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January 4, 2017 16:51
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/** | |
* The following code is derived from the original code from: http://schemingdeveloper.com. | |
* The derived version was developed by Rune Skovbo Johansen - http://runevision.com | |
* | |
* Modifications in the derived version: | |
* | |
* - Averaged normals are calculated as a weighted average based on face area, | |
* known as "face weighted normals" or "area weighted normals". | |
* | |
* - An ignoreFactor parameter has been added which can cull normals from the average | |
* if their weight is smaller than a certain fraction of the largest weight. | |
* This can be used to make large faces completely flat, distributing the curvature | |
* completely to adjacent smaller faces. | |
*/ | |
/** | |
* The following code was taken from: http://schemingdeveloper.com | |
* | |
* Visit our game studio website: http://stopthegnomes.com | |
* | |
* License: You may use this code however you see fit, as long as you give credit when | |
* explicitly asked and as long as you include this notice without any modifications. | |
* | |
* You may not publish a paid asset on Unity store if its main function is based on | |
* the following code, but you may publish a paid asset that uses this as part of a | |
* larger suite. You may still publish a free asset whose main function is using this | |
* script if you give us credit in the asset description. | |
* | |
* If you intend to use this in a Unity store asset, it would be appreciated, but | |
* not required, if you let us know with a link to the asset. | |
*/ | |
using System; | |
using System.Collections.Generic; | |
using UnityEngine; | |
public static class NormalSolver { | |
/// <summary> | |
/// Recalculate the normals of a mesh based on an angle threshold. This takes | |
/// into account distinct vertices that have the same position. | |
/// </summary> | |
/// <param name="mesh"></param> | |
/// <param name="angle"> | |
/// The smoothing angle. Note that triangles that already share | |
/// the same vertex will be smooth regardless of the angle! | |
/// </param> | |
/// <param name="ignoreFactor"> | |
/// A fraction between 0 and 1. | |
/// Weights smaller than this fraction relative to the largest weight are ignored. | |
/// </param> | |
public static void RecalculateNormals (this Mesh mesh, float angle, float ignoreFactor) { | |
var triangles = mesh.GetTriangles (0); | |
var vertices = mesh.vertices; | |
var triNormals = new Vector3[triangles.Length / 3]; //Normal of each triangle | |
var triNormalsWeighted = new Vector3[triangles.Length / 3]; //Weighted normal of each triangle | |
var normals = new Vector3[vertices.Length]; | |
angle = angle * Mathf.Deg2Rad; | |
var dictionary = new Dictionary<VertexKey, VertexEntry> (vertices.Length); | |
//Goes through all the triangles and gathers up data to be used later | |
for (var i = 0; i < triangles.Length; i += 3) { | |
int i1 = triangles[i]; | |
int i2 = triangles[i + 1]; | |
int i3 = triangles[i + 2]; | |
//Calculate the normal of the triangle | |
Vector3 p1 = vertices[i2] - vertices[i1]; | |
Vector3 p2 = vertices[i3] - vertices[i1]; | |
// By not normalizing the cross product, | |
// the face area is pre-multiplied onto the normal for free. | |
Vector3 normal = Vector3.Cross (p1, p2); | |
int triIndex = i / 3; | |
triNormalsWeighted[triIndex] = normal; | |
triNormals[triIndex] = normal.normalized; | |
VertexEntry entry; | |
VertexKey key; | |
//For each of the three points of the triangle | |
// > Add this triangle as part of the triangles they're connected to. | |
if (!dictionary.TryGetValue (key = new VertexKey (vertices[i1]), out entry)) { | |
entry = new VertexEntry (); | |
dictionary.Add (key, entry); | |
} | |
entry.Add (i1, triIndex); | |
if (!dictionary.TryGetValue (key = new VertexKey (vertices[i2]), out entry)) { | |
entry = new VertexEntry (); | |
dictionary.Add (key, entry); | |
} | |
entry.Add (i2, triIndex); | |
