336 lines
11 KiB
C#
336 lines
11 KiB
C#
using UnityEngine;
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using System.Collections.Generic;
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public class MeshShadowProjector : MonoBehaviour
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{
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[Header("投影设置")]
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public Light shadowLight;
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public Transform shadowWall;
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public string shadowLayerName = "Shadow";
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[Header("Mesh设置")]
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public bool keepOriginalMesh = true; // 是否保留原始mesh
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public float shadowIntensity = 0.5f; // 阴影强度
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private List<GameObject> modifiedObjects = new List<GameObject>();
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private Vector3 wallNormal;
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private Vector3 wallPosition;
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void Start()
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{
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if (shadowLight == null) shadowLight = FindObjectOfType<Light>();
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if (shadowWall == null) shadowWall = FindMainWall();
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CalculateWallPlane();
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GenerateAllShadowMeshes();
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}
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[ContextMenu("生成所有阴影Mesh")]
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public void GenerateAllShadowMeshes()
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{
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ClearAllShadowMeshes();
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var shadowObjects = FindObjectsInLayer(shadowLayerName);
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foreach (GameObject obj in shadowObjects)
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{
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GenerateShadowMesh(obj);
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}
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Debug.Log($"为 {modifiedObjects.Count} 个物体生成了阴影Mesh");
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}
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void GenerateShadowMesh(GameObject shadowCaster)
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{
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MeshFilter meshFilter = shadowCaster.GetComponent<MeshFilter>();
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if (meshFilter == null) return;
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// 获取原始mesh
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Mesh originalMesh = meshFilter.mesh;
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// 创建新的mesh（组合原始mesh + 投影mesh）
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Mesh combinedMesh = CreateCombinedMesh(originalMesh, shadowCaster.transform);
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// 应用新mesh
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if (keepOriginalMesh)
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{
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// 创建新物体来存放阴影mesh
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CreateShadowObject(shadowCaster, combinedMesh);
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}
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else
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{
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// 直接修改原物体
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meshFilter.mesh = combinedMesh;
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UpdateMeshCollider(shadowCaster, combinedMesh);
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modifiedObjects.Add(shadowCaster);
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}
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}
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Mesh CreateCombinedMesh(Mesh originalMesh, Transform objectTransform)
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{
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// 创建新mesh
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Mesh newMesh = new Mesh();
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List<Vector3> vertices = new List<Vector3>();
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List<int> triangles = new List<int>();
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List<Vector3> normals = new List<Vector3>();
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List<Vector2> uv = new List<Vector2>();
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// 1. 添加原始mesh的顶点和三角形
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vertices.AddRange(originalMesh.vertices);
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triangles.AddRange(originalMesh.triangles);
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// 复制原始法线和UV
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if (originalMesh.normals.Length == originalMesh.vertices.Length)
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normals.AddRange(originalMesh.normals);
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else
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for (int i = 0; i < originalMesh.vertices.Length; i++)
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normals.Add(Vector3.up);
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if (originalMesh.uv.Length == originalMesh.vertices.Length)
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uv.AddRange(originalMesh.uv);
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else
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for (int i = 0; i < originalMesh.vertices.Length; i++)
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uv.Add(Vector2.zero);
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// 2. 添加投影到墙面的顶点
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int originalVertexCount = vertices.Count;
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List<Vector3> projectedVertices = new List<Vector3>();
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List<int> projectedTriangles = new List<int>();
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// 投影每个顶点到墙面
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foreach (Vector3 localVertex in originalMesh.vertices)
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{
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Vector3 worldVertex = objectTransform.TransformPoint(localVertex);
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Vector3 projectedWorld = ProjectPointToWall(worldVertex);
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Vector3 projectedLocal = objectTransform.InverseTransformPoint(projectedWorld);
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projectedVertices.Add(projectedLocal);
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}
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// 添加投影顶点
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vertices.AddRange(projectedVertices);
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// 为投影顶点添加法线和UV
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for (int i = 0; i < projectedVertices.Count; i++)
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{
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normals.Add(-objectTransform.forward); // 面向墙面
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uv.Add(new Vector2(1, 1)); // 使用不同的UV区域
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}
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// 3. 创建连接原始mesh和投影mesh的侧面三角形
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for (int i = 0; i < originalMesh.triangles.Length; i += 3)
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{
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int v1 = originalMesh.triangles[i];
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int v2 = originalMesh.triangles[i + 1];
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int v3 = originalMesh.triangles[i + 2];
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// 对应的投影顶点索引
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int p1 = v1 + originalVertexCount;
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int p2 = v2 + originalVertexCount;
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int p3 = v3 + originalVertexCount;
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// 创建侧面四边形（两个三角形）
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// 三角形1
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projectedTriangles.Add(v1);
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projectedTriangles.Add(p1);
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projectedTriangles.Add(v2);
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projectedTriangles.Add(v2);
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projectedTriangles.Add(p1);
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projectedTriangles.Add(p2);
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// 三角形2
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projectedTriangles.Add(v2);
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projectedTriangles.Add(p2);
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projectedTriangles.Add(v3);
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projectedTriangles.Add(v3);
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projectedTriangles.Add(p2);
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projectedTriangles.Add(p3);
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// 三角形3
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projectedTriangles.Add(v3);
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projectedTriangles.Add(p3);
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projectedTriangles.Add(v1);
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projectedTriangles.Add(v1);
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projectedTriangles.Add(p3);
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projectedTriangles.Add(p1);
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}
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// 4. 添加投影面的三角形（反转原始三角形）
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int[] originalTriangles = originalMesh.triangles;
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for (int i = 0; i < originalTriangles.Length; i += 3)
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{
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// 反转 winding order
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projectedTriangles.Add(originalTriangles[i + 2] + originalVertexCount);
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projectedTriangles.Add(originalTriangles[i + 1] + originalVertexCount);
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projectedTriangles.Add(originalTriangles[i] + originalVertexCount);
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}
