created folder for all the nomai text related code, moved the old builder in there and copied over the spiral generator and auto placer from the nh-unity project

This commit is contained in:
FreezeDriedMangoes 2022-12-30 19:14:32 -05:00
parent 7681b0d2f2
commit 58aa10ce50
3 changed files with 785 additions and 0 deletions

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using System.Collections;
using System.Collections.Generic;
using System.Linq;
using UnityEngine;
[ExecuteInEditMode]
public class NomaiTextArcArranger : MonoBehaviour {
public List<SpiralManipulator> spirals = new List<SpiralManipulator>();
private Dictionary<int, int> sprialOverlapResolutionPriority = new Dictionary<int, int>();
private static int MAX_MOVE_DISTANCE = 2;
public float maxX = 4;
public float minX = -4;
public float maxY = 5f;
public float minY = -1f;
public static SpiralManipulator Place(GameObject spiralMeshHolder = null) {
if (spiralMeshHolder == null)
{
spiralMeshHolder = new GameObject("spiral holder");
spiralMeshHolder.AddComponent<NomaiTextArcArranger>();
}
var rootArc = NomaiTextArcBuilder.BuildSpiralGameObject(NomaiTextArcBuilder.adultSpiralProfile);
rootArc.transform.parent = spiralMeshHolder.transform;
rootArc.transform.localEulerAngles = new Vector3(0, 0, Random.Range(-60, 60));
var manip = rootArc.AddComponent<SpiralManipulator>();
if (Random.value < 0.5) manip.transform.localScale = new Vector3(-1, 1, 1); // randomly mirror
spiralMeshHolder.GetComponent<NomaiTextArcArranger>().spirals.Add(manip);
return manip;
}
private void OnDrawGizmosSelected()
{
var topLeft = new Vector3(minX, maxY) + transform.position;
var topRight = new Vector3(maxX, maxY) + transform.position;
var bottomRight = new Vector3(maxX, minY) + transform.position;
var bottomLeft = new Vector3(minX, minY) + transform.position;
Debug.DrawLine(topLeft, topRight, Color.red);
Debug.DrawLine(topRight, bottomRight, Color.red);
Debug.DrawLine(bottomRight, bottomLeft, Color.red);
Debug.DrawLine(bottomLeft, topLeft, Color.red);
}
public int AttemptOverlapResolution(Vector2Int overlappingSpirals)
{
if (!sprialOverlapResolutionPriority.ContainsKey(overlappingSpirals.x)) sprialOverlapResolutionPriority[overlappingSpirals.x] = 0;
if (!sprialOverlapResolutionPriority.ContainsKey(overlappingSpirals.y)) sprialOverlapResolutionPriority[overlappingSpirals.y] = 0;
int mirrorIndex = overlappingSpirals.x;
if (sprialOverlapResolutionPriority[overlappingSpirals.y] > sprialOverlapResolutionPriority[overlappingSpirals.x]) mirrorIndex = overlappingSpirals.y;
this.spirals[mirrorIndex].Mirror();
sprialOverlapResolutionPriority[mirrorIndex]--;
return mirrorIndex;
}
public Vector2Int Overlap()
{
var index = -1;
foreach (var s1 in spirals)
{
index++;
if (s1.parent == null) continue;
var jndex = -1;
foreach (var s2 in spirals)
{
jndex++;
if (s1 == s2) continue;
if (Vector3.Distance(s1.center, s2.center) > Mathf.Max(s1.NomaiTextLine.GetWorldRadius(), s2.NomaiTextLine.GetWorldRadius())) continue; // no overlap possible - too far away
var s1Points = s1.NomaiTextLine.GetPoints().Select(p => s1.transform.TransformPoint(p)).ToList();
var s2Points = s2.NomaiTextLine.GetPoints().Select(p => s2.transform.TransformPoint(p)).ToList();
var s1ThresholdForOverlap = Vector3.Distance(s1Points[0], s1Points[1]);
var s2ThresholdForOverlap = Vector3.Distance(s2Points[0], s2Points[1]);
var thresholdForOverlap = Mathf.Pow(Mathf.Max(s1ThresholdForOverlap, s2ThresholdForOverlap), 2); // square to save on computation (we'll work in distance squared from here on)
if (s1.parent == s2) s1Points.RemoveAt(0); // don't consider the base points so that we can check if children overlap their parents
if (s2.parent == s1) s2Points.RemoveAt(0); // (note: the base point of a child is always exactly overlapping with one of the parent's points)
foreach(var p1 in s1Points)
{
foreach(var p2 in s2Points)
{
if (Vector3.SqrMagnitude(p1-p2) <= thresholdForOverlap) return new Vector2Int(index, jndex); // s1 and s2 overlap
}
}
}
}
