/// <summary>
/// Returns the transform for this group's coordinate system
/// </summary>
/// <returns>The transform.</returns>
protected Matrix2D computeTransform()
{
var mat = Matrix2D.Identity;
if (originX != 0 || originY != 0)
{
mat = Matrix2D.Multiply(mat, Matrix2D.CreateTranslation(-originX, -originY, 0));
}
if (rotation != 0)
{
mat = Matrix2D.Multiply(mat, Matrix2D.CreateRotationZ(MathHelper.ToRadians(rotation)));
}
if (scaleX != 1 || scaleY != 1)
{
mat = Matrix2D.Multiply(mat, Matrix2D.CreateScale(scaleX, scaleY));
}
mat = Matrix2D.Multiply(mat, Matrix2D.CreateTranslation(x + originX, y + originY, 0));
// Find the first parent that transforms
Group parentGroup = parent;
while (parentGroup != null)
{
if (parentGroup.transform)
{
break;
}
parentGroup = parentGroup.parent;
}
if (parentGroup != null)
{
mat = Matrix2D.Multiply(mat, parentGroup.computeTransform());
}
return(mat);
}
