example: core-transparent-window now animates the window color and transparency

examples/core-transparent-window/App.zig

@@ -16,6 +16,9 @@ pub const main = mach.schedule(.{
 
 window: mach.ObjectID,
 title_timer: mach.time.Timer,
+color_timer: mach.time.Timer,
+color_time: f32 = 0.0,
+flip: bool = false,
 pipeline: *gpu.RenderPipeline,
 
 pub fn init(
@@ -34,6 +37,7 @@ pub fn init(
     app.* = .{
         .window = window,
         .title_timer = try mach.time.Timer.start(),
+        .color_timer = try mach.time.Timer.start(),
         .pipeline = undefined,
     };
 }
@@ -48,16 +52,6 @@ fn setupPipeline(core: *mach.Core, app: *App, window_id: mach.ObjectID) !void {
 
     // Blend state describes how rendered colors get blended
     var blend = gpu.BlendState{};
-    blend.alpha = .{
-        .dst_factor = .one_minus_src_alpha,
-        .src_factor = .one,
-        .operation = .add,
-    };
-    blend.color = .{
-        .dst_factor = .one_minus_src_alpha,
-        .src_factor = .src_alpha,
-        .operation = .add,
-    };
 
     // Color target describes e.g. the pixel format of the window we are rendering to.
     const color_target = gpu.ColorTargetState{
@@ -116,7 +110,7 @@ pub fn tick(app: *App, core: *mach.Core) void {
         }
     }
 
-    const window = core.windows.getValue(app.window);
+    var window = core.windows.getValue(app.window);
 
     // Grab the back buffer of the swapchain
     // TODO(Core)
@@ -130,7 +124,7 @@ pub fn tick(app: *App, core: *mach.Core) void {
     defer encoder.release();
 
     // Begin render pass
-    const sky_blue_background = gpu.Color{ .r = 0.776, .g = 0.988, .b = 1.0, .a = 0.0 };
+    const sky_blue_background = gpu.Color{ .r = 0.0, .g = 0.0, .b = 0.0, .a = 0.0 };
     const color_attachments = [_]gpu.RenderPassColorAttachment{.{
         .view = back_buffer_view,
         .clear_value = sky_blue_background,
@@ -155,28 +149,32 @@ pub fn tick(app: *App, core: *mach.Core) void {
     defer command.release();
     window.queue.submit(&[_]*gpu.CommandBuffer{command});
 
-    // update the window title every second
+    if (app.title_timer.read() >= 1.0) {
-    // if (app.title_timer.read() >= 1.0) {
+        app.title_timer.reset();
-    //     app.title_timer.reset();
+        // TODO(object): window-title
-    //     // TODO(object): window-title
+
-    //     // try updateWindowTitle(core);
+        // try updateWindowTitle(core);
-    // }
+    }
+
+    if (app.color_time >= 4.0 or app.color_time <= 0.0) {
+        app.color_time = @trunc(app.color_time);
+        app.flip = !app.flip;
+    }
+
+    if (!app.flip) {
+        app.color_time -= app.color_timer.lap();
+    } else {
+        app.color_time += app.color_timer.lap();
+    }
+
+    const red = mach.math.lerp(0.1, 0.6, mach.math.clamp(app.color_time, 0.0, 1.0));
+    const blue = mach.math.lerp(0.2, 0.6, mach.math.clamp(app.color_time - 1.0, 0.0, 1.0));
+    const green = mach.math.lerp(0.2, 0.6, mach.math.clamp(app.color_time - 2.0, 0.0, 1.0));
+    const alpha = mach.math.lerp(0.3, 1.0, app.color_time / 4.0);
+
+    core.windows.set(app.window, .color, .{ .transparent = .{ .color = .{ .r = red, .g = green, .b = blue, .a = alpha }, .titlebar = true } });
 }
 
 pub fn deinit(app: *App) void {
     app.pipeline.release();
 }
-
-// TODO(object): window-title
-// fn updateWindowTitle(core: *mach.Core) !void {
-//     try core.printTitle(
-//         core.main_window,
-//         "core-custom-entrypoint [ {d}fps ] [ Input {d}hz ]",
-//         .{
-//             // TODO(Core)
-//             core.frameRate(),
-//             core.inputRate(),
-//         },
-//     );
-//     core.schedule(.update);
-// }

src/Core.zig

@@ -74,6 +74,9 @@ windows: mach.Objects(
         /// Target frames per second
         refresh_rate: u32 = 0,
 
+        /// Color of the window background/titlebar
+        color: WindowColor = .system,
+
         // GPU
         // When `native` is not null, the rest of the fields have been
         // initialized.
@@ -657,6 +660,20 @@ pub const InputState = struct {
     }
 };
 
