runtime hooks

src/App.zig

@@ -9,9 +9,13 @@ pub fn init(alloc: std.mem.Allocator) !void {
     _ = alloc;
 }
 
+pub fn connect() !void {
+    try ImGui.hooks.frame.register(nu_imgui_frame);
+}
+
 pub fn deinit() void {}
 
-pub fn nu_frame() void {}
+// pub fn nu_frame() void {}
 
 // pub fn nu_events(events: []const Bus.Event) void {
 //     std.debug.print("{any}\n", .{events});

src/main.zig

@@ -33,17 +33,20 @@ pub fn main() !void {
     defer _ = gpa.detectLeaks();
     const alloc = gpa.allocator();
 
+    nu.init(alloc);
+    defer nu.deinit();
+
     try nu.Window.init(alloc);
     defer nu.Window.deinit();
 
     try nu.Render.init(alloc);
     defer nu.Render.deinit();
 
-    try nu.ImGui.init();
+    try nu.ImGui.init(alloc);
     defer nu.ImGui.deinit();
 
     try App.init(alloc);
     defer App.deinit();
 
-    try nu.run();
+    try nu.run(alloc);
 }

src/nu.zig

@@ -5,6 +5,9 @@ pub const Window = @import("nu/Window.zig");
 pub const Render = @import("nu/Render.zig");
 pub const ImGui = @import("nu/ImGui.zig");
 
+pub const Bus = @import("nu/Bus.zig");
+pub const Hook = @import("nu/hooks.zig").Hook;
+
 pub const Options = struct {
     window: Window.Options = .{},
     render: Render.Options = .{},
@@ -15,44 +18,81 @@ pub const options: Options = if (@hasDecl(root, "nu_options")) root.nu_options e
 pub const modules = root.nu_modules;
 pub const driver = root.nu_driver;
 
-pub fn run() !void {
-    try invoke_hook("nu_enter", .{});
+pub const Hooks = struct {
+    pub const Enter = Hook(fn () void);
+    pub const Events = Hook(fn ([]Bus.Event) void);
+    pub const Frame = Hook(fn () anyerror!void);
+    pub const Close = Hook(fn () void);
+
+    enter: Enter,
+    events: Events,
+    frame: Frame,
+    close: Close,
+};
+
+pub var hooks: Hooks = undefined;
+
+pub fn init(alloc: std.mem.Allocator) void {
+    hooks = .{
+        .enter = Hooks.Enter.init(alloc),
+        .events = Hooks.Events.init(alloc),
+        .frame = Hooks.Frame.init(alloc),
+        .close = Hooks.Close.init(alloc),
+    };
+}
+
+pub fn deinit() void {
+    hooks.enter.deinit();
+    hooks.events.deinit();
+    hooks.frame.deinit();
+    hooks.close.deinit();
+}
+
+pub fn run(alloc: std.mem.Allocator) !void {
+    // todo hooks should execute in priority order; then hook.register accepts a "priority" argument.
+    inline for (modules) |module| {
+        try module.connect();
+    }
+
+    hooks.enter.invoke(.{});
 
     while (driver.next()) |events| {
         if (events.len > 0) {
-            try invoke_hook("nu_events", .{events});
+            hooks.events.invoke(.{events});
         }
 
         // todo frame timer
-        try invoke_hook("nu_frame", .{});
+        const frame_results = try hooks.frame.invoke(alloc, .{});
+        defer alloc.free(frame_results);
+        for (frame_results) |result| result catch |err| return err;
 
         // todo fixed timestep
     }
 
-    try invoke_hook("nu_close", .{});
+    hooks.close.invoke(.{});
 }
 
-// todo specify hook type.
-//  - special handling for error unions
-//  - allow per-hook state somehow declared in the handler
-
-pub fn invoke_hook(comptime name: []const u8, args: anytype) !void {
-    inline for (modules) |module| {
-        if (@hasDecl(module, name)) {
-            try invoke(@field(module, name), args);
-        }
-    }
-}
-
-fn invoke(func: anytype, args: anytype) !void {
-    if (@typeInfo(@TypeOf(func)).Fn.return_type) |R| {
-        switch (@typeInfo(R)) {
-            .ErrorUnion => try @call(.auto, func, args),
-            .Void => @call(.auto, func, args),
-            else => {
-                @compileLog(func, @typeInfo(R));
-                @compileError("Invalid hook return type. Must be void or !void.");
-            },
-        }
-    }
-}
+// // todo specify hook type.
+// //  - special handling for error unions
+// //  - allow per-hook state somehow declared in the handler
+//
+// pub fn invoke_hook(comptime name: []const u8, args: anytype) !void {
+//     inline for (modules) |module| {
+//         if (@hasDecl(module, name)) {
+//             try invoke(@field(module, name), args);
+//         }
+//     }
+// }
+//
+// fn invoke(func: anytype, args: anytype) !void {
+//     if (@typeInfo(@TypeOf(func)).Fn.return_type) |R| {
+//         switch (@typeInfo(R)) {
+//             .ErrorUnion => try @call(.auto, func, args),
+//             .Void => @call(.auto, func, args),
+//             else => {
+//                 @compileLog(func, @typeInfo(R));
+//                 @compileError("Invalid hook return type. Must be void or !void.");
+//             },
+//         }
+//     }
+// }

src/nu/ImGui.zig

@@ -6,6 +6,7 @@ const vk = @import("vk");
 const nu = @import("../nu.zig");
 const au = @import("Render/au.zig");
 
