/// <summary>
/// カーブに沿ったポイントを作成
/// </summary>
private static void ComputeCurvePoints(SpiralMeshGenerator generator, out Vector3[] points)
{
float curveTimeMin = generator.radiusCurve[0].time;
float curveTimeMax = generator.radiusCurve[generator.radiusCurve.length - 1].time;
points = new Vector3[generator.curveDivsV];
for (int i = 0; i < generator.curveDivsV; i++)
{
float t = (float)i / (generator.curveDivsV - 1);
float radian = t * 2f * Mathf.PI * generator.loops;
float radius = generator.radiusCurve.Evaluate(Remap(t, 0f, 1f, curveTimeMin, curveTimeMax));
float x = Mathf.Cos(radian) * radius;
float y = generator.height * t;
float z = Mathf.Sin(radian) * radius;
points[i] = new Vector3(x, y, z);
}
}
/// <summary>
/// メッシュの更新
/// </summary>
public static void ComputeMesh(SpiralMeshGenerator generator, Mesh mesh)
{
var curveDivsU = Mathf.Max(2, generator.curveDivsU);
var curveDivsV = Mathf.Max(3, generator.curveDivsV);
var loops = Mathf.Max(0f, generator.loops);
var curveWidth = Mathf.Max(0f, generator.curveWidth);
var roll = generator.roll;
var vertexColorU = generator.vertexColorU;
var vertexColorV = generator.vertexColorV;
// compute points
Vector3[] points;
ComputeCurvePoints(generator, out points);
// compute vertex uvs, position, color
int vertexCount = curveDivsU * curveDivsV * 2;
var uv = new Vector2[vertexCount];
var tangents = new Vector4[vertexCount]; // along Texture-U direction
var vertices = new Vector3[vertexCount];
var colors = new Color32[vertexCount];
var up = new Vector3(0f, 1f, 0f); // up vector
float rollRadian = roll * Mathf.Deg2Rad;
for (int vi = 0; vi < curveDivsV; vi++)
{
// compute vectors
var forwardVector =
(vi + 1 < curveDivsV) ? (points[vi + 1] - points[vi]) : (points[vi] - points[vi - 1]);
forwardVector = forwardVector.normalized;
var rightVector = Vector3.Cross(up, forwardVector).normalized;
var normalVector = Vector3.Cross(rightVector, forwardVector).normalized;
float tv = (float)vi / (curveDivsV - 1); // values in [0, 1]
for (int ui = 0; ui < curveDivsU; ui++)
{
int vertexIndex = ui + vi * curveDivsU;
float tu = (float)ui / (curveDivsU - 1); // values in [0, 1]
// position
var tangent = rightVector * Mathf.Cos(rollRadian) + normalVector * Mathf.Sin(rollRadian);
vertices[vertexIndex] = points[vi] + curveWidth * tu * tangent;
tangents[vertexIndex] = new Vector4(tangent.x, tangent.y, tangent.z, 1f);
// color
var colorU = vertexColorU.Evaluate(tu);
var colorV = vertexColorV.Evaluate(tv);
colors[vertexIndex] = colorU * colorV;
// uv
uv[vertexIndex] = new Vector2(tu, tv);
}
}
// compute triangles
int triangleCount = (curveDivsU - 1) * (curveDivsV - 1) * 6;
int[] triangles = new int[triangleCount];
int ti = 0;
for (int vi = 0; vi < curveDivsV - 1; vi++)
{
for (int ui = 0; ui < curveDivsU - 1; ui++)
{
int pi = ui + vi * curveDivsU;
triangles[ti + 0] = pi;
triangles[ti + 1] = pi + curveDivsU;
triangles[ti + 2] = pi + 1;
triangles[ti + 3] = pi + 1;
triangles[ti + 4] = pi + curveDivsU;
triangles[ti + 5] = pi + curveDivsU + 1;
ti += 6;
}
}
// clear
mesh.triangles = null;
// set
mesh.vertices = vertices;
mesh.colors32 = colors;
mesh.uv = uv;
mesh.triangles = triangles;
mesh.tangents = tangents;
mesh.RecalculateNormals();
}
