glfw: ziggify Joystick hat bitmasks

Helps hexops/mach#37

Signed-off-by: Stephen Gutekanst <stephen@hexops.com>

glfw/src/hat.zig

@@ -1,16 +1,46 @@
-//! Joystick hat states
-//!
-//! See glfw.getJoystickHats for how these are used.
-
 const c = @import("c.zig").c;
 
-pub const centered = c.GLFW_HAT_CENTERED;
-pub const up = c.GLFW_HAT_UP;
-pub const right = c.GLFW_HAT_RIGHT;
-pub const down = c.GLFW_HAT_DOWN;
-pub const left = c.GLFW_HAT_LEFT;
+// must be in sync with GLFW C constants in hat state group, search for "@defgroup hat_state Joystick hat states"
+/// A bitmask of all Joystick hat states
+///
+/// See glfw.Joystick.getHats for how these are used.
+pub const Hat = packed struct {
+    centered: bool align(@alignOf(u8)) = false,
+    up: bool = false,
+    right: bool = false,
+    down: bool = false,
+    left: bool = false,
 
-pub const right_up = right | up;
-pub const right_down = right | down;
-pub const left_up = left | up;
-pub const left_down = left | down;
+    inline fn verifyIntType(comptime IntType: type) void {
+        comptime {
+            switch (@typeInfo(IntType)) {
+                .Int => {},
+                else => @compileError("Int was not of int type"),
+            }
+        }
+    }
+
+    pub inline fn toInt(comptime IntType: type, self: Hat) IntType {
+        verifyIntType(IntType);
+        return @bitCast(IntType, self);
+    }
+
+    pub inline fn fromInt(flags: anytype) Hat {
+        verifyIntType(@TypeOf(flags));
+        return @bitCast(Hat, flags);
+    }
+};
+
+/// Holds all GLFW hat values in their raw form.
+pub const RawHats = struct {
+    pub const centered = c.GLFW_HAT_CENTERED;
+    pub const up = c.GLFW_HAT_UP;
+    pub const right = c.GLFW_HAT_RIGHT;
+    pub const down = c.GLFW_HAT_DOWN;
+    pub const left = c.GLFW_HAT_LEFT;
+
+    pub const right_up = right | up;
+    pub const right_down = right | down;
+    pub const left_up = left | up;
+    pub const left_down = left | down;
+};