754 lines
28 KiB
Rust
754 lines
28 KiB
Rust
use crate::dynamics::RigidBodySet;
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use crate::geometry::{ColliderHandle, ColliderSet, ContactManifold, Shape, TOI};
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use crate::math::{Isometry, Point, Real, UnitVector, Vector};
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use crate::pipeline::{QueryFilter, QueryFilterFlags, QueryPipeline};
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use crate::utils;
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use na::{RealField, Vector2};
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use parry::bounding_volume::BoundingVolume;
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use parry::math::Translation;
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use parry::query::{DefaultQueryDispatcher, PersistentQueryDispatcher};
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#[derive(Copy, Clone, Debug, PartialEq)]
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/// A length measure used for various options of a character controller.
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pub enum CharacterLength {
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/// The length is specified relative to some of the character shape’s size.
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///
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/// For example setting `CharacterAutostep::max_height` to `CharacterLength::Relative(0.1)`
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/// for a shape with an height equal to 20.0 will result in a maximum step height
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/// of `0.1 * 20.0 = 2.0`.
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Relative(Real),
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/// The length is specified as an aboslute value, independent from the character shape’s size.
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///
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/// For example setting `CharacterAutostep::max_height` to `CharacterLength::Relative(0.1)`
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/// for a shape with an height equal to 20.0 will result in a maximum step height
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/// of `0.1` (the shape height is ignored in for this value).
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Absolute(Real),
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}
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impl CharacterLength {
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/// Returns `self` with its value changed by the closure `f` if `self` is the `Self::Absolute`
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/// variant.
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pub fn map_absolute(self, f: impl FnOnce(Real) -> Real) -> Self {
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if let Self::Absolute(value) = self {
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Self::Absolute(f(value))
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} else {
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self
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}
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}
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/// Returns `self` with its value changed by the closure `f` if `self` is the `Self::Relative`
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/// variant.
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pub fn map_relative(self, f: impl FnOnce(Real) -> Real) -> Self {
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if let Self::Relative(value) = self {
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Self::Relative(f(value))
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} else {
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self
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}
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}
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fn eval(self, value: Real) -> Real {
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match self {
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Self::Relative(x) => value * x,
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Self::Absolute(x) => x,
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}
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}
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}
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/// Configuration for the auto-stepping character controller feature.
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#[derive(Copy, Clone, Debug, PartialEq)]
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pub struct CharacterAutostep {
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/// The maximum step height a character can automatically step over.
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pub max_height: CharacterLength,
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/// The minimum width of free space that must be available after stepping on a stair.
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pub min_width: CharacterLength,
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/// Can the character automatically step over dynamic bodies too?
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pub include_dynamic_bodies: bool,
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}
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impl Default for CharacterAutostep {
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fn default() -> Self {
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Self {
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max_height: CharacterLength::Relative(0.25),
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min_width: CharacterLength::Relative(0.5),
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include_dynamic_bodies: true,
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}
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}
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}
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/// A collision between the character and its environment during its movement.
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#[derive(Copy, Clone, Debug)]
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pub struct CharacterCollision {
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/// The collider hit by the character.
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pub handle: ColliderHandle,
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/// The position of the character when the collider was hit.
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pub character_pos: Isometry<Real>,
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/// The translation that was already applied to the character when the hit happens.
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pub translation_applied: Vector<Real>,
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/// The translations that was still waiting to be applied to the character when the hit happens.
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pub translation_remaining: Vector<Real>,
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/// Geometric information about the hit.
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pub toi: TOI,
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}
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/// A character controller for kinematic bodies.
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#[derive(Copy, Clone, Debug)]
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pub struct KinematicCharacterController {
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/// The direction that goes "up". Used to determine where the floor is, and the floor’s angle.
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pub up: UnitVector<Real>,
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/// A small gap to preserve between the character and its surroundings.
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///
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/// This value should not be too large to avoid visual artifacts, but shouldn’t be too small
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/// (must not be zero) to improve numerical stability of the character controller.
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pub offset: CharacterLength,
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/// Should the character try to slide against the floor if it hits it?
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pub slide: bool,
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/// Should the character automatically step over small obstacles?
