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GPXSee/src/map/IMG/demtree.cpp
2025-01-17 07:38:31 +01:00

124 lines
2.9 KiB
C++

#include "demtree.h"
using namespace IMG;
#define DELTA 1e-9 /* ensure col+1/row+1 is in the next tile */
static double interpolate(double dx, double dy, double p0, double p1, double p2,
double p3)
{
return p0 * (1.0 - dx) * (1.0 - dy) + p1 * dx * (1.0 - dy)
+ p2 * dy * (1.0 - dx) + p3 * dx * dy;
}
static double val(const Matrix<qint16> &m, int row, int col)
{
qint16 v = m.at(row, col);
return (v == -32768) ? NAN : (double)v;
}
bool DEMTree::elevationCb(const MapData::Elevation *e, void *context)
{
ElevationCTX *ctx = (ElevationCTX*)context;
ctx->ele = elevation(ctx->tree, e, ctx->c);
return std::isnan(ctx->ele);
}
bool DEMTree::edgeCb(const MapData::Elevation *e, void *context)
{
EdgeCTX *ctx = (EdgeCTX*)context;
double x = (ctx->c.lon() - e->rect.left()) / e->xr;
double y = (e->rect.top() - ctx->c.lat()) / e->yr;
int row = qMin((int)y, e->m.h() - 1);
int col = qMin((int)x, e->m.w() - 1);
ctx->ele = val(e->m, row, col);
return std::isnan(ctx->ele);
}
double DEMTree::edge(const Tree &tree, const Coordinates &c)
{
double ele = NAN;
double min[2], max[2];
EdgeCTX ctx(c, ele);
min[0] = c.lon();
min[1] = c.lat();
max[0] = c.lon();
max[1] = c.lat();
tree.Search(min, max, edgeCb, &ctx);
return ele;
}
double DEMTree::elevation(const Tree &tree, const MapData::Elevation *e,
const Coordinates &c)
{
double x = (c.lon() - e->rect.left()) / e->xr;
double y = (e->rect.top() - c.lat()) / e->yr;
int row = qMin((int)y, e->m.h() - 1);
int col = qMin((int)x, e->m.w() - 1);
double p0 = val(e->m, row, col);
double p1 = (col == e->m.w() - 1)
? edge(tree, Coordinates(e->rect.left() + (col + 1) * e->xr + DELTA,
e->rect.top() - row * e->yr))
: val(e->m, row, col + 1);
double p2 = (row == e->m.h() - 1)
? edge(tree, Coordinates(e->rect.left() + col * e->xr,
e->rect.top() - (row + 1) * e->yr - DELTA))
: val(e->m, row + 1, col);
double p3 = ((col == e->m.w() - 1) || (row == e->m.h() - 1))
? edge(tree, Coordinates(e->rect.left() + (col + 1) * e->xr + DELTA,
e->rect.top() - (row + 1) * e->yr - DELTA))
: val(e->m, row + 1, col + 1);
return interpolate(x - col, y - row, p0, p1, p2, p3);
}
DEMTree::DEMTree(const QList<MapData::Elevation> &tiles)
{
double min[2], max[2];
for (int i = 0; i < tiles.size(); i++) {
const MapData::Elevation &e = tiles.at(i);
min[0] = e.rect.left();
min[1] = e.rect.bottom();
max[0] = e.rect.right();
max[1] = e.rect.top();
_tree.Insert(min, max, &e);
}
}
double DEMTree::elevation(const Coordinates &c) const
{
double ele = NAN;
double min[2], max[2];
ElevationCTX ctx(_tree, c, ele);
min[0] = c.lon();
min[1] = c.lat();
max[0] = c.lon();
max[1] = c.lat();
_tree.Search(min, max, elevationCb, &ctx);
return ele;
}
MatrixD DEMTree::elevation(const MatrixC &m) const
{
MatrixD ret(m.h(), m.w());
for (int i = 0; i < m.size(); i++)
ret.at(i) = elevation(m.at(i));
return ret;
}