/*
*  Triangle-Triangle Overlap Test Routines
*  July, 2002
*  Updated December 2003
*
*  This file contains C implementation of algorithms for
*  performing two and three-dimensional triangle-triangle intersection test
*  The algorithms and underlying theory are described in
*
* "Fast and Robust Triangle-Triangle Overlap Test
*  Using Orientation Predicates"  P. Guigue - O. Devillers
*
*  Journal of Graphics Tools, 8(1), 2003
*
*  Several geometric predicates are defined.  Their parameters are all
*  points.  Each point is an array of two or three real precision
*  floating point numbers. The geometric predicates implemented in
*  this file are:
*
*    int tri_tri_overlap_test_3d(p1,q1,r1,p2,q2,r2)
*    int tri_tri_overlap_test_2d(p1,q1,r1,p2,q2,r2)
*
*    int tri_tri_intersection_test_3d(p1,q1,r1,p2,q2,r2,
*                                     coplanar,source,target)
*
*       is a version that computes the segment of intersection when
*       the triangles overlap (and are not coplanar)
*
*    each function returns 1 if the triangles (including their
*    boundary) intersect, otherwise 0
*
*
*  Other information are available from the Web page
*  http:<i>//www.acm.org/jgt/papers/GuigueDevillers03/
*
*/

// modified by Aaron to better detect coplanarity

#define ZERO_TEST(x)  (x == 0)
//#define ZERO_TEST(x)  ((x) > -0.001 && (x) < .001)

#ifdef FLOAT_TETWILD_USE_FLOAT
typedef float real;                      // float
#else
typedef double real;                      // double
#endif

/* function prototype */

int tri_tri_overlap_test_3d(real p1[3], real q1[3], real r1[3],
                            real p2[3], real q2[3], real r2[3]);


int coplanar_tri_tri3d(real  p1[3], real  q1[3], real  r1[3],
                       real  p2[3], real  q2[3], real  r2[3],
                       real  N1[3], real  N2[3]);


int tri_tri_overlap_test_2d(real p1[2], real q1[2], real r1[2],
                            real p2[2], real q2[2], real r2[2]);


int tri_tri_intersection_test_3d(real p1[3], real q1[3], real r1[3],
                                 real p2[3], real q2[3], real r2[3],
                                 int * coplanar,
                                 real source[3],real target[3]);

/* coplanar returns whether the triangles are coplanar
*  source and target are the endpoints of the segment of
*  intersection if it exists)
*/


/* some 3D macros */

#define CROSS(dest,v1,v2)                       \
               dest[0]=v1[1]*v2[2]-v1[2]*v2[1]; \
               dest[1]=v1[2]*v2[0]-v1[0]*v2[2]; \
               dest[2]=v1[0]*v2[1]-v1[1]*v2[0];

#define DOT(v1,v2) (v1[0]*v2[0]+v1[1]*v2[1]+v1[2]*v2[2])



#define SUB(dest,v1,v2) dest[0]=v1[0]-v2[0]; \
                        dest[1]=v1[1]-v2[1]; \
                        dest[2]=v1[2]-v2[2];


#define SCALAR(dest,alpha,v) dest[0] = alpha * v[0]; \
                             dest[1] = alpha * v[1]; \
                             dest[2] = alpha * v[2];



#define CHECK_MIN_MAX(p1,q1,r1,p2,q2,r2) {\
  SUB(v1,p2,q1)\
  SUB(v2,p1,q1)\
  CROSS(N1,v1,v2)\
  SUB(v1,q2,q1)\
  if (DOT(v1,N1) > 0.0f) return 0;\
  SUB(v1,p2,p1)\
  SUB(v2,r1,p1)\
  CROSS(N1,v1,v2)\
  SUB(v1,r2,p1) \
  if (DOT(v1,N1) > 0.0f) return 0;\
  else return 1; }



