public Vector4f CrossProduct(Vector4f other)
{
Vector4f ret = new Vector4f();
ret.X = Y * other.Z - other.Y * Z;
ret.Y = Z * other.X - other.Z * X;
ret.Z = X * other.Y - other.X * Y;
ret.W = 1;
return ret;
}
public static void GenerateSphere(float radius, int subdivisions, out Vector4f[] outPoints, out Vector4f[] outNormals, out short[] outIndices)
{
// starting with a octahedron, subdivide the surfaces
List<Vector4f> points = new List<Vector4f>(new Vector4f[]
{
new Vector4f(1, 0, 0, 1),
new Vector4f(0, 1, 0, 1),
new Vector4f(0, 0, 1, 1),
new Vector4f(0, -1 ,0, 1),
new Vector4f(-1, 0, 0, 1),
new Vector4f(0, 0, -1, 1),
}
);
List<short> indices = new List<short>(new short[]
{
0, 1, 2,
0, 2, 3,
4, 3, 2,
1, 4, 2,
0, 5, 1,
3, 5, 0,
5, 4, 1,
5, 3, 4,
}
);
for (int i = 0; i < subdivisions; i++)
{
List<short> newIndices = new List<short>();
for (int j = 0; j < indices.Count; j += 3)
{
Vector4f np3 = points[indices[j]] + points[indices[j + 1]];
Vector4f np4 = points[indices[j + 1]] + points[indices[j + 2]];
Vector4f np5 = points[indices[j]] + points[indices[j + 2]];
np3 = np3.Normalize();
np4 = np4.Normalize();
np5 = np5.Normalize();
short i0 = indices[j];
short i1 = indices[j + 1];
short i2 = indices[j + 2];
short i3 = (short)points.Count;
points.Add(np3);
short i4 = (short)points.Count;
points.Add(np4);
short i5 = (short)points.Count;
points.Add(np5);
newIndices.Add(i0);
newIndices.Add(i3);
newIndices.Add(i5);
newIndices.Add(i3);
newIndices.Add(i4);
newIndices.Add(i5);
newIndices.Add(i1);
newIndices.Add(i4);
newIndices.Add(i3);
newIndices.Add(i2);
newIndices.Add(i5);
newIndices.Add(i4);
}
indices = newIndices;
}
outPoints = points.ToArray();
outIndices = indices.ToArray();
List<Vector4f> normals = new List<Vector4f>();
for (int i = 0; i < outIndices.Length; i++)
{
normals.Add(outPoints[outIndices[i]].Normalize());
}
outNormals = normals.ToArray();
for (int i = 0; i < outPoints.Length; i++)
{
outPoints[i] = outPoints[i].Scale(radius);
}
}
public static Vector4f RandomVector4f()
{
Vector4f ret = new Vector4f();
ret.X = Random.Next(255) - 127;
ret.Y = Random.Next(255) - 127;
ret.Z = Random.Next(255) - 127;
ret = ret.Normalize();
return ret;
}
public float DotProduct(Vector4f other)
{
return X * other.X + Y * other.Y + Z * other.Z;
}