return new Vector2Int(-1, -1);
}
public void Step() {
// TODO: after setting child position on parent in Step(), check to see if this spiral exits the bounds - if so, move it away until it no longer does
// this ensures that a spiral can never be outside the bounds, it makes them rigid
// TODO: for integration with NH - before generating spirals, seed the RNG with the hash of the XML filename for this convo
// and add an option to specify the seed
var index = -1;
foreach (var s1 in spirals)
{
index++;
if (s1.parent == null) continue;
//
// Calculate the force s1 should experience
//
Vector2 force = Vector2.zero;
foreach (var s2 in spirals)
{
if (s1 == s2) continue;
if (s1.parent == s2) continue;
if (s1 == s2.parent) continue;
// push away from other spirals
var f = (s2.center - s1.center);
force -= f / Mathf.Pow(f.magnitude, 6);
var f2 = (s2.localPosition - s1.localPosition);
force -= f2 / Mathf.Pow(f2.magnitude, 6);
}
// push away from the edges
if (s1.center.y < minY+s1.transform.parent.position.y) force += new Vector2(0, Mathf.Pow(10f*minY - 10f*s1.center.y, 6));
if (s1.center.x < minX+s1.transform.parent.position.x) force += new Vector2(Mathf.Pow(10f*minX - 10f*s1.center.x, 6), 0);
if (s1.center.y > maxY+s1.transform.parent.position.y) force -= new Vector2(0, Mathf.Pow(10f*maxY - 10f*s1.center.y, 6));
if (s1.center.x > maxX+s1.transform.parent.position.x) force -= new Vector2(Mathf.Pow(10f*maxX - 10f*s1.center.x, 6), 0);
//
// renormalize the force magnitude (keeps force sizes reasonable, and improves stability in the case of small forces)
//
var avg = 1; // the size of vector required to get a medium push
var scale = 0.75f;
force = force.normalized * scale * (1 / (1 + Mathf.Exp(avg-force.magnitude)) - 1 / (1 + Mathf.Exp(avg))); // apply a sigmoid-ish smoothing operation, so only giant forces actually move the spirals
//
// apply the forces as we go to increase stability?
//
var spiral = s1;
var parentPoints = spiral.parent.GetComponent<NomaiTextLine>().GetPoints();
// pick the parent point that's closest to center+force, and move to there
var idealPoint = spiral.position + force;
var bestPointIndex = 0;
var bestPointDistance = 99999999f;
for (var j = SpiralManipulator.MIN_PARENT_POINT; j < SpiralManipulator.MAX_PARENT_POINT; j++)
{
// skip this point if it's already occupied by ANOTHER spiral (if it's occupied by this spiral, DO count it)
if (j != spiral._parentPointIndex && spiral.parent.occupiedParentPoints.Contains(j)) continue;
var point = parentPoints[j];
point = spiral.parent.transform.TransformPoint(point);
var dist = Vector2.Distance(point, idealPoint);
if (dist < bestPointDistance) {
bestPointDistance = dist;
bestPointIndex = j;
}
}
//
// limit the distance a spiral can move in a single step
//
bestPointIndex = spiral._parentPointIndex + Mathf.Min(MAX_MOVE_DISTANCE, Mathf.Max(-MAX_MOVE_DISTANCE, bestPointIndex - spiral._parentPointIndex)); // minimize step size to help stability
//
// actually move the spiral
//
SpiralManipulator.PlaceChildOnParentPoint(spiral, spiral.parent, bestPointIndex);
}
}
}
[ExecuteInEditMode]
public class SpiralManipulator : MonoBehaviour {
public SpiralManipulator parent;
public List<SpiralManipulator> children = new List<SpiralManipulator>();
public HashSet<int> occupiedParentPoints = new HashSet<int>();
public int _parentPointIndex = -1;
public static int MIN_PARENT_POINT = 3;
public static int MAX_PARENT_POINT = 26;
private NomaiTextLine _NomaiTextLine;
public NomaiTextLine NomaiTextLine
{
get
{
if (_NomaiTextLine == null) _NomaiTextLine = GetComponent<NomaiTextLine>();
return _NomaiTextLine;
}
}
public Vector2 center {
get { return NomaiTextLine.GetWorldCenter(); }
}
public Vector2 localPosition {
get { return new Vector2(this.transform.localPosition.x, this.transform.localPosition.y); }
}
public Vector2 position {
get { return new Vector2(this.transform.position.x, this.transform.position.y); }
}
public SpiralManipulator AddChild() {
var index = Random.Range(MIN_PARENT_POINT, MAX_PARENT_POINT);
