/// <summary>
/// min(ax + by + cz + d) = min(ax) + min(by) + min(cz) + min(d)
/// max(ax + by + cz + d) = max(ax) + max(by) + max(cz) + max(d)
///
/// Prev_Box = [min, max] = [c - r, c + r] = [min(cx +- rx, cy +- ry, cz +- rz), max(cx +- rx, cy +- ry, cz +- rz)]
/// Post_Box = [M(c-r), M(c+r)] = [min(M(cx +- rx, cy +- ry, cz +- rz, 1)), max(M(cx +- rx, cy +- ry, cz +- rz, 1))]
/// =[min(M0(cx +- rx) + M1(cy +- ry) + M2(cz +- rz) + M3), max(M0(cx +- rx)+ M1(cy +- ry)+ M2(cz +- rz)+M3)]
/// =[min(M0(cx +- rx)) + min(M1(cy +- ry)) + min(M2(cz +- rz)) + M3, max(M0(cx +- rx)) + max(M1(cy +- ry)) + max(M2(cz +- rz)) + M3]
/// </summary>
public void UpdateTransform()
{
ModelWorldMatrix = Drawer.transform.localToWorldMatrix;
Vector3 xa = ModelWorldMatrix.GetColumn(0) * Model.Box.Min.x;
Vector3 xb = ModelWorldMatrix.GetColumn(0) * Model.Box.Max.x;
Vector3 ya = ModelWorldMatrix.GetColumn(1) * Model.Box.Min.y;
Vector3 yb = ModelWorldMatrix.GetColumn(1) * Model.Box.Max.y;
Vector3 za = ModelWorldMatrix.GetColumn(2) * Model.Box.Min.z;
Vector3 zb = ModelWorldMatrix.GetColumn(2) * Model.Box.Max.z;
Vector3 last = ModelWorldMatrix.GetColumn(3);
float w = 1.0f / ModelWorldMatrix[3, 3];
Box.Min = w * (Vector3.Min(xa, xb) + Vector3.Min(ya, yb) + Vector3.Min(za, zb) + last);
Box.Max = w * (Vector3.Max(xa, xb) + Vector3.Max(ya, yb) + Vector3.Max(za, zb) + last);
Box.ToMidSize();
}
