adding file reloading

engine/core/src/core.zig

@@ -248,5 +248,7 @@ pub const console = @import("console.zig");
 
 pub const configVars = @import("configVars.zig");
 
+pub const loopDelay = engine.loopDelay;
+
 pub const getConfigVar = configVars.getConfigVar;
 pub const configVar = configVars.configVar;

engine/core/src/engine.zig

@@ -388,4 +388,20 @@ pub const NeonObjectParams = struct {
     isCore: bool = false,
 };
 
+const Src = std.builtin.SourceLocation;
+pub fn loopDelay(comptime src: Src, interval: f64, dt: f64, comptime S: type, capture: S) void {
+    const C = struct {
+        pub const s = src;
+        pub var __timeleft: f64 = 0.0;
+        pub var __interval: f64 = 0.0;
+    };
+    C.__interval -= dt;
+
+    if (C.__timeleft <= 0.0) {
+        S.func(capture);
+        while (C.__timeleft < 0)
+            C.__timeleft += interval;
+    }
+}
+
 test "comptime registration implementation" {}

engine/core/src/extern/externModule.zig

@@ -0,0 +1,64 @@
+// modules for managing loading dynamic libraries
+//
+// i want hot swapping
+//
+// 1. add a folder to the watch list
+
+pub const FileWatchEntry = struct {
+    path: []const u8,
+    stamp: i128 = 0,
+    cbCtx: ?*anyopaque,
+
+    loadCallback: *const fn (*@This(), ?*anyopaque) void,
+
+    // staging path is under .cache/modules/<module hash>/
+    pub fn copyToStaging(self: *@This()) !void {
+        const fileName = p2.
+        const dir = try std.fs.cwd().makePath();
+        std.fs.cwd().copyFile(self.path, dir, "", options: CopyFileOptions)
+    }
+
+    pub fn checkUpdateTime(self: *@This()) bool {
+        const stat = std.fs.cwd().statFile(self.path) catch false;
+        if (stat.mtime != self.stamp) {
+            self.stamp = stat.mtime;
+        }
+    }
+};
+
+pub const ModuleLoader = struct {
+    backingAllocator: std.mem.Allocator,
+    arena: std.heap.ArenaAllocator,
+    allocator: std.mem.Allocator = undefined,
+
+    files: std.ArrayListUnmanaged(FileWatchEntry) = .{},
+
+    pub fn create(allocator: std.mem.Allocator) !*@This() {
+        const self = try allocator.create(@This());
+
+        self.* = .{
+            .backingAllocator = allocator,
+            .arena = try std.heap.ArenaAllocator.init(allocator),
+        };
+
+        self.allocator = self.arena.allocator();
+
+        return self;
+    }
+
+    pub fn destroy(self: *@This()) void {
+        self.arena.deinit();
+        self.backingAllocator.destroy(self);
+    }
+
+    pub fn checkForFileUpdates(self: *@This()) void {
+        for (self.files.items) |*f| {
+            if (f.checkTime()) {
+                f.loadCallback(f.cbCtx);
+            }
+        }
+    }
+};
+
+const std = @import("std");
+const p2 = @import("p2");

engine/core/src/externObject.zig

@@ -0,0 +1,11 @@
+// script objects.
+
+pub const ObjectTable = extern struct {
+    create: *const fn (allocator: *anyopaque) callconv(.C) ?*anyopaque,
+    tick: *const fn (*anyopaque, f64) callconv(.C) void,
+    destroy: *const fn (p: *anyopaque) callconv(.C) ?*anyopaque,
+};
+
+// eg. in C
+//
+// object Struc

engine/core/src/gameObject.zig

@@ -0,0 +1 @@
+

engine/core/tests/tests.zig

@@ -25,7 +25,7 @@ test "simple systems setup for core" {
     try test_consoleCommands();
     try test_gameObjects(std.testing.allocator);
 
