parry2d/shape/
composite_shape.rs

1use crate::math::Pose;
2use crate::partitioning::Bvh;
3use crate::query::details::NormalConstraints;
4use crate::shape::Shape;
5
6/// Trait implemented by shapes composed of multiple simpler shapes.
7///
8/// A composite shape is composed of several shapes. For example, this can
9/// be a convex decomposition of a concave shape; or a triangle-mesh.
10///
11/// This trait is mostly useful for using composite shapes as trait-objects.
12/// For other use-cases, call methods from [`TypedCompositeShape`] to avoid
13/// dynamic dispatches instead.
14#[cfg(feature = "alloc")]
15pub trait CompositeShape {
16    /// Applies a function to one sub-shape of this composite shape.
17    ///
18    /// This method is mostly useful for using composite shapes as trait-objects.
19    /// For other use-cases, call methods from [`TypedCompositeShape`] to avoid
20    /// dynamic dispatches instead.
21    ///
22    /// Note that if your structure also implements `TypedCompositeShape`, this method
23    /// can be implemented simply as:
24    /// ```rust ignore
25    /// self.map_untyped_part_at(shape_id, f);
26    /// ```
27    fn map_part_at(
28        &self,
29        shape_id: u32,
30        f: &mut dyn FnMut(Option<&Pose>, &dyn Shape, Option<&dyn NormalConstraints>),
31    );
32
33    /// Gets the acceleration structure of the composite shape.
34    fn bvh(&self) -> &Bvh;
35}
36
37#[cfg(feature = "alloc")]
38pub trait TypedCompositeShape: CompositeShape {
39    type PartShape: ?Sized + Shape;
40    type PartNormalConstraints: ?Sized + NormalConstraints;
41
42    fn map_typed_part_at<T>(
43        &self,
44        shape_id: u32,
45        f: impl FnMut(Option<&Pose>, &Self::PartShape, Option<&Self::PartNormalConstraints>) -> T,
46    ) -> Option<T>;
47
48    // TODO: we need this method because the compiler won't want
49    // to cast `&Self::PartShape` to `&dyn Shape` because it complains
50    // that `PartShape` is not `Sized`.
51    fn map_untyped_part_at<T>(
52        &self,
53        shape_id: u32,
54        f: impl FnMut(Option<&Pose>, &dyn Shape, Option<&dyn NormalConstraints>) -> T,
55    ) -> Option<T>;
56}
57
58#[cfg(feature = "alloc")]
59impl TypedCompositeShape for dyn CompositeShape + '_ {
60    type PartShape = dyn Shape;
61    type PartNormalConstraints = dyn NormalConstraints;
62
63    fn map_typed_part_at<T>(
64        &self,
65        shape_id: u32,
66        mut f: impl FnMut(Option<&Pose>, &Self::PartShape, Option<&Self::PartNormalConstraints>) -> T,
67    ) -> Option<T> {
68        let mut result = None;
69        self.map_part_at(shape_id, &mut |pose, part, normals| {
70            result = Some(f(pose, part, normals));
71        });
72        result
73    }
74
75    fn map_untyped_part_at<T>(
76        &self,
77        shape_id: u32,
78        mut f: impl FnMut(Option<&Pose>, &dyn Shape, Option<&dyn NormalConstraints>) -> T,
79    ) -> Option<T> {
80        let mut result = None;
81        self.map_part_at(shape_id, &mut |pose, part, normals| {
82            result = Some(f(pose, part, normals));
83        });
84        result
85    }
86}
87
88/// A helper struct that implements scene queries on any composite shapes.
89///
90/// For example, the `RayCast` implementation of a composite shape can use this wrapper or
91/// provide its own implementation. This is for working around the lack of specialization in
92/// (stable) rust. If we did have specialization, this would just be a blanket implementation
93/// of all the geometric query traits for all `S: CompositeShape`.
94pub struct CompositeShapeRef<'a, S: ?Sized>(pub &'a S);
parry2d/shape/composite_shape.rs

parry2d/shape/
composite_shape.rs
