Add a scroll wheel hack for the Mac

glut.rc

@@ -15,6 +15,12 @@ extern mod std;
 
 pub mod glut;
 
+#[cfg(target_os="macos")]
+pub mod machack;
+#[cfg(not(target_os="macos"))]
+#[path="machackstub.rs"]
+pub mod machack;
+
 #[cfg(test)]
 pub mod test;
 

machack.rs

@@ -0,0 +1,36 @@
+extern mod cocoa;
+
+use glut::mouse_callback_tls_key;
+
+use core::cast::transmute;
+use core::local_data::local_data_get;
+use machack::cocoa::base::{SEL, class_addMethod, id, msg_send_double, objc_getClass};
+use machack::cocoa::base::{sel_registerName};
+
+extern fn scrollWheelImpl(this: id, _cmd: SEL, event: id) {
+    unsafe {
+        let sel_deltaY = sel_registerName(transmute(&"deltaY"[0]));
+        let delta_y = msg_send_double(event, sel_deltaY);
+        let button = if delta_y == 0.0 {
+            return
+        } else if delta_y > 0.0 {
+            3
+        } else {
+            4
+        };
+        let callback = local_data_get(mouse_callback_tls_key).get();
+        (*callback)(button, 1, 0, 0);
+    }
+}
+
+pub fn perform_scroll_wheel_hack() {
+    unsafe {
+        let sel_scrollWheel = sel_registerName(transmute(&"scrollWheel:"[0]));
+        let class_GLUTView = objc_getClass(transmute(&"GLUTView"[0]));
+        class_addMethod(class_GLUTView,
+                        sel_scrollWheel,
+                        transmute(scrollWheelImpl),
+                        transmute(&"v@:@"[0]));
+    }
+}
+

machackstub.rs

@@ -0,0 +1,4 @@
+pub fn perform_scroll_wheel_hack() {
+    // Just a stub.
+}
+