-    try generateRandomSamples();
+    // try generateRandomSamples();
 
     try memory.dumpTimeline("test-core-timeline.txt");
 }

extras/gameExtras/snippets.zig

@@ -0,0 +1,15 @@
+allocator: std.mem.allocator,
+
+pub fn create(allocator: std.mem.Allocator) !*@This() {
+    const self = try allocator.create(@This());
+
+    self.* = .{
+        .allocator = allocator,
+    };
+
+    return self;
+}
+
+const std = @import("std");
+const backlog = @import("Backlog");
+const core = backlog.core;

extras/gameExtras/src/ecsEventDebugger.zig

@@ -0,0 +1,17 @@
+allocator: std.mem.allocator,
+
+pub fn create(allocator: std.mem.Allocator) !*@This() {
+    const self = try allocator.create(@This());
+
+    self.* = .{
+        .allocator = allocator,
+    };
+
+    return self;
+}
+
+const std = @import("std");
+const backlog = @import("Backlog");
+const core = backlog.core;
+const rend = backlog.rend;
+const ig = backlog.imgui.api;

lib/cimgui/src/cimgui.zig

@@ -4627,6 +4627,11 @@ pub inline fn textFmt(comptime fmt: []const u8, args: anytype) !void {
     textUnformatted(@ptrCast(buffer.ptr), buffer.ptr + buffer.len);
 }
 
+pub inline fn textf(comptime f: []const u8, args: anytype) void {
+    const buffer = std.fmt.bufPrint(&textFmtBuffer, f, args) catch return;
+    textUnformatted(@ptrCast(buffer.ptr), buffer.ptr + buffer.len);
+}
+
 // pub inline fn textV(fmt: [*c]const u8, args: list) void { //igTextV
 //     c.igTextV(fmt, args);
 // }

lib/p2/src/p2.zig

@@ -73,6 +73,16 @@ pub const Span = spans.Span;
 
 pub const shell = @import("utils/shell.zig");
 
+pub fn sharedLibName(comptime s: []const u8) []const u8 {
+    const os_tag = @import("builtin").os.tag;
+    if (os_tag == .linux) {
+        return s ++ ".so";
+    } else if (os_tag == .macos) {
+        return s ++ ".dynlib";
+    } else {
+        return s ++ ".dll";
+    }
+}
 comptime {
     std.testing.refAllDecls(utils);
     std.testing.refAllDecls(static_structures);

lib/packer/build.zig

@@ -10,8 +10,13 @@ pub fn build(b: *std.Build) void {
         .target = target,
         .optimize = optimize,
         .root_source_file = b.path("src/packer.zig"),
+        .link_libc = true,
+        .link_libcpp = true,
     });
 
+    mod.addIncludePath(b.path("src/include"));
+    mod.addCSourceFile(.{ .file = b.path("src/watcher.cpp"), .flags = &.{} });
+
     const p2mod = p2dep.module("p2");
     mod.addImport("p2", p2mod);
 

lib/packer/src/packerfs.zig

@@ -53,6 +53,16 @@ pub const Settings = struct {
     contentFolderExtraPaths: []const []const u8 = &[_][]const u8{}, // By default, this will mount the content/ folder on disk.
 };
 
+pub const WatchCallback = struct {
+    func: *const fn ([]const u8, ?*anyopaque) void,
+    ctx: ?*anyopaque = null,
+    path: []const u8,
+
+    pub inline fn call(self: *@This(), path: []const u8) void {
+        self.func(path, self.ctx);
+    }
+};
+
 pub const PackerFS = struct {
     allocator: std.mem.Allocator,
     fileHeaders: std.ArrayListUnmanaged(PackedFileEntry) = .{},
@@ -67,6 +77,8 @@ pub const PackerFS = struct {
 
     lock: std.Thread.Mutex = .{},
 
+    fileWatchCallbacks: std.ArrayListUnmanaged(WatchCallback) = .{},
+
     pub const PakMounting = struct {
         filePath: []const u8, // path to the file
         bytes: []align(8) u8 = undefined,
@@ -114,6 +126,48 @@ pub const PackerFS = struct {
         }
     };
 
