private Vector3 Unproject(Vector3 mouse, int width, int height)
{
if (modelview == Matrix4.Zero || projection == Matrix4.Zero)
{
return(Vector3.Zero);
}
Vector4 vec;
vec.X = 2.0f * mouse.X / (float)width - 1;
vec.Y = -(2.0f * mouse.Y / (float)height - 1);
vec.Z = mouse.Z;
vec.W = 1.0f;
Matrix4 viewInv = Matrix4.Invert(modelview);
Matrix4 projInv = Matrix4.Invert(projection);
Vector4.Transform(ref vec, ref projInv, out vec);
Vector4.Transform(ref vec, ref viewInv, out vec);
if (vec.W > float.Epsilon || vec.W < -float.Epsilon)
{
vec.X /= vec.W;
vec.Y /= vec.W;
vec.Z /= vec.W;
}
return(new Vector3(vec.X, vec.Y, vec.Z));
}
private Vector3 ClickToWorld(Vector2 p)
{
var vec = new Vector4(
p.X / (float)this.Width * 2f - 1f,
-(p.Y / (float)this.Height * 2f - 1f),
0f, 1f);
var viewInv = Matrix4.Invert(modelview);
var projInv = Matrix4.Invert(projection);
Vector4.Transform(ref vec, ref projInv, out vec);
Vector4.Transform(ref vec, ref viewInv, out vec);
return(new Vector3(vec.X, vec.Y, vec.Z));
}