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Creates a flat mesh based on a spline, useful for roads.
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//Produces a flat mesh based on a spline, useful for creating roads. | |
public class SplineMesh : MonoBehaviour | |
{ | |
public static Mesh CreateSplineMesh(Vector3[] splinePoints, float[] widthPoints) | |
{ | |
Mesh mesh = new Mesh(); | |
Vector3[] vertices = new Vector3[splinePoints.Length * 2]; | |
//Create new vertices at both sides of the spline point | |
for (int i = 0; i < splinePoints.Length; i++) | |
{ | |
if (i * 2 < vertices.Length - 1) | |
{ | |
Vector3 leftDirection = Vector3.zero; | |
Vector3 rightDirection = Vector3.zero; | |
Vector3 heading = Vector3.zero; | |
if (i < splinePoints.Length - 1) | |
{ | |
heading = splinePoints[i+1] - splinePoints[i]; | |
} | |
else | |
{ | |
heading = splinePoints[i] - splinePoints[i-1]; | |
} | |
heading = heading / heading.magnitude; | |
leftDirection = Quaternion.Euler(0, -90, 0) * heading; | |
rightDirection = Quaternion.Euler(0, 90, 0) * heading; | |
vertices[i * 2] = splinePoints[i] + leftDirection * widthPoints[i]; | |
vertices[i * 2 + 1] = splinePoints[i] + rightDirection * widthPoints[i]; | |
} | |
} | |
//Calculate triangles based on created vertices | |
int[] triangles = new int[vertices.Length * 3]; | |
bool oddTriangle = true; | |
for (int i = 0; i < vertices.Length; i++) | |
{ | |
if (i + 2 < vertices.Length) | |
{ | |
//Odd numbered triangles need to be reversed | |
if (oddTriangle) | |
{ | |
triangles[i * 3] = i + 1; | |
triangles[i * 3 + 1] = i; | |
triangles[i * 3 + 2] = i + 2; | |
} | |
else | |
{ | |
triangles[i * 3] = i; | |
triangles[i * 3 + 1] = i + 1; | |
triangles[i * 3 + 2] = i + 2; | |
} | |
oddTriangle = !oddTriangle; | |
} | |
} | |
triangles[triangles.Length - 1] = vertices.Length - 1; | |
//Strectch UV over every normal | |
Vector2[] newUVs = new Vector2[vertices.Length]; | |
for (int i = 0; i < newUVs.Length; i += 4) | |
{ | |
if (i + 3 < newUVs.Length) | |
{ | |
newUVs[i] = new Vector2(0, 1); | |
newUVs[i + 1] = new Vector2(0, 0); | |
newUVs[i + 2] = new Vector2(1, 1); | |
newUVs[i + 3] = new Vector2(1, 0); | |
} | |
} | |
mesh.RecalculateNormals(); | |
mesh.RecalculateTangents(); | |
mesh.vertices = vertices; | |
mesh.triangles = triangles; | |
mesh.uv = newUVs; | |
return mesh; | |
} | |
} |
Author
turbohermit
commented
Jan 3, 2018
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