+    pub fn addFileChangedCallback(
+        self: *@This(),
+        path: []const u8,
+        cb: *const fn ([]const u8, ?*anyopaque) void,
+        ctx: ?*anyopaque,
+    ) !void {
+        const x = WatchCallback{
+            .func = cb,
+            .ctx = ctx,
+            .path = path,
+        };
+
+        try self.fileWatchCallbacks.append(self.allocator, x);
+    }
+
+    pub fn watchCallback(path: [*c]const u8, ctx: ?*anyopaque) callconv(.C) void {
+        const self: *@This() = @ptrCast(@alignCast(ctx));
+        // std.debug.print("WE GOT OURSELFS A FUCKIN CALLBAKC FOR A PATH MOTHERF- {s} {p} {d}\n", .{ path, ctx.?, self.pakMountings.items.len });
+
+        for (self.fileWatchCallbacks.items) |*watch| {
+            // std.debug.print("checking {s} {s}\n", .{ watch.path, path });
+            if (std.mem.eql(u8, watch.path, std.mem.span(path))) {
+                watch.call(std.mem.span(path));
+            }
+            // std.debug.print("registered callback: {s}\n", .{watch.path});
+        }
+    }
+
+    pub fn watchPath(self: *@This(), path: []const u8) void {
+        // std.debug.print("self = {x}\n", .{@intFromPtr(self)});
+        const p = self.stringArena.allocator().dupeZ(u8, path) catch return;
+        const watch = watcher.createWatchPoint(
+            p,
+            watchCallback,
+            self,
+        ) orelse {
+            std.debug.print("Unable to create watch point, {s}\n", .{p});
+            return;
+        };
+        _ = watch;
+    }
+
     // todo: implement load memory to file then-map setup.
     // for systems which do not support mmap
 
@@ -164,6 +218,26 @@ pub const PackerFS = struct {
         return @intCast(self.fileHeaders.items.len);
     }
 
+    pub fn resolveContentFile(self: *@This(), allocator: std.mem.Allocator, path: []const u8) !?[]u8 {
+        for (self.contentPaths.items) |contentPath| {
+            // std.debug.print("{s}\n", .{contentPath});
+            const fullPath = try std.fmt.allocPrint(self.stringArena.allocator(), "{s}/{s}", .{ contentPath, path });
+            defer self.stringArena.allocator().free(fullPath);
+
+            var exists: bool = true;
+
+            std.fs.cwd().access(fullPath, .{}) catch |err| {
+                exists = if (err == error.FileNotFound) false else true;
+            };
+
+            if (exists) {
+                return try allocator.dupe(u8, fullPath);
+            }
+        }
+
+        return null;
+    }
+
     pub fn fileExists(self: *@This(), path: []const u8) bool {
         self.lock.lock();
         defer self.lock.unlock();
@@ -231,6 +305,7 @@ pub const PackerFS = struct {
         return self.stringArena.allocator();
     }
 
+    // if skipLoading is set bytes will contain an empty path
     fn loadFileDirect(self: *@This(), basePath: []const u8, path: []const u8) !?PackerBytesMapping {
         // if we made it to this function we can assume that the file does not exist in existing pak mounting references.
         // nor does it exist in self.fileHandlesByName
@@ -347,6 +422,7 @@ pub const PackerFS = struct {
         self.contentPaths.deinit(self.allocator);
         self.stringArena.deinit();
         self.lock.unlock();
+        self.fileWatchCallbacks.deinit(self.allocator);
         self.allocator.destroy(self);
     }
 
