spine-runtimes/spine-csharp/src/PhysicsConstraint.cs

303 lines
9.9 KiB
C#

/******************************************************************************
* 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
* derivative works of the Spine Runtimes is permitted under the terms and
* 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
* Spine Editor license and redistribution of the Products in any form must
* include this license and copyright notice.
*
* THE SPINE RUNTIMES ARE PROVIDED BY ESOTERIC SOFTWARE LLC "AS IS" AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES,
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*****************************************************************************/
using System;
namespace Spine {
/// <summary>
/// Stores the current pose for a physics constraint. A physics constraint applies physics to bones.
/// <para>
/// See <a href="http://esotericsoftware.com/spine-physics-constraints">Physics constraints</a> in the Spine User Guide.</para>
/// </summary>
public class PhysicsConstraint : Constraint<PhysicsConstraint, PhysicsConstraintData, PhysicsConstraintPose> {
internal BonePose bone;
bool reset = true;
float ux, uy, cx, cy, tx, ty;
float xOffset, xLag, xVelocity;
float yOffset, yLag, yVelocity;
float rotateOffset, rotateLag, rotateVelocity;
float scaleOffset, scaleLag, scaleVelocity;
float remaining, lastTime;
public PhysicsConstraint (PhysicsConstraintData data, Skeleton skeleton)
: base(data, new PhysicsConstraintPose(), new PhysicsConstraintPose()) {
if (skeleton == null) throw new ArgumentNullException("skeleton", "skeleton cannot be null.");
bone = skeleton.bones.Items[data.bone.index].constrained;
}
override public IConstraint Copy (Skeleton skeleton) {
var copy = new PhysicsConstraint(data, skeleton);
copy.pose.Set(pose);
return copy;
}
public void Reset (Skeleton skeleton) {
remaining = 0;
lastTime = skeleton.time;
reset = true;
xOffset = 0;
xLag = 0;
xVelocity = 0;
yOffset = 0;
yLag = 0;
yVelocity = 0;
rotateOffset = 0;
rotateLag = 0;
rotateVelocity = 0;
scaleOffset = 0;
scaleLag = 0;
scaleVelocity = 0;
}
/// <summary>
/// Translates the physics constraint so next <see cref="Update(Skeleton, Physics)"/> forces are applied as if the bone moved an
/// additional amount in world space.
/// </summary>
public void Translate (float x, float y) {
ux -= x;
uy -= y;
cx -= x;
cy -= y;
}
/// <summary>
/// Rotates the physics constraint so next <see cref="Update(Skeleton, Physics)"/> forces are applied as if the bone rotated around
/// the specified point in world space.
/// </summary>
public void Rotate (float x, float y, float degrees) {
float r = degrees * MathUtils.DegRad, cos = (float)Math.Cos(r), sin = (float)Math.Sin(r);
float dx = cx - x, dy = cy - y;
Translate(dx * cos - dy * sin - dx, dx * sin + dy * cos - dy);
}
/// <summary>Applies the constraint to the constrained bones.</summary>
override public void Update (Skeleton skeleton, Physics physics) {
PhysicsConstraintPose p = applied;
float mix = p.mix;
if (mix == 0) return;
bool x = data.x > 0, y = data.y > 0, rotateOrShearX = data.rotate > 0 || data.shearX > 0, scaleX = data.scaleX > 0;
BonePose bone = this.bone;
float l = bone.bone.data.length, t = data.step, z = 0;
switch (physics) {
case Physics.None:
return;
case Physics.Reset:
Reset(skeleton);
goto case Physics.Update; // Fall through.
