/******************************************************************************
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* Spine Runtimes Software License v2.5
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*
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* Copyright (c) 2013-2016, Esoteric Software
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* All rights reserved.
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*
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* You are granted a perpetual, non-exclusive, non-sublicensable, and
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* non-transferable license to use, install, execute, and perform the Spine
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* Runtimes software and derivative works solely for personal or internal
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* use. Without the written permission of Esoteric Software (see Section 2 of
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* the Spine Software License Agreement), you may not (a) modify, translate,
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* adapt, or develop new applications using the Spine Runtimes or otherwise
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* create derivative works or improvements of the Spine Runtimes or (b) remove,
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* delete, alter, or obscure any trademarks or any copyright, trademark, patent,
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* or other intellectual property or proprietary rights notices on or in the
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* Software, including any copy thereof. Redistributions in binary or source
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* form must include this license and terms.
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*
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* THIS SOFTWARE IS PROVIDED BY ESOTERIC SOFTWARE "AS IS" AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
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* EVENT SHALL ESOTERIC SOFTWARE BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES, BUSINESS INTERRUPTION, OR LOSS OF
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* USE, DATA, OR PROFITS) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER
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* IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*****************************************************************************/
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using System;
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namespace Spine {
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public class IkConstraint : IConstraint {
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internal IkConstraintData data;
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internal ExposedList<Bone> bones = new ExposedList<Bone>();
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internal Bone target;
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internal float mix;
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internal int bendDirection;
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public IkConstraintData Data { get { return data; } }
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public int Order { get { return data.order; } }
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public ExposedList<Bone> Bones { get { return bones; } }
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public Bone Target { get { return target; } set { target = value; } }
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public int BendDirection { get { return bendDirection; } set { bendDirection = value; } }
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public float Mix { get { return mix; } set { mix = value; } }
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public IkConstraint (IkConstraintData data, Skeleton skeleton) {
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if (data == null) throw new ArgumentNullException("data", "data cannot be null.");
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if (skeleton == null) throw new ArgumentNullException("skeleton", "skeleton cannot be null.");
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this.data = data;
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mix = data.mix;
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bendDirection = data.bendDirection;
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bones = new ExposedList<Bone>(data.bones.Count);
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foreach (BoneData boneData in data.bones)
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bones.Add(skeleton.FindBone(boneData.name));
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target = skeleton.FindBone(data.target.name);
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}
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public void Update () {
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Apply();
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}
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public void Apply () {
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Bone target = this.target;
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ExposedList<Bone> bones = this.bones;
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switch (bones.Count) {
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case 1:
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Apply(bones.Items[0], target.worldX, target.worldY, mix);
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break;
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case 2:
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Apply(bones.Items[0], bones.Items[1], target.worldX, target.worldY, bendDirection, mix);
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break;
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}
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}
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override public String ToString () {
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return data.name;
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}
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/// <summary>Adjusts the bone rotation so the tip is as close to the target position as possible. The target is specified
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/// in the world coordinate system.</summary>
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static public void Apply (Bone bone, float targetX, float targetY, float alpha) {
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if (!bone.appliedValid) bone.UpdateAppliedTransform();
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Bone p = bone.parent;
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float id = 1 / (p.a * p.d - p.b * p.c);
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float x = targetX - p.worldX, y = targetY - p.worldY;
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float tx = (x * p.d - y * p.b) * id - bone.ax, ty = (y * p.a - x * p.c) * id - bone.ay;
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float rotationIK = MathUtils.Atan2(ty, tx) * MathUtils.RadDeg - bone.ashearX - bone.arotation;
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if (bone.ascaleX < 0) rotationIK += 180;
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if (rotationIK > 180)
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rotationIK -= 360;
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else if (rotationIK < -180) rotationIK += 360;
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bone.UpdateWorldTransform(bone.ax, bone.ay, bone.arotation + rotationIK * alpha, bone.ascaleX, bone.ascaleY, bone.ashearX,
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bone.ashearY);
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}
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/// <summary>Adjusts the parent and child bone rotations so the tip of the child is as close to the target position as
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/// possible. The target is specified in the world coordinate system.</summary>
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/// <param name="child">A direct descendant of the parent bone.</param>
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static public void Apply (Bone parent, Bone child, float targetX, float targetY, int bendDir, float alpha) {
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if (alpha == 0) {
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child.UpdateWorldTransform ();
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return;
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}
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//float px = parent.x, py = parent.y, psx = parent.scaleX, psy = parent.scaleY, csx = child.scaleX;
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if (!parent.appliedValid) parent.UpdateAppliedTransform();
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if (!child.appliedValid) child.UpdateAppliedTransform();
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float px = parent.ax, py = parent.ay, psx = parent.ascaleX, psy = parent.ascaleY, csx = child.ascaleX;
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int os1, os2, s2;
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if (psx < 0) {
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psx = -psx;
