Set and get user data

lib/minifb/src/minifb.zig

@@ -9,7 +9,18 @@ pub fn rgb(r: u8, g: u8, b: u8) u32 {
     return @intCast(u32, r) << 16 | @intCast(u32, g) << 8 | b;
 }
 
-pub const Window = struct{
+pub const KeyMod = packed struct {
+    shift: bool = false,
+    control: bool = false,
+    alt: bool = false,
+    super: bool = false,
+    capsLock: bool = false,
+    numLock: bool = false,
+    reserved: u26 = 0,
+};
+
+pub fn Window(comptime TUserData: type) type {
+    return struct {
         cwin: *minifb_c.mfb_window,
 
         pub const UpdateError = error {
@@ -26,25 +37,26 @@ pub const Window = struct{
             fullscreenDesktop: bool = false,
             borderless: bool = false,
             alwaysOnTop: bool = false,
+            reserved: u27 = 0,
         };
 
-    pub fn open(title: [*:0]const u8, width: u32, height: u32, flags: OpenFlags) !Window {
+        pub fn open(title: [*:0]const u8, width: u32, height: u32, flags: OpenFlags) !Window(TUserData) {
-        const intFlags: u32 = @bitCast(u5, flags);
+            const intFlags = @bitCast(u32, flags);
             const cTitle = @as([*c]const u8, title);
             const cwin: ?*minifb_c.mfb_window = minifb_c.mfb_open_ex(cTitle, width, height, intFlags);
             if (cwin) |value| {
-            return Window {.cwin=value};
+                return Window(TUserData) {.cwin=value};
             } else {
                 return error.ItBroke;
             }
             
         }
 
-    pub fn waitSync(self: Window) bool {
+        pub fn waitSync(self: Window(TUserData)) bool {
             return minifb_c.mfb_wait_sync(self.cwin);
         }
 
-    pub fn update(self:Window, buffer: []u32) UpdateError!State {
+        pub fn update(self: Window(TUserData), buffer: []u32) UpdateError!State {
             const rawState = minifb_c.mfb_update(self.cwin, buffer.ptr);
             switch (rawState) {
                 .STATE_OK => return State.ok,
@@ -54,7 +66,29 @@ pub const Window = struct{
                 else => return UpdateError.InternalError,
             }
         }
+
+        pub fn setUserData(self: Window(TUserData), data: *TUserData) void {
+            minifb_c.mfb_set_user_data(self.cwin, data);
+        }
+
+        pub fn getUserData(self: Window(TUserData)) ?*TUserData {
+            return @ptrCast(?*TUserData, @alignCast(@alignOf(?*TUserData), minifb_c.mfb_get_user_data(self.cwin)));
+        }
+        
+        test "user data is null if never set" {
+            const win = try Window(u8).open("", 100, 100);
+            const data = win.getUserData();
+            testing.expectEqual(null, data);
+        }
+
+        test "user data is not null if previously set" {
+            const win = try Window(u8).open("", 100, 100);
+            var data: u8 = 42;
+            win.setUserData(&data);
+            testing.expectEqual(42, win.getUserData().?.*);
+        }
     };
+}
 
 pub fn getTargetFPS() u32 {
     return minifb_c.mfb_get_target_fps();

src/main.zig

@@ -17,8 +17,6 @@ const Coords = struct {
 
 const State = struct {
     period: f64,
-    bgValue: u8 = 0,
-    increasing: bool = true,
     timer: mfb.Timer,
 
     pub fn init(period: f64) !State {
@@ -97,15 +95,20 @@ pub fn main() !void {
     var gp_allocator = std.heap.GeneralPurposeAllocator(.{}){};
     const alloc = &gp_allocator.allocator;
 
-    var win = mfb.Window.open("Hello minifb-zig", Width, Height, .{.resizable=true}) catch unreachable;
-    mfb.setTargetFPS(7);
-
     var state = try State.init(3);
     defer state.deinit();
 
+    var win = mfb.Window(State).open("Hello minifb-zig", Width, Height, .{.resizable=true}) catch unreachable;
+    mfb.setTargetFPS(7);
+    win.setUserData(&state);
+
     var buf = try Buffer.init(alloc, Width, Height);
     defer buf.deinit();
 
+    var aliasedState = win.getUserData();
+    if (aliasedState) |value| {
+        std.log.info("Period: {d}", .{value.*.period});
+    }
     state.render(buf);
     while (win.waitSync()) {
         state.render(buf);