HTMesh.cpp

#include <cstdlib>
#include <iostream>
 
#include "HTMesh.h"
#include "MeshBuffer.h"
#include "MeshIterator.h"
 
#include "SpatialVector.h"
#include "SpatialIndex.h"
#include "RangeConvex.h"
#include "HtmRange.h"
#include "HtmRangeIterator.h"
 
/******************************************************************************
 * Note: There is "complete" checking for duplicate points in the line and
 * polygon intersection routines below.  This may have a slight performance
 * impact on indexing lines and polygons.
 *
 * -- James B. Bowlin
 *****************************************************************************/
 
HTMesh::HTMesh(int level, int buildLevel, int numBuffers)
    : m_level(level), m_buildLevel(buildLevel), m_numBuffers(numBuffers), htmDebug(0)
{
    name = "HTMesh";
    if (m_buildLevel > 0)
    {
        if (m_buildLevel > m_level)
            m_buildLevel = m_level;
        htm = new SpatialIndex(m_level, m_buildLevel);
    }
    else
    {
        htm = new SpatialIndex(m_level);
    }
 
    edge       = 2. / 3.14; //  inverse of roughly 1/4 circle
    numTrixels = 8;
    for (int i = m_level; i--;)
    {
        numTrixels *= 4;
        edge *= 2.0;
    }
    edge   = 1.0 / edge; // roughly length of one edge (radians)
    edge10 = edge / 10.0;
    eps    = 1.0e-6; // arbitrary small number
 
    magicNum   = numTrixels;
    degree2Rad = 3.1415926535897932385E0 / 180.0;
 
    // Allocate MeshBuffers
    m_meshBuffer = (MeshBuffer **)malloc(sizeof(MeshBuffer *) * numBuffers);
    if (m_meshBuffer == nullptr)
    {
        fprintf(stderr, "Out of memory allocating %d MeshBuffers.\n", numBuffers);
        exit(0);
    }
    for (int i = 0; i < numBuffers; i++)
    {
        m_meshBuffer[i] = new MeshBuffer(this);
    }
}
 
HTMesh::~HTMesh()
{
    delete htm;
    for (BufNum i = 0; i < m_numBuffers; i++)
        delete m_meshBuffer[i];
    free(m_meshBuffer);
}
 
Trixel HTMesh::index(double ra, double dec) const
{
    return (Trixel)htm->idByPoint(SpatialVector(ra, dec)) - magicNum;
}
 
bool HTMesh::performIntersection(RangeConvex *convex, BufNum bufNum)
{
    if (!validBufNum(bufNum))
        return false;
 
    convex->setOlevel(m_level);
    HtmRange range;
    convex->intersect(htm, &range);
    HtmRangeIterator iterator(&range);
 
    MeshBuffer *buffer = m_meshBuffer[bufNum];
    buffer->reset();
    while (iterator.hasNext())
    {
        buffer->append((Trixel)iterator.next() - magicNum);
    }
 
    if (buffer->error())
    {
        fprintf(stderr, "%s: trixel overflow.\n", name);
        return false;
    };
 
    return true;
}
 
// CIRCLE
void HTMesh::intersect(double ra, double dec, double radius, BufNum bufNum)
{
    double d = cos(radius * degree2Rad);
    SpatialConstraint c(SpatialVector(ra, dec), d);
    RangeConvex convex;
    convex.add(c); // [ed:RangeConvex::add]
 
    if (!performIntersection(&convex, bufNum))
        printf("In intersect(%f, %f, %f)\n", ra, dec, radius);
}
 
// TRIANGLE
void HTMesh::intersect(double ra1, double dec1, double ra2, double dec2, double ra3, double dec3, BufNum bufNum)
{
    if (fabs(ra1 - ra3) + fabs(dec1 - dec3) < eps)
        return intersect(ra1, dec1, ra2, dec2);
 
    else if (fabs(ra1 - ra2) + fabs(dec1 - dec2) < eps)
        return intersect(ra1, dec1, ra3, dec3);
 
    else if (fabs(ra2 - ra3) + fabs(dec2 - dec3) < eps)
        return intersect(ra1, dec1, ra2, dec2);
 
    SpatialVector p1(ra1, dec1);
    SpatialVector p2(ra2, dec2);
    SpatialVector p3(ra3, dec3);
    RangeConvex convex(&p1, &p2, &p3);
 
    if (!performIntersection(&convex, bufNum))
        printf("In intersect(%f, %f, %f, %f, %f, %f)\n", ra1, dec1, ra2, dec2, ra3, dec3);
}
 
// QUADRILATERAL
void HTMesh::intersect(double ra1, double dec1, double ra2, double dec2, double ra3, double dec3, double ra4,
                       double dec4, BufNum bufNum)
{
    if (fabs(ra1 - ra4) + fabs(dec1 - dec4) < eps)
        return intersect(ra2, dec2, ra3, dec3, ra4, dec4);
 
    else if (fabs(ra1 - ra2) + fabs(dec1 - dec2) < eps)
        return intersect(ra2, dec2, ra3, dec3, ra4, dec4);
 
    else if (fabs(ra2 - ra3) + fabs(dec2 - dec3) < eps)
        return intersect(ra1, dec1, ra2, dec2, ra4, dec4);
 
    else if (fabs(ra3 - ra4) + fabs(dec3 - dec4) < eps)
        return intersect(ra1, dec1, ra2, dec2, ra4, dec4);
 
