feat: implement video sync

This commit is contained in:
Rekai Nyangadzayi Musuka 2022-03-14 05:16:02 -03:00
parent 8e3f48837d
commit c538079ad4
2 changed files with 58 additions and 11 deletions

View File

@ -4,8 +4,18 @@ const Bus = @import("Bus.zig");
const Scheduler = @import("scheduler.zig").Scheduler; const Scheduler = @import("scheduler.zig").Scheduler;
const Arm7tdmi = @import("cpu.zig").Arm7tdmi; const Arm7tdmi = @import("cpu.zig").Arm7tdmi;
const Timer = std.time.Timer;
const Thread = std.Thread;
const Atomic = std.atomic.Atomic; const Atomic = std.atomic.Atomic;
const cycles_per_frame: u64 = 160 * (308 * 4); const cycles_per_frame: u64 = 160 * (308 * 4);
const clock_rate: u64 = 1 << 24;
const clock_period: u64 = std.time.ns_per_s / clock_rate;
const frame_period = (clock_period * cycles_per_frame);
const sync_to_video: bool = true;
const log = std.log.scoped(.Emulation);
pub fn runFrame(sched: *Scheduler, cpu: *Arm7tdmi, bus: *Bus) void { pub fn runFrame(sched: *Scheduler, cpu: *Arm7tdmi, bus: *Bus) void {
var cycles: u64 = 0; var cycles: u64 = 0;
@ -19,8 +29,33 @@ pub fn runFrame(sched: *Scheduler, cpu: *Arm7tdmi, bus: *Bus) void {
} }
} }
pub fn runEmuThread(quit: *Atomic(bool), pause: *Atomic(bool), sched: *Scheduler, cpu: *Arm7tdmi, bus: *Bus) void { pub fn runEmuThread(quit: *Atomic(bool), pause: *Atomic(bool), fps: *Atomic(u64), sched: *Scheduler, cpu: *Arm7tdmi, bus: *Bus) void {
var timer = Timer.start() catch unreachable;
log.info("EmuThread has begun execution", .{});
while (!quit.load(.Unordered)) { while (!quit.load(.Unordered)) {
if (!pause.load(.Unordered)) runFrame(sched, cpu, bus); if (!pause.load(.Unordered)) {
runFrame(sched, cpu, bus);
const diff = timer.lap();
var ns_late: u64 = undefined;
const didUnderflow = @subWithOverflow(u64, diff, frame_period, &ns_late);
// We were more than an entire frame late....
if (!didUnderflow and ns_late > frame_period) continue;
// Negate the u64 so that we add to the amount of time sleeping
if (didUnderflow) ns_late = ~ns_late +% 1;
if (sync_to_video) std.time.sleep(frame_period -% ns_late);
fps.store(emuFps(diff), .Unordered);
}
} }
} }
fn emuFps(left: u64) u64 {
@setRuntimeSafety(false);
return @floatToInt(u64, @intToFloat(f64, std.time.ns_per_s) / @intToFloat(f64, left));
}

View File

@ -84,9 +84,10 @@ pub fn main() anyerror!void {
// Init Atomics // Init Atomics
var quit = Atomic(bool).init(false); var quit = Atomic(bool).init(false);
var pause = Atomic(bool).init(false); var pause = Atomic(bool).init(false);
var emu_fps = Atomic(u64).init(0);
// Create Emulator Thread // Create Emulator Thread
const emu_thread = try Thread.spawn(.{}, emu.runEmuThread, .{ &quit, &pause, &scheduler, &cpu, &bus }); const emu_thread = try Thread.spawn(.{}, emu.runEmuThread, .{ &quit, &pause, &emu_fps, &scheduler, &cpu, &bus });
defer emu_thread.join(); defer emu_thread.join();
// Initialize SDL // Initialize SDL
@ -94,8 +95,9 @@ pub fn main() anyerror!void {
if (status < 0) sdlPanic(); if (status < 0) sdlPanic();
defer SDL.SDL_Quit(); defer SDL.SDL_Quit();
var title_buf: [0x20]u8 = [_]u8{0x00} ** 0x20; var title_buf: [0x20]u8 = std.mem.zeroes([0x20]u8);
const title = try std.fmt.bufPrint(&title_buf, "ZBA | {s}", .{bus.pak.title}); var title = try std.fmt.bufPrint(&title_buf, "ZBA | {s}", .{bus.pak.title});
correctTitleSlice(&title);
var window = SDL.SDL_CreateWindow( var window = SDL.SDL_CreateWindow(
title.ptr, title.ptr,
@ -107,15 +109,14 @@ pub fn main() anyerror!void {
) orelse sdlPanic(); ) orelse sdlPanic();
defer SDL.SDL_DestroyWindow(window); defer SDL.SDL_DestroyWindow(window);
var renderer = SDL.SDL_CreateRenderer(window, -1, SDL.SDL_RENDERER_ACCELERATED) orelse sdlPanic(); var renderer = SDL.SDL_CreateRenderer(window, -1, SDL.SDL_RENDERER_ACCELERATED | SDL.SDL_RENDERER_PRESENTVSYNC) orelse sdlPanic();
defer SDL.SDL_DestroyRenderer(renderer); defer SDL.SDL_DestroyRenderer(renderer);
const texture = SDL.SDL_CreateTexture(renderer, SDL.SDL_PIXELFORMAT_BGR555, SDL.SDL_TEXTUREACCESS_STREAMING, 240, 160) orelse sdlPanic(); const texture = SDL.SDL_CreateTexture(renderer, SDL.SDL_PIXELFORMAT_BGR555, SDL.SDL_TEXTUREACCESS_STREAMING, 240, 160) orelse sdlPanic();
defer SDL.SDL_DestroyTexture(texture); defer SDL.SDL_DestroyTexture(texture);
// Init FPS Timer // Init FPS Timer
// var fps_buf: [0x100]u8 = [_]u8{0x00} ** 0x100; var dyn_title_buf: [0x100]u8 = [_]u8{0x00} ** 0x100;
// var timer = Timer.start() catch unreachable;
emu_loop: while (true) { emu_loop: while (true) {
var event: SDL.SDL_Event = undefined; var event: SDL.SDL_Event = undefined;
@ -169,9 +170,8 @@ pub fn main() anyerror!void {
_ = SDL.SDL_RenderCopy(renderer, texture, null, null); _ = SDL.SDL_RenderCopy(renderer, texture, null, null);
SDL.SDL_RenderPresent(renderer); SDL.SDL_RenderPresent(renderer);
// const fps = std.time.ns_per_s / timer.lap(); const dyn_title = std.fmt.bufPrint(&dyn_title_buf, "{s} [Emu FPS: {d}] ", .{ title, emu_fps.load(.Unordered) }) catch unreachable;
// const fps_title = std.fmt.bufPrint(&fps_buf, "{s} [FPS: {d}]", .{ title, fps }) catch unreachable; SDL.SDL_SetWindowTitle(window, dyn_title.ptr);
// SDL.SDL_SetWindowTitle(window, fps_title.ptr);
pause.store(false, .Unordered); pause.store(false, .Unordered);
} }
@ -188,3 +188,15 @@ const CliError = error{
InsufficientOptions, InsufficientOptions,
UnneededOptions, UnneededOptions,
}; };
/// The slice considers some null values to be a part of the string
/// so change the length of the slice so that isn't the case
// FIXME: This is awful and bad
fn correctTitleSlice(title: *[]u8) void {
for (title.*) |char, i| {
if (char == 0) {
title.len = i;
break;
}
}
}