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pub autostep: Option<CharacterAutostep>,
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/// The maximum angle (radians) between the floor’s normal and the `up` vector that the
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/// character is able to climb.
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pub max_slope_climb_angle: Real,
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/// The minimum angle (radians) between the floor’s normal and the `up` vector before the
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/// character starts to slide down automatically.
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pub min_slope_slide_angle: Real,
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/// Should the character be automatically snapped to the ground if the distance between
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/// the ground and its feed are smaller than the specified threshold?
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pub snap_to_ground: Option<CharacterLength>,
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}
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impl Default for KinematicCharacterController {
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fn default() -> Self {
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Self {
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up: Vector::y_axis(),
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offset: CharacterLength::Relative(0.01),
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slide: true,
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autostep: Some(CharacterAutostep::default()),
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max_slope_climb_angle: Real::frac_pi_4(),
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min_slope_slide_angle: Real::frac_pi_4(),
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snap_to_ground: Some(CharacterLength::Relative(0.2)),
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}
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}
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}
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/// The effective movement computed by the character controller.
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pub struct EffectiveCharacterMovement {
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/// The movement to apply.
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pub translation: Vector<Real>,
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/// Is the character touching the ground after applying `EffectiveKineamticMovement::translation`?
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pub grounded: bool,
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/// Is the character sliding down a slope due to slope angle being larger than `min_slope_slide_angle`?
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pub is_sliding_down_slope: bool,
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}
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impl KinematicCharacterController {
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fn check_and_fix_penetrations(&self) {
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/*
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// 1/ Check if the body is grounded and if there are penetrations.
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let mut grounded = false;
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let mut penetrating = false;
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let mut contacts = vec![];
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let aabb = shape
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.compute_aabb(shape_pos)
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.loosened(self.offset);
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queries.colliders_with_aabb_intersecting_aabb(&aabb, |handle| {
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// TODO: apply the filter.
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if let Some(collider) = colliders.get(*handle) {
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if let Ok(Some(contact)) = parry::query::contact(
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&shape_pos,
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shape,
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collider.position(),
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collider.shape(),
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self.offset,
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) {
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contacts.push((contact, collider));
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}
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}
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true
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});
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*/
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}
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/// Computes the possible movement for a shape.
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pub fn move_shape(
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&self,
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dt: Real,
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bodies: &RigidBodySet,
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colliders: &ColliderSet,
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queries: &QueryPipeline,
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character_shape: &dyn Shape,
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character_pos: &Isometry<Real>,
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desired_translation: Vector<Real>,
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filter: QueryFilter,
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mut events: impl FnMut(CharacterCollision),
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) -> EffectiveCharacterMovement {
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let mut result = EffectiveCharacterMovement {
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translation: Vector::zeros(),
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grounded: false,
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is_sliding_down_slope: false,
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};
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let dims = self.compute_dims(character_shape);
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// 1. Check and fix penetrations.
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self.check_and_fix_penetrations();
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let mut translation_remaining = desired_translation;
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let grounded_at_starting_pos = self.detect_grounded_status_and_apply_friction(
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dt,
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bodies,
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colliders,
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queries,
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character_shape,
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character_pos,
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&dims,
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filter,
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None,
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None,
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);
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let mut max_iters = 20;
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let mut kinematic_friction_translation = Vector::zeros();
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let offset = self.offset.eval(dims.y);
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while let Some((translation_dir, translation_dist)) =
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UnitVector::try_new_and_get(translation_remaining, 1.0e-5)
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{
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if max_iters == 0 {
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break;
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} else {
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max_iters -= 1;
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}
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// 2. Cast towards the movement direction.
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if let Some((handle, toi)) = queries.cast_shape(
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bodies,
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colliders,
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&(Translation::from(result.translation) * character_pos),
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&translation_dir,
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character_shape,
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translation_dist + offset,
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false,
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filter,
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) {
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// We hit something, compute the allowed self.
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let allowed_dist =
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(toi.toi - (-toi.normal1.dot(&translation_dir)) * offset).max(0.0);
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let allowed_translation = *translation_dir * allowed_dist;
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result.translation += allowed_translation;
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translation_remaining -= allowed_translation;
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events(CharacterCollision {
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handle,
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character_pos: Translation::from(result.translation) * character_pos,
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translation_applied: result.translation,
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translation_remaining,
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toi,
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});
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// Try to go up stairs.
