268 lines
7.9 KiB
C
268 lines
7.9 KiB
C
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/* 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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// 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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// 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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#include <math.h>
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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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/* 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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/* 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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/* begin calculating determinant - also used to calculate U parameter */
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IGL_RAY_TRI_CROSS(pvec, dir, edge2);
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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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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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/* calculate distance from vert0 to ray origin */
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IGL_RAY_TRI_SUB(tvec, orig, vert0);
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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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/* prepare to test V parameter */
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IGL_RAY_TRI_CROSS(qvec, tvec, edge1);
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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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/* calculate t, ray intersects triangle */
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*t = IGL_RAY_TRI_DOT(edge2, qvec) * inv_det;
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return 1;
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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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/* 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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/* begin calculating determinant - also used to calculate U parameter */
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IGL_RAY_TRI_CROSS(pvec, dir, edge2);
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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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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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/* 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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/* prepare to test V parameter */
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IGL_RAY_TRI_CROSS(qvec, tvec, edge1);
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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 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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/* 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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/* prepare to test V parameter */
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IGL_RAY_TRI_CROSS(qvec, tvec, edge1);
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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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inv_det = 1.0 / det;
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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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return 1;
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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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/* 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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/* begin calculating determinant - also used to calculate U parameter */
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IGL_RAY_TRI_CROSS(pvec, dir, edge2);
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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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/* 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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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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/* prepare to test V parameter */
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IGL_RAY_TRI_CROSS(qvec, tvec, edge1);
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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 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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/* prepare to test V parameter */
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IGL_RAY_TRI_CROSS(qvec, tvec, edge1);
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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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/* 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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return 1;
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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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/* 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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/* begin calculating determinant - also used to calculate U parameter */
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IGL_RAY_TRI_CROSS(pvec, dir, edge2);
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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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/* 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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IGL_RAY_TRI_CROSS(qvec, tvec, edge1);
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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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/* 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 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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/* 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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*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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return 1;
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}
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#endif
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