Calculate Normal for vertexes

[jorn79]

Hi,

I'm creating a 3D landscape using a heightmap. The landscape is working, but I'm trying to create normals for the vertexes. Could anyone verify that I'm doing this correctly? Or maybe point me in the right direction


Regards,

Jørn

for( int y = 0; y < _Height; y++ )
{
	for( int x = 0; x < _Width; x++ )
        {
        	try
                {
                	Vector3 p0 = _Vertexes[x + y * _Width].Position;
					Vector3 p1 = _Vertexes[-1 + x + y * _Width].Position - p0;
                	Vector3 p2 = _Vertexes[-_Width + x + y * _Width].Position - p0;
                	Vector3 p3 = _Vertexes[1 + ( -_Width ) + x + y * _Width].Position - p0;
                	Vector3 p4 = _Vertexes[1 + x + y * _Width].Position - p0;
                	Vector3 p5 = _Vertexes[_Width + x + y * _Width].Position - p0;
                	Vector3 p6 = _Vertexes[-1 + _Width + x + y * _Width].Position - p0;

                	Vector3 n1 = Vector3.Cross( p2, p1 );
                	Vector3 n2 = Vector3.Cross( p3, p2 );
                	Vector3 n3 = Vector3.Cross( p4, p3 );
                	Vector3 n4 = Vector3.Cross( p5, p4 );
                	Vector3 n5 = Vector3.Cross( p6, p5 );
                	Vector3 n6 = Vector3.Cross( p1, p6 );

                	n1.Normalize();
                	n2.Normalize();
                	n3.Normalize();
                	n4.Normalize();
                	n5.Normalize();
                	n6.Normalize();

                	Vector3 normal =
                	    ( n1 + n2 + n3 + n4 + n5 + n6 );
                	normal.X /= 6f;
                	normal.Y /= 6f;
                	normal.Z /= 6f;
                	_Vertexes[x + y * _Width].Normal = normal;
		}
		catch
		{
			// Don't care about vertexes at the borders at this point...
		}
	}
}