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if !self.handle_stairs(
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bodies,
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colliders,
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queries,
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character_shape,
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&(Translation::from(result.translation) * character_pos),
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&dims,
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filter,
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handle,
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&mut translation_remaining,
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&mut result,
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) {
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// No stairs, try to move along slopes.
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translation_remaining =
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self.handle_slopes(&toi, &translation_remaining, &mut result);
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}
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} else {
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// No interference along the path.
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result.translation += translation_remaining;
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translation_remaining.fill(0.0);
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break;
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}
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result.grounded = self.detect_grounded_status_and_apply_friction(
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dt,
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bodies,
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colliders,
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queries,
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character_shape,
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&(Translation::from(result.translation) * character_pos),
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&dims,
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filter,
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Some(&mut kinematic_friction_translation),
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Some(&mut translation_remaining),
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);
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if !self.slide {
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break;
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}
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}
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// If needed, and if we are not already grounded, snap to the ground.
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if grounded_at_starting_pos {
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self.snap_to_ground(
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bodies,
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colliders,
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queries,
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character_shape,
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&(Translation::from(result.translation) * character_pos),
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&dims,
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filter,
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&mut result,
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);
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}
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// Return the result.
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result
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}
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fn snap_to_ground(
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&self,
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bodies: &RigidBodySet,
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colliders: &ColliderSet,
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queries: &QueryPipeline,
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character_shape: &dyn Shape,
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character_pos: &Isometry<Real>,
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dims: &Vector2<Real>,
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filter: QueryFilter,
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result: &mut EffectiveCharacterMovement,
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) -> Option<(ColliderHandle, TOI)> {
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if let Some(snap_distance) = self.snap_to_ground {
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if result.translation.dot(&self.up) < -1.0e-5 {
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let snap_distance = snap_distance.eval(dims.y);
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let offset = self.offset.eval(dims.y);
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if let Some((hit_handle, hit)) = queries.cast_shape(
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bodies,
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colliders,
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character_pos,
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&-self.up,
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character_shape,
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snap_distance + offset,
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false,
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filter,
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) {
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// Apply the snap.
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result.translation -= *self.up * (hit.toi - offset).max(0.0);
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result.grounded = true;
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return Some((hit_handle, hit));
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}
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}
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}
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None
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}
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fn predict_ground(&self, up_extends: Real) -> Real {
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self.offset.eval(up_extends) * 1.1
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}
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fn detect_grounded_status_and_apply_friction(
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&self,
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dt: Real,
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bodies: &RigidBodySet,
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colliders: &ColliderSet,
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queries: &QueryPipeline,
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character_shape: &dyn Shape,
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character_pos: &Isometry<Real>,
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dims: &Vector2<Real>,
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filter: QueryFilter,
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mut kinematic_friction_translation: Option<&mut Vector<Real>>,
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mut translation_remaining: Option<&mut Vector<Real>>,
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) -> bool {
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let prediction = self.predict_ground(dims.y);
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// TODO: allow custom dispatchers.
