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53 lines
1.6 KiB
C++
53 lines
1.6 KiB
C++
#ifndef OPENMW_COMPONENTS_MISC_PATHGRIDUTILS_H
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#define OPENMW_COMPONENTS_MISC_PATHGRIDUTILS_H
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#include "convert.hpp"
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#include <components/esm3/loadpgrd.hpp>
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#include <osg/Vec3f>
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#include <stdexcept>
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namespace Misc
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{
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// Slightly cheaper version for comparisons.
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// Caller needs to be careful for very short distances (i.e. less than 1)
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// or when accumuating the results i.e. (a + b)^2 != a^2 + b^2
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//
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inline float distanceSquared(const ESM::Pathgrid::Point& point, const osg::Vec3f& pos)
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{
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return (Misc::Convert::makeOsgVec3f(point) - pos).length2();
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}
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// Return the closest pathgrid point index from the specified position
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// coordinates. NOTE: Does not check if there is a sensible way to get there
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// (e.g. a cliff in front).
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//
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// NOTE: pos is expected to be in local coordinates, as is grid->mPoints
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//
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inline std::size_t getClosestPoint(const ESM::Pathgrid& grid, const osg::Vec3f& pos)
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{
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if (grid.mPoints.empty())
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throw std::invalid_argument("Pathgrid has no points");
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float minDistance = distanceSquared(grid.mPoints[0], pos);
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std::size_t closestIndex = 0;
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// TODO: if this full scan causes performance problems mapping pathgrid
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// points to a quadtree may help
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for (std::size_t i = 1; i < grid.mPoints.size(); ++i)
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{
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const float distance = distanceSquared(grid.mPoints[i], pos);
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if (minDistance > distance)
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{
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minDistance = distance;
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closestIndex = i;
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}
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}
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return closestIndex;
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}
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}
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#endif
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