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tried to apply the same numerical stability improvement to edge collisions - inconclusive

main
_ 2021-12-18 20:11:15 +00:00
parent dec16c4079
commit 6fbddb3c86
1 changed files with 11 additions and 8 deletions
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19
src/physics.rs
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@ -191,21 +191,24 @@ pub fn get_candidate (world: &[Triangle], p0: Vec3, p1: Vec3, radius: f32)
continue; continue;
} }
let t = (a_ray.x - discriminant.sqrt ()) / (p1 - p0).length (); let denom = (p1 - p0).length ();
let t_times_denom = a_ray.x - discriminant.sqrt ();
if t < 0.0 || t > 1.0 { if t_times_denom < 0.0 || t_times_denom > denom {
// The cylinder is along the line, // The cylinder is along the line,
// but outside the line segment // but outside the line segment
//triangles_hit.push_back (i); //triangles_hit.push_back (i);
continue; continue;
} }
let p_impact = p0 * (1.0 - t) + p1 * (t); let p_impact_times_denom = p0 * (denom - t_times_denom) + p1 * (t_times_denom);
let p_impact = p_impact_times_denom / denom;
let impact_along_cylinder = Vec3::dot (cylinder_axis, p_impact); let impact_along_cylinder_times_denom = Vec3::dot (cylinder_axis, p_impact_times_denom);
let impact_along_cylinder = impact_along_cylinder_times_denom / denom;
let a_along_cylinder = Vec3::dot (cylinder_axis, a); let a_along_cylinder = Vec3::dot (cylinder_axis, a);
if impact_along_cylinder < a_along_cylinder || impact_along_cylinder > Vec3::dot (cylinder_axis, b) if impact_along_cylinder_times_denom < a_along_cylinder * denom || impact_along_cylinder_times_denom > Vec3::dot (cylinder_axis, b) * denom
{ {
// The infinite cylinder is on the line segment, // The infinite cylinder is on the line segment,
// but the finite cylinder is not. // but the finite cylinder is not.
@ -220,7 +223,7 @@ pub fn get_candidate (world: &[Triangle], p0: Vec3, p1: Vec3, radius: f32)
if speed_towards_edge > 0.0 && speed_into_triangle >= 0.0 { if speed_towards_edge > 0.0 && speed_into_triangle >= 0.0 {
let c = Collision { let c = Collision {
t, t: t_times_denom / denom,
p_impact, p_impact,
normal: edge_normal, normal: edge_normal,
i, i,
@ -446,8 +449,8 @@ mod test {
] { ] {
let a = physics_step (&params, &world, radius, &body_before); let a = physics_step (&params, &world, radius, &body_before);
assert! (a.body.pos.distance_squared (e.body.pos) < 0.00125); assert! (a.body.pos.distance_squared (e.body.pos) <= 0.00125);
assert! (a.body.vel.distance_squared (e.body.vel) < 0.00125); assert! (a.body.vel.distance_squared (e.body.vel) <= 0.00125);
assert_eq! (a.triangles_hit, e.triangles_hit); assert_eq! (a.triangles_hit, e.triangles_hit);
assert_eq! (a.kill, e.kill); assert_eq! (a.kill, e.kill);
} }