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let dispatcher = DefaultQueryDispatcher;
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let mut manifolds: Vec<ContactManifold> = vec![];
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let character_aabb = character_shape
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.compute_aabb(character_pos)
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.loosened(prediction);
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let mut grounded = false;
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queries.colliders_with_aabb_intersecting_aabb(&character_aabb, |handle| {
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if let Some(collider) = colliders.get(*handle) {
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if filter.test(bodies, *handle, collider) {
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manifolds.clear();
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let pos12 = character_pos.inv_mul(collider.position());
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let _ = dispatcher.contact_manifolds(
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&pos12,
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character_shape,
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collider.shape(),
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prediction,
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&mut manifolds,
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&mut None,
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);
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if let (Some(kinematic_friction_translation), Some(translation_remaining)) = (
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kinematic_friction_translation.as_deref_mut(),
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translation_remaining.as_deref_mut(),
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) {
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let init_kinematic_friction_translation = *kinematic_friction_translation;
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let kinematic_parent = collider
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.parent
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.and_then(|p| bodies.get(p.handle))
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.filter(|rb| rb.is_kinematic());
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for m in &manifolds {
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if self.is_grounded_at_contact_manifold(m, character_pos, dims) {
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grounded = true;
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}
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if let Some(kinematic_parent) = kinematic_parent {
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let mut num_active_contacts = 0;
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let mut manifold_center = Point::origin();
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let normal = -(character_pos * m.local_n1);
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for contact in &m.points {
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if contact.dist <= prediction {
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num_active_contacts += 1;
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let contact_point = collider.position() * contact.local_p2;
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let target_vel =
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kinematic_parent.velocity_at_point(&contact_point);
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let normal_target_mvt = target_vel.dot(&normal) * dt;
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let normal_current_mvt = translation_remaining.dot(&normal);
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manifold_center += contact_point.coords;
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*translation_remaining +=
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normal * (normal_target_mvt - normal_current_mvt);
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}
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}
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if num_active_contacts > 0 {
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let target_vel = kinematic_parent.velocity_at_point(
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&(manifold_center / num_active_contacts as Real),
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);
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let tangent_platform_mvt =
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(target_vel - normal * target_vel.dot(&normal)) * dt;
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kinematic_friction_translation.zip_apply(
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&tangent_platform_mvt,
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|y, x| {
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if x.abs() > (*y).abs() {
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*y = x;
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}
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},
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);
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}
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}
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}
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*translation_remaining +=
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*kinematic_friction_translation - init_kinematic_friction_translation;
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} else {
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for m in &manifolds {
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if self.is_grounded_at_contact_manifold(m, character_pos, dims) {
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grounded = true;
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return false; // We can stop the search early.
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}
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}
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}
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}
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}
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true
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});
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grounded
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}
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fn is_grounded_at_contact_manifold(
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&self,
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manifold: &ContactManifold,
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character_pos: &Isometry<Real>,
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dims: &Vector2<Real>,
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) -> bool {
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let normal = -(character_pos * manifold.local_n1);
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if normal.dot(&self.up) >= 1.0e-5 {
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let prediction = self.predict_ground(dims.y);
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for contact in &manifold.points {
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if contact.dist <= prediction {
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return true;
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}
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}
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}
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false
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}
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fn handle_slopes(
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&self,
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hit: &TOI,
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translation_remaining: &Vector<Real>,
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result: &mut EffectiveCharacterMovement,
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) -> Vector<Real> {
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let [vertical_translation, horizontal_translation] =
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self.split_into_components(translation_remaining);
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let slope_translation = subtract_hit(*translation_remaining, hit);
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// Check if there is a slope to climb.
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let angle_with_floor = self.up.angle(&hit.normal1);
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// We are climbing if the movement along the slope goes upward, and the angle with the
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// floor is smaller than pi/2 (in which case we hit some some sort of ceiling).
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//
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// NOTE: part of the slope will already be handled by auto-stepping if it was enabled.
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// Therefore, `climbing` may not always be `true` when climbing on a slope at
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// slow speed.
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let climbing = self.up.dot(&slope_translation) >= 0.0 && self.up.dot(&hit.normal1) > 0.0;
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if climbing && angle_with_floor >= self.max_slope_climb_angle {
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// Prevent horizontal movement from pushing through the slope.
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vertical_translation
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} else if !climbing && angle_with_floor <= self.min_slope_slide_angle {
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// Prevent the vertical movement from sliding down.
