public static Mesh GetBounds(IEnumerable <GameObject> objs, Matrix4x4 worldToLocal)
{
var hasMesh = objs.Where(o => o.GetComponent <MeshFilter>()).Where(o => o.GetComponent <MeshFilter>().sharedMesh != null);
var vertices = hasMesh.SelectMany(m => m.GetComponent <MeshFilter>().sharedMesh.vertices.Select(v => m.transform.localToWorldMatrix.MultiplyPoint3x4(v)));
var flattened = from v in vertices select new Vector3(v.x, 0, v.z);
var distinct = flattened.Distinct();
var extremes = vertices.Aggregate(
new { min = Mathf.Infinity, max = Mathf.NegativeInfinity },
(curr, v) => new { min = v.y <curr.min?v.y : curr.min, max = v.y> curr.max ? v.y : curr.max });
var convex = ConvexHullAlgorithms.GrahamScan(distinct.ToList());
//Actually switching dimension order here, shouldn't matter (No Loss Of Generality);
int[] triangulated = (new Triangulator(convex.Select(v => new Vector2(v.x, v.z)))).Triangulate();
var verts = new List <Vector3>();
var uvs = new List <Vector2>();
var tris = new List <int>();
verts.InsertRange(0, convex.Select(v => new Vector3(v.x, extremes.min, v.z)));
var distances = Functional.Zip(verts, verts.Skip(1), ((v1, v2) => Vector2.Distance(v1, v2)));
var distancesNormalized = (from d in distances select d / distances.Sum()).ToList();
for (int i = 0; i < verts.Count; i++)
{
//Totally ghetto UV mapping algorithm
//NOT diffeomorphic to texture domain
//NO CONTINUOUS FIRST DERIVATIVE
//NORMALS MAY CRY
//#YOLO
if (i == 0)
{
uvs.Add(new Vector2(0, 0.25f));
}
else
{
uvs.Add(new Vector2(distancesNormalized[i - 1], 0.25f));
}
}
tris.InsertRange(0, triangulated);
var increment = verts.Count;
verts.InsertRange(increment, convex.Select(v => new Vector3(v.x, extremes.max, v.z)));
var buffer = uvs.Select(v => v + new Vector2(0, 0.5f)).ToList();
uvs.InsertRange(increment, buffer);
tris.InsertRange(tris.Count, triangulated.Select(i => i + increment));
for (int i = 0; i < convex.Count - 1; i++)
{
//convex is sorted counterclockwise looking from above y,
//So clockwise from outside would mean going i => i + increment => i + 1
tris.Add(i);
tris.Add(i + increment);
tris.Add(i + 1);
tris.Add(i + increment);
tris.Add(i + increment + 1);
tris.Add(i + 1);
}
var outputMesh = new Mesh();
outputMesh.vertices = verts.Select(v => worldToLocal.MultiplyPoint3x4(v)).ToArray();
outputMesh.uv = uvs.ToArray();
outputMesh.triangles = tris.ToArray();
outputMesh.RecalculateNormals();
outputMesh.RecalculateBounds();
return(outputMesh);
}
public void RecalculateBounds()
{
Transform[] transforms = (Transform[])GetComponentsInChildren <Transform>();
GetComponent <MeshFilter>().sharedMesh = ConvexHullAlgorithms.GetBounds(transforms.Select(x => x.gameObject), transform.worldToLocalMatrix);
GetComponent <MeshCollider>().sharedMesh = GetComponent <MeshFilter>().sharedMesh;
}
