1 files changed, 90 insertions, 8 deletions

diff --git a/src/geometry/interaction_groups.rs b/src/geometry/interaction_groups.rs
index b2961d9..09a20e9 100644
--- a/src/geometry/interaction_groups.rs
+++ b/src/geometry/interaction_groups.rs
@@ -18,14 +18,14 @@
 #[repr(C)]
 pub struct InteractionGroups {
     /// Groups memberships.
-    pub memberships: u32,
+    pub memberships: Group,
     /// Groups filter.
-    pub filter: u32,
+    pub filter: Group,
 }
 
 impl InteractionGroups {
     /// Initializes with the given interaction groups and interaction mask.
-    pub const fn new(memberships: u32, filter: u32) -> Self {
+    pub const fn new(memberships: Group, filter: Group) -> Self {
         Self {
             memberships,
             filter,
@@ -34,22 +34,22 @@ impl InteractionGroups {
 
     /// Allow interaction with everything.
     pub const fn all() -> Self {
-        Self::new(u32::MAX, u32::MAX)
+        Self::new(Group::ALL, Group::ALL)
     }
 
     /// Prevent all interactions.
     pub const fn none() -> Self {
-        Self::new(0, 0)
+        Self::new(Group::NONE, Group::NONE)
     }
 
     /// Sets the group this filter is part of.
-    pub const fn with_memberships(mut self, memberships: u32) -> Self {
+    pub const fn with_memberships(mut self, memberships: Group) -> Self {
         self.memberships = memberships;
         self
     }
 
     /// Sets the interaction mask of this filter.
-    pub const fn with_filter(mut self, filter: u32) -> Self {
+    pub const fn with_filter(mut self, filter: Group) -> Self {
         self.filter = filter;
         self
     }
@@ -60,7 +60,10 @@ impl InteractionGroups {
     /// with the filter of `rhs`, and vice-versa.
     #[inline]
     pub const fn test(self, rhs: Self) -> bool {
-        (self.memberships & rhs.filter) != 0 && (rhs.memberships & self.filter) != 0
+        // NOTE: since const ops is not stable, we have to convert `Group` into u32
+        // to use & operator in const context.
+        (self.memberships.bits() & rhs.filter.bits()) != 0
+            && (rhs.memberships.bits() & self.filter.bits()) != 0
     }
 }
 
@@ -69,3 +72,82 @@ impl Default for InteractionGroups {
         Self::all()
     }
 }
+
+use bitflags::bitflags;
+
+bitflags! {
+    /// A bit mask identifying groups for interaction.
+    #[cfg_attr(feature = "serde-serialize", derive(Serialize, Deserialize))]
+    #[allow(missing_docs)]
+    pub struct Group: u32 {
+        /// The group n°1.
+        const GROUP_1 = 1 << 0;
+        /// The group n°2.
+        const GROUP_2 = 1 << 1;
+        /// The group n°3.
+        const GROUP_3 = 1 << 2;
+        /// The group n°4.
+        const GROUP_4 = 1 << 3;
+        /// The group n°5.
+        const GROUP_5 = 1 << 4;
+        /// The group n°6.
+        const GROUP_6 = 1 << 5;
+        /// The group n°7.
+        const GROUP_7 = 1 << 6;
+        /// The group n°8.
+        const GROUP_8 = 1 << 7;
+        /// The group n°9.
+        const GROUP_9 = 1 << 8;
+        /// The group n°10.
+        const GROUP_10 = 1 << 9;
+        /// The group n°11.
+        const GROUP_11 = 1 << 10;
+        /// The group n°12.
+        const GROUP_12 = 1 << 11;
+        /// The group n°13.
+        const GROUP_13 = 1 << 12;
+        /// The group n°14.
+        const GROUP_14 = 1 << 13;
+        /// The group n°15.
+        const GROUP_15 = 1 << 14;
+        /// The group n°16.
+        const GROUP_16 = 1 << 15;
+        /// The group n°17.
+        const GROUP_17 = 1 << 16;
+        /// The group n°18.
+        const GROUP_18 = 1 << 17;
+        /// The group n°19.
+        const GROUP_19 = 1 << 18;
+        /// The group n°20.
+        const GROUP_20 = 1 << 19;
+        /// The group n°21.
+        const GROUP_21 = 1 << 20;
+        /// The group n°22.
+        const GROUP_22 = 1 << 21;
+        /// The group n°23.
+        const GROUP_23 = 1 << 22;
+        /// The group n°24.
+        const GROUP_24 = 1 << 23;
+        /// The group n°25.
+        const GROUP_25 = 1 << 24;
+        /// The group n°26.
+        const GROUP_26 = 1 << 25;
+        /// The group n°27.
+        const GROUP_27 = 1 << 26;
+        /// The group n°28.
+        const GROUP_28 = 1 << 27;
+        /// The group n°29.
+        const GROUP_29 = 1 << 28;
+        /// The group n°30.
+        const GROUP_30 = 1 << 29;
+        /// The group n°31.
+        const GROUP_31 = 1 << 30;
+        /// The group n°32.
+        const GROUP_32 = 1 << 31;
+
+        /// All of the groups.
+        const ALL = u32::MAX;
+        /// None of the groups.
+        const NONE = 0;
+    }
+}