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horizontal_translation
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} else {
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// Let it slide
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result.is_sliding_down_slope = true;
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slope_translation
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}
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}
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fn split_into_components(&self, translation: &Vector<Real>) -> [Vector<Real>; 2] {
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let vertical_translation = *self.up * (self.up.dot(translation));
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let horizontal_translation = *translation - vertical_translation;
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[vertical_translation, horizontal_translation]
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}
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fn compute_dims(&self, character_shape: &dyn Shape) -> Vector2<Real> {
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let extents = character_shape.compute_local_aabb().extents();
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let up_extent = extents.dot(&self.up);
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let side_extent = (extents - *self.up * up_extent).norm();
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Vector2::new(side_extent, up_extent)
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}
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fn handle_stairs(
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&self,
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bodies: &RigidBodySet,
|
||
colliders: &ColliderSet,
|
||
queries: &QueryPipeline,
|
||
character_shape: &dyn Shape,
|
||
character_pos: &Isometry<Real>,
|
||
dims: &Vector2<Real>,
|
||
mut filter: QueryFilter,
|
||
stair_handle: ColliderHandle,
|
||
translation_remaining: &mut Vector<Real>,
|
||
result: &mut EffectiveCharacterMovement,
|
||
) -> bool {
|
||
let autostep = match self.autostep {
|
||
Some(autostep) => autostep,
|
||
None => return false,
|
||
};
|
||
|
||
let offset = self.offset.eval(dims.y);
|
||
let min_width = autostep.min_width.eval(dims.x) + offset;
|
||
let max_height = autostep.max_height.eval(dims.y) + offset;
|
||
|
||
if !autostep.include_dynamic_bodies {
|
||
if colliders
|
||
.get(stair_handle)
|
||
.and_then(|co| co.parent)
|
||
.and_then(|p| bodies.get(p.handle))
|
||
.map(|b| b.is_dynamic())
|
||
== Some(true)
|
||
{
|
||
// The "stair" is a dynamic body, which the user wants to ignore.
|
||
return false;
|
||
}
|
||
|
||
filter.flags |= QueryFilterFlags::EXCLUDE_DYNAMIC;
|
||
}
|
||
|
||
let shifted_character_pos = Translation::from(*self.up * max_height) * character_pos;
|
||
|
||
let horizontal_dir = match (*translation_remaining
|
||
- *self.up * translation_remaining.dot(&self.up))
|
||
.try_normalize(1.0e-5)
|
||
{
|
||
Some(dir) => dir,
|
||
None => return false,
|
||
};
|
||
|
||
if queries
|
||
.cast_shape(
|
||
bodies,
|
||
colliders,
|
||
character_pos,
|
||
&self.up,
|
||
character_shape,
|
||
max_height,
|
||
false,
|
||
filter,
|
||
)
|
||
.is_some()
|
||
{
|
||
// We can’t go up.
|
||
return false;
|
||
}
|
||
|
||
if queries
|
||
.cast_shape(
|
||
bodies,
|
||
colliders,
|
||
&shifted_character_pos,
|
||
&horizontal_dir,
|
||
character_shape,
|
||
min_width,
|
||
false,
|
||
filter,
|
||
)
|
||
.is_some()
|
||
{
|
||
// We don’t have enough room on the stair to stay on it.
|
||
return false;
|
||
}
|
||
|
||
// Check that we are not getting into a ramp that is too steep
|
||
// after stepping.
|
||
if let Some((_, hit)) = queries.cast_shape(
|
||
bodies,
|
||
colliders,
|
||
&(Translation::from(horizontal_dir * min_width) * shifted_character_pos),
|
||
&-self.up,
|
||
character_shape,
|
||
max_height,
|
||
false,
|
||
filter,
|
||
) {
|
||
let [vertical_slope_translation, horizontal_slope_translation] = self
|
||
.split_into_components(translation_remaining)
|
||
.map(|remaining| subtract_hit(remaining, &hit));
|
||
|
||
let slope_translation = horizontal_slope_translation + vertical_slope_translation;
|
||
|
||
let angle_with_floor = self.up.angle(&hit.normal1);
|
||
let climbing = self.up.dot(&slope_translation) >= 0.0;
|
||
|
||
if climbing && angle_with_floor > self.max_slope_climb_angle {
|
||
return false; // The target ramp is too steep.
|
||
}
|
||
}
|
||
|
||
// We can step, we need to find the actual step height.
|
||
let step_height = max_height
|
||
- queries
|
||
.cast_shape(
|
||
bodies,
|
||
colliders,
|
||
&(Translation::from(horizontal_dir * min_width) * shifted_character_pos),
|
||
&-self.up,
|
||
character_shape,
|
||
max_height,
|
||
false,
|
||
filter,
|
||
)
|
||
.map(|hit| hit.1.toi)
|
||
.unwrap_or(max_height);
|
||
|
||
// Remove the step height from the vertical part of the self.
|
||
let step = *self.up * step_height;
|
||
*translation_remaining -= step;
|
||
|
||
// Advance the collider on the step horizontally, to make sure further
|
||
// movement won’t just get stuck on its edge.
