125 lines
3.2 KiB
C#
125 lines
3.2 KiB
C#
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using System;
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using Unity.Mathematics;
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using UnityEngine;
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using UnityEngine.Splines;
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#if UNITY_EDITOR
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using System.IO;
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using UnityEditor;
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#endif
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namespace Unity.Splines.Examples
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{
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// Example showing how to extend Spline class through inheritance.
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[Serializable]
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public class RollercoasterTrack : Spline
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{
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const string k_GeneratedMeshDirectory = "Assets/Generated/Rollercoaster";
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[SerializeField, Range(.1f, 10f)]
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float m_TrackWidth = 1f;
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[SerializeField]
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int m_TracksPerMeter = 2;
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[SerializeField]
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Mesh m_Mesh;
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public Mesh mesh
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{
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get
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{
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if (m_Mesh != null)
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return m_Mesh;
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m_Mesh = new Mesh();
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// In the editor it's usually convenient to save the mesh as an asset rather than generate it on the
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// fly any time the scene is loaded.
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#if UNITY_EDITOR
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Directory.CreateDirectory(k_GeneratedMeshDirectory);
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var path = AssetDatabase.GenerateUniqueAssetPath($"{k_GeneratedMeshDirectory}/Track.asset");
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AssetDatabase.CreateAsset(m_Mesh, path);
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AssetDatabase.ImportAsset(path);
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#endif
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return m_Mesh;
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}
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}
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// When working in the editor, instead of rebuilding the mesh any time the spline changes (which can be often
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// especially when moving knots), we'll schedule updates once per-frame.
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#if UNITY_EDITOR
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[NonSerialized]
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bool m_RebuildScheduled;
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#endif
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protected override void OnSplineChanged()
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{
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base.OnSplineChanged();
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#if UNITY_EDITOR
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if (m_RebuildScheduled)
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return;
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m_RebuildScheduled = true;
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EditorApplication.delayCall += () =>
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{
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RebuildTracks();
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m_RebuildScheduled = false;
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};
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#else
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RebuildTracks();
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#endif
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}
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// Generate a set of ties along the spline path.
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public void RebuildTracks()
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{
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using var spline = new NativeSpline(this);
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var len = spline.GetLength();
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var tieCount = (int) (len * m_TracksPerMeter);
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mesh.Clear();
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Vector3[] positions = new Vector3[tieCount * 4];
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Vector3[] normals = new Vector3[tieCount * 4];
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int[] indices = new int[tieCount * 6];
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for (int i = 0; i < tieCount; i++)
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{
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float t = (float) i / (tieCount - 1);
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var position = SplineUtility.EvaluatePosition(spline, t);
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var forward = SplineUtility.EvaluateTangent(spline, t);
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var tangent = (quaternion) Quaternion.LookRotation(forward);
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int a = i * 4 + 0,
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b = i * 4 + 1,
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c = i * 4 + 2,
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d = i * 4 + 3;
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positions[a] = position + math.mul(tangent, new float3(-m_TrackWidth * .5f, 0f, -0.25f));
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positions[b] = position + math.mul(tangent, new float3( m_TrackWidth * .5f, 0f, -0.25f));
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positions[c] = position + math.mul(tangent, new float3(-m_TrackWidth * .5f, 0f, 0.25f));
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positions[d] = position + math.mul(tangent, new float3( m_TrackWidth * .5f, 0f, 0.25f));
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normals[a] = Vector3.up;
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normals[b] = Vector3.up;
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normals[c] = Vector3.up;
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normals[d] = Vector3.up;
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indices[i*6+0] = c;
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indices[i*6+1] = b;
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indices[i*6+2] = a;
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indices[i*6+3] = b;
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indices[i*6+4] = c;
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indices[i*6+5] = d;
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}
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mesh.vertices = positions;
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mesh.normals = normals;
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mesh.subMeshCount = 1;
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mesh.SetIndices(indices, MeshTopology.Triangles, 0);
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}
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}
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}
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