[5] | 1 | /* |
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| 2 | ----------------------------------------------------------------------------- |
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| 3 | This source file is part of OGRE |
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| 4 | (Object-oriented Graphics Rendering Engine) |
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| 5 | For the latest info, see http://www.ogre3d.org/ |
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| 6 | |
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| 7 | Copyright (c) 2000-2006 Torus Knot Software Ltd |
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| 8 | Also see acknowledgements in Readme.html |
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| 9 | |
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| 10 | This program is free software; you can redistribute it and/or modify it under |
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| 11 | the terms of the GNU Lesser General Public License as published by the Free Software |
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| 12 | Foundation; either version 2 of the License, or (at your option) any later |
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| 13 | version. |
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| 14 | |
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| 15 | This program is distributed in the hope that it will be useful, but WITHOUT |
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| 16 | ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS |
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| 17 | FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. |
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| 18 | |
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| 19 | You should have received a copy of the GNU Lesser General Public License along with |
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| 20 | this program; if not, write to the Free Software Foundation, Inc., 59 Temple |
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| 21 | Place - Suite 330, Boston, MA 02111-1307, USA, or go to |
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| 22 | http://www.gnu.org/copyleft/lesser.txt. |
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| 23 | |
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| 24 | You may alternatively use this source under the terms of a specific version of |
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| 25 | the OGRE Unrestricted License provided you have obtained such a license from |
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| 26 | Torus Knot Software Ltd. |
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| 27 | ----------------------------------------------------------------------------- |
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| 28 | */ |
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| 29 | #include "OgreStableHeaders.h" |
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| 30 | #include "OgreSimpleSpline.h" |
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| 31 | #include "OgreVector4.h" |
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| 32 | #include "OgreMatrix4.h" |
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| 33 | |
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| 34 | |
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| 35 | |
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| 36 | namespace Ogre { |
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| 37 | |
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| 38 | //--------------------------------------------------------------------- |
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| 39 | SimpleSpline::SimpleSpline() |
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| 40 | { |
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| 41 | // Set up matrix |
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| 42 | // Hermite polynomial |
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| 43 | mCoeffs[0][0] = 2; |
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| 44 | mCoeffs[0][1] = -2; |
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| 45 | mCoeffs[0][2] = 1; |
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| 46 | mCoeffs[0][3] = 1; |
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| 47 | mCoeffs[1][0] = -3; |
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| 48 | mCoeffs[1][1] = 3; |
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| 49 | mCoeffs[1][2] = -2; |
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| 50 | mCoeffs[1][3] = -1; |
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| 51 | mCoeffs[2][0] = 0; |
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| 52 | mCoeffs[2][1] = 0; |
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| 53 | mCoeffs[2][2] = 1; |
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| 54 | mCoeffs[2][3] = 0; |
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| 55 | mCoeffs[3][0] = 1; |
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| 56 | mCoeffs[3][1] = 0; |
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| 57 | mCoeffs[3][2] = 0; |
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| 58 | mCoeffs[3][3] = 0; |
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| 59 | |
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| 60 | mAutoCalc = true; |
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| 61 | } |
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| 62 | //--------------------------------------------------------------------- |
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| 63 | SimpleSpline::~SimpleSpline() |
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| 64 | { |
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| 65 | } |
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| 66 | //--------------------------------------------------------------------- |
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| 67 | void SimpleSpline::addPoint(const Vector3& p) |
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| 68 | { |
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| 69 | mPoints.push_back(p); |
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| 70 | if (mAutoCalc) |
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| 71 | { |
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| 72 | recalcTangents(); |
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| 73 | } |
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| 74 | } |
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| 75 | //--------------------------------------------------------------------- |
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| 76 | Vector3 SimpleSpline::interpolate(Real t) |
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| 77 | { |
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| 78 | // Currently assumes points are evenly spaced, will cause velocity |
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| 79 | // change where this is not the case |
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| 80 | // TODO: base on arclength? |
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| 81 | |
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| 82 | |
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| 83 | // Work out which segment this is in |
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| 84 | Real fSeg = t * (mPoints.size() - 1); |
