93 lines
4.1 KiB
C#
93 lines
4.1 KiB
C#
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using UnityEngine;
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using System.Collections;
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namespace Obi
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{
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public static class ObiMeshUtils
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{
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// Temporary vector3 values
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static Vector3 tv1, tv2, tv3, tv4;
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public static bool RayIntersectsTriangle(Vector3 origin,
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Vector3 dir,
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Vector3 vert0,
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Vector3 vert1,
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Vector3 vert2,
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ref float distance,
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ref Vector3 normal)
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{
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float det;
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ObiVectorMath.Subtract(vert0, vert1, ref tv1);
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ObiVectorMath.Subtract(vert0, vert2, ref tv2);
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ObiVectorMath.Cross(dir, tv2, ref tv4);
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det = Vector3.Dot(tv1, tv4);
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if (det < Mathf.Epsilon)
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return false;
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ObiVectorMath.Subtract(vert0, origin, ref tv3);
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float u = Vector3.Dot(tv3, tv4);
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if (u < 0f || u > det)
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return false;
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ObiVectorMath.Cross(tv3, tv1, ref tv4);
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float v = Vector3.Dot(dir, tv4);
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if (v < 0f || u + v > det)
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return false;
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distance = Vector3.Dot(tv2, tv4) * (1f / det);
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ObiVectorMath.Cross(tv1, tv2, ref normal);
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return true;
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}
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/**
* Find the nearest triangle intersected by InWorldRay on this mesh. InWorldRay is in world space.
* @hit contains information about the hit point. @distance limits how far from @InWorldRay.origin the hit
* point may be. @cullingMode determines what face orientations are tested (Culling.Front only tests front
* faces, Culling.Back only tests back faces, and Culling.FrontBack tests both).
* Ray origin and position values are in local space.
*/
public static bool WorldRaycast(Ray InWorldRay, Matrix4x4 transform, Vector3[] vertices, int[] triangles, out ObiRaycastHit hit, float distance = Mathf.Infinity)
{
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Ray ray = InWorldRay;
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if (transform != null)
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{
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Matrix4x4 inv = transform.inverse;
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ray.origin = inv.MultiplyPoint3x4(ray.origin);
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ray.direction = inv.MultiplyVector(ray.direction);
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}
return MeshRaycast(ray, vertices, triangles, out hit, distance);
}
/**
* Cast a ray (in model space) against a mesh.
*/
public static bool MeshRaycast(Ray InRay, Vector3[] vertices, int[] triangles, out ObiRaycastHit hit, float distance = Mathf.Infinity)
{
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Vector3 hitNormal = Vector3.zero; // vars used in loop
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Vector3 vert0, vert1, vert2;
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Vector3 origin = InRay.origin, direction = InRay.direction;
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hit = new ObiRaycastHit(Mathf.Infinity,
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Vector3.zero,
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Vector3.zero,
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-1);
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/**
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* Iterate faces, testing for nearest hit to ray origin.
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*/
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for (int CurTri = 0; CurTri < triangles.Length; CurTri += 3)
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{
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if (CurTri + 2 >= triangles.Length) continue;
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if (triangles[CurTri + 2] >= vertices.Length) continue;
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vert0 = vertices[triangles[CurTri + 0]];
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vert1 = vertices[triangles[CurTri + 1]];
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vert2 = vertices[triangles[CurTri + 2]];
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// Second pass, test intersection with triangle
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if (RayIntersectsTriangle(origin, direction, vert0, vert1, vert2, ref distance, ref hitNormal))
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{
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if (distance < hit.distance)
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{
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hit.distance = distance;
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hit.triangle = CurTri / 3;
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hit.position = InRay.GetPoint(hit.distance);
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hit.normal = hitNormal;
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}
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}
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}
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return hit.triangle > -1;
}
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}
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}
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