public static void ExtrudeMesh(Mesh srcMesh, Mesh extrudedMesh, Matrix4x4[] extrusion, Edge[] edges, bool invertFaces, CapMode capMode)
{
int extrudedVertexCount = edges.Length * 2 * extrusion.Length;
int triIndicesPerStep = edges.Length * 6;
int extrudedTriIndexCount = triIndicesPerStep * (extrusion.Length - 1);
Vector3[] inputVertices = srcMesh.vertices;
Vector2[] inputUV = srcMesh.uv;
int[] inputTriangles = srcMesh.triangles;
Vector3[] vertices = new Vector3[extrudedVertexCount + srcMesh.vertexCount * 2];
Vector2[] uvs = new Vector2[vertices.Length];
int[] triangles = new int[extrudedTriIndexCount + inputTriangles.Length * (int)capMode];
// Build extruded vertices
int v = 0;
for (int i = 0; i < extrusion.Length; i++)
{
Matrix4x4 matrix = extrusion[i];
float vcoord = (float)i / (extrusion.Length - 1);
foreach (Edge e in edges)
{
vertices[v + 0] = matrix.MultiplyPoint(inputVertices[e.vertexIndex[0]]);
vertices[v + 1] = matrix.MultiplyPoint(inputVertices[e.vertexIndex[1]]);
uvs[v + 0] = new Vector2(inputUV[e.vertexIndex[0]].x, vcoord);
uvs[v + 1] = new Vector2(inputUV[e.vertexIndex[1]].x, vcoord);
v += 2;
}
}
// Build cap vertices
// The bottom mesh we scale along it's negative extrusion direction. This way extruding a half sphere results in a capsule.
if (capMode != CapMode.None)
{
for (int c = 0; c < 2; c++)
{
Matrix4x4 matrix = extrusion[c == 0 ? 0 : extrusion.Length - 1];
int firstCapVertex = c == 0 ? extrudedVertexCount : extrudedVertexCount + inputVertices.Length;
for (int i = 0; i < inputVertices.Length; i++)
{
vertices[firstCapVertex + i] = matrix.MultiplyPoint(inputVertices[i]);
uvs[firstCapVertex + i] = inputUV[i];
}
}
}
// Build extruded triangles
for (int i = 0; i < extrusion.Length - 1; i++)
{
int baseVertexIndex = (edges.Length * 2) * i;
int nextVertexIndex = (edges.Length * 2) * (i + 1);
for (int e = 0; e < edges.Length; e++)
{
int triIndex = i * triIndicesPerStep + e * 6;
triangles[triIndex + 0] = baseVertexIndex + e * 2;
triangles[triIndex + 1] = nextVertexIndex + e * 2;
triangles[triIndex + 2] = baseVertexIndex + e * 2 + 1;
triangles[triIndex + 3] = nextVertexIndex + e * 2;
triangles[triIndex + 4] = nextVertexIndex + e * 2 + 1;
triangles[triIndex + 5] = baseVertexIndex + e * 2 + 1;
}
}
// build cap triangles
int triCount = inputTriangles.Length / 3;
/*
* // Top
* {
* int firstCapVertex = extrudedVertexCount;
* int firstCapTriIndex = extrudedTriIndexCount;
* for (int i=0;i<triCount;i++)
* {
* triangles[i*3 + firstCapTriIndex + 0] = inputTriangles[i * 3 + 1] + firstCapVertex;
* triangles[i*3 + firstCapTriIndex + 1] = inputTriangles[i * 3 + 2] + firstCapVertex;
* triangles[i*3 + firstCapTriIndex + 2] = inputTriangles[i * 3 + 0] + firstCapVertex;
* }
* }*/
// Bottom
if (capMode != CapMode.None)
{
int firstCapVertex = extrudedVertexCount + inputVertices.Length;
int firstCapTriIndex = extrudedTriIndexCount /*+ inputTriangles.Length*/;
for (int i = 0; i < triCount; i++)
{
triangles[i * 3 + firstCapTriIndex + 0] = inputTriangles[i * 3 + 0] + firstCapVertex;
triangles[i * 3 + firstCapTriIndex + 1] = inputTriangles[i * 3 + 2] + firstCapVertex;
triangles[i * 3 + firstCapTriIndex + 2] = inputTriangles[i * 3 + 1] + firstCapVertex;
}
}
if (invertFaces)
{
for (int i = 0; i < triangles.Length / 3; i++)
{
int temp = triangles[i * 3 + 0];
triangles[i * 3 + 0] = triangles[i * 3 + 1];
triangles[i * 3 + 1] = temp;
}
}
extrudedMesh.Clear();
extrudedMesh.name = "extruded";
extrudedMesh.vertices = vertices;
extrudedMesh.uv = uvs;
extrudedMesh.triangles = triangles;
extrudedMesh.RecalculateNormals();
;
}
public static void ExtrudeMesh(Mesh srcMesh, Mesh extrudedMesh, Matrix4x4[] extrusion, bool invertFaces, CapMode capMode)
{
Edge[] edges = BuildManifoldEdges(srcMesh);
ExtrudeMesh(srcMesh, extrudedMesh, extrusion, edges, invertFaces, capMode);
}
