axmol/core/3d/Ray.cpp

/****************************************************************************
Copyright (c) 2014-2016 Chukong Technologies Inc.
Copyright (c) 2017-2018 Xiamen Yaji Software Co., Ltd.

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#include "3d/Ray.h"

namespace ax
{

Ray::Ray() : _direction(0, 0, 1) {}

Ray::Ray(const Ray& ray)
{
    set(ray._origin, ray._direction);
}

Ray::Ray(const Vec3& origin, const Vec3& direction)
{
    set(origin, direction);
}

Ray::~Ray() {}

bool Ray::intersects(const AABB& box, float* distance) const
{
    float lowt = 0.0f;
    float t;
    bool hit = false;
    Vec3 hitpoint;
    const Vec3& min     = box._min;
    const Vec3& max     = box._max;
    const Vec3& rayorig = _origin;
    const Vec3& raydir  = _direction;

    // Check origin inside first
    if (rayorig > min && rayorig < max)
        return true;

    // Check each face in turn, only check closest 3
    // Min x
    if (rayorig.x <= min.x && raydir.x > 0)
    {
        t = (min.x - rayorig.x) / raydir.x;
        if (t >= 0)
        {
            // Substitute t back into ray and check bounds and dist
            hitpoint = rayorig + raydir * t;
            if (hitpoint.y >= min.y && hitpoint.y <= max.y && hitpoint.z >= min.z && hitpoint.z <= max.z &&
                (!hit || t < lowt))
            {
                hit  = true;
                lowt = t;
            }
        }
    }
    // Max x
    if (rayorig.x >= max.x && raydir.x < 0)
    {
        t = (max.x - rayorig.x) / raydir.x;
        if (t >= 0)
        {
            // Substitute t back into ray and check bounds and dist
            hitpoint = rayorig + raydir * t;
            if (hitpoint.y >= min.y && hitpoint.y <= max.y && hitpoint.z >= min.z && hitpoint.z <= max.z &&
                (!hit || t < lowt))
            {
                hit  = true;
                lowt = t;
            }
        }
    }
    // Min y
    if (rayorig.y <= min.y && raydir.y > 0)
    {
        t = (min.y - rayorig.y) / raydir.y;
        if (t >= 0)
        {
            // Substitute t back into ray and check bounds and dist
            hitpoint = rayorig + raydir * t;
            if (hitpoint.x >= min.x && hitpoint.x <= max.x && hitpoint.z >= min.z && hitpoint.z <= max.z &&
                (!hit || t < lowt))
            {
                hit  = true;
                lowt = t;
            }
        }
    }
    // Max y
    if (rayorig.y >= max.y && raydir.y < 0)
    {
        t = (max.y - rayorig.y) / raydir.y;
        if

            (t >= 0)
        {
            // Substitute t back into ray and check bounds and dist
            hitpoint = rayorig + raydir * t;
            if (hitpoint.x >= min.x && hitpoint.x <= max.x && hitpoint.z >= min.z && hitpoint.z <= max.z &&
                (!hit || t < lowt))
            {
                hit  = true;
                lowt = t;
            }
        }
    }
    // Min z
    if (rayorig.z <= min.z && raydir.z > 0)
    {
        t = (min.z - rayorig.z) / raydir.z;
        if (t >= 0)
        {
            // Substitute t back into ray and check bounds and dist
            hitpoint = rayorig + raydir * t;
            if (hitpoint.x >= min.x && hitpoint.x <= max.x && hitpoint.y >= min.y && hitpoint.y <= max.y &&
                (!hit || t < lowt))
            {
                hit  = true;
                lowt = t;
            }
        }
    }
    // Max z
    if (rayorig.z >= max.z && raydir.z < 0)
    {
        t = (max.z - rayorig.z) / raydir.z;
        if (t >= 0)
        {
            // Substitute t back into ray and check bounds and dist
            hitpoint = rayorig + raydir * t;
            if (hitpoint.x >= min.x && hitpoint.x <= max.x && hitpoint.y >= min.y && hitpoint.y <= max.y &&
                (!hit || t < lowt))
            {
                hit  = true;
                lowt = t;
            }
        }
    }

    if (distance)
        *distance = lowt;

    return hit;
}

bool Ray::intersects(const OBB& obb, float* distance) const
{
    AABB aabb;
    aabb._min = -obb._extents;
    aabb._max = obb._extents;

    Ray ray;
    ray._direction = _direction;
    ray._origin    = _origin;

    Mat4 mat = Mat4::IDENTITY;
    mat.m[0] = obb._xAxis.x;
    mat.m[1] = obb._xAxis.y;
    mat.m[2] = obb._xAxis.z;

    mat.m[4] = obb._yAxis.x;
    mat.m[5] = obb._yAxis.y;
    mat.m[6] = obb._yAxis.z;

    mat.m[8]  = obb._zAxis.x;
    mat.m[9]  = obb._zAxis.y;
    mat.m[10] = obb._zAxis.z;

    mat.m[12] = obb._center.x;
    mat.m[13] = obb._center.y;
    mat.m[14] = obb._center.z;

    mat = mat.getInversed();

    ray.transform(mat);

    return ray.intersects(aabb, distance);
}

float Ray::dist(const Plane& plane) const
{
    float ndd = Vec3::dot(plane.getNormal(), _direction);
    if (ndd == 0)
        return 0.0f;
    float ndo = Vec3::dot(plane.getNormal(), _origin);
    return (plane.getDist() - ndo) / ndd;
}

Vec3 Ray::intersects(const Plane& plane) const
{
    float dis = this->dist(plane);
    return _origin + dis * _direction;
}

void Ray::set(const Vec3& origin, const Vec3& direction)
{
    _origin    = origin;
    _direction = direction;
    _direction.normalize();
}

void Ray::transform(const Mat4& matrix)
{
    matrix.transformPoint(&_origin);
    matrix.transformVector(&_direction);
    _direction.normalize();
}

}