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| 85 | unsigned int segIdx = (unsigned int)fSeg; |
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| 86 | // Apportion t |
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| 87 | t = fSeg - segIdx; |
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| 88 | |
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| 89 | return interpolate(segIdx, t); |
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| 90 | |
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| 91 | } |
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| 92 | //--------------------------------------------------------------------- |
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| 93 | Vector3 SimpleSpline::interpolate(unsigned int fromIndex, Real t) |
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| 94 | { |
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| 95 | // Bounds check |
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| 96 | assert (fromIndex < mPoints.size() && |
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| 97 | "fromIndex out of bounds"); |
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| 98 | |
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| 99 | if ((fromIndex + 1) == mPoints.size()) |
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| 100 | { |
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| 101 | // Duff request, cannot blend to nothing |
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| 102 | // Just return source |
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| 103 | return mPoints[fromIndex]; |
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| 104 | |
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| 105 | } |
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| 106 | |
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| 107 | // Fast special cases |
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| 108 | if (t == 0.0f) |
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| 109 | { |
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| 110 | return mPoints[fromIndex]; |
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| 111 | } |
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| 112 | else if(t == 1.0f) |
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| 113 | { |
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| 114 | return mPoints[fromIndex + 1]; |
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| 115 | } |
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| 116 | |
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| 117 | // Real interpolation |
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| 118 | // Form a vector of powers of t |
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| 119 | Real t2, t3; |
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| 120 | t2 = t * t; |
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| 121 | t3 = t2 * t; |
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| 122 | Vector4 powers(t3, t2, t, 1); |
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| 123 | |
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| 124 | |
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| 125 | // Algorithm is ret = powers * mCoeffs * Matrix4(point1, point2, tangent1, tangent2) |
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| 126 | Vector3& point1 = mPoints[fromIndex]; |
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| 127 | Vector3& point2 = mPoints[fromIndex+1]; |
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| 128 | Vector3& tan1 = mTangents[fromIndex]; |
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| 129 | Vector3& tan2 = mTangents[fromIndex+1]; |
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| 130 | Matrix4 pt; |
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| 131 | |
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| 132 | pt[0][0] = point1.x; |
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| 133 | pt[0][1] = point1.y; |
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| 134 | pt[0][2] = point1.z; |
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| 135 | pt[0][3] = 1.0f; |
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| 136 | pt[1][0] = point2.x; |
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| 137 | pt[1][1] = point2.y; |
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| 138 | pt[1][2] = point2.z; |
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| 139 | pt[1][3] = 1.0f; |
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| 140 | pt[2][0] = tan1.x; |
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| 141 | pt[2][1] = tan1.y; |
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| 142 | pt[2][2] = tan1.z; |
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| 143 | pt[2][3] = 1.0f; |
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| 144 | pt[3][0] = tan2.x; |
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| 145 | pt[3][1] = tan2.y; |
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| 146 | pt[3][2] = tan2.z; |
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| 147 | pt[3][3] = 1.0f; |
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| 148 | |
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| 149 | Vector4 ret = powers * mCoeffs * pt; |
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| 150 | |
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| 151 | |
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| 152 | return Vector3(ret.x, ret.y, ret.z); |
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| 153 | |
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| 154 | |
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| 155 | |
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| 156 | |
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| 157 | } |
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| 158 | //--------------------------------------------------------------------- |
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| 159 | void SimpleSpline::recalcTangents(void) |
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| 160 | { |
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| 161 | // Catmull-Rom approach |
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| 162 | // |
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| 163 | // tangent[i] = 0.5 * (point[i+1] - point[i-1]) |
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| 164 | // |
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| 165 | // Assume endpoint tangents are parallel with line with neighbour |
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| 166 | |
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| 167 | size_t i, numPoints; |
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| 168 | bool isClosed; |
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| 169 | |
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| 170 | numPoints = mPoints.size(); |
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| 171 | if (numPoints < 2) |
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| 172 | { |
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| 173 | // Can't do anything yet |
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| 174 | return; |
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| 175 | } |
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| 176 | |
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| 177 | // Closed or open? |
