spine-runtimes/spine-ts/spine-core/src/PhysicsConstraint.ts
2025-04-05 13:42:13 -04:00

302 lines
9.3 KiB
TypeScript

/******************************************************************************
* Spine Runtimes License Agreement
* Last updated April 5, 2025. Replaces all prior versions.
*
* Copyright (c) 2013-2025, Esoteric Software LLC
*
* Integration of the Spine Runtimes into software or otherwise creating
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* conditions of Section 2 of the Spine Editor License Agreement:
* http://esotericsoftware.com/spine-editor-license
*
* Otherwise, it is permitted to integrate the Spine Runtimes into software
* or otherwise create derivative works of the Spine Runtimes (collectively,
* "Products"), provided that each user of the Products must obtain their own
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import { Bone } from "./Bone.js";
import { PhysicsConstraintData } from "./PhysicsConstraintData.js";
import { Physics, Skeleton } from "./Skeleton.js";
import { Updatable } from "./Updatable.js";
import { MathUtils } from "./Utils.js";
/** Stores the current pose for a physics constraint. A physics constraint applies physics to bones.
* <p>
* See <a href="http://esotericsoftware.com/spine-physics-constraints">Physics constraints</a> in the Spine User Guide. */
export class PhysicsConstraint implements Updatable {
readonly data: PhysicsConstraintData;
bone: Bone;
inertia = 0;
strength = 0;
damping = 0;
massInverse = 0;
wind = 0;
gravity = 0;
mix = 0;
_reset = true;
ux = 0;
uy = 0;
cx = 0;
cy = 0;
tx = 0;
ty = 0;
xOffset = 0;
xVelocity = 0;
yOffset = 0;
yVelocity = 0;
rotateOffset = 0;
rotateVelocity = 0;
scaleOffset = 0
scaleVelocity = 0;
active = false;
readonly skeleton: Skeleton;
remaining = 0;
lastTime = 0;
constructor (data: PhysicsConstraintData, skeleton: Skeleton) {
this.data = data;
this.skeleton = skeleton;
let bone = skeleton.findBone(data.bone.name);
if (!bone) throw new Error(`Couldn't find bone ${data.bone.name}.`);
this.bone = skeleton.bones[data.bone.index];
this.inertia = data.inertia;
this.strength = data.strength;
this.damping = data.damping;
this.massInverse = data.massInverse;
this.wind = data.wind;
this.gravity = data.gravity;
this.mix = data.mix;
}
reset () {
this.remaining = 0;
this.lastTime = this.skeleton.time;
this._reset = true;
this.xOffset = 0;
this.xVelocity = 0;
this.yOffset = 0;
this.yVelocity = 0;
this.rotateOffset = 0;
this.rotateVelocity = 0;
this.scaleOffset = 0;
this.scaleVelocity = 0;
}
setToSetupPose () {
const data = this.data;
this.inertia = data.inertia;
this.strength = data.strength;
this.damping = data.damping;
this.massInverse = data.massInverse;
this.wind = data.wind;
this.gravity = data.gravity;
this.mix = data.mix;
}
isActive () {
return this.active;
}
/** Applies the constraint to the constrained bones. */
update (physics: Physics) {
const mix = this.mix;
if (mix == 0) return;
const x = this.data.x > 0, y = this.data.y > 0, rotateOrShearX = this.data.rotate > 0 || this.data.shearX > 0, scaleX = this.data.scaleX > 0;
const bone = this.bone;
const l = bone.data.length;
switch (physics) {
case Physics.none:
return;
case Physics.reset:
this.reset();
// Fall through.
