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comparison Framework/Toolbox/GeometryToolbox.h @ 175:15d92d93738b wasm

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fix interpolation with negative coordinates
author Sebastien Jodogne <s.jodogne@gmail.com>
date Fri, 09 Mar 2018 10:06:40 +0100
parents 316324f42848
children 83200c4d07ca
comparison
equal deleted inserted replaced
174:a7674c0ae4ac 175:15d92d93738b
133 { 133 {
134 // This function only works on fractional parts 134 // This function only works on fractional parts
135 assert(x >= 0 && y >= 0 && x < 1 && y < 1); 135 assert(x >= 0 && y >= 0 && x < 1 && y < 1);
136 136
137 // https://en.wikipedia.org/wiki/Bilinear_interpolation#Unit_square 137 // https://en.wikipedia.org/wiki/Bilinear_interpolation#Unit_square
138 return f00 * (1 - x) * (1 - y) + f01 * x * (1 - y) + f10 * (1 - x) * y + f11 * x * y; 138 return (f00 * (1.0f - x) * (1.0f - y) +
139 f01 * x * (1.0f - y) +
140 f10 * (1.0f - x) * y +
141 f11 * x * y);
139 } 142 }
140 143
141 144
142 float OrthancStone::GeometryToolbox::ComputeBilinearInterpolation(float x, 145 float OrthancStone::GeometryToolbox::ComputeBilinearInterpolation(float x,
143 float y, 146 float y,
144 float f00, 147 float f00,
145 float f01, 148 float f01,
146 float f10, 149 float f10,
147 float f11) 150 float f11)
148 { 151 {
149 assert(x >= 0 && y >= 0);
150
151 // Compute the fractional part of (x,y) 152 // Compute the fractional part of (x,y)
152 float xx = x - std::floor(x); 153 float xx = x - std::floor(x);
153 float yy = y - std::floor(y); 154 float yy = y - std::floor(y);
154 155
155 return ComputeBilinearInterpolationInternal(xx, yy, f00, f01, f10, f11); 156 return ComputeBilinearInterpolationInternal(xx, yy, f00, f01, f10, f11);
166 float f100, 167 float f100,
167 float f101, 168 float f101,
168 float f110, 169 float f110,
169 float f111) 170 float f111)
170 { 171 {
171 assert(x >= 0 && y >= 0 && z >= 0);
172
173 float xx = x - std::floor(x); 172 float xx = x - std::floor(x);
174 float yy = y - std::floor(y); 173 float yy = y - std::floor(y);
175 float zz = z - std::floor(z); 174 float zz = z - std::floor(z);
176 175
177 // "In practice, a trilinear interpolation is identical to two 176 // "In practice, a trilinear interpolation is identical to two
178 // bilinear interpolation combined with a linear interpolation" 177 // bilinear interpolation combined with a linear interpolation"
179 // https://en.wikipedia.org/wiki/Trilinear_interpolation#Method 178 // https://en.wikipedia.org/wiki/Trilinear_interpolation#Method
180 float a = ComputeBilinearInterpolationInternal(xx, yy, f000, f001, f010, f011); 179 float a = ComputeBilinearInterpolationInternal(xx, yy, f000, f001, f010, f011);
181 float b = ComputeBilinearInterpolationInternal(xx, yy, f100, f101, f110, f111); 180 float b = ComputeBilinearInterpolationInternal(xx, yy, f100, f101, f110, f111);
182 181
183 return (1 - zz) * a + zz * b; 182 return (1.0f - zz) * a + zz * b;
184 } 183 }