->get_low_processor_usage_mode_sleep_usec()); //apply some delay to force idle time - else { - uint32_t frame_delay = Engine::get_singleton()->get_frame_delay(); - if (frame_delay) - OS::get_singleton()->delay_usec(Engine::get_singleton()->get_frame_delay() * 1000); + const uint32_t frame_delay = Engine::get_singleton()->get_frame_delay(); + if (frame_delay) { + // Add fixed frame delay to decrease CPU/GPU usage. This doesn't take + // the actual frame time into account. + // Due to the high fluctuation of the actual sleep duration, it's not recommended + // to use this as a FPS limiter. + OS::get_singleton()->delay_usec(frame_delay * 1000); } - int target_fps = Engine::get_singleton()->get_target_fps(); + // Add a dynamic frame delay to decrease CPU/GPU usage. This takes the + // previous frame time into account for a smoother result. + uint64_t dynamic_delay = 0; + if (OS::get_singleton()->is_in_low_processor_usage_mode() || !OS::get_singleton()->can_draw()) { + dynamic_delay = OS::get_singleton()->get_low_processor_usage_mode_sleep_usec(); + } + const int target_fps = Engine::get_singleton()->get_target_fps(); if (target_fps > 0 && !Engine::get_singleton()->is_editor_hint()) { - uint64_t time_step = 1000000L / target_fps; - target_ticks += time_step; + // Override the low processor usage mode sleep delay if the target FPS is lower. + dynamic_delay = MAX(dynamic_delay, (uint64_t)(1000000 / target_fps)); + } + + if (dynamic_delay > 0) { + target_ticks += dynamic_delay; uint64_t current_ticks = OS::get_singleton()->get_ticks_usec(); - if (current_ticks < target_ticks) OS::get_singleton()->delay_usec(target_ticks - current_ticks); + + if (current_ticks < target_ticks) { + OS::get_singleton()->delay_usec(target_ticks - current_ticks); + } + current_ticks = OS::get_singleton()->get_ticks_usec(); - target_ticks = MIN(MAX(target_ticks, current_ticks - time_step), current_ticks + time_step); + target_ticks = MIN(MAX(target_ticks, current_ticks - dynamic_delay), current_ticks + dynamic_delay); } #ifdef TOOLS_ENABLED