Add cone support.

5 files changed, 119 insertions, 11 deletions

diff --git a/src/geometry/collider.rs b/src/geometry/collider.rs
index c6cf6d0..f952b15 100644
--- a/src/geometry/collider.rs
+++ b/src/geometry/collider.rs
@@ -1,10 +1,10 @@
 use crate::dynamics::{MassProperties, RigidBodyHandle, RigidBodySet};
-#[cfg(feature = "dim3")]
-use crate::geometry::PolygonalFeatureMap;
 use crate::geometry::{
-    Ball, Capsule, ColliderGraphIndex, Contact, Cuboid, Cylinder, HeightField, InteractionGraph,
-    Polygon, Proximity, Ray, RayIntersection, Shape, ShapeType, Triangle, Trimesh,
+    Ball, Capsule, ColliderGraphIndex, Contact, Cuboid, HeightField, InteractionGraph, Polygon,
+    Proximity, Ray, RayIntersection, Shape, ShapeType, Triangle, Trimesh,
 };
+#[cfg(feature = "dim3")]
+use crate::geometry::{Cone, Cylinder, PolygonalFeatureMap};
 use crate::math::{AngVector, Isometry, Point, Rotation, Vector};
 use downcast_rs::{impl_downcast, DowncastSync};
 use erased_serde::Serialize;
@@ -40,6 +40,13 @@ impl ColliderShape {
         ColliderShape(Arc::new(Cylinder::new(half_height, radius)))
     }
 
+    /// Initialize a cone shape defined by its half-height
+    /// (along along the y axis) and its basis radius.
+    #[cfg(feature = "dim3")]
+    pub fn cone(half_height: f32, radius: f32) -> Self {
+        ColliderShape(Arc::new(Cone::new(half_height, radius)))
+    }
+
     /// Initialize a cuboid shape defined by its half-extents.
     pub fn cuboid(half_extents: Vector<f32>) -> Self {
         ColliderShape(Arc::new(Cuboid::new(half_extents)))
@@ -171,6 +178,13 @@ impl<'de> serde::Deserialize<'de> for ColliderShape {
                             .ok_or_else(|| serde::de::Error::invalid_length(0, &self))?;
                         Arc::new(shape) as Arc<dyn Shape>
                     }
+                    #[cfg(feature = "dim3")]
+                    Some(ShapeType::Cone) => {
+                        let shape: Cone = seq
+                            .next_element()?
+                            .ok_or_else(|| serde::de::Error::invalid_length(0, &self))?;
+                        Arc::new(shape) as Arc<dyn Shape>
+                    }
                     None => {
                         return Err(serde::de::Error::custom(
                             "found invalid shape type to deserialize",
@@ -328,6 +342,13 @@ impl ColliderBuilder {
         Self::new(ColliderShape::cylinder(half_height, radius))
     }
 