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| 178 | if (mPoints[0] == mPoints[numPoints-1]) |
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| 179 | { |
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| 180 | isClosed = true; |
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| 181 | } |
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| 182 | else |
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| 183 | { |
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| 184 | isClosed = false; |
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| 185 | } |
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| 186 | |
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| 187 | mTangents.resize(numPoints); |
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| 188 | |
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| 189 | |
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| 190 | |
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| 191 | for(i = 0; i < numPoints; ++i) |
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| 192 | { |
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| 193 | if (i ==0) |
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| 194 | { |
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| 195 | // Special case start |
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| 196 | if (isClosed) |
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| 197 | { |
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| 198 | // Use numPoints-2 since numPoints-1 is the last point and == [0] |
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| 199 | mTangents[i] = 0.5 * (mPoints[1] - mPoints[numPoints-2]); |
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| 200 | } |
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| 201 | else |
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| 202 | { |
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| 203 | mTangents[i] = 0.5 * (mPoints[1] - mPoints[0]); |
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| 204 | } |
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| 205 | } |
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| 206 | else if (i == numPoints-1) |
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| 207 | { |
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| 208 | // Special case end |
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| 209 | if (isClosed) |
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| 210 | { |
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| 211 | // Use same tangent as already calculated for [0] |
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| 212 | mTangents[i] = mTangents[0]; |
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| 213 | } |
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| 214 | else |
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| 215 | { |
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| 216 | mTangents[i] = 0.5 * (mPoints[i] - mPoints[i-1]); |
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| 217 | } |
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| 218 | } |
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| 219 | else |
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| 220 | { |
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| 221 | mTangents[i] = 0.5 * (mPoints[i+1] - mPoints[i-1]); |
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| 222 | } |
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| 223 | |
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| 224 | } |
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| 225 | |
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| 226 | |
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| 227 | |
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| 228 | } |
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| 229 | //--------------------------------------------------------------------- |
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| 230 | const Vector3& SimpleSpline::getPoint(unsigned short index) const |
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| 231 | { |
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| 232 | assert (index < mPoints.size() && "Point index is out of bounds!!"); |
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| 233 | |
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| 234 | return mPoints[index]; |
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| 235 | } |
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| 236 | //--------------------------------------------------------------------- |
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| 237 | unsigned short SimpleSpline::getNumPoints(void) const |
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| 238 | { |
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| 239 | return (unsigned short)mPoints.size(); |
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| 240 | } |
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| 241 | //--------------------------------------------------------------------- |
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| 242 | void SimpleSpline::clear(void) |
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| 243 | { |
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| 244 | mPoints.clear(); |
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| 245 | mTangents.clear(); |
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| 246 | } |
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| 247 | //--------------------------------------------------------------------- |
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| 248 | void SimpleSpline::updatePoint(unsigned short index, const Vector3& value) |
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| 249 | { |
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| 250 | assert (index < mPoints.size() && "Point index is out of bounds!!"); |
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| 251 | |
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| 252 | mPoints[index] = value; |
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| 253 | if (mAutoCalc) |
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| 254 | { |
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| 255 | recalcTangents(); |
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| 256 | } |
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| 257 | } |
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| 258 | //--------------------------------------------------------------------- |
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| 259 | void SimpleSpline::setAutoCalculate(bool autoCalc) |
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| 260 | { |
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| 261 | mAutoCalc = autoCalc; |
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| 262 | } |
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| 263 | |
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| 264 | |
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| 265 | |
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| 266 | |
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| 267 | } |
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| 268 | |
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| 269 | |
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| 270 | |
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| 271 | |
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