diff options
| author | chai <chaifix@163.com> | 2021-05-12 14:06:59 +0800 |
|---|---|---|
| committer | chai <chaifix@163.com> | 2021-05-12 14:06:59 +0800 |
| commit | 4756f47d587eaf8db5b54118d0ed7cbdadad403d (patch) | |
| tree | 58a5e819aedb40e367ba2d0a98d6457c4f504c0a | |
| parent | db44a6e164c2072a6526bb4e588e7590df4e08c4 (diff) | |
+model tangent normal viwer
| -rw-r--r-- | UnityCollection/Assets/Tools/ModelTBNShow.cs | 89 |
1 files changed, 89 insertions, 0 deletions
diff --git a/UnityCollection/Assets/Tools/ModelTBNShow.cs b/UnityCollection/Assets/Tools/ModelTBNShow.cs new file mode 100644 index 0000000..a1f431c --- /dev/null +++ b/UnityCollection/Assets/Tools/ModelTBNShow.cs @@ -0,0 +1,89 @@ +// 显示模型的normal, tangnent, binormal
+using System.Collections;
+using System.Collections.Generic;
+using UnityEngine;
+
+public class ModelTBNShow : MonoBehaviour
+{
+ [Range(0f, 10f)]
+ public float tbnLen = 0.1f;
+ [Range(0, 1000)]
+ public int maxShowNum = 100;
+ public bool showNormal = true;
+ public bool showTangent = true;
+ public bool showBiTangent = true;
+
+ MeshFilter meshFilter;
+ Mesh sharedMesh;
+
+ Matrix4x4 localToWorld;
+ Matrix4x4 localToWorldInverseTranspose;
+
+ private void OnDrawGizmos()
+ {
+ meshFilter = GetComponent<MeshFilter>();
+ sharedMesh = meshFilter.sharedMesh;
+
+ localToWorld = meshFilter.transform.localToWorldMatrix;
+ localToWorldInverseTranspose = localToWorld.inverse.transpose;
+
+ Vector3[] vertices = sharedMesh.vertices;
+ Vector3[] normals = sharedMesh.normals;
+ Vector4[] tangents = sharedMesh.tangents;
+
+ int tangentsLen = (tangents != null ? tangents.Length : 0);
+ Vector3[] biTangents = new Vector3[tangentsLen];
+ Vector3[] tangentsData = new Vector3[tangentsLen];
+ for (int i = 0; i < tangentsLen; i++)
+ {
+ //切向量数据 Vector4 转 Vector3
+ tangentsData[i].x = tangents[i].x;
+ tangentsData[i].y = tangents[i].y;
+ tangentsData[i].z = tangents[i].z;
+ //计算副切线 cross(法向量，切向量)*坐标系方向参数
+ biTangents[i] = Vector3.Cross(normals[i], tangentsData[i]) * tangents[i].w;
+ }
+
+ /*
+ * localToWorld 将 顶点位置 从模型坐标系转到世界坐标系矩阵
+ * localToWorldInverseTranspose 将 向量 从模型坐标系转到世界坐标系矩阵
+ * 1、切向量t和副切向量b 由于方向与纹理坐标系一致 使用localToWorld和localToWorldInverseTranspose矩阵转换到世界坐标系 结果相同
+ * 2、normal 由于模型有非等比缩放的情况，缩放后顶点的法向量使用localToWorld矩阵转换的结果不正确
+ * 设矩阵M为切向量t的转换矩阵,矩阵G为法向量n的转换矩阵,
+ * 转换后的切向量且t2 = M*t， 转换后的法向量n2 = G*n，同时要求 n2 * t2 = 0
+ * 所以 (G*n)' * (M*t) = 0 => n'*G'*M*t = 0 (n'表示向量n的转置, G'表示矩阵G的转置)
+ * 已知 n'*t = 0(法向量和切向量垂直)， 此时如果令 G'*M = I(单位矩阵)
+ * 则有 n'*G'*M*t = n'*I*t = n'*t = 0 成立
+ * 可得 G'*M = I => G = (inverse(M))'
+ */
+ if (showNormal) DrawVectors(vertices, normals, ref localToWorld, ref localToWorldInverseTranspose, Color.red, tbnLen);
+ if (showTangent) DrawVectors(vertices, tangentsData, ref localToWorld, ref localToWorld, Color.green, tbnLen);
+ if (showBiTangent) DrawVectors(vertices, biTangents, ref localToWorld, ref localToWorld, Color.blue, tbnLen);
+ }
+
+ /*显示向量
+ * vertexs 向量初始位置
+ * vectors 向量方向
+ * vertexMatrix 向量初始位置从模型坐标系转到世界坐标系矩阵
+ * vectorMatrix 向量方向从模型坐标系转到世界坐标系矩阵
+ * color 向量颜色
+ * */
+ void DrawVectors(Vector3[] vertexs, Vector3[] vectors, ref Matrix4x4 vertexMatrix, ref Matrix4x4 vectorMatrix, Color color, float vectorLen)
+ {
+ Gizmos.color = color;
+ int len = (vertexs == null || vectors == null ? 0 : vertexs.Length);
+ len = Mathf.Min(len, maxShowNum);
+ if (vertexs.Length != vectors.Length)
+ {
+ Debug.LogError("vertexs lenght not equal vectors length!!!");
+ return;
+ }
+ for (int i = 0; i < len; i++)
+ {
+ Vector3 vertexData = vertexMatrix.MultiplyPoint(vertexs[i]);
+ Vector3 vectorData = vectorMatrix.MultiplyVector(vectors[i]);
+ vectorData.Normalize();
+ Gizmos.DrawLine(vertexData, vertexData + vectorData * vectorLen);
+ }
+ }
+}
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