/* Permutation in a canonical form of T2's vertices */

#define TRI_TRI_3D(p1,q1,r1,p2,q2,r2,dp2,dq2,dr2) { \
  if (dp2 > 0.0f) { \
     if (dq2 > 0.0f) CHECK_MIN_MAX(p1,r1,q1,r2,p2,q2) \
     else if (dr2 > 0.0f) CHECK_MIN_MAX(p1,r1,q1,q2,r2,p2)\
     else CHECK_MIN_MAX(p1,q1,r1,p2,q2,r2) }\
  else if (dp2 < 0.0f) { \
    if (dq2 < 0.0f) CHECK_MIN_MAX(p1,q1,r1,r2,p2,q2)\
    else if (dr2 < 0.0f) CHECK_MIN_MAX(p1,q1,r1,q2,r2,p2)\
    else CHECK_MIN_MAX(p1,r1,q1,p2,q2,r2)\
  } else { \
    if (dq2 < 0.0f) { \
      if (dr2 >= 0.0f)  CHECK_MIN_MAX(p1,r1,q1,q2,r2,p2)\
      else CHECK_MIN_MAX(p1,q1,r1,p2,q2,r2)\
    } \
    else if (dq2 > 0.0f) { \
      if (dr2 > 0.0f) CHECK_MIN_MAX(p1,r1,q1,p2,q2,r2)\
      else  CHECK_MIN_MAX(p1,q1,r1,q2,r2,p2)\
    } \
    else  { \
      if (dr2 > 0.0f) CHECK_MIN_MAX(p1,q1,r1,r2,p2,q2)\
      else if (dr2 < 0.0f) CHECK_MIN_MAX(p1,r1,q1,r2,p2,q2)\
      else return coplanar_tri_tri3d(p1,q1,r1,p2,q2,r2,N1,N2);\
     }}}



/*
*
*  Three-dimensional Triangle-Triangle Overlap Test
*
*/


int tri_tri_overlap_test_3d(real p1[3], real q1[3], real r1[3],

                            real p2[3], real q2[3], real r2[3])
{
    real dp1, dq1, dr1, dp2, dq2, dr2;
    real v1[3], v2[3];
    real N1[3], N2[3];

    /* Compute distance signs  of p1, q1 and r1 to the plane of
       triangle(p2,q2,r2) */


    SUB(v1,p2,r2)
    SUB(v2,q2,r2)
    CROSS(N2,v1,v2)

    SUB(v1,p1,r2)
    dp1 = DOT(v1,N2);
    SUB(v1,q1,r2)
    dq1 = DOT(v1,N2);
    SUB(v1,r1,r2)
    dr1 = DOT(v1,N2);

    if (((dp1 * dq1) > 0.0f) && ((dp1 * dr1) > 0.0f))  return 0;

    /* Compute distance signs  of p2, q2 and r2 to the plane of
       triangle(p1,q1,r1) */


    SUB(v1,q1,p1)
    SUB(v2,r1,p1)
    CROSS(N1,v1,v2)

    SUB(v1,p2,r1)
    dp2 = DOT(v1,N1);
    SUB(v1,q2,r1)
    dq2 = DOT(v1,N1);
    SUB(v1,r2,r1)
    dr2 = DOT(v1,N1);

    if (((dp2 * dq2) > 0.0f) && ((dp2 * dr2) > 0.0f)) return 0;

    /* Permutation in a canonical form of T1's vertices */




    if (dp1 > 0.0f) {
        if (dq1 > 0.0f) TRI_TRI_3D(r1,p1,q1,p2,r2,q2,dp2,dr2,dq2)
        else if (dr1 > 0.0f) TRI_TRI_3D(q1,r1,p1,p2,r2,q2,dp2,dr2,dq2)
        else TRI_TRI_3D(p1,q1,r1,p2,q2,r2,dp2,dq2,dr2)
    } else if (dp1 < 0.0f) {
        if (dq1 < 0.0f) TRI_TRI_3D(r1,p1,q1,p2,q2,r2,dp2,dq2,dr2)
        else if (dr1 < 0.0f) TRI_TRI_3D(q1,r1,p1,p2,q2,r2,dp2,dq2,dr2)
        else TRI_TRI_3D(p1,q1,r1,p2,r2,q2,dp2,dr2,dq2)
    } else {
        if (dq1 < 0.0f) {
            if (dr1 >= 0.0f) TRI_TRI_3D(q1,r1,p1,p2,r2,q2,dp2,dr2,dq2)
            else TRI_TRI_3D(p1,q1,r1,p2,q2,r2,dp2,dq2,dr2)
        }
        else if (dq1 > 0.0f) {
            if (dr1 > 0.0f) TRI_TRI_3D(p1,q1,r1,p2,r2,q2,dp2,dr2,dq2)
            else TRI_TRI_3D(q1,r1,p1,p2,q2,r2,dp2,dq2,dr2)
        }
        else  {
            if (dr1 > 0.0f) TRI_TRI_3D(r1,p1,q1,p2,q2,r2,dp2,dq2,dr2)
            else if (dr1 < 0.0f) TRI_TRI_3D(r1,p1,q1,p2,r2,q2,dp2,dr2,dq2)
            else return coplanar_tri_tri3d(p1,q1,r1,p2,q2,r2,N1,N2);
        }
    }
};



