Fix 3D velocity controls

demo3/src/main.rs

@@ -136,7 +136,9 @@ fn main() {
 
         let mut event_handled = false;
         while !event_handled {
+            if camera_velocity.is_zero() {
                 events.push(sdl_event_pump.wait_event());
+            }
             for event in sdl_event_pump.poll_iter() {
                 events.push(event);
             }
@@ -178,6 +180,11 @@ fn main() {
 
                 event_handled = true;
             }
+
+            // FIXME(pcwalton): This is so ugly!
+            if !camera_velocity.is_zero() {
+                event_handled = true;
+            }
         }
     }
 }

geometry/src/point.rs

@@ -238,6 +238,15 @@ impl Point4DF32 {
     pub fn approx_eq(&self, other: &Point4DF32, epsilon: f32) -> bool {
         self.0.approx_eq(other.0, epsilon)
     }
+
+    /// Checks to see whether this *homogeneous* coordinate equals zero.
+    ///
+    /// Note that since this treats the coordinate as a homogeneous coordinate, the `w` is ignored.
+    // TODO(pcwalton): Optimize with SIMD.
+    #[inline]
+    pub fn is_zero(self) -> bool {
+        self.x() == 0.0 && self.y() == 0.0 && self.z() == 0.0
+    }
 }
 
 impl Add<Point4DF32> for Point4DF32 {