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			267 lines
		
	
	
	
		
			7.9 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			267 lines
		
	
	
	
		
			7.9 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
| /* Ray-Triangle Intersection Test Routines          */
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| /* Different optimizations of my and Ben Trumbore's */
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| /* code from journals of graphics tools (JGT)       */
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| /* http://www.acm.org/jgt/                          */
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| /* by Tomas Moller, May 2000                        */
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| 
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| 
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| // Alec: this file is listed as "Public Domain"
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| // http://fileadmin.cs.lth.se/cs/Personal/Tomas_Akenine-Moller/code/
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| 
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| // Alec: I've added an include guard, made all functions inline and added
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| // IGL_RAY_TRI_ to #define macros
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| #ifndef IGL_RAY_TRI_C
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| #define IGL_RAY_TRI_C
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| 
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| #include <math.h>
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| 
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| #define IGL_RAY_TRI_EPSILON 0.000001
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| #define IGL_RAY_TRI_CROSS(dest,v1,v2) \
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|           dest[0]=v1[1]*v2[2]-v1[2]*v2[1]; \
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|           dest[1]=v1[2]*v2[0]-v1[0]*v2[2]; \
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|           dest[2]=v1[0]*v2[1]-v1[1]*v2[0];
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| #define IGL_RAY_TRI_DOT(v1,v2) (v1[0]*v2[0]+v1[1]*v2[1]+v1[2]*v2[2])
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| #define IGL_RAY_TRI_SUB(dest,v1,v2) \
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|           dest[0]=v1[0]-v2[0]; \
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|           dest[1]=v1[1]-v2[1]; \
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|           dest[2]=v1[2]-v2[2]; 
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| 
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| /* the original jgt code */
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| inline int intersect_triangle(double orig[3], double dir[3],
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| 		       double vert0[3], double vert1[3], double vert2[3],
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| 		       double *t, double *u, double *v)
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| {
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|    double edge1[3], edge2[3], tvec[3], pvec[3], qvec[3];
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|    double det,inv_det;
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| 
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|    /* find vectors for two edges sharing vert0 */
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|    IGL_RAY_TRI_SUB(edge1, vert1, vert0);
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|    IGL_RAY_TRI_SUB(edge2, vert2, vert0);
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| 
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|    /* begin calculating determinant - also used to calculate U parameter */
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|    IGL_RAY_TRI_CROSS(pvec, dir, edge2);
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| 
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|    /* if determinant is near zero, ray lies in plane of triangle */
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|    det = IGL_RAY_TRI_DOT(edge1, pvec);
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| 
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|    if (det > -IGL_RAY_TRI_EPSILON && det < IGL_RAY_TRI_EPSILON)
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|      return 0;
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|    inv_det = 1.0 / det;
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| 
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|    /* calculate distance from vert0 to ray origin */
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|    IGL_RAY_TRI_SUB(tvec, orig, vert0);
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| 
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|    /* calculate U parameter and test bounds */
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|    *u = IGL_RAY_TRI_DOT(tvec, pvec) * inv_det;
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|    if (*u < 0.0 || *u > 1.0)
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|      return 0;
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| 
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|    /* prepare to test V parameter */
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|    IGL_RAY_TRI_CROSS(qvec, tvec, edge1);
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| 
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|    /* calculate V parameter and test bounds */
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|    *v = IGL_RAY_TRI_DOT(dir, qvec) * inv_det;
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|    if (*v < 0.0 || *u + *v > 1.0)
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|      return 0;
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| 
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|    /* calculate t, ray intersects triangle */
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|    *t = IGL_RAY_TRI_DOT(edge2, qvec) * inv_det;
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| 
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|    return 1;
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| }
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| 
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| 
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| /* code rewritten to do tests on the sign of the determinant */
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| /* the division is at the end in the code                    */
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| inline int intersect_triangle1(double orig[3], double dir[3],
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| 			double vert0[3], double vert1[3], double vert2[3],
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| 			double *t, double *u, double *v)
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| {
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|    double edge1[3], edge2[3], tvec[3], pvec[3], qvec[3];
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|    double det,inv_det;
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| 
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|    /* find vectors for two edges sharing vert0 */
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|    IGL_RAY_TRI_SUB(edge1, vert1, vert0);
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|    IGL_RAY_TRI_SUB(edge2, vert2, vert0);