case Physics.Update:
float delta = Math.Max(skeleton.time - lastTime, 0), aa = remaining;
remaining += delta;
lastTime = skeleton.time;
float bx = bone.worldX, by = bone.worldY;
if (reset) {
reset = false;
ux = bx;
uy = by;
} else {
float a = remaining, i = p.inertia, f = skeleton.data.referenceScale, d = -1, m = 0, e = 0, qx = data.limit * delta,
qy = qx * Math.Abs(skeleton.ScaleY);
qx *= Math.Abs(skeleton.ScaleX);
if (x || y) {
if (x) {
float u = (ux - bx) * i;
xOffset += u > qx ? qx : u < -qx ? -qx : u;
ux = bx;
}
if (y) {
float u = (uy - by) * i;
yOffset += u > qy ? qy : u < -qy ? -qy : u;
uy = by;
}
if (a >= t) {
float xs = xOffset, ys = yOffset;
d = (float)Math.Pow(p.damping, 60 * t);
m = t * p.massInverse;
e = p.strength;
float w = f * p.wind, g = f * p.gravity;
float ax = (w * skeleton.windX + g * skeleton.gravityX) * skeleton.scaleX;
float ay = (w * skeleton.windY + g * skeleton.gravityY) * skeleton.ScaleY;
do {
if (x) {
xVelocity += (ax - xOffset * e) * m;
xOffset += xVelocity * t;
xVelocity *= d;
}
if (y) {
yVelocity -= (ay + yOffset * e) * m;
yOffset += yVelocity * t;
yVelocity *= d;
}
a -= t;
} while (a >= t);
xLag = xOffset - xs;
yLag = yOffset - ys;
}
z = Math.Max(0, 1 - a / t);
if (x) bone.worldX += (xOffset - xLag * z) * mix * data.x;
if (y) bone.worldY += (yOffset - yLag * z) * mix * data.y;
}
if (rotateOrShearX || scaleX) {
float ca = (float)Math.Atan2(bone.c, bone.a), c, s, mr = 0, dx = cx - bone.worldX, dy = 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 = (data.rotate + data.shearX) * mix;
z = rotateLag * Math.Max(0, 1 - aa / t);
float r = (float)Math.Atan2(dy + ty, dx + tx) - ca - (rotateOffset - z) * mr;
rotateOffset += (r - (float)Math.Ceiling(r * MathUtils.InvPI2 - 0.5f) * MathUtils.PI2) * i;
r = (rotateOffset - z) * mr + ca;
c = (float)Math.Cos(r);
s = (float)Math.Sin(r);
if (scaleX) {
r = l * bone.WorldScaleX;
if (r > 0) scaleOffset += (dx * c + dy * s) * i / r;
}
} else {
c = (float)Math.Cos(ca);
s = (float)Math.Sin(ca);
float r = l * bone.WorldScaleX - scaleLag * Math.Max(0, 1 - aa / t);
if (r > 0) scaleOffset += (dx * c + dy * s) * i / r;
}
a = remaining;
if (a >= t) {
if (d == -1) {
d = (float)Math.Pow(p.damping, 60 * t);
m = t * p.massInverse;
e = p.strength;
}
float ax = p.wind * skeleton.windX + p.gravity * skeleton.gravityX;
float ay = p.wind * skeleton.windY + p.gravity * skeleton.gravityY;
float rs = rotateOffset, ss = scaleOffset, h = l / f;
if (Spine.Bone.yDown) ay = -ay;
while (true) {
a -= t;
if (scaleX) {
scaleVelocity += (ax * c - ay * s - scaleOffset * e) * m;
scaleOffset += scaleVelocity * t;
scaleVelocity *= d;
}
if (rotateOrShearX) {
rotateVelocity -= ((ax * s + ay * c) * h + rotateOffset * e) * m;
rotateOffset += rotateVelocity * t;
rotateVelocity *= d;
if (a < t) break;
float r = rotateOffset * mr + ca;
c = (float)Math.Cos(r);
s = (float)Math.Sin(r);
} else if (a < t) //
break;
}
rotateLag = rotateOffset - rs;
scaleLag = scaleOffset - ss;
}
z = Math.Max(0, 1 - a / t);
}
remaining = a;
}
cx = bone.worldX;
cy = bone.worldY;
break;
case Physics.Pose:
z = Math.Max(0, 1 - remaining / t);
if (x) bone.worldX += (xOffset - xLag * z) * mix * data.x;
if (y) bone.worldY += (yOffset - yLag * z) * mix * data.y;
break;
}
if (rotateOrShearX) {
float o = (rotateOffset - rotateLag * z) * mix, s, c, a;
if (data.shearX > 0) {
float r = 0;
if (data.rotate > 0) {
r = o * data.rotate;
s = (float)Math.Sin(r);
c = (float)Math.Cos(r);
a = bone.b;
bone.b = c * a - s * bone.d;
bone.d = s * a + c * bone.d;
}
r += o * data.shearX;
s = (float)Math.Sin(r);
c = (float)Math.Cos(r);
a = bone.a;
bone.a = c * a - s * bone.c;
bone.c = s * a + c * bone.c;
} else {
o *= data.rotate;
s = (float)Math.Sin(o);
c = (float)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) {
float s = 1 + (scaleOffset - scaleLag * z) * mix * data.scaleX;
bone.a *= s;
bone.c *= s;
}
if (physics != Physics.Pose) {
tx = l * bone.a;
ty = l * bone.c;
}
bone.ModifyWorld(skeleton.update);
}
override public void Sort (Skeleton skeleton) {
Bone bone = this.bone.bone;
skeleton.SortBone(bone);
skeleton.updateCache.Add(this);
skeleton.SortReset(bone.children);
skeleton.Constrained(bone);
}
override public bool IsSourceActive { get { return bone.bone.active; } }
/// <summary>The bone constrained by this physics constraint.</summary>
public BonePose Bone { get { return bone; } set { bone = value; } }
}
}