WIP fix collision

This commit is contained in:
Ludvig Böklin 2021-05-16 16:55:01 +02:00
parent 12f546a075
commit 6d4bf431a3
3 changed files with 104 additions and 19 deletions

10
Cargo.lock generated
View File

@ -2415,6 +2415,15 @@ dependencies = [
"serde",
]
[[package]]
name = "inline_tweak"
version = "1.0.8"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "7033e97b20277cc0d043226d1940fa7719ff08d2305d1fc7421e53066d00eb4b"
dependencies = [
"lazy_static",
]
[[package]]
name = "inotify"
version = "0.7.1"
@ -5633,6 +5642,7 @@ version = "0.9.0"
dependencies = [
"hashbrown",
"indexmap",
"inline_tweak",
"ordered-float 2.1.1",
"rand 0.8.3",
"rayon",

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@ -31,4 +31,4 @@ slab = "0.4.2"
specs = { git = "https://github.com/amethyst/specs.git", features = ["serde", "storage-event-control", "derive"], rev = "5a9b71035007be0e3574f35184acac1cd4530496" }
# Tweak running code
# inline_tweak = { version = "1.0.8", features = ["release_tweak"] }
inline_tweak = { version = "1.0.8", features = ["release_tweak"] }

View File

@ -13,7 +13,7 @@ use common::{
states,
terrain::{Block, TerrainGrid},
uid::Uid,
util::{Projection, SpatialGrid},
util::{Dir, Plane, Projection, SpatialGrid},
vol::{BaseVol, ReadVol},
};
use common_base::{prof_span, span};
@ -27,6 +27,46 @@ use specs::{
use std::ops::Range;
use vek::*;
enum CollisionKind {
Inelastic, // when coefficient of restitution is zero
Elastic, // when coefficient of restitution is 1
}
/// Collision between two objects, resulting in a change in their respective
/// trajectories.
fn collision(
(mass, vel): (&Mass, Vel),
(mass_other, vel_other): (&Mass, Vel),
collision_kind: CollisionKind, // coefficient_of_restitution: f32,
collision_normal: Dir,
) -> (Vel, Vel) {
let (m1, m2) = (mass.0, mass_other.0);
let (v1, v2) = (vel.0, vel_other.0);
// velocities projected along the collision normal
let (u1, u2) = (
v1.projected(&collision_normal),
v2.projected(&collision_normal),
);
match collision_kind {
CollisionKind::Inelastic => {
// Breaks conservation of energy as we do not account for internal heat or
// deformation
let v = (m1 * u1 + m2 * u2) / (m1 + m2);
(Vel(v1 - u1 + v), Vel(v2 - u2 + v))
// (Vel(v + vp1), Vel(v + vp2))
},
CollisionKind::Elastic => {
// combined mass
let m = m1 + m2;
(
Vel(v1 - u1 + ((m1 - m2) * u1 + 2.0 * m2 * u2) / m),
Vel(v2 - u2 + ((m2 - m1) * u2 + 2.0 * m1 * u1) / m),
)
},
}
}
/// The density of the fluid as a function of submersion ratio in given fluid
/// where it is assumed that any unsubmersed part is is air.
// TODO: Better suited partial submersion curve?
@ -305,7 +345,7 @@ impl<'a> PhysicsData<'a> {
}
#[allow(clippy::nonminimal_bool)]
fn apply_pushback(&mut self, job: &mut Job<Sys>, spatial_grid: &SpatialGrid) {
fn collide_entities(&mut self, job: &mut Job<Sys>, spatial_grid: &SpatialGrid) {
span!(_guard, "Apply pushback");
job.cpu_stats.measure(ParMode::Rayon);
let PhysicsData {
@ -372,7 +412,7 @@ impl<'a> PhysicsData<'a> {
let is_projectile = projectile.is_some();
let mut vel_delta = Vec3::zero();
// let initial_vel = vel.clone();
let query_center = previous_cache.center.xy();
let query_radius = previous_cache.collision_boundary;
@ -390,6 +430,7 @@ impl<'a> PhysicsData<'a> {
entity,
uid,
pos,
// write.velocities.get(entity),
previous_cache,
mass,
read.colliders.get(entity),
@ -402,6 +443,7 @@ impl<'a> PhysicsData<'a> {
entity_other,
other,
pos_other,
// vel_other,
previous_cache_other,
mass_other,
collider_other,
@ -457,15 +499,14 @@ impl<'a> PhysicsData<'a> {
entity_entity_collisions += 1;
}
// Don't apply repulsive force to projectiles or if
// we're
// colliding
// with a terrain-like entity, or if we are a
// terrain-like
// entity
// Don't apply repulsive force to projectiles or if we're
// colliding with a terrain-like entity, or if we are a
// terrain-like entity
//
// Don't apply force when entity is a sticky which is on the
// ground (or on the wall)
//
// Don't collide entities moving away from each other
if !(is_sticky && !is_mid_air)
&& diff.magnitude_squared() > 0.0
&& !is_projectile
@ -475,13 +516,48 @@ impl<'a> PhysicsData<'a> {
)
&& !matches!(collider, Some(Collider::Voxel { .. }))
{
let force = 400.0
* (collision_dist - diff.magnitude())
* mass_other.0
/ (mass.0 + mass_other.0);
let rel_mv_dir = Dir::from_unnormalized(
previous_cache.velocity_dt
- previous_cache_other.velocity_dt,
);
let dir_from_other =
Dir::from_unnormalized(pos - pos_other)
.or(rel_mv_dir);
let d = rel_mv_dir
.and_then(|rel_vel| {
Some(rel_vel.dot(*dir_from_other?))
})
.unwrap_or_default();
vel_delta +=
Vec3::from(diff.normalized()) * force * step_delta;
if d < inline_tweak::tweak!(-0.01) {
// temp hack to avoid refactor
let vel_other = Vel(previous_cache_other
.velocity_dt
/ read.dt.0.max(0.001));
// Change velocity
vel.0 = collision(
(mass, *vel),
(mass_other, vel_other),
CollisionKind::Inelastic,
dir_from_other.unwrap_or_default(),
)
.0
.0;
}
// Pushback
if inline_tweak::tweak!(false) {
let speed: f32 = inline_tweak::tweak!(10.0);
let overlap = collision_dist - diff.magnitude();
// let a: f32 = inline_tweak::tweak!(-1.0);
if overlap.is_sign_positive() {
vel.0 += *dir_from_other.unwrap_or_default()
* speed
* mass_other.0
/ (mass.0 + mass_other.0)
* step_delta;
}
}
}
collided = true;
@ -490,8 +566,7 @@ impl<'a> PhysicsData<'a> {
},
);
// Change velocity
vel.0 += vel_delta * read.dt.0;
// vel.0 = vel_;
// Metrics
PhysicsMetrics {
@ -1212,7 +1287,7 @@ impl<'a> System<'a> for Sys {
physics_data.maintain_pushback_cache();
let spatial_grid = physics_data.construct_spatial_grid();
physics_data.apply_pushback(job, &spatial_grid);
physics_data.collide_entities(job, &spatial_grid);
let voxel_collider_spatial_grid = physics_data.construct_voxel_collider_spatial_grid();
physics_data.handle_movement_and_terrain(job, &voxel_collider_spatial_grid);