var child = NomaiTextArcArranger.Place(this.transform.parent.gameObject);
PlaceChildOnParentPoint(child, this, index);
child.GetComponent<SpiralManipulator>().parent = this;
this.children.Add(child.GetComponent<SpiralManipulator>());
return child.GetComponent<SpiralManipulator>();
}
public void Mirror()
{
this.transform.localScale = new Vector3(-this.transform.localScale.x, 1, 1);
if (this.parent != null) SpiralManipulator.PlaceChildOnParentPoint(this, this.parent, this._parentPointIndex);
}
public void UpdateChildren()
{
foreach(var child in this.children)
{
PlaceChildOnParentPoint(child, this, child._parentPointIndex);
}
}
public static int PlaceChildOnParentPoint(SpiralManipulator child, SpiralManipulator parent, int parentPointIndex, bool updateChildren=true)
{
// track which points on the parent are being occupied
if (child._parentPointIndex != -1) parent.occupiedParentPoints.Remove(child._parentPointIndex);
child._parentPointIndex = parentPointIndex; // just in case this function was called without setting this value
parent.occupiedParentPoints.Add(parentPointIndex);
// get the parent's points and make parentPointIndex valid
var _points = parent.GetComponent<NomaiTextLine>().GetPoints();
parentPointIndex = Mathf.Max(0, Mathf.Min(parentPointIndex, _points.Length-1));
// calculate the normal at point by using the neighboring points to approximate the tangent (and account for mirroring, which means all points are actually at (-point.x, point.y) )
var normal = _points[Mathf.Min(parentPointIndex+1, _points.Length-1)] - _points[Mathf.Max(parentPointIndex-1, 0)];
if (parent.transform.localScale.x < 0) normal = new Vector3(-normal.x, normal.y, normal.z);
float rot = Mathf.Atan2(normal.y, normal.x) * Mathf.Rad2Deg;
if (parent.transform.localScale.x < 0) rot += 180; // account for mirroring again (without doing this, the normal points inward on mirrored spirals, instead of outward)
// get the location the child spiral should be at (and yet again account for mirroring)
var point = _points[parentPointIndex];
if (parent.transform.localScale.x < 0) point = new Vector3(-point.x, point.y, point.z);
// set the child's position and rotation according to calculations
child.transform.localPosition = Quaternion.Euler(0, 0, parent.transform.localEulerAngles.z) * point + parent.transform.localPosition;
child.transform.localEulerAngles = new Vector3(0, 0, rot + parent.transform.localEulerAngles.z);
// recursive update on all children so they move along with the parent
if (updateChildren)
{
child.UpdateChildren();
}
return parentPointIndex;
}
}

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using System.Collections;
using System.Collections.Generic;
using System.Linq;
using UnityEngine;
using UnityEditor;
using System.Reflection;
public static class NomaiTextArcBuilder {
public static int i = 0;
public static SpiralProfile spiralProfile;
public static bool removeBakedInRotationAndPosition = true;
public static void PlaceAdult()
{
BuildSpiralGameObject(adultSpiralProfile, "Text Arc Prefab " + (i++));
}
public static void PlaceChild()
{
BuildSpiralGameObject(childSpiralProfile, "Text Arc Prefab " + (i++));
}
public static GameObject BuildSpiralGameObject(SpiralProfile profile, string goName="New Nomai Spiral")
{
var g = new GameObject(goName);
g.transform.localPosition = Vector3.zero;
g.transform.localEulerAngles = Vector3.zero;
var m = new SpiralMesh(profile);
m.Randomize();
m.updateMesh();
g.AddComponent<MeshFilter>().sharedMesh = m.mesh;
g.AddComponent<MeshRenderer>().sharedMaterial = new Material(Shader.Find("Sprites/Default"));
g.GetComponent<MeshRenderer>().sharedMaterial.color = Color.magenta;
var owNomaiTextLine = g.AddComponent<NomaiTextLine>();
//
// rotate mesh to face up
//
var norm = m.skeleton[1] - m.skeleton[0];
float r = Mathf.Atan2(-norm.y, norm.x) * Mathf.Rad2Deg;
if (m.mirror) r += 180;
var ang = m.mirror ? 90-r : -90-r;
// using m.sharedMesh causes old meshes to disappear for some reason, idk why