if (!dictionary.TryGetValue (key = new VertexKey (vertices[i3]), out entry)) { | |
entry = new VertexEntry (); | |
dictionary.Add (key, entry); | |
} | |
entry.Add (i3, triIndex); | |
} | |
//Foreach point in space (not necessarily the same vertex index!) | |
//{ | |
// Foreach triangle T1 that point belongs to | |
// { | |
// Foreach other triangle T2 (including self) that point belongs to and that | |
// meets any of the following: | |
// 1) The corresponding vertex is actually the same vertex | |
// 2) The angle between the two triangles is less than the smoothing angle | |
// { | |
// > Add to the set of contributing normals | |
// } | |
// > Add the normals in the set together, excluding those smaller than the threshold. | |
// > Normalize the resulting vector to find the average | |
// > Assign the normal to corresponding vertex of T1 | |
// } | |
//} | |
List<Vector3> normalSet = new List<Vector3> (); | |
foreach (var value in dictionary.Values) { | |
for (var i = 0; i < value.Count; ++i) { | |
normalSet.Clear (); | |
float longest = 0; | |
for (var j = 0; j < value.Count; ++j) { | |
bool use = false; | |
if (value.VertexIndex[i] == value.VertexIndex[j]) { | |
use = true; | |
} | |
else { | |
float dot = Vector3.Dot ( | |
triNormals[value.TriangleIndex[i]], | |
triNormals[value.TriangleIndex[j]]); | |
dot = Mathf.Clamp (dot, -0.99999f, 0.99999f); | |
float acos = Mathf.Acos (dot); | |
if (acos <= angle) | |
use = true; | |
} | |
if (use) { | |
Vector3 normal = triNormalsWeighted[value.TriangleIndex[j]]; | |
normalSet.Add (normal); | |
float length = normal.magnitude; | |
if (length > longest) | |
longest = length; | |
} | |
} | |
var sum = new Vector3 (); | |
var threshold = longest * ignoreFactor; | |
for (int j = 0; j < normalSet.Count; j++) { | |
if (normalSet[j].magnitude >= threshold) | |
sum += normalSet[j]; | |
} | |
normals[value.VertexIndex[i]] = sum.normalized; | |
} | |
} | |
mesh.normals = normals; | |
} | |
private struct VertexKey { | |
private readonly long _x; | |
private readonly long _y; | |
private readonly long _z; | |
//Change this if you require a different precision. | |
private const int Tolerance = 100000; | |
public VertexKey (Vector3 position) { | |
_x = (long)(Mathf.Round (position.x * Tolerance)); | |
_y = (long)(Mathf.Round (position.y * Tolerance)); | |
_z = (long)(Mathf.Round (position.z * Tolerance)); | |
} | |
public override bool Equals (object obj) { | |
var key = (VertexKey)obj; | |
return _x == key._x && _y == key._y && _z == key._z; | |
} | |
public override int GetHashCode () { | |
return (_x * 7 ^ _y * 13 ^ _z * 27).GetHashCode (); | |
} | |
} | |
private sealed class VertexEntry { | |
public int[] TriangleIndex = new int[4]; | |
public int[] VertexIndex = new int[4]; | |
private int _reserved = 4; | |
private int _count; | |
public int Count { get { return _count; } } | |
public void Add (int vertIndex, int triIndex) { | |
//Auto-resize the arrays when needed | |
if (_reserved == _count) { | |
_reserved *= 2; | |
Array.Resize (ref TriangleIndex, _reserved); | |
Array.Resize (ref VertexIndex, _reserved); | |
} | |
TriangleIndex[_count] = triIndex; | |
VertexIndex[_count] = vertIndex; | |
++_count; | |
} | |
} | |
} |
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using UnityEngine; | |
using UnityEditor; | |
public class SmoothEdgePostProcessor : AssetPostprocessor { | |
void OnPostprocessModel (GameObject g) { | |
Apply(g.transform); | |
} | |
void Apply (Transform t) { | |
MeshFilter filter = t.GetComponent<MeshFilter> (); | |
if (filter != null && filter.sharedMesh != null) | |
ModifyMesh (filter.sharedMesh); | |
// Recurse | |
foreach (Transform child in t) | |
Apply(child); | |
} | |
void ModifyMesh (Mesh mesh) { | |
NormalSolver.RecalculateNormals (mesh, 180, 0.5f); | |
} | |
} |
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Thanks for the contribution Francesco! I'll leave the original code as is, but people who need your vertex splitting can then get it from your comment.