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os1 = 180;
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s2 = -1;
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} else {
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os1 = 0;
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s2 = 1;
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}
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if (psy < 0) {
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psy = -psy;
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s2 = -s2;
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}
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if (csx < 0) {
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csx = -csx;
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os2 = 180;
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} else
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os2 = 0;
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float cx = child.ax, cy, cwx, cwy, a = parent.a, b = parent.b, c = parent.c, d = parent.d;
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bool u = Math.Abs(psx - psy) <= 0.0001f;
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if (!u) {
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cy = 0;
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cwx = a * cx + parent.worldX;
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cwy = c * cx + parent.worldY;
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} else {
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cy = child.ay;
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cwx = a * cx + b * cy + parent.worldX;
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cwy = c * cx + d * cy + parent.worldY;
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}
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Bone pp = parent.parent;
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a = pp.a;
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b = pp.b;
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c = pp.c;
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d = pp.d;
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float id = 1 / (a * d - b * c), x = targetX - pp.worldX, y = targetY - pp.worldY;
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float tx = (x * d - y * b) * id - px, ty = (y * a - x * c) * id - py;
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x = cwx - pp.worldX;
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y = cwy - pp.worldY;
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float dx = (x * d - y * b) * id - px, dy = (y * a - x * c) * id - py;
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float l1 = (float)Math.Sqrt(dx * dx + dy * dy), l2 = child.data.length * csx, a1, a2;
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if (u) {
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l2 *= psx;
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float cos = (tx * tx + ty * ty - l1 * l1 - l2 * l2) / (2 * l1 * l2);
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if (cos < -1)
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cos = -1;
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else if (cos > 1) cos = 1;
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a2 = (float)Math.Acos(cos) * bendDir;
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a = l1 + l2 * cos;
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b = l2 * MathUtils.Sin(a2);
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a1 = MathUtils.Atan2(ty * a - tx * b, tx * a + ty * b);
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} else {
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a = psx * l2;
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b = psy * l2;
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float aa = a * a, bb = b * b, dd = tx * tx + ty * ty, ta = MathUtils.Atan2(ty, tx);
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c = bb * l1 * l1 + aa * dd - aa * bb;
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float c1 = -2 * bb * l1, c2 = bb - aa;
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d = c1 * c1 - 4 * c2 * c;
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if (d >= 0) {
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float q = (float)Math.Sqrt(d);
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if (c1 < 0) q = -q;
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q = -(c1 + q) / 2;
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float r0 = q / c2, r1 = c / q;
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float r = Math.Abs(r0) < Math.Abs(r1) ? r0 : r1;
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if (r * r <= dd) {
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y = (float)Math.Sqrt(dd - r * r) * bendDir;
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a1 = ta - MathUtils.Atan2(y, r);
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a2 = MathUtils.Atan2(y / psy, (r - l1) / psx);
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goto outer;
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}
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}
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float minAngle = 0, minDist = float.MaxValue, minX = 0, minY = 0;
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float maxAngle = 0, maxDist = 0, maxX = 0, maxY = 0;
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x = l1 + a;
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d = x * x;
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if (d > maxDist) {
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maxAngle = 0;
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maxDist = d;
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maxX = x;
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}
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x = l1 - a;
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d = x * x;
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if (d < minDist) {
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minAngle = MathUtils.PI;
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minDist = d;
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minX = x;
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}
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float angle = (float)Math.Acos(-a * l1 / (aa - bb));
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x = a * MathUtils.Cos(angle) + l1;
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y = b * MathUtils.Sin(angle);
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d = x * x + y * y;
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if (d < minDist) {
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minAngle = angle;
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minDist = d;
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minX = x;
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minY = y;
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}
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if (d > maxDist) {
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maxAngle = angle;
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maxDist = d;
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maxX = x;
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maxY = y;
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}
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if (dd <= (minDist + maxDist) / 2) {
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a1 = ta - MathUtils.Atan2(minY * bendDir, minX);
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a2 = minAngle * bendDir;
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} else {
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a1 = ta - MathUtils.Atan2(maxY * bendDir, maxX);
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a2 = maxAngle * bendDir;
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}
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}
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outer:
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float os = MathUtils.Atan2(cy, cx) * s2;
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float rotation = parent.arotation;
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a1 = (a1 - os) * MathUtils.RadDeg + os1 - rotation;
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if (a1 > 180)
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a1 -= 360;
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else if (a1 < -180) a1 += 360;
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parent.UpdateWorldTransform(px, py, rotation + a1 * alpha, parent.scaleX, parent.ascaleY, 0, 0);
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rotation = child.arotation;
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a2 = ((a2 + os) * MathUtils.RadDeg - child.ashearX) * s2 + os2 - rotation;
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if (a2 > 180)
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a2 -= 360;
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else if (a2 < -180) a2 += 360;
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child.UpdateWorldTransform(cx, cy, rotation + a2 * alpha, child.ascaleX, child.ascaleY, child.ashearX, child.ashearY);
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}
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}
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}
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