int coplanar_tri_tri3d(real p1[3], real q1[3], real r1[3],
                       real p2[3], real q2[3], real r2[3],
                       real normal_1[3], real normal_2[3]){

    real P1[2],Q1[2],R1[2];
    real P2[2],Q2[2],R2[2];

    real n_x, n_y, n_z;

    n_x = ((normal_1[0]<0)?-normal_1[0]:normal_1[0]);
    n_y = ((normal_1[1]<0)?-normal_1[1]:normal_1[1]);
    n_z = ((normal_1[2]<0)?-normal_1[2]:normal_1[2]);


    /* Projection of the triangles in 3D onto 2D such that the area of
       the projection is maximized. */


    if (( n_x > n_z ) && ( n_x >= n_y )) {
        // Project onto plane YZ

        P1[0] = q1[2]; P1[1] = q1[1];
        Q1[0] = p1[2]; Q1[1] = p1[1];
        R1[0] = r1[2]; R1[1] = r1[1];

        P2[0] = q2[2]; P2[1] = q2[1];
        Q2[0] = p2[2]; Q2[1] = p2[1];
        R2[0] = r2[2]; R2[1] = r2[1];

    } else if (( n_y > n_z ) && ( n_y >= n_x )) {
        // Project onto plane XZ

        P1[0] = q1[0]; P1[1] = q1[2];
        Q1[0] = p1[0]; Q1[1] = p1[2];
        R1[0] = r1[0]; R1[1] = r1[2];

        P2[0] = q2[0]; P2[1] = q2[2];
        Q2[0] = p2[0]; Q2[1] = p2[2];
        R2[0] = r2[0]; R2[1] = r2[2];

    } else {
        // Project onto plane XY

        P1[0] = p1[0]; P1[1] = p1[1];
        Q1[0] = q1[0]; Q1[1] = q1[1];
        R1[0] = r1[0]; R1[1] = r1[1];

        P2[0] = p2[0]; P2[1] = p2[1];
        Q2[0] = q2[0]; Q2[1] = q2[1];
        R2[0] = r2[0]; R2[1] = r2[1];
    }

    return tri_tri_overlap_test_2d(P1,Q1,R1,P2,Q2,R2);

};



/*
*
*  Three-dimensional Triangle-Triangle Intersection
*
*/

/*
   This macro is called when the triangles surely intersect
   It constructs the segment of intersection of the two triangles
   if they are not coplanar.
*/

