72 lines
1.9 KiB
C++
Executable File
72 lines
1.9 KiB
C++
Executable File
/*
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* Copyright 2017 The Cartographer Authors
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include "cartographer/io/color.h"
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#include <cmath>
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#include "cartographer/common/port.h"
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#include "glog/logging.h"
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namespace cartographer {
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namespace io {
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namespace {
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constexpr float kInitialHue = 0.69f;
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constexpr float kSaturation = 0.85f;
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constexpr float kValue = 0.77f;
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FloatColor HsvToRgb(const float h, const float s, const float v) {
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const float h_6 = (h == 1.f) ? 0.f : 6 * h;
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const int h_i = std::floor(h_6);
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const float f = h_6 - h_i;
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const float p = v * (1.f - s);
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const float q = v * (1.f - f * s);
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const float t = v * (1.f - (1.f - f) * s);
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if (h_i == 0) {
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return {{v, t, p}};
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} else if (h_i == 1) {
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return {{q, v, p}};
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} else if (h_i == 2) {
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return {{p, v, t}};
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} else if (h_i == 3) {
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return {{p, q, v}};
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} else if (h_i == 4) {
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return {{t, p, v}};
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} else if (h_i == 5) {
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return {{v, p, q}};
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} else {
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return {{0.f, 0.f, 0.f}};
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}
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}
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} // namespace
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FloatColor GetColor(int id) {
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CHECK_GE(id, 0);
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// Uniform color sampling using the golden ratio from
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// http://martin.ankerl.com/2009/12/09/how-to-create-random-colors-programmatically/
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constexpr float kGoldenRatioConjugate = 0.6180339887498949f;
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const float hue = std::fmod(kInitialHue + kGoldenRatioConjugate * id, 1.f);
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return HsvToRgb(hue, kSaturation, kValue);
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}
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} // namespace io
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} // namespace cartographer
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