init: zig wayland hello world client

Adapted the example from chapters 7 and 8 of the Wayland book
(https://wayland-book.com/) into Zig.

1 files changed, 200 insertions, 0 deletions

diff --git a/src/main.zig b/src/main.zig
new file mode 100644
index 0000000..5f83b8e
--- /dev/null
+++ b/src/main.zig
@@ -0,0 +1,200 @@
+const std = @import("std");
+const mem = std.mem;
+const posix = std.posix;
+
+const wayland = @import("wayland");
+const wl = wayland.client.wl;
+const xdg = wayland.client.xdg;
+
+const RegistryContext = struct {
+    shm: ?*wl.Shm,
+    compositor: ?*wl.Compositor,
+    wm_base: ?*xdg.WmBase,
+};
+
+const Window = struct {
+    shm: *wl.Shm,
+    wl_surface: *wl.Surface,
+    width: i32,
+    height: i32,
+    offset: f32,
+    last_frame: u32,
+    run: bool,
+
+    pub fn drawFrame(state: *Window) !*wl.Buffer {
+        const stride = state.width * 4;
+        const size = stride * state.height;
+
+        const fd = try posix.memfd_create("zigway", 0);
+        defer posix.close(fd);
+        try posix.ftruncate(fd, @intCast(size));
+        var data = try posix.mmap(
+            null,
+            @intCast(size),
+            posix.PROT.READ | posix.PROT.WRITE,
+            .{ .TYPE = .SHARED },
+            fd,
+            0,
+        );
+        defer posix.munmap(data);
+
+        const pool = try state.shm.createPool(fd, size);
+        defer pool.destroy();
+        const buffer = try pool.createBuffer(0, state.width, state.height, stride, .argb8888);
+
+        const canvas: *[]u32 = @ptrCast(&data);
+        const box_side = 12;
+        var offset: u32 = @intFromFloat(state.offset);
+        offset = @rem(offset, box_side);
+        const height: u32 = @intCast(state.height);
+        const width: u32 = @intCast(state.width);
+        for (0..height) |y| {
+            for (0..width) |x| {
+                if ((x + offset + (y + offset) / box_side * box_side) % (box_side * 2) < box_side) {
+                    canvas.*[y * width + x] = 0xFF0E0E0E;
+                } else {
+                    canvas.*[y * width + x] = 0xFF2F2F2F;
+                }
+            }
+        }
+
+        buffer.setListener(?*void, bufferListener, null);
+        return buffer;
+    }
+};
+
+pub fn main() !void {
+    const display = try wl.Display.connect(null);
+    defer display.disconnect();
+    const registry = try display.getRegistry();
+
+    var ctx = RegistryContext{
+        .shm = null,
+        .compositor = null,
+        .wm_base = null,
+    };
+
+    registry.setListener(*RegistryContext, registryListener, &ctx);
+    if (display.roundtrip() != .SUCCESS) return error.RoundTripFailed;
+
+    const compositor = ctx.compositor orelse return error.NoWlCompositor;
+    const wm_base = ctx.wm_base orelse return error.NoXdgWmBase;
+
+    var state = Window{
+        .shm = ctx.shm orelse return error.NoWlShm,
+        .wl_surface = try compositor.createSurface(),
+        .width = 480,
+        .height = 360,
+        .offset = 0.0,
+        .last_frame = 0,
+        .run = true,
+    };
+    defer state.wl_surface.destroy();
+
+    const xdg_surface = try wm_base.getXdgSurface(state.wl_surface);
+    defer xdg_surface.destroy();
+    const xdg_toplevel = try xdg_surface.getToplevel();
+    defer xdg_toplevel.destroy();
+
+    xdg_surface.setListener(*Window, xdgSurfaceListener, &state);
+    xdg_toplevel.setListener(*Window, xdgToplevelListener, &state);
+    wm_base.setListener(?*void, xdgWmBaseListener, null);
+
+    xdg_toplevel.setTitle("Hello, wayland!");
+
+    state.wl_surface.commit();
+
+    const wl_cb = try state.wl_surface.frame();
+    wl_cb.setListener(*Window, frameListener, &state);
+
+    while (state.run) {
+        if (display.dispatch() != .SUCCESS) return error.DispatchFailed;
+    }
+}
+
+fn registryListener(registry: *wl.Registry, event: wl.Registry.Event, ctx: *RegistryContext) void {
+    switch (event) {
+        .global => |global| {
+            std.debug.print("inteface: {s}, version {}, name {}\n", .{
+                global.interface,
+                global.version,
+                global.name,
+            });
+            if (mem.orderZ(u8, global.interface, wl.Compositor.getInterface().name) == .eq) {
+                ctx.compositor = registry.bind(global.name, wl.Compositor, 6) catch return;
+            } else if (mem.orderZ(u8, global.interface, wl.Shm.getInterface().name) == .eq) {
+                ctx.shm = registry.bind(global.name, wl.Shm, 1) catch return;
+            } else if (mem.orderZ(u8, global.interface, xdg.WmBase.getInterface().name) == .eq) {
+                ctx.wm_base = registry.bind(global.name, xdg.WmBase, 2) catch return;
+            }
+        },
+        .global_remove => {},
+    }
+}
+
+fn xdgSurfaceListener(xdg_surface: *xdg.Surface, event: xdg.Surface.Event, state: *Window) void {
+    switch (event) {
+        .configure => |configure| {
+            xdg_surface.ackConfigure(configure.serial);
+            brk: {
+                const buffer = state.drawFrame() catch |err| {
+                    std.debug.print("error drawing frame {}\n", .{err});
+                    break :brk;
+                };
+                state.wl_surface.attach(buffer, 0, 0);
+            }
+            state.wl_surface.commit();
+        },
+    }
+}
+
+fn xdgToplevelListener(_: *xdg.Toplevel, event: xdg.Toplevel.Event, state: *Window) void {
+    switch (event) {
+        .configure => |configure| {
+            state.height = if (configure.height != 0) configure.height else state.height;
+            state.width = if (configure.width != 0) configure.width else state.width;
+        },
+        .close => state.run = false,
+    }
+}
+fn xdgWmBaseListener(wm_base: *xdg.WmBase, event: xdg.WmBase.Event, _: ?*void) void {
+    switch (event) {
+        .ping => |ping| {
+            wm_base.pong(ping.serial);
+        },
+    }
+}
+
+fn bufferListener(buffer: *wl.Buffer, event: wl.Buffer.Event, _: ?*void) void {
+    switch (event) {
+        .release => buffer.destroy(),
+    }
+}
+
+fn frameListener(wl_cb: *wl.Callback, event: wl.Callback.Event, state: *Window) void {
+    switch (event) {
+        .done => |done| {
+            wl_cb.destroy();
+            const new_cb = state.wl_surface.frame() catch |err| {
+                std.debug.print("unable to get frame {}\n", .{err});
+                state.run = false;
+                return;
+            };
+            new_cb.setListener(*Window, frameListener, state);
+
+            if (state.last_frame != 0) {
+                const elapsed: f32 = @floatFromInt(done.callback_data -% state.last_frame);
+                state.offset += elapsed / 1000.0 * 48.0;
+            }
+            defer state.last_frame = done.callback_data;
+
+            const buffer = state.drawFrame() catch |err| {
+                std.debug.print("error drawing frame {}\n", .{err});
+                return;
+            };
+            state.wl_surface.attach(buffer, 0, 0);
+            state.wl_surface.damageBuffer(0, 0, std.math.maxInt(i32), std.math.maxInt(i32));
+            state.wl_surface.commit();
+        },
+    }
+}