#define CONSTRUCT_INTERSECTION(p1,q1,r1,p2,q2,r2) { \
  SUB(v1,q1,p1) \
  SUB(v2,r2,p1) \
  CROSS(N,v1,v2) \
  SUB(v,p2,p1) \
  if (DOT(v,N) > 0.0f) {\
    SUB(v1,r1,p1) \
    CROSS(N,v1,v2) \
    if (DOT(v,N) <= 0.0f) { \
      SUB(v2,q2,p1) \
      CROSS(N,v1,v2) \
      if (DOT(v,N) > 0.0f) { \
	SUB(v1,p1,p2) \
	SUB(v2,p1,r1) \
	alpha = DOT(v1,N2) / DOT(v2,N2); \
	SCALAR(v1,alpha,v2) \
	SUB(source,p1,v1) \
	SUB(v1,p2,p1) \
	SUB(v2,p2,r2) \
	alpha = DOT(v1,N1) / DOT(v2,N1); \
	SCALAR(v1,alpha,v2) \
	SUB(target,p2,v1) \
	return 1; \
      } else { \
	SUB(v1,p2,p1) \
	SUB(v2,p2,q2) \
	alpha = DOT(v1,N1) / DOT(v2,N1); \
	SCALAR(v1,alpha,v2) \
	SUB(source,p2,v1) \
	SUB(v1,p2,p1) \
	SUB(v2,p2,r2) \
	alpha = DOT(v1,N1) / DOT(v2,N1); \
	SCALAR(v1,alpha,v2) \
	SUB(target,p2,v1) \
	return 1; \
      } \
    } else { \
      return 0; \
    } \
  } else { \
    SUB(v2,q2,p1) \
    CROSS(N,v1,v2) \
    if (DOT(v,N) < 0.0f) { \
      return 0; \
    } else { \
      SUB(v1,r1,p1) \
      CROSS(N,v1,v2) \
      if (DOT(v,N) >= 0.0f) { \
	SUB(v1,p1,p2) \
	SUB(v2,p1,r1) \
	alpha = DOT(v1,N2) / DOT(v2,N2); \
	SCALAR(v1,alpha,v2) \
	SUB(source,p1,v1) \
	SUB(v1,p1,p2) \
	SUB(v2,p1,q1) \
	alpha = DOT(v1,N2) / DOT(v2,N2); \
	SCALAR(v1,alpha,v2) \
	SUB(target,p1,v1) \
	return 1; \
      } else { \
	SUB(v1,p2,p1) \
	SUB(v2,p2,q2) \
	alpha = DOT(v1,N1) / DOT(v2,N1); \
	SCALAR(v1,alpha,v2) \
	SUB(source,p2,v1) \
	SUB(v1,p1,p2) \
	SUB(v2,p1,q1) \
	alpha = DOT(v1,N2) / DOT(v2,N2); \
	SCALAR(v1,alpha,v2) \
	SUB(target,p1,v1) \
	return 1; \
      }}}}



#define TRI_TRI_INTER_3D(p1,q1,r1,p2,q2,r2,dp2,dq2,dr2) { \
  if (dp2 > 0.0f) { \
     if (dq2 > 0.0f) CONSTRUCT_INTERSECTION(p1,r1,q1,r2,p2,q2) \
     else if (dr2 > 0.0f) CONSTRUCT_INTERSECTION(p1,r1,q1,q2,r2,p2)\
     else CONSTRUCT_INTERSECTION(p1,q1,r1,p2,q2,r2) }\
  else if (dp2 < 0.0f) { \
    if (dq2 < 0.0f) CONSTRUCT_INTERSECTION(p1,q1,r1,r2,p2,q2)\
    else if (dr2 < 0.0f) CONSTRUCT_INTERSECTION(p1,q1,r1,q2,r2,p2)\
    else CONSTRUCT_INTERSECTION(p1,r1,q1,p2,q2,r2)\
  } else { \
    if (dq2 < 0.0f) { \
      if (dr2 >= 0.0f)  CONSTRUCT_INTERSECTION(p1,r1,q1,q2,r2,p2)\
      else CONSTRUCT_INTERSECTION(p1,q1,r1,p2,q2,r2)\
    } \
    else if (dq2 > 0.0f) { \
      if (dr2 > 0.0f) CONSTRUCT_INTERSECTION(p1,r1,q1,p2,q2,r2)\
      else  CONSTRUCT_INTERSECTION(p1,q1,r1,q2,r2,p2)\
    } \
    else  { \
      if (dr2 > 0.0f) CONSTRUCT_INTERSECTION(p1,q1,r1,r2,p2,q2)\
      else if (dr2 < 0.0f) CONSTRUCT_INTERSECTION(p1,r1,q1,r2,p2,q2)\
      else { \
       	*coplanar = 1; \
	return coplanar_tri_tri3d(p1,q1,r1,p2,q2,r2,N1,N2);\
     } \
  }} }


/*
   The following version computes the segment of intersection of the
   two triangles if it exists.
   coplanar returns whether the triangles are coplanar
   source and target are the endpoints of the line segment of intersection
*/

int tri_tri_intersection_test_3d(real p1[3], real q1[3], real r1[3],
                                 real p2[3], real q2[3], real r2[3],
                                 int * coplanar,
                                 real source[3], real target[3] )

{
    real dp1, dq1, dr1, dp2, dq2, dr2;
    real v1[3], v2[3], v[3];
    real N1[3], N2[3], N[3];
    real alpha;

    // Compute distance signs  of p1, q1 and r1
    // to the plane of triangle(p2,q2,r2)


