public void GenerateTangents(LocalPools pools)
{
var tan1 = pools.PopVector3Array(Vertices.Count);
var tan2 = pools.PopVector3Array(Vertices.Count);
for (int t = 0; t < Triangles.Count; t += 3)
{
int i1 = Triangles[t + 0];
int i2 = Triangles[t + 1];
int i3 = Triangles[t + 2];
VertexDataFixed vd1 = Vertices[i1];
VertexDataFixed vd2 = Vertices[i2];
VertexDataFixed vd3 = Vertices[i3];
Vector3 v1 = vd1.Vertex;
Vector3 v2 = vd2.Vertex;
Vector3 v3 = vd3.Vertex;
Vector2 w1 = vd1.UV;
Vector2 w2 = vd2.UV;
Vector2 w3 = vd3.UV;
float x1 = v2.x - v1.x;
float y1 = v2.y - v1.y;
float z1 = v2.z - v1.z;
float x2 = v3.x - v1.x;
float y2 = v3.y - v1.y;
float z2 = v3.z - v1.z;
float s1 = w2.x - w1.x;
float s2 = w3.x - w1.x;
float t1 = w2.y - w1.y;
float t2 = w3.y - w1.y;
// Avoid division by zero
float div = s1 * t2 - s2 * t1;
float r = (Mathf.Abs(div) > Mathf.Epsilon) ? (1f / div) : 0f;
Vector3 sdir = new Vector3((t2 * x1 - t1 * x2) * r, (t2 * y1 - t1 * y2) * r, (t2 * z1 - t1 * z2) * r);
Vector3 tdir = new Vector3((s1 * x2 - s2 * x1) * r, (s1 * y2 - s2 * y1) * r, (s1 * z2 - s2 * z1) * r);
tan1[i1] += sdir;
tan1[i2] += sdir;
tan1[i3] += sdir;
tan2[i1] += tdir;
tan2[i2] += tdir;
tan2[i3] += tdir;
}
for (int v = 0; v < Vertices.Count; ++v)
{
VertexDataFixed vd = Vertices[v];
Vector3 n = vd.Normal;
Vector3 t = tan1[v];
//Vector3 tmp = (t - n*Vector3.Dot(n, t)).normalized;
//tangents[v] = new Vector4(tmp.x, tmp.y, tmp.z);
Vector3.OrthoNormalize(ref n, ref t);
vd.Tangent = new Vector4(
t.x, t.y, t.z,
(Vector3.Dot(Vector3.Cross(n, t), tan2[v]) < 0.0f) ? -1.0f : 1.0f
);
tan1[v] = Vector3.zero;
tan2[v] = Vector3.zero;
}
pools.PushVector3Array(tan1);
pools.PushVector3Array(tan2);
}
public void AddVertex(ref VertexDataFixed vertex)
{
Vertices.Add(vertex);
}