@@ -414,3 +490,5 @@ pub const PackerFS = struct {
         return .{ .allocator = allocator, .data = rv, .sources = sourcePath };
     }
 };
+
+const watcher = @import("watcher.zig");

lib/packer/src/watcher.cpp

@@ -0,0 +1,17 @@
+#include <FileWatch.hpp>
+
+extern "C" void* createWatchPoint(
+    const char* watchPath,
+    void(*cb)(const char*, void*),
+    void* ctx
+){
+    auto* watch = new filewatch::FileWatch<std::string>(
+        watchPath,
+        [cb, ctx] (const std::string& path, const filewatch::Event change_type) {
+            std::cout <<  event_to_string(change_type) << std::endl;
+            cb(path.c_str(), ctx);
+        }
+    );
+
+    return watch;
+}

lib/packer/src/watcher.zig

@@ -0,0 +1,7 @@
+pub const CallbackType = *const fn ([*c]const u8, ?*anyopaque) callconv(.C) void;
+
+pub extern fn createWatchPoint(
+    [*c]const u8,
+    CallbackType,
+    ?*anyopaque,
+) callconv(.C) ?*anyopaque;

lib/packer/tests/test.zig

@@ -116,3 +116,27 @@ test "packerfs_test" {
 
     std.debug.print("littleEndian {any}", .{packer.littleEndian});
 }
+
+fn fileChangedCb(pathChanged: []const u8, ctx: ?*anyopaque) void {
+    _ = ctx;
+    std.debug.print("pathChanged {s}\n", .{pathChanged});
+}
+
+test "packer file watch" {
+    var fs = try PackerFS.init(std.testing.allocator, .{});
+    defer fs.destroy();
+    std.fs.cwd().deleteFile("test_output/test2.txt") catch {};
+    try fs.addContentPath("test_output");
+
+    fs.watchPath("test_output");
+    try fs.addFileChangedCallback("test2.txt", fileChangedCb, null);
+
+    var file = try std.fs.cwd().createFile("test_output/test2.txt", .{});
+    std.time.sleep(100000000);
+
+    std.debug.print("writing to file\n", .{});
+    // var file = try std.fs.cwd().openFile("test_output/test2.txt", .{ .mode = .read_write });
+    try file.writeAll("what the fuck bro");
+    std.time.sleep(400000000);
+    // std.time.sleep(5000000000);
+}

projects/build.zig

@@ -21,4 +21,17 @@ pub fn build(b: *std.Build) void {
     blbuild.addExtraModule(sampleGame, "videoplayer");
     blbuild.addExtraModule(sampleGame, "doomplayer");
     blbuild.addExtraModule(sampleGame, "bsp");
+
+    const sampleGameExtern = b.addSharedLibrary(.{
+        .root_source_file = b.path("sampleGame/externGame/externGame.zig"),
+        .link_libc = true,
+        .optimize = optimize,
+        .target = target,
+        .name = "externGame",
+    });
+
+    const installExtern = b.addInstallArtifact(sampleGameExtern, .{
+        .dest_dir = .{ .override = .{ .custom = "modules" } },
+    });
+    b.getInstallStep().dependOn(&installExtern.step);
 }

projects/sampleGame/externGame/externGame.zig

@@ -0,0 +1,5 @@
+pub export fn add(a: i32, b: i32) i32 {
+    return a + b + 32000;
+}
+
+const std = @import("std");

projects/sampleGame/main.zig

@@ -28,7 +28,9 @@ rendererDebugger: *extras.RendererDebug = undefined,
 
 tbMap: ?*bsp.maploader.TBMap = null,
 
-fileWatch: f64 = 3.0,
+addFunc: ?*const fn (i32, i32) callconv(.C) i32 = undefined,
+
+modules: std.AutoHashMapUnmanaged(u32, []const u8) = .{},
 
 pub var NeonObjectTable: core.EngineObjectVTable = core.EngineObjectVTable.from(@This());
 
@@ -172,6 +174,14 @@ pub fn loadMap(self: *@This()) void {
     core.engine_log("map loaded", .{});
 }
 
