//--------------------------------------------------------------------------------------------------
///
//--------------------------------------------------------------------------------------------------
void DrawableVectors::vectorMatrix(size_t vectorIndex, float vectorMatArray[16])
{
const Vec3f& anchorPt = m_vertexArray->get(vectorIndex);
Vec3f vec = m_vectorArray->get(vectorIndex);
float length = vec.length();
Quatf rotQuat;
// This should really be a ratio eval based on length of vector
// Copied from VTOVectorDrawer.cpp. TODO: refactor
static const float TINY_VEC_COMP = 0.0000000001f;
bool negZOnly = vec.z() < 0.0f && Math::abs(vec.x()) < TINY_VEC_COMP && Math::abs(vec.y()) < TINY_VEC_COMP;
if (negZOnly)
{
rotQuat.set(0.0f, 1.0f, 0.0f, 0.0f);
}
else
{
const Vec3f s = Vec3f::Z_AXIS;
Vec3f d = vec/length;
Vec3f v = s + d;
Vec3f cross = v ^ d;
float dot = v*d;
rotQuat.set(cross.x(), cross.y(), cross.z(), dot);
}
float Nq = rotQuat.x()*rotQuat.x() + rotQuat.y()*rotQuat.y() + rotQuat.z()*rotQuat.z() + rotQuat.w()*rotQuat.w();
float s = (Nq > 0.0f) ? (2.0f/Nq) : 0.0f;
float xs = rotQuat.x()*s;
float ys = rotQuat.y()*s;
float zs = rotQuat.z()*s;
float wx = rotQuat.w()*xs;
float wy = rotQuat.w()*ys;
float wz = rotQuat.w()*zs;
float xx = rotQuat.x()*xs;
float xy = rotQuat.x()*ys;
float xz = rotQuat.x()*zs;
float yy = rotQuat.y()*ys;
float yz = rotQuat.y()*zs;
float zz = rotQuat.z()*zs;
vectorMatArray[0] = length*(1.0f - (yy + zz));
vectorMatArray[1] = length*(xy + wz);
vectorMatArray[2] = length*(xz - wy);
vectorMatArray[3] = 0.0f;
vectorMatArray[4] = length*(xy - wz);
vectorMatArray[5] = length*(1.0f - (xx + zz));
vectorMatArray[6] = length*(yz + wx);
vectorMatArray[7] = 0.0f;
vectorMatArray[8] = length*(xz + wy);
vectorMatArray[9] = length*(yz - wx);
vectorMatArray[10] = length*(1.0f - (xx + yy));
vectorMatArray[11] = 0.0f;
// Set the translation
vectorMatArray[12] = anchorPt.x();
vectorMatArray[13] = anchorPt.y();
vectorMatArray[14] = anchorPt.z();
vectorMatArray[15] = 1.0f;
}
