India/cocos2d-x/cocos/vr/CCVRDistortion.cpp

/****************************************************************************
 Copyright (c) 2016 Google Inc.
 Copyright (c) 2016 Chukong Technologies Inc.
 Copyright (c) 2017-2018 Xiamen Yaji Software Co., Ltd.

 http://www.cocos2d-x.org

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 all copies or substantial portions of the Software.

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 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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#include "vr/CCVRDistortion.h"
#include <math.h>

NS_CC_BEGIN

Distortion::Distortion()
{
    _coefficients[0] = 0.441f;
    _coefficients[1] = 0.156f;
}

void Distortion::setCoefficients(float *coefficients)
{
    for (int i = 0; i < s_numberOfCoefficients; i++)
    {
        _coefficients[i] = coefficients[i];
    }
}

float *Distortion::coefficients()
{
    return _coefficients;
}

float Distortion::distortionFactor(float radius)
{
    float result = 1.0f;
    float rFactor = 1.0f;
    float squaredRadius = radius * radius;
    for (int i = 0; i < s_numberOfCoefficients; i++)
    {
        rFactor *= squaredRadius;
        result += _coefficients[i] * rFactor;
    }
    return result;
}

float Distortion::distort(float radius)
{
    return radius * distortionFactor(radius);
}

float Distortion::distortInverse(float radius)
{
    float r0 = radius / 0.9f;
    float r = radius * 0.9f;
    float dr0 = radius - distort(r0);
    while (fabsf(r - r0) > 0.0001f)
    {
        float dr = radius - distort(r);
        float r2 = r - dr * ((r - r0) / (dr - dr0));
        r0 = r;
        r = r2;
        dr0 = dr;
    }
    return r;
}

NS_CC_END