OpenMW/components/detournavigator/tilebounds.hpp

#ifndef OPENMW_COMPONENTS_DETOURNAVIGATOR_TILEBOUNDS_H
#define OPENMW_COMPONENTS_DETOURNAVIGATOR_TILEBOUNDS_H

#include <components/misc/convert.hpp>

#include <osg/Vec2f>
#include <osg/Vec2i>

#include <BulletCollision/CollisionShapes/btCollisionShape.h>
#include <LinearMath/btTransform.h>

#include <algorithm>
#include <optional>
#include <tuple>

namespace DetourNavigator
{
    struct TileBounds
    {
        osg::Vec2f mMin;
        osg::Vec2f mMax;
    };

    inline bool operator<(const TileBounds& lhs, const TileBounds& rhs) noexcept
    {
        return std::tie(lhs.mMin, lhs.mMax) < std::tie(rhs.mMin, rhs.mMax);
    }

    inline std::optional<TileBounds> getIntersection(const TileBounds& a, const TileBounds& b) noexcept
    {
        const float minX = std::max(a.mMin.x(), b.mMin.x());
        const float maxX = std::min(a.mMax.x(), b.mMax.x());
        if (minX > maxX)
            return std::nullopt;
        const float minY = std::max(a.mMin.y(), b.mMin.y());
        const float maxY = std::min(a.mMax.y(), b.mMax.y());
        if (minY > maxY)
            return std::nullopt;
        return TileBounds {osg::Vec2f(minX, minY), osg::Vec2f(maxX, maxY)};
    }

    inline TileBounds maxCellTileBounds(const osg::Vec2i& position, int size)
    {
        return TileBounds {
            osg::Vec2f(position.x(), position.y()) * size,
            osg::Vec2f(position.x() + 1, position.y() + 1) * size
        };
    }

    inline TileBounds makeObjectTileBounds(const btCollisionShape& shape, const btTransform& transform)
    {
        btVector3 aabbMin;
        btVector3 aabbMax;
        shape.getAabb(transform, aabbMin, aabbMax);
        return TileBounds {Misc::Convert::toOsgXY(aabbMin), Misc::Convert::toOsgXY(aabbMax)};
    }
}

#endif