From eab5bcac0029e4e298e1f194133c21580098508d Mon Sep 17 00:00:00 2001 From: antonioginer Date: Sat, 16 Nov 2019 22:06:13 +0100 Subject: Remove up to one frame of input latency. (#5901) * Remove up to one frame of input latency. Makes MAME virtually lagless on VRR monitors. * Use empty parentheses and clean interface member calls * Add new option -instant_blit to make this feature optional * Rename new option to -lowlatency, -ll --- src/emu/emuopts.cpp | 1 + src/emu/emuopts.h | 2 ++ src/emu/video.cpp | 10 +++++++++- src/emu/video.h | 1 + 4 files changed, 13 insertions(+), 1 deletion(-) (limited to 'src/emu') diff --git a/src/emu/emuopts.cpp b/src/emu/emuopts.cpp index eb7c9bdbf27..8af8541d32c 100644 --- a/src/emu/emuopts.cpp +++ b/src/emu/emuopts.cpp @@ -88,6 +88,7 @@ const options_entry emu_options::s_option_entries[] = { OPTION_SLEEP, "1", OPTION_BOOLEAN, "enable sleeping, which gives time back to other applications when idle" }, { OPTION_SPEED "(0.01-100)", "1.0", OPTION_FLOAT, "controls the speed of gameplay, relative to realtime; smaller numbers are slower" }, { OPTION_REFRESHSPEED ";rs", "0", OPTION_BOOLEAN, "automatically adjust emulation speed to keep the emulated refresh rate slower than the host screen" }, + { OPTION_LOWLATENCY ";ll", "0", OPTION_BOOLEAN, "draws new frame before throttling to reduce input latency" }, // render options { nullptr, nullptr, OPTION_HEADER, "CORE RENDER OPTIONS" }, diff --git a/src/emu/emuopts.h b/src/emu/emuopts.h index 970a90c67da..a1a23e77a2b 100644 --- a/src/emu/emuopts.h +++ b/src/emu/emuopts.h @@ -75,6 +75,7 @@ #define OPTION_SLEEP "sleep" #define OPTION_SPEED "speed" #define OPTION_REFRESHSPEED "refreshspeed" +#define OPTION_LOWLATENCY "lowlatency" // core render options #define OPTION_KEEPASPECT "keepaspect" @@ -352,6 +353,7 @@ public: bool sleep() const { return m_sleep; } float speed() const { return float_value(OPTION_SPEED); } bool refresh_speed() const { return m_refresh_speed; } + bool low_latency() const { return bool_value(OPTION_LOWLATENCY); } // core render options bool keep_aspect() const { return bool_value(OPTION_KEEPASPECT); } diff --git a/src/emu/video.cpp b/src/emu/video.cpp index d8bea693005..fa0efb88a89 100644 --- a/src/emu/video.cpp +++ b/src/emu/video.cpp @@ -91,6 +91,7 @@ video_manager::video_manager(running_machine &machine) , m_seconds_to_run(machine.options().seconds_to_run()) , m_auto_frameskip(machine.options().auto_frameskip()) , m_speed(original_speed_setting()) + , m_low_latency(machine.options().low_latency()) , m_empty_skip_count(0) , m_frameskip_level(machine.options().frameskip()) , m_frameskip_counter(0) @@ -229,7 +230,7 @@ void video_manager::frame_update(bool from_debugger) // if we're throttling, synchronize before rendering attotime current_time = machine().time(); - if (!from_debugger && !skipped_it && effective_throttle()) + if (!from_debugger && !skipped_it && !m_low_latency && effective_throttle()) update_throttle(current_time); // ask the OSD to update @@ -237,6 +238,13 @@ void video_manager::frame_update(bool from_debugger) machine().osd().update(!from_debugger && skipped_it); g_profiler.stop(); + // we synchronize after rendering instead of before, if low latency mode is enabled + if (!from_debugger && !skipped_it && m_low_latency && effective_throttle()) + update_throttle(current_time); + + // get most recent input now + machine().osd().input_update(); + emulator_info::periodic_check(); // perform tasks for this frame diff --git a/src/emu/video.h b/src/emu/video.h index b8b1c408773..5ccfe2b99b0 100644 --- a/src/emu/video.h +++ b/src/emu/video.h @@ -163,6 +163,7 @@ private: u32 m_seconds_to_run; // number of seconds to run before quitting bool m_auto_frameskip; // flag: true if we're automatically frameskipping u32 m_speed; // overall speed (*1000) + bool m_low_latency; // flag: true if we are throttling after blitting // frameskipping u8 m_empty_skip_count; // number of empty frames we have skipped -- cgit v1.2.3