+const Hook = @import("hooks.zig").Hook;
 const Render = @import("Render.zig");
 const Window = @import("Window.zig");
 
@@ -14,6 +15,11 @@ pub usingnamespace im;
 
 pub const Options = struct {};
 
+pub const Hooks = struct {
+    pub const Frame = Hook(fn () void);
+    frame: Frame,
+};
+
 pub fn loader_wrapper(procname: [*c]const u8, _: ?*anyopaque) callconv(.C) vk.PfnVoidFunction {
     return au.glfwGetInstanceProcAddress(au.I.handle, procname);
 }
@@ -21,7 +27,9 @@ pub fn loader_wrapper(procname: [*c]const u8, _: ?*anyopaque) callconv(.C) vk.Pf
 var ctx: *im.ImGuiContext = undefined;
 var descriptor_pool: vk.DescriptorPool = undefined;
 
-pub fn init() !void {
+pub var hooks: Hooks = undefined;
+
+pub fn init(alloc: std.mem.Allocator) !void {
     ctx = im.igCreateContext(null) orelse {
         return error.igCreateContextFailed;
     };
@@ -77,6 +85,24 @@ pub fn init() !void {
     if (!im.impl.ImGui_ImplVulkan_CreateFontsTexture()) {
         return error.igVulkanFontTextureFailed;
     }
+
+    hooks = .{
+        .frame = Hooks.Frame.init(alloc),
+    };
+    errdefer hooks.frame.deinit();
+}
+
+pub fn deinit() void {
+    hooks.frame.deinit();
+    im.impl.ImGui_ImplVulkan_Shutdown();
+    au.D.destroyDescriptorPool(descriptor_pool, null);
+    im.impl.ImGui_ImplGlfw_Shutdown();
+    im.igDestroyContext(ctx);
+}
+
+pub fn connect() !void {
+    try nu.hooks.frame.register(nu_frame);
+    try Render.hooks.present.register(nu_render_present);
 }
 
 pub fn nu_frame() !void {
@@ -84,7 +110,7 @@ pub fn nu_frame() !void {
     im.impl.ImGui_ImplVulkan_NewFrame();
     im.igNewFrame();
 
-    try nu.invoke_hook("nu_imgui_frame", .{});
+    hooks.frame.invoke(.{});
 
     im.igEndFrame();
     im.igRender();
@@ -97,10 +123,3 @@ pub fn nu_render_present(cmd: au.CommandBufferProxy) void {
         null,
     );
 }
-
-pub fn deinit() void {
-    im.impl.ImGui_ImplVulkan_Shutdown();
-    au.D.destroyDescriptorPool(descriptor_pool, null);
-    im.impl.ImGui_ImplGlfw_Shutdown();
-    im.igDestroyContext(ctx);
-}

src/nu/Render.zig

@@ -9,6 +9,8 @@ const vk = @import("vk");
 const nu = @import("../nu.zig");
 const au = @import("Render/au.zig");
 
+const Hook = @import("hooks.zig").Hook;
+
 pub const Options = struct {
     app_name: [*:0]const u8 = "nu-au-app",
     app_version: struct {
@@ -27,6 +29,14 @@ pub const Options = struct {
     frames_in_flight: u8 = 3,
 };
 
+pub const Hooks = struct {
+    pub const Present = Hook(fn (au.CommandBufferProxy) void);
+
+    present: Present,
+};
+
+pub var hooks: Hooks = undefined;
+
 var sc: au.SwapChain = undefined;
 var flights: au.Flights = undefined;
 
@@ -40,6 +50,21 @@ pub fn init(alloc: std.mem.Allocator) !void {
 
     flights = try au.Flights.init(alloc, nu.options.render.frames_in_flight);
     errdefer flights.deinit();
+
+    hooks = .{ .present = Hooks.Present.init(alloc) };
+    errdefer hooks.present.deinit();
+}
+
+pub fn deinit() void {
+    hooks.present.deinit();
+    flights.deinit();
+    sc.deinit();
+    au.deinit();
+}
+
+pub fn connect() !void {
+    try nu.hooks.frame.register(nu_frame);
+    try nu.hooks.close.register(nu_close);
 }
 
 pub fn nu_frame() !void {
@@ -70,7 +95,7 @@ pub fn nu_frame() !void {
 
         // todo manage frame in flight state for each hook; pass the current flight in as context.
         // will need some comptime -> anytype mapping.
-        try nu.invoke_hook("nu_render_present", .{cmd});
+        hooks.present.invoke(.{cmd});
 
         target.end_rendering(cmd);
         try cmd.endCommandBuffer();
@@ -102,12 +127,8 @@ pub fn nu_frame() !void {
     }
 }
 
-pub fn nu_close() !void {
-    try au.D.deviceWaitIdle();
-}
-
-pub fn deinit() void {
-    flights.deinit();
-    sc.deinit();
-    au.deinit();
+pub fn nu_close() void {
+    au.D.deviceWaitIdle() catch |err| {
+        std.debug.panic("Device wait failed: {!}", .{err});
+    };
 }

src/nu/Window.zig

@@ -21,7 +21,7 @@ pub const Options = struct {
     x11_instance_name: [*:0]const u8 = "floating_window",
 };
 
-var bus: Bus = undefined;
+var bus: Bus = undefined; // todo bus should probably move to engine.
 pub var handle: *c.GLFWwindow = undefined;
 var unfocused_rate: f32 = 1.0 / 20.0;