var mesh = g.GetComponent<MeshFilter>().mesh;
if (removeBakedInRotationAndPosition)
{
var meshCopy = mesh;
var newVerts = meshCopy.vertices.Select(v => Quaternion.Euler(-90, 0, 0) * Quaternion.Euler(0, ang, 0) * v).ToArray();
meshCopy.vertices = newVerts;
meshCopy.RecalculateBounds();
}
AssetDatabase.CreateAsset(mesh, "Assets/Spirals/"+(profile.profileName)+"spiral" + (NomaiTextArcBuilder.i) + ".asset");
g.GetComponent<MeshFilter>().sharedMesh = AssetDatabase.LoadAssetAtPath("Assets/Spirals/"+(profile.profileName)+"spiral" + (NomaiTextArcBuilder.i) + ".asset", typeof(Mesh)) as Mesh;
NomaiTextArcBuilder.i++;
//
// set up NomaiTextArc stuff
//
var _points = m.skeleton
.Select((compiled) =>
Quaternion.Euler(-90, 0, 0) * Quaternion.Euler(0, ang, 0) * (new Vector3(compiled.x, 0, compiled.y)) // decompile them, rotate them by ang, and then rotate them to be vertical, like the base game spirals are
)
.ToList();
var _lengths = _points.Take(_points.Count()-1).Select((point, i) => Vector3.Distance(point, _points[i+1])).ToArray();
var _totalLength = _lengths.Aggregate(0f, (acc, length) => acc + length);
var _state = NomaiTextLine.VisualState.UNREAD;
var _textLineLocation = NomaiText.Location.UNSPECIFIED;
var _center = _points.Aggregate(Vector3.zero, (acc, point) => acc + point) / (float)_points.Count();
var _radius = _points.Aggregate(0f, (acc, point) => Mathf.Max(Vector3.Distance(_center, point), acc));
var _active = true;
(typeof (NomaiTextLine)).InvokeMember("_points", BindingFlags.SetField | BindingFlags.Instance | BindingFlags.NonPublic, null, owNomaiTextLine, new object[] { _points.ToArray() });
(typeof (NomaiTextLine)).InvokeMember("_lengths", BindingFlags.SetField | BindingFlags.Instance | BindingFlags.NonPublic, null, owNomaiTextLine, new object[] { _lengths });
(typeof (NomaiTextLine)).InvokeMember("_totalLength", BindingFlags.SetField | BindingFlags.Instance | BindingFlags.NonPublic, null, owNomaiTextLine, new object[] { _totalLength });
(typeof (NomaiTextLine)).InvokeMember("_state", BindingFlags.SetField | BindingFlags.Instance | BindingFlags.NonPublic, null, owNomaiTextLine, new object[] { _state });
(typeof (NomaiTextLine)).InvokeMember("_textLineLocation", BindingFlags.SetField | BindingFlags.Instance | BindingFlags.NonPublic, null, owNomaiTextLine, new object[] { _textLineLocation });
(typeof (NomaiTextLine)).InvokeMember("_center", BindingFlags.SetField | BindingFlags.Instance | BindingFlags.NonPublic, null, owNomaiTextLine, new object[] { _center });
(typeof (NomaiTextLine)).InvokeMember("_radius", BindingFlags.SetField | BindingFlags.Instance | BindingFlags.NonPublic, null, owNomaiTextLine, new object[] { _radius });
(typeof (NomaiTextLine)).InvokeMember("_active", BindingFlags.SetField | BindingFlags.Instance | BindingFlags.NonPublic, null, owNomaiTextLine, new object[] { _active });
return g;
}
//
//
// Handle the connection between game objects and spiral meshes
//
//
public struct SpiralProfile {
// all of the Vector2 params here refer to a range of valid values
public string profileName;
public bool canMirror;
public Vector2 a;
public Vector2 b;
public Vector2 endS;
public Vector2 skeletonScale;
public int numSkeletonPoints;
public float uvScale;
public float innerWidth; // width at the tip
public float outerWidth; // width at the base
public Material material;
}
public static SpiralProfile adultSpiralProfile = new SpiralProfile() {
profileName="Adult",
canMirror = false, // we don't want to mirror the actual mesh itself anymore, we'll just mirror the game object using localScale.x
a = new Vector2(0.5f, 0.5f),
b = new Vector2(0.3f, 0.6f),
endS = new Vector2(0, 50f),
skeletonScale = new Vector2(0.01f, 0.01f),
numSkeletonPoints = 51,
innerWidth = 0.001f,
outerWidth = 0.05f,
uvScale = 4.9f,
};
public static SpiralProfile childSpiralProfile = new SpiralProfile() {
profileName="Child",
canMirror = false, // we don't want to mirror the actual mesh itself anymore, we'll just mirror the game object using localScale.x
a = new Vector2(0.9f, 0.9f),