case Physics.update:
const skeleton = this.skeleton;
const delta = Math.max(this.skeleton.time - this.lastTime, 0);
this.remaining += delta;
this.lastTime = skeleton.time;
const bx = bone.worldX, by = bone.worldY;
if (this._reset) {
this._reset = false;
this.ux = bx;
this.uy = by;
} else {
let a = this.remaining, i = this.inertia, t = this.data.step, f = this.skeleton.data.referenceScale, d = -1;
let qx = this.data.limit * delta, qy = qx * Math.abs(skeleton.scaleY);
qx *= Math.abs(skeleton.scaleX);
if (x || y) {
if (x) {
const u = (this.ux - bx) * i;
this.xOffset += u > qx ? qx : u < -qx ? -qx : u;
this.ux = bx;
}
if (y) {
const u = (this.uy - by) * i;
this.yOffset += u > qy ? qy : u < -qy ? -qy : u;
this.uy = by;
}
if (a >= t) {
d = Math.pow(this.damping, 60 * t);
const m = this.massInverse * t, e = this.strength, w = this.wind * f * skeleton.scaleX, g = this.gravity * f * skeleton.scaleY;
do {
if (x) {
this.xVelocity += (w - this.xOffset * e) * m;
this.xOffset += this.xVelocity * t;
this.xVelocity *= d;
}
if (y) {
this.yVelocity -= (g + this.yOffset * e) * m;
this.yOffset += this.yVelocity * t;
this.yVelocity *= d;
}
a -= t;
} while (a >= t);
}
if (x) bone.worldX += this.xOffset * mix * this.data.x;
if (y) bone.worldY += this.yOffset * mix * this.data.y;
}
if (rotateOrShearX || scaleX) {
let ca = Math.atan2(bone.c, bone.a), c = 0, s = 0, mr = 0;
let dx = this.cx - bone.worldX, dy = this.cy - bone.worldY;
if (dx > qx)
dx = qx;
else if (dx < -qx) //
dx = -qx;
if (dy > qy)
dy = qy;
else if (dy < -qy) //
dy = -qy;
if (rotateOrShearX) {
mr = (this.data.rotate + this.data.shearX) * mix;
let r = Math.atan2(dy + this.ty, dx + this.tx) - ca - this.rotateOffset * mr;
this.rotateOffset += (r - Math.ceil(r * MathUtils.invPI2 - 0.5) * MathUtils.PI2) * i;
r = this.rotateOffset * mr + ca;
c = Math.cos(r);
s = Math.sin(r);
if (scaleX) {
r = l * bone.getWorldScaleX();
if (r > 0) this.scaleOffset += (dx * c + dy * s) * i / r;
}
} else {
c = Math.cos(ca);
s = Math.sin(ca);
const r = l * bone.getWorldScaleX();
if (r > 0) this.scaleOffset += (dx * c + dy * s) * i / r;
}
a = this.remaining;
if (a >= t) {
if (d == -1) d = Math.pow(this.damping, 60 * t);
const m = this.massInverse * t, e = this.strength, w = this.wind, g = (Skeleton.yDown ? -this.gravity : this.gravity), h = l / f;
while (true) {
a -= t;
if (scaleX) {
this.scaleVelocity += (w * c - g * s - this.scaleOffset * e) * m;
this.scaleOffset += this.scaleVelocity * t;
this.scaleVelocity *= d;
}
if (rotateOrShearX) {
this.rotateVelocity -= ((w * s + g * c) * h + this.rotateOffset * e) * m;
this.rotateOffset += this.rotateVelocity * t;
this.rotateVelocity *= d;
if (a < t) break;
const r = this.rotateOffset * mr + ca;
c = Math.cos(r);
s = Math.sin(r);
} else if (a < t) //
break;
}
}
}
this.remaining = a;
}
this.cx = bone.worldX;
this.cy = bone.worldY;
break;
case Physics.pose:
if (x) bone.worldX += this.xOffset * mix * this.data.x;
if (y) bone.worldY += this.yOffset * mix * this.data.y;
}
if (rotateOrShearX) {
let o = this.rotateOffset * mix, s = 0, c = 0, a = 0;
if (this.data.shearX > 0) {
let r = 0;
if (this.data.rotate > 0) {
r = o * this.data.rotate;
s = Math.sin(r);
c = Math.cos(r);
a = bone.b;
bone.b = c * a - s * bone.d;
bone.d = s * a + c * bone.d;
}
r += o * this.data.shearX;
s = Math.sin(r);
c = Math.cos(r);
a = bone.a;
bone.a = c * a - s * bone.c;
bone.c = s * a + c * bone.c;
} else {
o *= this.data.rotate;
s = Math.sin(o);
c = Math.cos(o);
a = bone.a;
bone.a = c * a - s * bone.c;
bone.c = s * a + c * bone.c;
a = bone.b;
bone.b = c * a - s * bone.d;
bone.d = s * a + c * bone.d;
}
}
if (scaleX) {
const s = 1 + this.scaleOffset * mix * this.data.scaleX;
bone.a *= s;
bone.c *= s;
}
if (physics != Physics.pose) {
this.tx = l * bone.a;
this.ty = l * bone.c;
}
bone.updateAppliedTransform();
}
/** Translates the physics constraint so next {@link #update(Physics)} forces are applied as if the bone moved an additional
* amount in world space. */
translate (x: number, y: number) {
this.ux -= x;
this.uy -= y;
this.cx -= x;
this.cy -= y;
}
/** Rotates the physics constraint so next {@link #update(Physics)} forces are applied as if the bone rotated around the
* specified point in world space. */
rotate (x: number, y: number, degrees: number) {
const r = degrees * MathUtils.degRad, cos = Math.cos(r), sin = Math.sin(r);
const dx = this.cx - x, dy = this.cy - y;
this.translate(dx * cos - dy * sin - dx, dx * sin + dy * cos - dy);
}
}