+    /// Initialize a new collider builder with a cone shape defined by its half-height
+    /// (along along the y axis) and its basis radius.
+    #[cfg(feature = "dim3")]
+    pub fn cone(half_height: f32, radius: f32) -> Self {
+        Self::new(ColliderShape::cone(half_height, radius))
+    }
+
     /// Initialize a new collider builder with a cuboid shape defined by its half-extents.
     #[cfg(feature = "dim2")]
     pub fn cuboid(hx: f32, hy: f32) -> Self {
diff --git a/src/geometry/contact_generator/contact_dispatcher.rs b/src/geometry/contact_generator/contact_dispatcher.rs
index 01bbc46..70ac84c 100644
--- a/src/geometry/contact_generator/contact_dispatcher.rs
+++ b/src/geometry/contact_generator/contact_dispatcher.rs
@@ -76,7 +76,9 @@ impl ContactDispatcher for DefaultContactDispatcher {
             | (ShapeType::Capsule, ShapeType::Ball)
             | (ShapeType::Ball, ShapeType::Capsule)
             | (ShapeType::Cylinder, ShapeType::Ball)
-            | (ShapeType::Ball, ShapeType::Cylinder) => (
+            | (ShapeType::Ball, ShapeType::Cylinder)
+            | (ShapeType::Cone, ShapeType::Ball)
+            | (ShapeType::Ball, ShapeType::Cone) => (
                 PrimitiveContactGenerator {
                     generate_contacts: super::generate_contacts_ball_convex,
                     ..PrimitiveContactGenerator::default()
@@ -99,7 +101,10 @@ impl ContactDispatcher for DefaultContactDispatcher {
                     None,
                 )
             }
-            (ShapeType::Cylinder, _) | (_, ShapeType::Cylinder) => (
+            (ShapeType::Cylinder, _)
+            | (_, ShapeType::Cylinder)
+            | (ShapeType::Cone, _)
+            | (_, ShapeType::Cone) => (
                 PrimitiveContactGenerator {
                     generate_contacts: super::generate_contacts_pfm_pfm,
                     ..PrimitiveContactGenerator::default()
diff --git a/src/geometry/mod.rs b/src/geometry/mod.rs
index 71573ed..d569248 100644
--- a/src/geometry/mod.rs
+++ b/src/geometry/mod.rs
@@ -35,6 +35,9 @@ pub type HeightField = ncollide::shape::HeightField<f32>;
 /// A cylindrical shape.
 #[cfg(feature = "dim3")]
 pub type Cylinder = ncollide::shape::Cylinder<f32>;
+/// A cone shape.
+#[cfg(feature = "dim3")]
+pub type Cone = ncollide::shape::Cone<f32>;
 /// An axis-aligned bounding box.
 pub type AABB = ncollide::bounding_volume::AABB<f32>;
 /// Event triggered when two non-sensor colliders start or stop being in contact.
diff --git a/src/geometry/polygonal_feature_map.rs b/src/geometry/polygonal_feature_map.rs
index 70be5d0..fc5e066 100644
--- a/src/geometry/polygonal_feature_map.rs
+++ b/src/geometry/polygonal_feature_map.rs
@@ -1,5 +1,5 @@
 use crate::geometry::PolyhedronFace;
-use crate::geometry::{cuboid, Cuboid, Cylinder, Triangle};
+use crate::geometry::{cuboid, Cone, Cuboid, Cylinder, Triangle};
 use crate::math::{Point, Vector};
 use approx::AbsDiffEq;
 use na::{Unit, Vector2, Vector3};
@@ -85,3 +85,49 @@ impl PolygonalFeatureMap for Cylinder {
         }
     }
 }
+
+impl PolygonalFeatureMap for Cone {
+    fn local_support_feature(&self, dir: &Unit<Vector<f32>>, out_features: &mut PolyhedronFace) {
+        // About feature ids. It is very similar to the feature ids of cylinders.
+        // At all times, we consider our cone to be approximated as follows:
+        // - The curved part is approximated by a single segment.
+        // - The flat cap of the cone is approximated by a square.
+        // - The curved-part segment has a feature ID of 0, and its endpoint with negative
+        //   `y` coordinate has an ID of 1.
+        // - The bottom cap has its vertices with feature ID of 1,3,5,7 (in counter-clockwise order
+        //   when looking at the cap with an eye looking towards +y).
+        // - The bottom cap has its four edge feature IDs of 2,4,6,8, in counter-clockwise order.