b = new Vector2(0.305f, 0.4f),
endS = new Vector2(16f, 60f),
skeletonScale = new Vector2(0.002f, 0.005f),
numSkeletonPoints = 51,
innerWidth = 0.001f/10f,
outerWidth = 2f*0.05f,
uvScale = 4.9f/3.5f,
};
//
//
// Construct spiral meshes from the mathematical spirals generated below
//
//
public class SpiralMesh: MathematicalSpiral {
public List<Vector3> skeleton;
public List<Vector2> skeletonOutsidePoints;
public int numSkeletonPoints = 51; // seems to be Mobius' default
public float innerWidth = 0.001f; // width at the tip
public float outerWidth = 0.05f; //0.107f; // width at the base
public float uvScale = 4.9f; //2.9f;
private float baseUVScale = 1f / 300f;
public float uvOffset = 0;
public Mesh mesh;
public SpiralMesh(SpiralProfile profile): base(profile) {
this.numSkeletonPoints = profile.numSkeletonPoints;
this.innerWidth = profile.innerWidth;
this.outerWidth = profile.outerWidth;
this.uvScale = profile.uvScale;
this.uvOffset = UnityEngine.Random.value;
}
public override void Randomize() {
base.Randomize();
uvOffset = UnityEngine.Random.value; // this way even two spirals that are exactly the same shape will look different (this changes the starting point of the handwriting texture)
}
internal void updateMesh() {
skeleton = this.getSkeleton(numSkeletonPoints);
skeletonOutsidePoints = this.getSkeletonOutsidePoints(numSkeletonPoints);
List<Vector3> vertsSide1 = skeleton.Select((skeletonPoint, index) => {
Vector3 normal = new Vector3(cos(skeletonPoint.z), 0, sin(skeletonPoint.z));
float width = lerp(((float) index) / ((float) skeleton.Count()), outerWidth, innerWidth);
return new Vector3(skeletonPoint.x, 0, skeletonPoint.y) + width * normal;
}).ToList();
List<Vector3> vertsSide2 = skeleton.Select((skeletonPoint, index) => {
Vector3 normal = new Vector3(cos(skeletonPoint.z), 0, sin(skeletonPoint.z));
float width = lerp(((float) index) / ((float) skeleton.Count()), outerWidth, innerWidth);
return new Vector3(skeletonPoint.x, 0, skeletonPoint.y) - width * normal;
}).ToList();
Vector3[] newVerts = vertsSide1.Zip(vertsSide2, (f, s) => new [] {
f,
s
}).SelectMany(f =>f).ToArray(); // interleave vertsSide1 and vertsSide2
List<int> triangles = new List<int>();
for (int i = 0; i<newVerts.Length - 2; i += 2) {
/*
| |
| |
2 *-----* 3
| |
| |
| |
0 *-----* 1
| |
*/
triangles.Add(i + 2);
triangles.Add(i + 1);
triangles.Add(i);
triangles.Add(i + 2);
triangles.Add(i + 3);
triangles.Add(i + 1);
}
var startT = tFromArcLen(startS);
var endT = tFromArcLen(endS);
var rangeT = endT - startT;
var rangeS = endS - startS;
Vector2[] uvs = new Vector2[newVerts.Length];
Vector2[] uv2s = new Vector2[newVerts.Length];
for (int i = 0; i<skeleton.Count(); i++) {
float fraction = 1 - ((float) i) / ((float) skeleton.Count()); // casting is so uuuuuuuugly
// note: cutting the sprial into numPoints equal slices of arclen would
// provide evenly spaced skeleton points
// on the other hand, cutting the spiral into numPoints equal slices of t
// will cluster points in areas of higher detail. this is the way Mobius does it, so it is the way we also will do it
float inputT = startT + rangeT * fraction;
float inputS = tToArcLen(inputT);
float sFraction = (inputS - startS) / rangeS;
float absoluteS = (inputS - startS);
float u = absoluteS * uvScale * baseUVScale + uvOffset;
uvs[i * 2] = new Vector2(u, 0);
uvs[i * 2 + 1] = new Vector2(u, 1);
uv2s[i * 2] = new Vector2(1 - sFraction, 0);
uv2s[i * 2 + 1] = new Vector2(1 - sFraction, 1);
}
Vector3[] normals = new Vector3[newVerts.Length];
for (int i = 0; i<newVerts.Length; i++) normals[i] = new Vector3(0, 0, 1);
if (mesh == null){
mesh = new Mesh();
}
mesh.vertices = newVerts.ToArray();
mesh.triangles = triangles.ToArray().Reverse().ToArray(); // triangles need to be reversed so the spirals face the right way (I generated them backwards above, on accident)
mesh.uv = uvs;
mesh.uv2 = uv2s;
mesh.normals = normals;
mesh.RecalculateBounds();
}
}
//
//
// Construct the mathematical spirals that Nomai arcs are built from
