/// <summary>
/// Detects if this AABB contains another one
/// </summary>
/// <param name="aabb">AABB</param>
/// <returns>Returns true if the specified AABB is contained otherwise false</returns>
public bool Contains(AxisAlignedBox aabb)
{
Vector3 distance;
Vector3.Subtract(ref Center, ref aabb.Center, out distance);
return (Math.Abs(distance.X) + aabb.HalfSize.X <= HalfSize.X)
& (Math.Abs(distance.Y) + aabb.HalfSize.Y <= HalfSize.Y)
& (Math.Abs(distance.Z) + aabb.HalfSize.Z <= HalfSize.Z);
}
/// <summary>
/// Constructor of AxisAlignedBox
/// </summary>
/// <param name="aabb">Source AxisAlignedBox</param>
public AxisAlignedBox(AxisAlignedBox aabb)
{
SetFromAabb(aabb);
}
/// <summary>
/// Sets this AABB from another one
/// </summary>
/// <param name="aabb">Source aabb</param>
public void SetFromAabb(AxisAlignedBox aabb)
{
Center = aabb.Center;
HalfSize = aabb.HalfSize;
}
/// <summary>
/// Merge the AABB with a specified AABB
/// </summary>
/// <param name="aabb">Source AABB</param>
public void Merge(AxisAlignedBox aabb)
{
Vector3 max, min, otherMax, otherMin;
Vector3.Add(ref Center, ref HalfSize, out max);
Vector3.Add(ref aabb.Center, ref aabb.HalfSize, out otherMax);
Vector3.Subtract(ref Center, ref HalfSize, out min);
Vector3.Subtract(ref aabb.Center, ref aabb.HalfSize, out otherMin);
Vector3.Max(ref max, ref otherMax, out max);
Vector3.Min(ref min, ref otherMin, out min);
if ((!float.IsPositiveInfinity(max.X)) && (!float.IsPositiveInfinity(max.Y))
&& (!float.IsPositiveInfinity(max.Z)))
{
Vector3 maxPlusMin;
Vector3.Add(ref max, ref min, out maxPlusMin);
Vector3.Multiply(ref maxPlusMin, 0.5f, out Center);
}
Vector3 maxMinusMin;
Vector3.Subtract(ref max, ref min, out maxMinusMin);
Vector3.Multiply(ref maxMinusMin, 0.5f, out Center);
}
/// <summary>
/// Detects if this AABB intersects with another one
/// </summary>
/// <param name="aabb">AABB</param>
/// <returns>Returns true if the two AABB intersects otherwise false</returns>
public bool Intersects(AxisAlignedBox aabb)
{
Vector3 distance, sumHalfSize;
Vector3.Subtract(ref Center, ref aabb.Center, out distance);
Vector3.Add(ref HalfSize, ref aabb.HalfSize, out sumHalfSize);
return (Math.Abs(distance.X) <= sumHalfSize.X) & (Math.Abs(distance.Y) <= sumHalfSize.Y)
& (Math.Abs(distance.Z) <= sumHalfSize.Z);
}
/// <summary>
/// Updates the buffers
/// </summary>
/// <param name="box">Boundig box used to update buffers data</param>
internal void UpdateBox(AxisAlignedBox box)
{
Vector3 min = box.Minimum;
Vector3 max = box.Maximum;
Vector3 xOffset = new Vector3((max.X - min.X), 0, 0);
Vector3 zOffset = new Vector3(0, 0, (max.Z - min.Z));
Vector3 minOpposite;
Vector3 maxOpposite;
Vector3.Add(ref xOffset, ref zOffset, out minOpposite);
Vector3.Subtract(ref max, ref minOpposite, out maxOpposite);
Vector3.Add(ref min, ref minOpposite, out minOpposite);
// Front vertices
_vertices[FrontTopRight].Position = max;
_vertices[FrontBottomRight].Position = minOpposite;
Vector3.Subtract(ref max, ref xOffset, out _vertices[FrontTopLeft].Position);
Vector3.Subtract(ref minOpposite, ref xOffset, out _vertices[FrontBottomLeft].Position);
// Bottom vertices
_vertices[BackBottomLeft].Position = min;
_vertices[BackTopLeft].Position = maxOpposite;
Vector3.Add(ref min, ref xOffset, out _vertices[BackBottomRight].Position);
Vector3.Add(ref maxOpposite, ref xOffset, out _vertices[BackTopRight].Position);
_vbo.SetData(_vertices);
}
