3DGradientMap.cpp

/*This file is part of the FEBio Studio source code and is licensed under the MIT license
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See Copyright-FEBio-Studio.txt for details.

Copyright (c) 2021 University of Utah, The Trustees of Columbia University in
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#include "stdafx.h"
#include "3DGradientMap.h"

//=============================================================================
// C3DGradientMap
//=============================================================================

C3DGradientMap::C3DGradientMap(C3DImage& im, BOX box) : m_im(im), m_box(box)
{

}

C3DGradientMap::~C3DGradientMap()
{
}

template<class pType> vec3f C3DGradientMap::ValueTemplate(int i, int j, int k)
{
    pType* data = (pType*)m_im.GetBytes();

    // get the image dimensions
	int nx = m_im.Width();
	int ny = m_im.Height();
	int nz = m_im.Depth();

	float dxi = (nx - 1.f) / (float)m_box.Width();
	float dyi = (ny - 1.f) / (float)m_box.Height();
	float dzi = (nz - 1.f) / (float)m_box.Depth();

    // calculate the gradient
	vec3f r;

    // x-component
	if (i == 0) r.x = ((float)data[nx*(k*ny + j) + i + 1] - (float)data[nx*(k*ny + j) + i]) * dxi;
	else if (i == nx - 1) r.x = ((float)data[nx*(k*ny + j) + i] - (float)data[nx*(k*ny + j) + i - 1]) * dxi;
	else r.x = ((float)data[nx*(k*ny + j) + i + 1] - (float)data[nx*(k*ny + j) + i - 1]) * (0.5f*dxi);

	// y-component
	if (j == 0) r.y = ((float)data[nx*(k*ny + j + 1) + i] - (float)data[nx*(k*ny + j) + i]) * dyi;
	else if (j == ny - 1) r.y = ((float)data[nx*(k*ny + j) + i] - (float)data[nx*(k*ny + j - 1) + i]) * dyi;
	else r.y = ((float)data[nx*(k*ny + j + 1) + i] - (float)data[nx*(k*ny + j - 1) + i]) * (0.5f*dyi);

	// z-component
	if (k == 0) r.z = ((float)data[nx*((k + 1)*ny + j) + i] - (float)data[nx*(k*ny + j) + i]) * dzi;
	else if (k == nz - 1) r.z = ((float)data[nx*(k*ny + j) + i] - (float)data[nx*((k - 1)*ny + j) + i]) * dzi;
	else r.z = ((float)data[nx*((k + 1)*ny + j) + i] - (float)data[nx*((k - 1)*ny + j) + i]) * (0.5f*dzi);

    return r;
}

vec3f C3DGradientMap::Value(int i, int j, int k)
{
	switch (m_im.PixelType())
    {
    case CImage::UINT_8:
        return ValueTemplate<uint8_t>(i, j, k);
    case CImage::INT_8:
        return ValueTemplate<int8_t>(i, j, k);
    case CImage::UINT_16:
        return ValueTemplate<uint16_t>(i, j, k);
    case CImage::INT_16:
        return ValueTemplate<int16_t>(i, j, k);
    case CImage::UINT_32:
        return ValueTemplate<uint16_t>(i, j, k);
    case CImage::INT_32:
        return ValueTemplate<int16_t>(i, j, k);
    case CImage::UINT_RGB8:
        return ValueTemplate<uint8_t>(i, j, k);
    case CImage::INT_RGB8:
        return ValueTemplate<int8_t>(i, j, k);
    case CImage::UINT_RGB16:
        return ValueTemplate<uint16_t>(i, j, k);
    case CImage::INT_RGB16:
        return ValueTemplate<int16_t>(i, j, k);
    case CImage::REAL_32:
        return ValueTemplate<float>(i, j, k);
    case CImage::REAL_64:
        return ValueTemplate<double>(i, j, k);
    default:
        assert(false);
    }

	// we shouldn't get here, but added it to avoid compiler warning
	return vec3f(0.f, 0.f, 0.f);
}