//
//
public class MathematicalSpiral {
public bool mirror;
public float a;
public float b; // 0.3-0.6
public float startSOnParent;
public float scale;
public List<MathematicalSpiral> children;
public float x;
public float y;
public float ang;
public float startS = 42.87957f; // go all the way down to 0, all the way up to 50
public float endS = 342.8796f;
SpiralProfile profile;
public MathematicalSpiral(SpiralProfile profile) {
this.profile = profile;
this.Randomize();
}
public MathematicalSpiral(float startSOnParent = 0, bool mirror = false, float len = 300, float a = 0.5f, float b = 0.43f, float scale = 0.01f) {
this.mirror = mirror;
this.a = a;
this.b = b;
this.startSOnParent = startSOnParent;
this.scale = scale;
this.children = new List<MathematicalSpiral>();
this.x = 0;
this.y = 0;
this.ang = 0;
}
public virtual void Randomize() {
this.a = UnityEngine.Random.Range(profile.a.x, profile.a.y); //0.5f;
this.b = UnityEngine.Random.Range(profile.b.x, profile.b.y);
this.startS = UnityEngine.Random.Range(profile.endS.x, profile.endS.y);
this.scale = UnityEngine.Random.Range(profile.skeletonScale.x, profile.skeletonScale.y);
if (profile.canMirror) this.mirror = UnityEngine.Random.value<0.5f;
}
internal virtual void updateChild(MathematicalSpiral child) {
Vector3 pointAndNormal = getDrawnSpiralPointAndNormal(child.startSOnParent);
var cx = pointAndNormal.x;
var cy = pointAndNormal.y;
var cang = pointAndNormal.z;
child.x = cx;
child.y = cy;
child.ang = cang + (child.mirror ? Mathf.PI : 0);
}
public virtual void addChild(MathematicalSpiral child) {
updateChild(child);
this.children.Add(child);
}
public virtual void updateChildren() {
this.children.ForEach(child => {
updateChild(child);
child.updateChildren();
});
}
// note: each Vector3 in this list is of form <x, y, angle in radians of the normal at this point>
public List<Vector3> getSkeleton(int numPoints) {
var skeleton =
WalkAlongSpiral(numPoints)
.Select(input => {
float inputS = input.y;
var skeletonPoint = getDrawnSpiralPointAndNormal(inputS);
return skeletonPoint;
})
.Reverse()
.ToList();
return skeleton;
}
public List<Vector2> getSkeletonOutsidePoints(int numPoints) {
var outsidePoints =
WalkAlongSpiral(numPoints)
.Select(input => {
float inputT = input.x;
float inputS = input.y;
var skeletonPoint = getDrawnSpiralPointAndNormal(inputS);
var deriv = spiralDerivative(inputT);
var outsidePoint = new Vector2(skeletonPoint.x, skeletonPoint.y) - (new Vector2(-deriv.y, deriv.x)).normalized * 0.1f;
return outsidePoint;
})
.Reverse()
.ToList();
return outsidePoints;
}
// generate a list of <inputT, inputS> evenly distributed over the whole spiral. `numPoints` number of <inputT, inputS> pairs are generated
public IEnumerable<Vector2> WalkAlongSpiral(int numPoints) {
var endT = tFromArcLen(endS);
var startT = tFromArcLen(startS);
var rangeT = endT - startT;
for (int i = 0; i<numPoints; i++) {
float fraction = ((float) i) / ((float) numPoints - 1f); // casting is so uuuuuuuugly
// note: cutting the sprial into numPoints equal slices of arclen would
// provide evenly spaced skeleton points
// on the other hand, cutting the spiral into numPoints equal slices of t
// will cluster points in areas of higher detail. this is the way Mobius does it, so it is the way we also will do it
float inputT = startT + rangeT * fraction;
float inputS = tToArcLen(inputT);
yield return new Vector2(inputT, inputS);
}
}
// all of this math is based off of this:
// https://www.desmos.com/calculator/9gdfgyuzf6
//
// note: t refers to theta, and s refers to arc length
//
// get the (x, y) coordinates and the normal angle at the given location (measured in arcLen) of a spiral with the given parameters
// note: arcLen is inverted so that 0 refers to what we consider the start of the Nomai spiral
public Vector3 getDrawnSpiralPointAndNormal(float arcLen) {
float offsetX = this.x;
float offsetY = this.y;
float offsetAngle = this.ang;
var startS = this.endS; // I know this is funky, but just go with it for now.