+fn moduleChangedCallback(pathChanged: []const u8, ctx: ?*anyopaque) void {
+    const self: *@This() = @ptrCast(@alignCast(ctx));
+
+    core.engine_log("moduleChanged {s}", .{pathChanged});
+    var name = core.MakeName(pathChanged);
+    self.modules.put(self.allocator, name.handle(), name.utf8()) catch {};
+}
+
 pub fn prepare(self: *@This()) !void {
     core.engine_log(">>>>>>> game prepare", .{});
     var z = core.tracy.ZoneN(@src(), "PREPARING GAME");
@@ -180,6 +190,11 @@ pub fn prepare(self: *@This()) !void {
     try script.loadTypes("scripts");
     try script.runScriptFile("scripts/prepare.lua");
 
+    core.fs().watchPath("zig-out/modules");
+    try core.fs().addFileChangedCallback(core.sharedLibName("externGame"), moduleChangedCallback, self);
+
+    try self.tryLoadExtern("externGame");
+
     self.rendererDebugger = try extras.RendererDebug.create(self.allocator); //try core.createObject(extras.RendererDebug, .{});
 
     self.objectSpawner = try extras.ObjectSpawner.create(self.allocator);
@@ -361,17 +376,39 @@ pub fn getMouseMovement(self: *@This()) core.Vector2f {
     return rv;
 }
 
+pub fn tryLoadExtern(self: *@This(), gameName: []const u8) !void {
+    var buf = std.mem.zeroes([256]u8);
+
+    const os_tag = @import("builtin").os.tag;
+
+    var suffix: []const u8 = "dll";
+    if (os_tag == .linux) {
+        suffix = "so";
+    } else if (os_tag == .macos) {
+        suffix = "dynlib";
+    }
+
+    const path = try std.fmt.bufPrint(&buf, "zig-out/bin/{s}.{s}", .{ gameName, suffix });
+    var lib = try std.DynLib.open(path);
+    // std.debug.print("path: {s}", .{path});
+
+    self.addFunc = lib.lookup(@TypeOf(self.addFunc.?), "add");
+}
+
 pub fn tick(self: *@This(), dt: f64) void {
     const fdt: f32 = @floatCast(dt);
 
     _ = ig.dockSpaceOverViewport(ig.getMainViewport(), .{ .passthru_central_node = true }, null);
 
-    self.loadMap2() catch unreachable;
+    // self.loadMap2() catch unreachable;
 
-    self.fileWatch -= dt;
-    if (self.fileWatch < 0) {
-        self.fileWatch = 3.0;
-    }
+    core.loopDelay(@src(), 1.0, dt, struct {
+        s: @TypeOf(self),
+
+        pub fn func(c: @This()) void {
+            c.s.tryLoadExtern("externGame") catch unreachable;
+        }
+    }, .{ .s = self });
 
     const z1 = tracy.ZoneN(@src(), "inputDebugger");
     if (!self.mouseLook) {
@@ -441,6 +478,15 @@ pub fn tick(self: *@This(), dt: f64) void {
             ig.textFmt("- f2 to route all inputs to the doom player", .{}) catch return;
             ig.textFmt("- movingLight checkbox makes the light stop moving with you", .{}) catch return;
 
+            ig.textf("1 + 2 = {d}", .{self.addFunc.?(1, 2)});
+
+            {
+                ig.textf("modules dirty: ", .{});
+                var i = self.modules.iterator();
+                while (i.next()) |n| {
+                    ig.textf("{s} pending reload", .{n.value_ptr.*});
+                }
+            }
             if (ig.smallButton("reload map")) {
                 self.loadMap2() catch unreachable;
             }
@@ -472,6 +518,7 @@ pub fn tick(self: *@This(), dt: f64) void {
 }
 
 pub fn deinit(self: *@This()) void {
+    self.modules.deinit(self.allocator);
     self.rendererDebugger.destroy();
     DoomPlayer.DoomCanvas.cleanupDoom();
     self.fpcamera.destroy();