Files
SpineViewer/SpineRuntimes/SpineRuntime21/IkConstraint.cs
2025-03-05 16:07:40 +08:00

151 lines
6.6 KiB
C#

/******************************************************************************
* Spine Runtimes Software License
* Version 2.1
*
* Copyright (c) 2013, Esoteric Software
* All rights reserved.
*
* You are granted a perpetual, non-exclusive, non-sublicensable and
* non-transferable license to install, execute and perform the Spine Runtimes
* Software (the "Software") solely for internal use. Without the written
* permission of Esoteric Software (typically granted by licensing Spine), you
* may not (a) modify, translate, adapt or otherwise create derivative works,
* improvements of the Software or develop new applications using the Software
* or (b) remove, delete, alter or obscure any trademarks or any copyright,
* trademark, patent or other intellectual property or proprietary rights
* notices on or in the Software, including any copy thereof. Redistributions
* in binary or source form must include this license and terms.
*
* THIS SOFTWARE IS PROVIDED BY ESOTERIC SOFTWARE "AS IS" AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
* EVENT SHALL ESOTERIC SOFTARE BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
* OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*****************************************************************************/
using System;
using System.Collections.Generic;
namespace SpineRuntime21 {
public class IkConstraint {
private const float radDeg = 180 / (float)Math.PI;
internal IkConstraintData data;
internal List<Bone> bones = new List<Bone>();
internal Bone target;
internal int bendDirection;
internal float mix;
public IkConstraintData Data { get { return data; } }
public List<Bone> Bones { get { return bones; } }
public Bone Target { get { return target; } set { target = value; } }
public int BendDirection { get { return bendDirection; } set { bendDirection = value; } }
public float Mix { get { return mix; } set { mix = value; } }
public IkConstraint (IkConstraintData data, Skeleton skeleton) {
if (data == null) throw new ArgumentNullException("data cannot be null.");
if (skeleton == null) throw new ArgumentNullException("skeleton cannot be null.");
this.data = data;
mix = data.mix;
bendDirection = data.bendDirection;
bones = new List<Bone>(data.bones.Count);
foreach (BoneData boneData in data.bones)
bones.Add(skeleton.FindBone(boneData.name));
target = skeleton.FindBone(data.target.name);
}
public void apply () {
Bone target = this.target;
List<Bone> bones = this.bones;
switch (bones.Count) {
case 1:
apply(bones[0], target.worldX, target.worldY, mix);
break;
case 2:
apply(bones[0], bones[1], target.worldX, target.worldY, bendDirection, mix);
break;
}
}
override public String ToString () {
return data.name;
}
/// <summary>Adjusts the bone rotation so the tip is as close to the target position as possible. The target is specified
/// in the world coordinate system.</summary>
static public void apply (Bone bone, float targetX, float targetY, float alpha) {
float parentRotation = (!bone.data.inheritRotation || bone.parent == null) ? 0 : bone.parent.worldRotation;
float rotation = bone.rotation;
float rotationIK = (float)Math.Atan2(targetY - bone.worldY, targetX - bone.worldX) * radDeg;
if (bone.worldFlipX != (bone.worldFlipY != Bone.yDown)) rotationIK = -rotationIK;
rotationIK -= parentRotation;
bone.rotationIK = rotation + (rotationIK - rotation) * alpha;
}
/// <summary>Adjusts the parent and child bone rotations so the tip of the child is as close to the target position as
/// possible. The target is specified in the world coordinate system.</summary>
/// <param name="child">Any descendant bone of the parent.</param>
static public void apply (Bone parent, Bone child, float targetX, float targetY, int bendDirection, float alpha) {
float childRotation = child.rotation, parentRotation = parent.rotation;
if (alpha == 0) {
child.rotationIK = childRotation;
parent.rotationIK = parentRotation;
return;
}
float positionX, positionY;
Bone parentParent = parent.parent;
if (parentParent != null) {
parentParent.worldToLocal(targetX, targetY, out positionX, out positionY);
targetX = (positionX - parent.x) * parentParent.worldScaleX;
targetY = (positionY - parent.y) * parentParent.worldScaleY;
} else {
targetX -= parent.x;
targetY -= parent.y;
}
if (child.parent == parent) {
positionX = child.x;
positionY = child.y;
} else {
child.parent.localToWorld(child.x, child.y, out positionX, out positionY);
parent.worldToLocal(positionX, positionY, out positionX, out positionY);
}
float childX = positionX * parent.worldScaleX, childY = positionY * parent.worldScaleY;
float offset = (float)Math.Atan2(childY, childX);
float len1 = (float)Math.Sqrt(childX * childX + childY * childY), len2 = child.data.length * child.worldScaleX;
// Based on code by Ryan Juckett with permission: Copyright (c) 2008-2009 Ryan Juckett, http://www.ryanjuckett.com/
float cosDenom = 2 * len1 * len2;
if (cosDenom < 0.0001f) {
child.rotationIK = childRotation + ((float)Math.Atan2(targetY, targetX) * radDeg - parentRotation - childRotation)
* alpha;
return;
}
float cos = (targetX * targetX + targetY * targetY - len1 * len1 - len2 * len2) / cosDenom;
if (cos < -1)
cos = -1;
else if (cos > 1)
cos = 1;
float childAngle = (float)Math.Acos(cos) * bendDirection;
float adjacent = len1 + len2 * cos, opposite = len2 * (float)Math.Sin(childAngle);
float parentAngle = (float)Math.Atan2(targetY * adjacent - targetX * opposite, targetX * adjacent + targetY * opposite);
float rotation = (parentAngle - offset) * radDeg - parentRotation;
if (rotation > 180)
rotation -= 360;
else if (rotation < -180) //
rotation += 360;
parent.rotationIK = parentRotation + rotation * alpha;
rotation = (childAngle + offset) * radDeg - childRotation;
if (rotation > 180)
rotation -= 360;
else if (rotation < -180) //
rotation += 360;
child.rotationIK = childRotation + (rotation + parent.worldRotation - child.parent.worldRotation) * alpha;
}
}
}