    SpatialVector p1(ra1, dec1);
    SpatialVector p2(ra2, dec2);
    SpatialVector p3(ra3, dec3);
    SpatialVector p4(ra4, dec4);
    RangeConvex convex(&p1, &p2, &p3, &p4);
 
    if (!performIntersection(&convex, bufNum))
        printf("In intersect(%f, %f, %f, %f, %f, %f, %f, %f)\n", ra1, dec1, ra2, dec2, ra3, dec3, ra4, dec4);
}
 
void HTMesh::toXYZ(double ra, double dec, double *x, double *y, double *z)
{
    ra *= degree2Rad;
    dec *= degree2Rad;
 
    double sinRa  = sin(ra);
    double cosRa  = cos(ra);
    double sinDec = sin(dec);
    double cosDec = cos(dec);
 
    *x = cosDec * cosRa;
    *y = cosDec * sinRa;
    *z = sinDec;
}
 
// Intersect a line segment by forming a very thin triangle to use for the
// intersection.  Use cross product to ensure we have a perpendicular vector.
 
// LINE
void HTMesh::intersect(double ra1, double dec1, double ra2, double dec2, BufNum bufNum)
{
    double x1, y1, z1, x2, y2, z2;
 
    //if (ra1 == 0.0 || ra1 == 180.00) ra1 += 0.1;
    //if (ra2 == 0.0 || ra2 == 180.00) ra2 -= 0.1;
    //if (dec1 == 0.0 ) dec1 += 0.1;
    //if (dec2 == 0.0 ) dec2 -= 0.1;
 
    // convert to Cartesian. Ugh.
    toXYZ(ra1, dec1, &x1, &y1, &z1);
    toXYZ(ra2, dec2, &x2, &y2, &z2);
 
    // Check if points are too close
    double len;
    len = fabs(x1 - x2);
    len += fabs(y1 - y2);
    len += fabs(z1 - z2);
 
    if (htmDebug > 0)
    {
        printf("htmDebug = %d\n", htmDebug);
        printf("p1 = (%f, %f, %f)\n", x1, y1, z1);
        printf("p2 = (%f, %f, %f)\n", x2, y2, z2);
        printf("edge: %f (radians) %f (degrees)\n", edge, edge / degree2Rad);
        printf("len : %f (radians) %f (degrees)\n", len, len / degree2Rad);
    }
 
    if (len < edge10)
        return intersect(ra1, len, bufNum);
 
    // Cartesian cross product => perpendicular!.  Ugh.
    double cx = y1 * z2 - z1 * y2;
    double cy = z1 * x2 - x1 * z2;
    double cz = x1 * y2 - y1 * x2;
 
    if (htmDebug > 0)
        printf("cp  = (%f, %f, %f)\n", cx, cy, cz);
 
    double norm = edge10 / (fabs(cx) + fabs(cy) + fabs(cz));
 
    // give it length edge/10
    cx *= norm;
    cy *= norm;
    cz *= norm;
 
    if (htmDebug > 0)
        printf("cpn  = (%f, %f, %f)\n", cx, cy, cz);
 
    // add it to (ra1, dec1)
    cx += x1;
    cy += y1;
    cz += z1;
 
    if (htmDebug > 0)
        printf("cpf  = (%f, %f, %f)\n", cx, cy, cz);
 
    // back to spherical
    norm        = sqrt(cx * cx + cy * cy + cz * cz);
    double ra0  = atan2(cy, cx) / degree2Rad;
    double dec0 = asin(cz / norm) / degree2Rad;
 
    if (htmDebug > 0)
        printf("new ra, dec = (%f, %f)\n", ra0, dec0);
 
    SpatialVector p1(ra1, dec1);
    SpatialVector p0(ra0, dec0);
    SpatialVector p2(ra2, dec2);
    RangeConvex convex(&p1, &p0, &p2);
 
    if (!performIntersection(&convex, bufNum))
        printf("In intersect(%f, %f, %f, %f)\n", ra1, dec1, ra2, dec2);
}
 
MeshBuffer *HTMesh::meshBuffer(BufNum bufNum)
{
    if (!validBufNum(bufNum))
        return nullptr;
    return m_meshBuffer[bufNum];
}
 
int HTMesh::intersectSize(BufNum bufNum)
{
    if (!validBufNum(bufNum))
        return 0;
    return m_meshBuffer[bufNum]->size();
}
 
void HTMesh::vertices(Trixel id, double *ra1, double *dec1, double *ra2, double *dec2, double *ra3, double *dec3)
{
    SpatialVector v1, v2, v3;
    htm->nodeVertex(id + magicNum, v1, v2, v3);
    *ra1  = v1.ra();
    *dec1 = v1.dec();
    *ra2  = v2.ra();
    *dec2 = v2.dec();
    *ra3  = v3.ra();
    *dec3 = v3.dec();
}