    SUB(v1,p2,r2)
    SUB(v2,q2,r2)
    CROSS(N2,v1,v2)

    SUB(v1,p1,r2)
    dp1 = DOT(v1,N2);
    SUB(v1,q1,r2)
    dq1 = DOT(v1,N2);
    SUB(v1,r1,r2)
    dr1 = DOT(v1,N2);

    if (((dp1 * dq1) > 0.0f) && ((dp1 * dr1) > 0.0f))  return 0;

    // Compute distance signs  of p2, q2 and r2
    // to the plane of triangle(p1,q1,r1)


    SUB(v1,q1,p1)
    SUB(v2,r1,p1)
    CROSS(N1,v1,v2)

    SUB(v1,p2,r1)
    dp2 = DOT(v1,N1);
    SUB(v1,q2,r1)
    dq2 = DOT(v1,N1);
    SUB(v1,r2,r1)
    dr2 = DOT(v1,N1);

    if (((dp2 * dq2) > 0.0f) && ((dp2 * dr2) > 0.0f)) return 0;

    // Permutation in a canonical form of T1's vertices


    //  printf("d1 = [%f %f %f], d2 = [%f %f %f]\n", dp1, dq1, dr1, dp2, dq2, dr2);
    /*
    // added by Aaron
    if (ZERO_TEST(dp1) || ZERO_TEST(dq1) ||ZERO_TEST(dr1) ||ZERO_TEST(dp2) ||ZERO_TEST(dq2) ||ZERO_TEST(dr2))
      {
        coplanar = 1;
        return 0;
      }
    */


    if (dp1 > 0.0f) {
        if (dq1 > 0.0f) TRI_TRI_INTER_3D(r1,p1,q1,p2,r2,q2,dp2,dr2,dq2)
        else if (dr1 > 0.0f) TRI_TRI_INTER_3D(q1,r1,p1,p2,r2,q2,dp2,dr2,dq2)

        else TRI_TRI_INTER_3D(p1,q1,r1,p2,q2,r2,dp2,dq2,dr2)
    } else if (dp1 < 0.0f) {
        if (dq1 < 0.0f) TRI_TRI_INTER_3D(r1,p1,q1,p2,q2,r2,dp2,dq2,dr2)
        else if (dr1 < 0.0f) TRI_TRI_INTER_3D(q1,r1,p1,p2,q2,r2,dp2,dq2,dr2)
        else TRI_TRI_INTER_3D(p1,q1,r1,p2,r2,q2,dp2,dr2,dq2)
    } else {
        if (dq1 < 0.0f) {
            if (dr1 >= 0.0f) TRI_TRI_INTER_3D(q1,r1,p1,p2,r2,q2,dp2,dr2,dq2)
            else TRI_TRI_INTER_3D(p1,q1,r1,p2,q2,r2,dp2,dq2,dr2)
        }
        else if (dq1 > 0.0f) {
            if (dr1 > 0.0f) TRI_TRI_INTER_3D(p1,q1,r1,p2,r2,q2,dp2,dr2,dq2)
            else TRI_TRI_INTER_3D(q1,r1,p1,p2,q2,r2,dp2,dq2,dr2)
        }
        else  {
            if (dr1 > 0.0f) TRI_TRI_INTER_3D(r1,p1,q1,p2,q2,r2,dp2,dq2,dr2)
            else if (dr1 < 0.0f) TRI_TRI_INTER_3D(r1,p1,q1,p2,r2,q2,dp2,dr2,dq2)
            else {
                // triangles are co-planar

                *coplanar = 1;
                return coplanar_tri_tri3d(p1,q1,r1,p2,q2,r2,N1,N2);
            }
        }
    }
};





/*
*
*  Two dimensional Triangle-Triangle Overlap Test
*
*/


/* some 2D macros */

#define ORIENT_2D(a, b, c)  ((a[0]-c[0])*(b[1]-c[1])-(a[1]-c[1])*(b[0]-c[0]))


