public static List <SlicingData> Slice(float slicing, Transform view, Renderer renderer, MeshFilter filter)
{
MeshData data = new MeshData(filter.sharedMesh);
return(Slice(slicing, view, renderer, filter, data));
}
public static List <SlicingData> Slice(float slicing, Transform view, Renderer renderer, MeshFilter filter, MeshData data)
{
slicing = Mathf.Clamp(slicing, 0.001f, 0.5f);
var viewMatrix = MathHelper.MakeViewMatrix(view.right, view.up, view.forward, view.position);
int closest, farthest;
// bounding box corners
Vector3[] corners = MeshHelper.GetBoundingBoxCorners(renderer.bounds);
MeshHelper.FindMinMaxCorners(corners, viewMatrix, out closest, out farthest);
var origin = corners[closest];
var to = corners[farthest];
Vector3 dir = view.forward;
float distance = Vector3.Project((to - origin), dir.normalized).magnitude;
List <SlicingData> slices = new List <SlicingData>();
for (float t = 0f, n = 1f + slicing; t < n; t += slicing)
{
Vector3 p = origin + dir * distance * t;
var plane = new Plane(dir.normalized, p);
var intersections = GetIntersections(plane, filter, data);
if (intersections.Count <= 0)
{
continue;
}
slices.Add(new SlicingData(viewMatrix, dir, intersections));
}
return(slices);
}
static List <Vector3> GetIntersections(Plane plane, MeshFilter filter, MeshData data)
{
List <Vector3> points = new List <Vector3>();
Vector3[] vertices = filter.sharedMesh.vertices;
Ray ray = new Ray();
Triangle start = new Triangle(-1, -1, -1);
int a = 0, b = 0;
/*
* Func<int, int, bool> debug = (int from, int to) => {
* var v0 = filter.transform.TransformPoint(vertices[a]);
* var v1 = filter.transform.TransformPoint(vertices[b]);
* Debug.DrawLine(v0, v1, new Color(1f, 0f, 0f, 1.0f), 50f);
* return true;
* };
*
* Func<Triangle, bool> debugTriangle = (Triangle t) => {
* var v0 = filter.transform.TransformPoint(vertices[t.a]);
* var v1 = filter.transform.TransformPoint(vertices[t.b]);
* var v2 = filter.transform.TransformPoint(vertices[t.c]);
* Debug.DrawLine(v0, v1, new Color(0f, 1f, 0f, 0.7f), 50f);
* Debug.DrawLine(v1, v2, new Color(0f, 1f, 0f, 0.7f), 50f);
* Debug.DrawLine(v2, v0, new Color(0f, 1f, 0f, 0.7f), 50f);
* return false;
* };
*/
Func <Triangle, int, int, bool> intersect = (Triangle tri, int ignore0, int ignore1) => {
for (int j = 0; j < 3; j++)
{
int index0 = tri[j];
int index1 = tri[(j + 1) % 3];
if ((index0 == ignore0 || index0 == ignore1) && (index1 == ignore0 || index1 == ignore1))
{
continue;
}
var v0 = filter.transform.TransformPoint(vertices[index0]);
var v1 = filter.transform.TransformPoint(vertices[index1]);
if (!plane.SameSide(v0, v1))
{
var dir = v1 - v0;
ray.origin = v0;
ray.direction = dir.normalized;
float distance;
if (plane.Raycast(ray, out distance))
{
a = index0;
b = index1;
points.Add(ray.GetPoint(distance));
}
return(true);
}
}
return(false);
};
List <Triangle> triangles = data.triangles;
for (int i = 0, n = triangles.Count; i < n; i++)
{
var tri = triangles[i];
if (intersect(tri, -1, -1))
{
start = tri;
// debug(a, b);
break;
}
}
// not found intersection
if (points.Count <= 0)
{
return(points);
}
Triangle next = data.GetCommon(start, a, b);
while (next != start)
{
if (!intersect(next, a, b))
{
break;
}
next = data.GetCommon(next, a, b);
if (next == null)
{
// Debug.Log ("null error");
break;
}
}
// Debug.Log (start == next);
return(points);
}
