zba/src/main.zig

97 lines
3.1 KiB
Zig

const std = @import("std");
const SDL = @import("sdl2");
const emu = @import("emu.zig");
const Bus = @import("Bus.zig");
const Arm7tdmi = @import("cpu.zig").Arm7tdmi;
const Scheduler = @import("scheduler.zig").Scheduler;
const Timer = std.time.Timer;
const window_scale = 3;
const gba_width = @import("ppu.zig").width;
const gba_height = @import("ppu.zig").height;
const buf_pitch = @import("ppu.zig").buf_pitch;
pub fn main() anyerror!void {
// Allocator for Emulator + CLI Aruments
var gpa = std.heap.GeneralPurposeAllocator(.{}){};
const alloc = gpa.allocator();
defer std.debug.assert(!gpa.deinit());
// Handle CLI Arguments
const args = try std.process.argsAlloc(alloc);
defer std.process.argsFree(alloc, args);
const zba_args: []const []const u8 = args[1..];
if (zba_args.len == 0) {
std.log.err("Expected PATH to Gameboy Advance ROM as a CLI argument", .{});
return;
} else if (zba_args.len > 1) {
std.log.err("Too many CLI arguments were provided", .{});
return;
}
// Initialize Emulator
var scheduler = Scheduler.init(alloc);
defer scheduler.deinit();
var bus = try Bus.init(alloc, &scheduler, zba_args[0]);
defer bus.deinit();
var cpu = Arm7tdmi.init(&scheduler, &bus);
cpu.skipBios();
// Initialize SDL
const status = SDL.SDL_Init(SDL.SDL_INIT_VIDEO | SDL.SDL_INIT_EVENTS | SDL.SDL_INIT_AUDIO);
if (status < 0) sdlPanic();
defer SDL.SDL_Quit();
var window = SDL.SDL_CreateWindow(
"Gameboy Advance Emulator",
SDL.SDL_WINDOWPOS_CENTERED,
SDL.SDL_WINDOWPOS_CENTERED,
gba_width * window_scale,
gba_height * window_scale,
SDL.SDL_WINDOW_SHOWN,
) orelse sdlPanic();
defer SDL.SDL_DestroyWindow(window);
var renderer = SDL.SDL_CreateRenderer(window, -1, SDL.SDL_RENDERER_ACCELERATED) orelse sdlPanic();
defer SDL.SDL_DestroyRenderer(renderer);
const texture = SDL.SDL_CreateTexture(renderer, SDL.SDL_PIXELFORMAT_BGR555, SDL.SDL_TEXTUREACCESS_STREAMING, 240, 160) orelse sdlPanic();
defer SDL.SDL_DestroyTexture(texture);
// Init FPS Timer
var timer = Timer.start() catch unreachable;
var title_buf: [0x30]u8 = [_]u8{0x00} ** 0x30;
emu_loop: while (true) {
emu.runFrame(&scheduler, &cpu, &bus);
var event: SDL.SDL_Event = undefined;
_ = SDL.SDL_PollEvent(&event);
switch (event.type) {
SDL.SDL_QUIT => break :emu_loop,
else => {},
}
const buf_ptr = bus.ppu.frame_buf.ptr;
_ = SDL.SDL_UpdateTexture(texture, null, buf_ptr, buf_pitch);
_ = SDL.SDL_RenderCopy(renderer, texture, null, null);
SDL.SDL_RenderPresent(renderer);
const fps = std.time.ns_per_s / timer.lap();
const title = std.fmt.bufPrint(&title_buf, "Gameboy Advance Emulator FPS: {d}", .{fps}) catch unreachable;
SDL.SDL_SetWindowTitle(window, title.ptr);
}
}
fn sdlPanic() noreturn {
const str = @as(?[*:0]const u8, SDL.SDL_GetError()) orelse "unknown error";
@panic(std.mem.sliceTo(str, 0));
}