+pub const WindowColor = union(enum) {
+    system: void, // Default window colors
+    transparent: struct {
+        color: gpu.Color,
+        // If true, and the OS supports it, the titlebar will also be set to color
+        titlebar: bool = false,
+    },
+    solid: struct {
+        color: gpu.Color,
+        // If titlebar is true, and the OS supports it, the titlebar will also be set to color
+        titlebar: bool = false,
+    },
+};
+
 pub const Event = union(enum) {
     key_press: KeyEvent,
     key_repeat: KeyEvent,
@@ -957,39 +974,6 @@ const RequestAdapterResponse = struct {
     message: ?[*:0]const u8,
 };
 
-// Verifies that a platform implementation exposes the expected function declarations.
-// comptime {
-//     // Core
-//     assertHasField(Platform, "surface_descriptor");
-//     assertHasField(Platform, "refresh_rate");
-
-//     assertHasDecl(Platform, "init");
-//     assertHasDecl(Platform, "deinit");
-
-//     assertHasDecl(Platform, "setTitle");
-
-//     assertHasDecl(Platform, "setDisplayMode");
-//     assertHasField(Platform, "display_mode");
-
-//     assertHasDecl(Platform, "setBorder");
-//     assertHasField(Platform, "border");
-
-//     assertHasDecl(Platform, "setHeadless");
-//     assertHasField(Platform, "headless");
-
-//     assertHasDecl(Platform, "setVSync");
-//     assertHasField(Platform, "vsync_mode");
-
-//     assertHasDecl(Platform, "setSize");
-//     assertHasField(Platform, "size");
-
-//     assertHasDecl(Platform, "setCursorMode");
-//     assertHasField(Platform, "cursor_mode");
-
-//     assertHasDecl(Platform, "setCursorShape");
-//     assertHasField(Platform, "cursor_shape");
-// }
-
 fn assertHasDecl(comptime T: anytype, comptime decl_name: []const u8) void {
     if (!@hasDecl(T, decl_name)) @compileError(@typeName(T) ++ " missing declaration: " ++ decl_name);
 }

src/core/Darwin.zig

@@ -70,6 +70,34 @@ pub fn tick(core: *Core) !void {
         if (core_window.native) |native| {
             const native_window: *objc.app_kit.Window = native.window;
 
+            if (core.windows.updated(window_id, .color)) {
+                switch (core_window.color) {
+                    .transparent => |wc| {
+                        const color = objc.app_kit.Color.colorWithRed_green_blue_alpha(
+                            wc.color.r,
+                            wc.color.g,
+                            wc.color.b,
+                            wc.color.a,
+                        );
+                        native_window.setBackgroundColor(color);
+                        native_window.setTitlebarAppearsTransparent(true);
+                    },
+                    .solid => |wc| {
+                        const color = objc.app_kit.Color.colorWithRed_green_blue_alpha(
+                            wc.color.r,
+                            wc.color.g,
+                            wc.color.b,
+                            wc.color.a,
+                        );
+                        native_window.setBackgroundColor(color);
+                        native_window.setTitlebarAppearsTransparent(false);
+                    },
+                    .system => {
+                        native_window.setTitlebarAppearsTransparent(false);
+                    },
+                }
+            }
+
             if (core.windows.updated(window_id, .title)) {
                 const string = objc.foundation.String.allocInit();
                 defer string.release();
@@ -123,6 +151,7 @@ fn initWindow(
         (if (core_window.display_mode == .windowed) objc.app_kit.WindowStyleMaskClosable else 0) |
         (if (core_window.display_mode == .windowed) objc.app_kit.WindowStyleMaskMiniaturizable else 0) |
         (if (core_window.display_mode == .windowed) objc.app_kit.WindowStyleMaskResizable else 0);
+    // (if (core_window.display_mode == .windowed) objc.app_kit.WindowStyleMaskFullSizeContentView else 0);
 
     const native_window_opt: ?*objc.app_kit.Window = objc.app_kit.Window.alloc().initWithContentRect_styleMask_backing_defer_screen(
         rect,
@@ -163,9 +192,28 @@ fn initWindow(
         native_window.setIsVisible(true);
         native_window.makeKeyAndOrderFront(null);
 
-        const color = objc.app_kit.Color.colorWithRed_green_blue_alpha(0.5, 0.5, 0.5, 0.5);
+        switch (core_window.color) {
-        native_window.setBackgroundColor(color);
+            .transparent => |wc| {
-        native_window.setTitlebarAppearsTransparent(true);
+                const color = objc.app_kit.Color.colorWithRed_green_blue_alpha(
+                    wc.color.r,
+                    wc.color.g,
+                    wc.color.b,
+                    wc.color.a,
+                );
+                native_window.setBackgroundColor(color);
+                native_window.setTitlebarAppearsTransparent(true);
+            },
+            .solid => |wc| {
+                const color = objc.app_kit.Color.colorWithRed_green_blue_alpha(
+                    wc.color.r,
+                    wc.color.g,
+                    wc.color.b,
+                    wc.color.a,
+                );
+                native_window.setBackgroundColor(color);
+            },
+            .system => {},
+        }
 
         const string = objc.foundation.String.allocInit();
         defer string.release();