UT/UT_Cdf.h

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/*
 * PROPRIETARY INFORMATION.  This software is proprietary to
 * Side Effects Software Inc., and is not to be reproduced,
 * transmitted, or disclosed in any way without written permission.
 *
 * Produced by:
 *      Andrew Clinton
 *      Side Effects Software Inc
 *      123 Front Street West, Suite 1401
 *      Toronto, Ontario
 *      Canada   M5J 2M2
 *      416-504-9876
 *
 * NAME:        UT_Cdf.h ( UT Library, C++)
 *
 * COMMENTS:    An N-Dimensional cumulative distribution function (CDF)
 *              for sampling.
 */

#ifndef __UT_Cdf__
#define __UT_Cdf__

#include "UT_API.h"
#include <SYS/SYS_Types.h>
#include "UT_Assert.h"
#include "UT_VoxelArray.h"

class UT_API UT_Cdf
{
public:
    /// Construct from a voxel array (dimensions = 3)
    /// Voxel values less than 0 will be treated as zero.
             UT_Cdf(const UT_VoxelArrayF &voxels);

    /// Construct from a float array
    ///         data    = row-major data
    ///         res     = resolution for each dimension
    ///         dim     = number of dimensions
    /// data values less than zero will be treated as zero.
             UT_Cdf(const fpreal *data, const int *res, int dim);
    virtual ~UT_Cdf();

    /// Draw an importance sample from the cdf.  sval and dval must have
    /// myDim entries.
    void        sample(const fpreal *sval, fpreal *dval);

    /// Get the average image value
    fpreal      getScaling()
                {
                    fpreal      scale = myCdf[0][myRes[0]-1];
                    int         i;

                    for (i = 0; i < myDim; i++)
                        scale /= (fpreal)myRes[i];

                    return scale;
                }

private:
             UT_Cdf() {}

    void        initCdf(int size);

private:
    fpreal      **myCdf;
    int          *myRes;
    int           myDim;
};

#endif

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