axmol/cocos/3d/CCRay.cpp

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#include "3d/CCRay.h"

NS_CC_BEGIN

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

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

Ray::~Ray()
{
}

bool Ray::intersects(const AABB& aabb) const
{
    Vec3 ptOnPlane;
    Vec3 min = aabb._min;
    Vec3 max = aabb._max;
    
    const Vec3& origin = _origin;
    const Vec3& dir = _direction;
    
    float t;
    
    if (dir.x != 0.f)
    {
        if (dir.x > 0)
            t = (min.x - origin.x) / dir.x;
        else
            t = (max.x - origin.x) / dir.x;
        
        if (t > 0.f)
        {
            ptOnPlane = origin + t * dir;

            if (min.y < ptOnPlane.y && ptOnPlane.y < max.y && min.z < ptOnPlane.z && ptOnPlane.z < max.z)
            {
                return true;
            }
        }
    }
    
    if (dir.y != 0.f)
    {
        if (dir.y > 0)
            t = (min.y - origin.y) / dir.y;
        else
            t = (max.y - origin.y) / dir.y;
        
        if (t > 0.f)
        {
            ptOnPlane = origin + t * dir;

            if (min.z < ptOnPlane.z && ptOnPlane.z < max.z && min.x < ptOnPlane.x && ptOnPlane.x < max.x)
            {
                return true;
            }
        }
    }
    
	if (dir.z != 0.f)
	{
        if (dir.z > 0)
            t = (min.z - origin.z) / dir.z;
        else
            t = (max.z - origin.z) / dir.z;
        
        if (t > 0.f)
        {
            ptOnPlane = origin + t * dir;
            
            if (min.x < ptOnPlane.x && ptOnPlane.x < max.x && min.y < ptOnPlane.y && ptOnPlane.y < max.y)
            {
                return true;
            }
        }
    }
    
    return false;
}

bool Ray::intersects(const OBB& obb) 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);
}

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();
}

NS_CC_END