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// 5. 合并所有三角形
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triangles.AddRange(projectedTriangles);
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// 6. 应用到新mesh
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newMesh.vertices = vertices.ToArray();
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newMesh.triangles = triangles.ToArray();
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newMesh.normals = normals.ToArray();
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newMesh.uv = uv.ToArray();
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newMesh.RecalculateBounds();
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newMesh.RecalculateTangents();
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return newMesh;
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}
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void CreateShadowObject(GameObject original, Mesh shadowMesh)
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{
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GameObject shadowObject = new GameObject($"{original.name}_ShadowMesh");
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shadowObject.transform.SetParent(original.transform);
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shadowObject.transform.localPosition = Vector3.zero;
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shadowObject.transform.localRotation = Quaternion.identity;
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shadowObject.transform.localScale = Vector3.one;
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// 添加Mesh Filter
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MeshFilter meshFilter = shadowObject.AddComponent<MeshFilter>();
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meshFilter.mesh = shadowMesh;
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// 添加Mesh Collider
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MeshCollider meshCollider = shadowObject.AddComponent<MeshCollider>();
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meshCollider.sharedMesh = shadowMesh;
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meshCollider.convex = false; // 对于复杂mesh使用非凸体
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// 可选：添加材质用于可视化
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MeshRenderer renderer = shadowObject.AddComponent<MeshRenderer>();
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renderer.material = original.GetComponent<MeshRenderer>().material;
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modifiedObjects.Add(shadowObject);
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}
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void UpdateMeshCollider(GameObject obj, Mesh mesh)
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{
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MeshCollider meshCollider = obj.GetComponent<MeshCollider>();
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if (meshCollider == null)
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meshCollider = obj.AddComponent<MeshCollider>();
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meshCollider.sharedMesh = mesh;
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meshCollider.convex = false;
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}
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Material CreateShadowMaterial()
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{
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Material material = new Material(Shader.Find("Standard"));
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material.color = new Color(0, 0, 0, shadowIntensity);
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material.SetFloat("_Mode", 2); // Fade mode
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material.SetInt("_SrcBlend", (int)UnityEngine.Rendering.BlendMode.SrcAlpha);
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material.SetInt("_DstBlend", (int)UnityEngine.Rendering.BlendMode.OneMinusSrcAlpha);
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material.SetInt("_ZWrite", 0);
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material.DisableKeyword("_ALPHATEST_ON");
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material.EnableKeyword("_ALPHABLEND_ON");
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material.DisableKeyword("_ALPHAPREMULTIPLY_ON");
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material.renderQueue = 3000;
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return material;
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}
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Vector3 ProjectPointToWall(Vector3 worldPoint)
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{
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Vector3 lightDirection = GetLightDirection(worldPoint);
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return IntersectWithWall(worldPoint, lightDirection);
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}
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Vector3 GetLightDirection(Vector3 targetPoint)
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{
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if (shadowLight.type == LightType.Directional)
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{
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return -shadowLight.transform.forward;
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}
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else
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{
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return (targetPoint - shadowLight.transform.position).normalized;
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}
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}
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Vector3 IntersectWithWall(Vector3 point, Vector3 direction)
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{
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float denominator = Vector3.Dot(direction, wallNormal);
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if (Mathf.Abs(denominator) < 0.0001f)
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return point;
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float t = Vector3.Dot(wallPosition - point, wallNormal) / denominator;
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return point + direction * t;
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}
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void CalculateWallPlane()
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{
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if (shadowWall != null)
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{
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wallPosition = shadowWall.position;
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wallNormal = -shadowWall.forward;
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}
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}
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Transform FindMainWall()
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{
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BoxCollider[] colliders = FindObjectsOfType<BoxCollider>();
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return colliders.Length > 0 ? colliders[0].transform : transform;
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}
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List<GameObject> FindObjectsInLayer(string layerName)
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{
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int layer = LayerMask.NameToLayer(layerName);
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List<GameObject> result = new List<GameObject>();
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foreach (GameObject obj in FindObjectsOfType<GameObject>())
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{
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if (obj.activeInHierarchy && obj.layer == layer)
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{
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result.Add(obj);
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}
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}
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return result;
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}
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[ContextMenu("清空所有阴影Mesh")]
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void ClearAllShadowMeshes()
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{
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foreach (GameObject obj in modifiedObjects)
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{
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if (obj != null)
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{
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if (obj.name.EndsWith("_ShadowMesh"))
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DestroyImmediate(obj);
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else
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ResetOriginalMesh(obj);
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}
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}
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modifiedObjects.Clear();
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}
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void ResetOriginalMesh(GameObject obj)
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{
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MeshFilter meshFilter = obj.GetComponent<MeshFilter>();
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if (meshFilter != null && meshFilter.mesh != null)
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{
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// 重新加载原始mesh
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Mesh originalMesh = Instantiate(Resources.Load<Mesh>(obj.name)) ?? CreateSimpleMesh();
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meshFilter.mesh = originalMesh;
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MeshCollider collider = obj.GetComponent<MeshCollider>();
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if (collider != null)
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collider.sharedMesh = originalMesh;
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}
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}
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Mesh CreateSimpleMesh()
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{
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// 创建默认的立方体mesh
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return GameObject.CreatePrimitive(PrimitiveType.Cube).GetComponent<MeshFilter>().sharedMesh;
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}
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void OnDestroy()
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{
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ClearAllShadowMeshes();
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}
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} |