diff --git a/src/emu.zig b/src/emu.zig index f4fb969..7489e5a 100644 --- a/src/emu.zig +++ b/src/emu.zig @@ -49,28 +49,42 @@ pub fn runEmuThread(quit: *Atomic(bool), pause: *Atomic(bool), fps: *Atomic(u64) // ns_late is non zero if we are late. var ns_late = timestamp -| wake_time; - // Calculate the new Thread wake time - wake_time += frame_period; + // log.info("timestamp: {} | late: {}", .{ timestamp, ns_late }); // If we're more than a frame late, skip the rest of this loop - if (ns_late > frame_period) continue; + // Recalculate what our new wake time should be so that we can + // get "back on track" + if (ns_late > frame_period) { + wake_time = timestamp + frame_period; + continue; + } - if (sync_to_video) std.time.sleep(frame_period - ns_late); + if (sync_to_video) { + // Employ several sleep calls in periods of 10ms + // By doing this the behaviour should average out to be + // more consistent - // Backup Busy Loop Routine - // if (sync_to_video) spinLoop(&timer, wake_time); + const sleep_for = frame_period - ns_late; + const loop_count = sleep_for / (std.time.ns_per_ms * 10); // How many groups of 10ms + + var i: usize = 0; + while (i < loop_count) : (i += 1) { + std.time.sleep(std.time.ns_per_ms * 10); + } + + // Spin to make up the difference if there is a need + // Make sure that we're using the old wake time and not the onne we recalcualted + spinLoop(&timer, wake_time); + } + + // Update to the new wake time + wake_time += frame_period; } } } fn spinLoop(timer: *Timer, wake_time: u64) void { - while (true) { - const timestamp = timer.read(); - - if (timestamp >= wake_time) { - break; - } - } + while (true) if (timer.read() > wake_time) break; } fn emuFps(left: u64) u64 { diff --git a/src/main.zig b/src/main.zig index 767f8ab..79beee9 100644 --- a/src/main.zig +++ b/src/main.zig @@ -177,7 +177,7 @@ pub fn main() anyerror!void { fps_avg.add(emu_fps.load(.Unordered)); const avg = fps_avg.calc(); - const dyn_title = std.fmt.bufPrint(&dyn_title_buf, "{s} [Emu: {d:0>3}fps, {d:0>3}%] ", .{ title, avg, (avg * 100 / 59) }) catch unreachable; + const dyn_title = std.fmt.bufPrint(&dyn_title_buf, "{s} [Emu: {d:0>3}fps, {d:0>3}%] ", .{ title, avg, (avg * 100 / 60) }) catch unreachable; SDL.SDL_SetWindowTitle(window, dyn_title.ptr); } diff --git a/src/util.zig b/src/util.zig index 05568a8..6e3db87 100644 --- a/src/util.zig +++ b/src/util.zig @@ -18,7 +18,7 @@ pub const FpsAverage = struct { } pub fn add(self: *Self, sample: u64) void { - if (self.sample_count == 1000) return self.reset(sample); + if (self.sample_count == 600) return self.reset(sample); self.total += sample; self.sample_count += 1;