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| 
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|    /* begin calculating determinant - also used to calculate U parameter */
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|    IGL_RAY_TRI_CROSS(pvec, dir, edge2);
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| 
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|    /* if determinant is near zero, ray lies in plane of triangle */
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|    det = IGL_RAY_TRI_DOT(edge1, pvec);
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| 
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|    if (det > IGL_RAY_TRI_EPSILON)
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|    {
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|       /* calculate distance from vert0 to ray origin */
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|       IGL_RAY_TRI_SUB(tvec, orig, vert0);
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|       
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|       /* calculate U parameter and test bounds */
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|       *u = IGL_RAY_TRI_DOT(tvec, pvec);
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|       if (*u < 0.0 || *u > det)
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| 	 return 0;
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|       
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|       /* prepare to test V parameter */
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|       IGL_RAY_TRI_CROSS(qvec, tvec, edge1);
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|       
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|       /* calculate V parameter and test bounds */
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|       *v = IGL_RAY_TRI_DOT(dir, qvec);
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|       if (*v < 0.0 || *u + *v > det)
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| 	 return 0;
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|       
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|    }
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|    else if(det < -IGL_RAY_TRI_EPSILON)
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|    {
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|       /* calculate distance from vert0 to ray origin */
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|       IGL_RAY_TRI_SUB(tvec, orig, vert0);
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|       
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|       /* calculate U parameter and test bounds */
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|       *u = IGL_RAY_TRI_DOT(tvec, pvec);
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| /*      printf("*u=%f\n",(float)*u); */
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| /*      printf("det=%f\n",det); */
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|       if (*u > 0.0 || *u < det)
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| 	 return 0;
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|       
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|       /* prepare to test V parameter */
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|       IGL_RAY_TRI_CROSS(qvec, tvec, edge1);
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|       
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|       /* calculate V parameter and test bounds */
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|       *v = IGL_RAY_TRI_DOT(dir, qvec) ;
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|       if (*v > 0.0 || *u + *v < det)
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| 	 return 0;
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|    }
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|    else return 0;  /* ray is parallel to the plane of the triangle */
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| 
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| 
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|    inv_det = 1.0 / det;
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| 
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|    /* calculate t, ray intersects triangle */
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|    *t = IGL_RAY_TRI_DOT(edge2, qvec) * inv_det;
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|    (*u) *= inv_det;
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|    (*v) *= inv_det;
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| 
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|    return 1;
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| }
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| 
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| /* code rewritten to do tests on the sign of the determinant */
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| /* the division is before the test of the sign of the det    */
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| inline int intersect_triangle2(double orig[3], double dir[3],
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| 			double vert0[3], double vert1[3], double vert2[3],
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| 			double *t, double *u, double *v)
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| {
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|    double edge1[3], edge2[3], tvec[3], pvec[3], qvec[3];
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|    double det,inv_det;
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| 
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|    /* find vectors for two edges sharing vert0 */
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|    IGL_RAY_TRI_SUB(edge1, vert1, vert0);
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|    IGL_RAY_TRI_SUB(edge2, vert2, vert0);
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| 
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|    /* begin calculating determinant - also used to calculate U parameter */
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|    IGL_RAY_TRI_CROSS(pvec, dir, edge2);
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| 
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|    /* if determinant is near zero, ray lies in plane of triangle */
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|    det = IGL_RAY_TRI_DOT(edge1, pvec);
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| 
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|    /* calculate distance from vert0 to ray origin */
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|    IGL_RAY_TRI_SUB(tvec, orig, vert0);
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|    inv_det = 1.0 / det;
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|    
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|    if (det > IGL_RAY_TRI_EPSILON)
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|    {
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|       /* calculate U parameter and test bounds */
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|       *u = IGL_RAY_TRI_DOT(tvec, pvec);
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|       if (*u < 0.0 || *u > det)
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| 	 return 0;
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|       
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|       /* prepare to test V parameter */
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|       IGL_RAY_TRI_CROSS(qvec, tvec, edge1);
