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/*
* Copyright (C) 2012 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef LATINIME_GEOMETRY_UTILS_H
#define LATINIME_GEOMETRY_UTILS_H
#include <cmath>
#include "defines.h"
#define DEBUG_DECODER false
#define M_PI_F 3.14159265f
#define ROUND_FLOAT_10000(f) ((f) < 1000.0f && (f) > 0.001f) \
? (floorf((f) * 10000.0f) / 10000.0f) : (f)
namespace latinime {
static inline float SQUARE_FLOAT(const float x) { return x * x; }
static inline float getSquaredDistanceFloat(const float x1, const float y1, const float x2,
const float y2) {
return SQUARE_FLOAT(x1 - x2) + SQUARE_FLOAT(y1 - y2);
}
static inline float getNormalizedSquaredDistanceFloat(const float x1, const float y1,
const float x2, const float y2, const float scale) {
return getSquaredDistanceFloat(x1, y1, x2, y2) / SQUARE_FLOAT(scale);
}
static inline float getDistanceFloat(const float x1, const float y1, const float x2,
const float y2) {
return hypotf(x1 - x2, y1 - y2);
}
static AK_FORCE_INLINE int getDistanceInt(const int x1, const int y1, const int x2, const int y2) {
return static_cast<int>(getDistanceFloat(static_cast<float>(x1), static_cast<float>(y1),
static_cast<float>(x2), static_cast<float>(y2)));
}
static AK_FORCE_INLINE float getAngle(const int x1, const int y1, const int x2, const int y2) {
const int dx = x1 - x2;
const int dy = y1 - y2;
if (dx == 0 && dy == 0) return 0;
return atan2f(static_cast<float>(dy), static_cast<float>(dx));
}
static AK_FORCE_INLINE float getAngleDiff(const float a1, const float a2) {
const float deltaA = fabsf(a1 - a2);
const float diff = ROUND_FLOAT_10000(deltaA);
if (diff > M_PI_F) {
const float normalizedDiff = 2.0f * M_PI_F - diff;
return ROUND_FLOAT_10000(normalizedDiff);
}
return diff;
}
static inline float pointToLineSegSquaredDistanceFloat(const float x, const float y, const float x1,
const float y1, const float x2, const float y2, const bool extend) {
const float ray1x = x - x1;
const float ray1y = y - y1;
const float ray2x = x2 - x1;
const float ray2y = y2 - y1;
const float dotProduct = ray1x * ray2x + ray1y * ray2y;
const float lineLengthSqr = SQUARE_FLOAT(ray2x) + SQUARE_FLOAT(ray2y);
const float projectionLengthSqr = dotProduct / lineLengthSqr;
float projectionX;
float projectionY;
if (!extend && projectionLengthSqr < 0.0f) {
projectionX = x1;
projectionY = y1;
} else if (!extend && projectionLengthSqr > 1.0f) {
projectionX = x2;
projectionY = y2;
} else {
projectionX = x1 + projectionLengthSqr * ray2x;
projectionY = y1 + projectionLengthSqr * ray2y;
}
return getSquaredDistanceFloat(x, y, projectionX, projectionY);
}
// Normal distribution N(u, sigma^2).
struct NormalDistribution {
NormalDistribution(const float u, const float sigma)
: mU(u), mSigma(sigma),
mPreComputedNonExpPart(1.0f / sqrtf(2.0f * M_PI_F * SQUARE_FLOAT(sigma))),
mPreComputedExponentPart(-1.0f / (2.0f * SQUARE_FLOAT(sigma))) {}
float getProbabilityDensity(const float x) const {
const float shiftedX = x - mU;
return mPreComputedNonExpPart * expf(mPreComputedExponentPart * SQUARE_FLOAT(shiftedX));
}
private:
DISALLOW_IMPLICIT_CONSTRUCTORS(NormalDistribution);
float mU; // mean value
float mSigma; // standard deviation
float mPreComputedNonExpPart; // = 1 / sqrt(2 * PI * sigma^2)
float mPreComputedExponentPart; // = -1 / (2 * sigma^2)
}; // struct NormalDistribution
} // namespace latinime
#endif // LATINIME_GEOMETRY_UTILS_H
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