QVector4D Cylinder::surfaceNormal(const QVector4D &p, const Ray &ray)
{
QVector4D lp = m_worldToObject * p;
QMatrix4x4 a = m_worldToObject.transposed();
a.setRow(3, QVector4D(0.0, 0.0, 0.0, 1.0));
if (m_hasCaps && fabs(fabs(lp.y()) - m_length * 0.5) < MathUtils::dEpsilon) {
// Return cap normal
QVector4D n;
if (lp.y() < 0.0)
n = QVector4D(0.0, -1.0, 0.0, 0.0);
else
n = QVector4D(0.0, 1.0, 0.0, 0.0);
return (a * n).normalized();
} else {
// calculate cylinder normal
QVector4D o = QVector4D(0.0, lp.y(), 0.0, 1.0);
QVector4D n = lp - o;
n = a * n;
QVector4D rd = -ray.direction();
if (QVector4D::dotProduct(n, rd) < 0)
return -n.normalized();
else
return n.normalized();
}
}
QVector4D Cone::surfaceNormal(const QVector4D &p, const Ray &ray)
{
QVector4D objectP = m_worldToObject * p;
QVector4D n = fabs(objectP.y()) < MathUtils::dEpsilon ? QVector4D(0.0, -1.0, 0.0, 0.0) : // We're on the base disc
QVector4D(objectP.x(), 1.0 - objectP.y(), objectP.z(), 0.0);
QMatrix4x4 a = m_worldToObject.transposed();
a.setRow(3, QVector4D(0.0, 0.0, 0.0, 1.0));
n = a * n;
return n.normalized();
}
void Ray::set(const QVector4D &o, const QVector4D &d)
{
m_o = o;
m_d = d.normalized();
}