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|       
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|       /* calculate V parameter and test bounds */
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|       *v = IGL_RAY_TRI_DOT(dir, qvec);
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|       if (*v < 0.0 || *u + *v > det)
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| 	 return 0;
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|       
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|    }
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|    else if(det < -IGL_RAY_TRI_EPSILON)
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|    {
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|       /* calculate U parameter and test bounds */
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|       *u = IGL_RAY_TRI_DOT(tvec, pvec);
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|       if (*u > 0.0 || *u < det)
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| 	 return 0;
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|       
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|       /* prepare to test V parameter */
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|       IGL_RAY_TRI_CROSS(qvec, tvec, edge1);
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|       
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|       /* calculate V parameter and test bounds */
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|       *v = IGL_RAY_TRI_DOT(dir, qvec) ;
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|       if (*v > 0.0 || *u + *v < det)
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| 	 return 0;
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|    }
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|    else return 0;  /* ray is parallel to the plane of the triangle */
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| 
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|    /* calculate t, ray intersects triangle */
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|    *t = IGL_RAY_TRI_DOT(edge2, qvec) * inv_det;
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|    (*u) *= inv_det;
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|    (*v) *= inv_det;
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| 
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|    return 1;
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| }
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| 
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| /* code rewritten to do tests on the sign of the determinant */
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| /* the division is before the test of the sign of the det    */
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| /* and one IGL_RAY_TRI_CROSS has been moved out from the if-else if-else */
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| inline int intersect_triangle3(double orig[3], double dir[3],
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| 			double vert0[3], double vert1[3], double vert2[3],
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| 			double *t, double *u, double *v)
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| {
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|    double edge1[3], edge2[3], tvec[3], pvec[3], qvec[3];
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|    double det,inv_det;
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| 
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|    /* find vectors for two edges sharing vert0 */
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|    IGL_RAY_TRI_SUB(edge1, vert1, vert0);
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|    IGL_RAY_TRI_SUB(edge2, vert2, vert0);
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| 
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|    /* begin calculating determinant - also used to calculate U parameter */
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|    IGL_RAY_TRI_CROSS(pvec, dir, edge2);
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| 
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|    /* if determinant is near zero, ray lies in plane of triangle */
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|    det = IGL_RAY_TRI_DOT(edge1, pvec);
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| 
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|    /* calculate distance from vert0 to ray origin */
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|    IGL_RAY_TRI_SUB(tvec, orig, vert0);
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|    inv_det = 1.0 / det;
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|    
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|    IGL_RAY_TRI_CROSS(qvec, tvec, edge1);
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|       
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|    if (det > IGL_RAY_TRI_EPSILON)
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|    {
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|       *u = IGL_RAY_TRI_DOT(tvec, pvec);
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|       if (*u < 0.0 || *u > det)
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| 	 return 0;
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|             
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|       /* calculate V parameter and test bounds */
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|       *v = IGL_RAY_TRI_DOT(dir, qvec);
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|       if (*v < 0.0 || *u + *v > det)
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| 	 return 0;
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|       
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|    }
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|    else if(det < -IGL_RAY_TRI_EPSILON)
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|    {
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|       /* calculate U parameter and test bounds */
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|       *u = IGL_RAY_TRI_DOT(tvec, pvec);
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|       if (*u > 0.0 || *u < det)
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| 	 return 0;
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|       
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|       /* calculate V parameter and test bounds */
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|       *v = IGL_RAY_TRI_DOT(dir, qvec) ;
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|       if (*v > 0.0 || *u + *v < det)
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| 	 return 0;
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|    }
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|    else return 0;  /* ray is parallel to the plane of the triangle */
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| 
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|    *t = IGL_RAY_TRI_DOT(edge2, qvec) * inv_det;
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|    (*u) *= inv_det;
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|    (*v) *= inv_det;
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| 
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|    return 1;
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| }
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| #endif
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