/// <summary>
/// Compute UV tangen space
/// </summary>
public void ComputeTangents()
{
if (this.Vertices.Length > 0)
{
if (this.Indices.Length > 0)
{
for (int i = 0; i < this.Indices.Length; i += 3)
{
var v0 = this.Vertices[(int)this.Indices[i + 0]];
var v1 = this.Vertices[(int)this.Indices[i + 1]];
var v2 = this.Vertices[(int)this.Indices[i + 2]];
GeometryUtil.ComputeNormals(
v0.Position.Value, v1.Position.Value, v2.Position.Value,
v0.Texture.Value, v1.Texture.Value, v2.Texture.Value,
out Vector3 tangent, out Vector3 binormal, out Vector3 normal);
v0.Tangent = tangent;
v1.Tangent = tangent;
v2.Tangent = tangent;
v0.BiNormal = binormal;
v1.BiNormal = binormal;
v2.BiNormal = binormal;
this.Vertices[(int)this.Indices[i + 0]] = v0;
this.Vertices[(int)this.Indices[i + 1]] = v1;
this.Vertices[(int)this.Indices[i + 2]] = v2;
}
}
else
{
for (int i = 0; i < this.Vertices.Length; i += 3)
{
var v0 = this.Vertices[i + 0];
var v1 = this.Vertices[i + 1];
var v2 = this.Vertices[i + 2];
GeometryUtil.ComputeNormals(
v0.Position.Value, v1.Position.Value, v2.Position.Value,
v0.Texture.Value, v1.Texture.Value, v2.Texture.Value,
out Vector3 tangent, out Vector3 binormal, out Vector3 normal);
v0.Tangent = tangent;
v1.Tangent = tangent;
v2.Tangent = tangent;
v0.BiNormal = binormal;
v1.BiNormal = binormal;
v2.BiNormal = binormal;
this.Vertices[i + 0] = v0;
this.Vertices[i + 1] = v1;
this.Vertices[i + 2] = v2;
}
}
this.VertexType = VertexData.GetVertexType(this.Vertices[0], this.Textured);
}
}
/// <summary>
/// Generates the height map normals
/// </summary>
/// <param name="cellSize">Cell size</param>
/// <returns>Returns the generated normals array</returns>
private static void ComputeHeightMapNormals(VertexData[] vertList, long width, long depth)
{
for (long x = 0; x < depth; x++)
{
for (long y = 0; y < width; y++)
{
long index1 = (y * width) + x;
Vector3 normal;
Vector3 tangent;
Vector3 binormal;
if (x == 0 || y == 0 || x == (depth - 1) || y == (width - 1))
{
// The vertices in the borders have always the up normal
normal = Vector3.UnitY;
tangent = Vector3.UnitX;
binormal = Vector3.UnitZ;
}
else
{
long index2;
long index3;
VertexData pos1 = vertList[index1];
VertexData pos2;
VertexData pos3;
index2 = ((y - 1) * width) + x;
index3 = (y * width) + (x - 1);
pos2 = vertList[index2];
pos3 = vertList[index3];
GeometryUtil.ComputeNormals(
pos1.Position.Value, pos3.Position.Value, pos2.Position.Value,
pos1.Texture.Value, pos3.Texture.Value, pos2.Texture.Value,
out Vector3 tan1, out Vector3 biNorm1, out Vector3 norm1);
index2 = (y * width) + (x - 1);
index3 = ((y + 1) * width) + (x - 1);
pos2 = vertList[index2];
pos3 = vertList[index3];
GeometryUtil.ComputeNormals(
pos1.Position.Value, pos3.Position.Value, pos2.Position.Value,
pos1.Texture.Value, pos3.Texture.Value, pos2.Texture.Value,
out Vector3 tan2, out Vector3 biNorm2, out Vector3 norm2);
index2 = ((y + 1) * width) + (x - 1);
index3 = ((y + 1) * width) + x;
pos2 = vertList[index2];
pos3 = vertList[index3];
GeometryUtil.ComputeNormals(
pos1.Position.Value, pos3.Position.Value, pos2.Position.Value,
pos1.Texture.Value, pos3.Texture.Value, pos2.Texture.Value,
out Vector3 tan3, out Vector3 biNorm3, out Vector3 norm3);
index2 = ((y + 1) * width) + x;
index3 = (y * width) + (x + 1);
pos2 = vertList[index2];
pos3 = vertList[index3];
GeometryUtil.ComputeNormals(
pos1.Position.Value, pos3.Position.Value, pos2.Position.Value,
pos1.Texture.Value, pos3.Texture.Value, pos2.Texture.Value,
out Vector3 tan4, out Vector3 biNorm4, out Vector3 norm4);
index2 = (y * width) + (x + 1);
index3 = ((y - 1) * width) + (x + 1);
pos2 = vertList[index2];
pos3 = vertList[index3];
GeometryUtil.ComputeNormals(
pos1.Position.Value, pos3.Position.Value, pos2.Position.Value,
pos1.Texture.Value, pos3.Texture.Value, pos2.Texture.Value,
out Vector3 tan5, out Vector3 biNorm5, out Vector3 norm5);
index2 = ((y - 1) * width) + (x + 1);
index3 = ((y - 1) * width) + x;
pos2 = vertList[index2];
pos3 = vertList[index3];
GeometryUtil.ComputeNormals(
pos1.Position.Value, pos3.Position.Value, pos2.Position.Value,
pos1.Texture.Value, pos3.Texture.Value, pos2.Texture.Value,
out Vector3 tan6, out Vector3 biNorm6, out Vector3 norm6);
Vector3 norm = (norm1 + norm2 + norm3 + norm4 + norm5 + norm6) / 6.0f;
Vector3 tang = (tan1 + tan2 + tan3 + tan4 + tan5 + tan6) / 6.0f;
Vector3 binorm = (biNorm1 + biNorm2 + biNorm3 + biNorm4 + biNorm5 + biNorm6) / 6.0f;
normal = Vector3.Normalize(norm);
tangent = Vector3.Normalize(tang);
binormal = Vector3.Normalize(binorm);
}
vertList[index1].Normal = normal;
vertList[index1].Tangent = tangent;
vertList[index1].BiNormal = binormal;
}
}
}
