parry2d 0.26.0

2 dimensional collision detection library in Rust.
Documentation 
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use crate::math::Pose;
use crate::partitioning::Bvh;
use crate::query::details::NormalConstraints;
use crate::shape::Shape;

/// Trait implemented by shapes composed of multiple simpler shapes.
///
/// A composite shape is composed of several shapes. For example, this can
/// be a convex decomposition of a concave shape; or a triangle-mesh.
///
/// This trait is mostly useful for using composite shapes as trait-objects.
/// For other use-cases, call methods from [`TypedCompositeShape`] to avoid
/// dynamic dispatches instead.
#[cfg(feature = "alloc")]
pub trait CompositeShape {
    /// Applies a function to one sub-shape of this composite shape.
    ///
    /// This method is mostly useful for using composite shapes as trait-objects.
    /// For other use-cases, call methods from [`TypedCompositeShape`] to avoid
    /// dynamic dispatches instead.
    ///
    /// Note that if your structure also implements `TypedCompositeShape`, this method
    /// can be implemented simply as:
    /// ```rust ignore
    /// self.map_untyped_part_at(shape_id, f);
    /// ```
    fn map_part_at(
        &self,
        shape_id: u32,
        f: &mut dyn FnMut(Option<&Pose>, &dyn Shape, Option<&dyn NormalConstraints>),
    );

    /// Gets the acceleration structure of the composite shape.
    fn bvh(&self) -> &Bvh;
}

#[cfg(feature = "alloc")]
pub trait TypedCompositeShape: CompositeShape {
    type PartShape: ?Sized + Shape;
    type PartNormalConstraints: ?Sized + NormalConstraints;

    fn map_typed_part_at<T>(
        &self,
        shape_id: u32,
        f: impl FnMut(Option<&Pose>, &Self::PartShape, Option<&Self::PartNormalConstraints>) -> T,
    ) -> Option<T>;

    // TODO: we need this method because the compiler won't want
    // to cast `&Self::PartShape` to `&dyn Shape` because it complains
    // that `PartShape` is not `Sized`.
    fn map_untyped_part_at<T>(
        &self,
        shape_id: u32,
        f: impl FnMut(Option<&Pose>, &dyn Shape, Option<&dyn NormalConstraints>) -> T,
    ) -> Option<T>;
}

#[cfg(feature = "alloc")]
impl TypedCompositeShape for dyn CompositeShape + '_ {
    type PartShape = dyn Shape;
    type PartNormalConstraints = dyn NormalConstraints;

    fn map_typed_part_at<T>(
        &self,
        shape_id: u32,
        mut f: impl FnMut(Option<&Pose>, &Self::PartShape, Option<&Self::PartNormalConstraints>) -> T,
    ) -> Option<T> {
        let mut result = None;
        self.map_part_at(shape_id, &mut |pose, part, normals| {
            result = Some(f(pose, part, normals));
        });
        result
    }

    fn map_untyped_part_at<T>(
        &self,
        shape_id: u32,
        mut f: impl FnMut(Option<&Pose>, &dyn Shape, Option<&dyn NormalConstraints>) -> T,
    ) -> Option<T> {
        let mut result = None;
        self.map_part_at(shape_id, &mut |pose, part, normals| {
            result = Some(f(pose, part, normals));
        });
        result
    }
}

/// A helper struct that implements scene queries on any composite shapes.
///
/// For example, the `RayCast` implementation of a composite shape can use this wrapper or
/// provide its own implementation. This is for working around the lack of specialization in
/// (stable) rust. If we did have specialization, this would just be a blanket implementation
/// of all the geometric query traits for all `S: CompositeShape`.
pub struct CompositeShapeRef<'a, S: ?Sized>(pub &'a S);