var startT = tFromArcLen(startS); // this is the `t` value for the root of the spiral (the end of the non-curled side)
var startPoint = spiralPoint(startT); // and this is the (x,y) location of the non-curled side, relative to the rest of the spiral. we'll offset everything so this is at (0,0) later
var startX = startPoint.x;
var startY = startPoint.y;
var t = tFromArcLen(arcLen);
var point = spiralPoint(t); // the absolute (x,y) location that corresponds to `arcLen`, before accounting for things like putting the start point at (0,0), or dealing with offsetX/offsetY/offsetAngle
var x = point.x;
var y = point.y;
var ang = normalAngle(t);
if (mirror) {
x = x + 2 * (startX - x);
ang = -ang + Mathf.PI;
}
// translate so that startPoint is at (0,0)
// (also scale the spiral)
var retX = scale * (x - startX);
var retY = scale * (y - startY);
// rotate offsetAngle rads
var retX2 = retX * cos(offsetAngle) -
retY * sin(offsetAngle);
var retY2 = retX * sin(offsetAngle) +
retY * cos(offsetAngle);
retX = retX2;
retY = retY2;
// translate for offsetX, offsetY
retX += offsetX;
retY += offsetY;
return new Vector3(retX, retY, ang + offsetAngle + Mathf.PI / 2f);
}
// the base formula for the spiral
public Vector2 spiralPoint(float t) {
var r = a * exp(b * t);
var retval = new Vector2(r * cos(t), r * sin(t));
return retval;
}
// the spiral's got two functions: x(t) and y(t)
// so it's got two derrivatives (with respect to t) x'(t) and y'(t)
public Vector2 spiralDerivative(float t) { // derrivative with respect to t
var r = a * exp(b * t);
return new Vector2(
-r * (sin(t) - b * cos(t)),
r * (b * sin(t) + cos(t))
);
}
// returns the length of the spiral between t0 and t1
public float spiralArcLength(float t0, float t1) {
return (a / b) * sqrt(b * b + 1) * (exp(b * t1) - exp(b * t0));
}
// converts from a value of t to the equivalent value of s (the value of s that corresponds to the same point on the spiral as t)
public float tToArcLen(float t) {
return spiralArcLength(0, t);
}
// reverse of above
public float tFromArcLen(float s) {
return ln(
1 + s / (
(a / b) *
sqrt(b * b + 1)
)
) / b;
}
// returns the angle of the spiral's normal at a given point
public float normalAngle(float t) {
var d = spiralDerivative(t);
var n = new Vector2(d.y, -d.x);
var angle = Mathf.Atan2(n.y, n.x);
return angle - Mathf.PI / 2;
}
}
// convenience, so the math above is more readable
private static float lerp(float a, float b, float t) {
return a * t + b * (1 - t);
}
private static float cos(float t) {
return Mathf.Cos(t);
}
private static float sin(float t) {
return Mathf.Sin(t);
}
private static float exp(float t) {
return Mathf.Exp(t);
}
private static float sqrt(float t) {
return Mathf.Sqrt(t);
}
private static float ln(float t) {
return Mathf.Log(t);
}
}