+        // - The bottom cap has its face feature ID of 9.
+        // - Note that at all times, one of the cap's vertices are the same as the curved-part
+        //   segment endpoints.
+        let dir2 = Vector2::new(dir.x, dir.z)
+            .try_normalize(f32::default_epsilon())
+            .unwrap_or(Vector2::x());
+
+        if dir.y > 0.0 {
+            // We return a segment lying on the cone's curved part.
+            out_features.vertices[0] = Point::new(
+                dir2.x * self.radius,
+                -self.half_height,
+                dir2.y * self.radius,
+            );
+            out_features.vertices[1] = Point::new(0.0, self.half_height, 0.0);
+            out_features.eids = [0, 0, 0, 0];
+            out_features.fid = 0;
+            out_features.num_vertices = 2;
+            out_features.vids = [1, 11, 11, 11];
+        } else {
+            // We return a square approximation of the cone cap.
+            let y = -self.half_height;
+            out_features.vertices[0] = Point::new(dir2.x * self.radius, y, dir2.y * self.radius);
+            out_features.vertices[1] = Point::new(-dir2.y * self.radius, y, dir2.x * self.radius);
+            out_features.vertices[2] = Point::new(-dir2.x * self.radius, y, -dir2.y * self.radius);
+            out_features.vertices[3] = Point::new(dir2.y * self.radius, y, -dir2.x * self.radius);
+
+            out_features.eids = [2, 4, 6, 8];
+            out_features.fid = 9;
+            out_features.num_vertices = 4;
+            out_features.vids = [1, 3, 5, 7];
+        }
+    }
+}
diff --git a/src/geometry/shape.rs b/src/geometry/shape.rs
index c9e0a3a..b972a3e 100644
--- a/src/geometry/shape.rs
+++ b/src/geometry/shape.rs
@@ -1,10 +1,10 @@
 use crate::dynamics::{MassProperties, RigidBodyHandle, RigidBodySet};
-#[cfg(feature = "dim3")]
-use crate::geometry::PolygonalFeatureMap;
 use crate::geometry::{
-    Ball, Capsule, ColliderGraphIndex, Contact, Cuboid, Cylinder, HeightField, InteractionGraph,
-    Polygon, Proximity, Ray, RayIntersection, Triangle, Trimesh,
+    Ball, Capsule, ColliderGraphIndex, Contact, Cuboid, HeightField, InteractionGraph, Polygon,
+    Proximity, Ray, RayIntersection, Triangle, Trimesh,
 };
+#[cfg(feature = "dim3")]
+use crate::geometry::{Cone, Cylinder, PolygonalFeatureMap};
 use crate::math::{AngVector, Isometry, Point, Rotation, Vector};
 use downcast_rs::{impl_downcast, DowncastSync};
 use erased_serde::Serialize;
@@ -35,6 +35,9 @@ pub enum ShapeType {
     #[cfg(feature = "dim3")]
     /// A cylindrical shape.
     Cylinder,
+    #[cfg(feature = "dim3")]
+    /// A cylindrical shape.
+    Cone,
     // /// A custom shape type.
     // Custom(u8),
 }
@@ -104,6 +107,11 @@ impl dyn Shape {
     pub fn as_cylinder(&self) -> Option<&Cylinder> {
         self.downcast_ref()
     }
+
+    /// Converts this abstract shape to a cone, if it is one.
+    pub fn as_cone(&self) -> Option<&Cone> {
+        self.downcast_ref()
+    }
 }
 
 impl Shape for Ball {
@@ -273,3 +281,28 @@ impl Shape for Cylinder {
         Some(self as &dyn PolygonalFeatureMap)
     }
 }
+
+#[cfg(feature = "dim3")]
+impl Shape for Cone {
+    #[cfg(feature = "serde-serialize")]
+    fn as_serialize(&self) -> Option<&dyn Serialize> {
+        Some(self as &dyn Serialize)
+    }
+
+    fn compute_aabb(&self, position: &Isometry<f32>) -> AABB<f32> {
+        self.bounding_volume(position)
+    }
+
+    fn mass_properties(&self, density: f32) -> MassProperties {
+        MassProperties::from_cone(density, self.half_height, self.radius)
+    }
+
+    fn shape_type(&self) -> ShapeType {
+        ShapeType::Cone
+    }
+
+    #[cfg(feature = "dim3")]
+    fn as_polygonal_feature_map(&self) -> Option<&dyn PolygonalFeatureMap> {
+        Some(self as &dyn PolygonalFeatureMap)
+    }
+}