#define INTERSECTION_TEST_VERTEX(P1, Q1, R1, P2, Q2, R2) {\
  if (ORIENT_2D(R2,P2,Q1) >= 0.0f)\
    if (ORIENT_2D(R2,Q2,Q1) <= 0.0f)\
      if (ORIENT_2D(P1,P2,Q1) > 0.0f) {\
	if (ORIENT_2D(P1,Q2,Q1) <= 0.0f) return 1; \
	else return 0;} else {\
	if (ORIENT_2D(P1,P2,R1) >= 0.0f)\
	  if (ORIENT_2D(Q1,R1,P2) >= 0.0f) return 1; \
	  else return 0;\
	else return 0;}\
    else \
      if (ORIENT_2D(P1,Q2,Q1) <= 0.0f)\
	if (ORIENT_2D(R2,Q2,R1) <= 0.0f)\
	  if (ORIENT_2D(Q1,R1,Q2) >= 0.0f) return 1; \
	  else return 0;\
	else return 0;\
      else return 0;\
  else\
    if (ORIENT_2D(R2,P2,R1) >= 0.0f) \
      if (ORIENT_2D(Q1,R1,R2) >= 0.0f)\
	if (ORIENT_2D(P1,P2,R1) >= 0.0f) return 1;\
	else return 0;\
      else \
	if (ORIENT_2D(Q1,R1,Q2) >= 0.0f) {\
	  if (ORIENT_2D(R2,R1,Q2) >= 0.0f) return 1; \
	  else return 0; }\
	else return 0; \
    else  return 0; \
 };



#define INTERSECTION_TEST_EDGE(P1, Q1, R1, P2, Q2, R2) { \
  if (ORIENT_2D(R2,P2,Q1) >= 0.0f) {\
    if (ORIENT_2D(P1,P2,Q1) >= 0.0f) { \
        if (ORIENT_2D(P1,Q1,R2) >= 0.0f) return 1; \
        else return 0;} else { \
      if (ORIENT_2D(Q1,R1,P2) >= 0.0f){ \
	if (ORIENT_2D(R1,P1,P2) >= 0.0f) return 1; else return 0;} \
      else return 0; } \
  } else {\
    if (ORIENT_2D(R2,P2,R1) >= 0.0f) {\
      if (ORIENT_2D(P1,P2,R1) >= 0.0f) {\
	if (ORIENT_2D(P1,R1,R2) >= 0.0f) return 1;  \
	else {\
	  if (ORIENT_2D(Q1,R1,R2) >= 0.0f) return 1; else return 0;}}\
      else  return 0; }\
    else return 0; }}



int ccw_tri_tri_intersection_2d(real p1[2], real q1[2], real r1[2],
                                real p2[2], real q2[2], real r2[2]) {
    if ( ORIENT_2D(p2,q2,p1) >= 0.0f ) {
        if ( ORIENT_2D(q2,r2,p1) >= 0.0f ) {
            if ( ORIENT_2D(r2,p2,p1) >= 0.0f ) return 1;
            else INTERSECTION_TEST_EDGE(p1,q1,r1,p2,q2,r2)
        } else {
            if ( ORIENT_2D(r2,p2,p1) >= 0.0f )
            INTERSECTION_TEST_EDGE(p1,q1,r1,r2,p2,q2)
            else INTERSECTION_TEST_VERTEX(p1,q1,r1,p2,q2,r2)}}
    else {
        if ( ORIENT_2D(q2,r2,p1) >= 0.0f ) {
            if ( ORIENT_2D(r2,p2,p1) >= 0.0f )
            INTERSECTION_TEST_EDGE(p1,q1,r1,q2,r2,p2)
            else  INTERSECTION_TEST_VERTEX(p1,q1,r1,q2,r2,p2)}
        else INTERSECTION_TEST_VERTEX(p1,q1,r1,r2,p2,q2)}
};


int tri_tri_overlap_test_2d(real p1[2], real q1[2], real r1[2],
                            real p2[2], real q2[2], real r2[2]) {
    if ( ORIENT_2D(p1,q1,r1) < 0.0f )
        if ( ORIENT_2D(p2,q2,r2) < 0.0f )
            return ccw_tri_tri_intersection_2d(p1,r1,q1,p2,r2,q2);
        else
            return ccw_tri_tri_intersection_2d(p1,r1,q1,p2,q2,r2);
    else
    if ( ORIENT_2D(p2,q2,r2) < 0.0f )
        return ccw_tri_tri_intersection_2d(p1,q1,r1,p2,r2,q2);
    else
        return ccw_tri_tri_intersection_2d(p1,q1,r1,p2,q2,r2);

};