|
||
let horizontal_nudge =
|
||
horizontal_dir * horizontal_dir.dot(translation_remaining).min(min_width);
|
||
*translation_remaining -= horizontal_nudge;
|
||
|
||
result.translation += step + horizontal_nudge;
|
||
true
|
||
}
|
||
|
||
/// For a given collision between a character and its environment, this method will apply
|
||
/// impulses to the rigid-bodies surrounding the character shape at the time of the collision.
|
||
/// Note that the impulse calculation is only approximate as it is not based on a global
|
||
/// constraints resolution scheme.
|
||
pub fn solve_character_collision_impulses(
|
||
&self,
|
||
dt: Real,
|
||
bodies: &mut RigidBodySet,
|
||
colliders: &ColliderSet,
|
||
queries: &QueryPipeline,
|
||
character_shape: &dyn Shape,
|
||
character_mass: Real,
|
||
collision: &CharacterCollision,
|
||
filter: QueryFilter,
|
||
) {
|
||
let extents = character_shape.compute_local_aabb().extents();
|
||
let up_extent = extents.dot(&self.up);
|
||
let movement_to_transfer =
|
||
*collision.toi.normal1 * collision.translation_remaining.dot(&collision.toi.normal1);
|
||
let prediction = self.predict_ground(up_extent);
|
||
|
||
// TODO: allow custom dispatchers.
|
||
let dispatcher = DefaultQueryDispatcher;
|
||
|
||
let mut manifolds: Vec<ContactManifold> = vec![];
|
||
let character_aabb = character_shape
|
||
.compute_aabb(&collision.character_pos)
|
||
.loosened(prediction);
|
||
|
||
queries.colliders_with_aabb_intersecting_aabb(&character_aabb, |handle| {
|
||
if let Some(collider) = colliders.get(*handle) {
|
||
if let Some(parent) = collider.parent {
|
||
if filter.test(bodies, *handle, collider) {
|
||
if let Some(body) = bodies.get(parent.handle) {
|
||
if body.is_dynamic() {
|
||
manifolds.clear();
|
||
let pos12 = collision.character_pos.inv_mul(collider.position());
|
||
let prev_manifolds_len = manifolds.len();
|
||
let _ = dispatcher.contact_manifolds(
|
||
&pos12,
|
||
character_shape,
|
||
collider.shape(),
|
||
prediction,
|
||
&mut manifolds,
|
||
&mut None,
|
||
);
|
||
|
||
for m in &mut manifolds[prev_manifolds_len..] {
|
||
m.data.rigid_body2 = Some(parent.handle);
|
||
m.data.normal = collision.character_pos * m.local_n1;
|
||
}
|
||
}
|
||
}
|
||
}
|
||
}
|
||
}
|
||
true
|
||
});
|
||
|
||
let velocity_to_transfer = movement_to_transfer * utils::inv(dt);
|
||
|
||
for manifold in &manifolds {
|
||
let body_handle = manifold.data.rigid_body2.unwrap();
|
||
let body = &mut bodies[body_handle];
|
||
|
||
for pt in &manifold.points {
|
||
if pt.dist <= prediction {
|
||
let body_mass = body.mass();
|
||
let contact_point = body.position() * pt.local_p2;
|
||
let delta_vel_per_contact = (velocity_to_transfer
|
||
- body.velocity_at_point(&contact_point))
|
||
.dot(&manifold.data.normal);
|
||
let mass_ratio = body_mass * character_mass / (body_mass + character_mass);
|
||
|
||
body.apply_impulse_at_point(
|
||
manifold.data.normal * delta_vel_per_contact.max(0.0) * mass_ratio,
|
||
contact_point,
|
||
true,
|
||
);
|
||
}
|
||
}
|
||
}
|
||
}
|
||
}
|
||
|
||
fn subtract_hit(translation: Vector<Real>, hit: &TOI) -> Vector<Real> {
|
||
let surface_correction = (-translation).dot(&hit.normal1).max(0.0);
|
||
// This fixes some instances of moving through walls
|
||
let surface_correction = surface_correction * (1.0 + 1.0e-5);
|
||
translation + *hit.normal1 * surface_correction
|
||
}
|