Initial commit.
This commit is contained in:
506
code/qcommon/tri_coll_test.cpp
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506
code/qcommon/tri_coll_test.cpp
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/* Triangle/triangle intersection test routine,
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* by Tomas Moller, 1997.
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* See article "A Fast Triangle-Triangle Intersection Test",
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* Journal of Graphics Tools, 2(2), 1997
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*
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* int tri_tri_intersect(float V0[3],float V1[3],float V2[3],
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* float U0[3],float U1[3],float U2[3])
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*
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* parameters: vertices of triangle 1: V0,V1,V2
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* vertices of triangle 2: U0,U1,U2
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* result : returns 1 if the triangles intersect, otherwise 0
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*
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*/
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// leave this at the top for PCH reasons...
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#include "common_headers.h"
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#include <math.h>
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#include "../game/q_shared.h"
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#include "../game/g_local.h"
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/* if USE_EPSILON_TEST is true then we do a check:
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if |dv|<EPSILON then dv=0.0;
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else no check is done (which is less robust)
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*/
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#define USE_EPSILON_TEST 1
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#define EPSILON 0.000001
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/* some macros */
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#define 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 DOT(v1,v2) (v1[0]*v2[0]+v1[1]*v2[1]+v1[2]*v2[2])
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#define 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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/* sort so that a<=b */
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#define SORT(a,b) \
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if(a>b) \
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{ \
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float c; \
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c=a; \
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a=b; \
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b=c; \
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}
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#define ISECT(VV0,VV1,VV2,D0,D1,D2,isect0,isect1) \
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isect0=VV0+(VV1-VV0)*D0/(D0-D1); \
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isect1=VV0+(VV2-VV0)*D0/(D0-D2);
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#define COMPUTE_INTERVALS(VV0,VV1,VV2,D0,D1,D2,D0D1,D0D2,isect0,isect1) \
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if(D0D1>0.0f) \
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{ \
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/* here we know that D0D2<=0.0 */ \
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/* that is D0, D1 are on the same side, D2 on the other or on the plane */ \
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ISECT(VV2,VV0,VV1,D2,D0,D1,isect0,isect1); \
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} \
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else if(D0D2>0.0f) \
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{ \
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/* here we know that d0d1<=0.0 */ \
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ISECT(VV1,VV0,VV2,D1,D0,D2,isect0,isect1); \
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} \
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else if(D1*D2>0.0f || D0!=0.0f) \
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{ \
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/* here we know that d0d1<=0.0 or that D0!=0.0 */ \
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ISECT(VV0,VV1,VV2,D0,D1,D2,isect0,isect1); \
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} \
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else if(D1!=0.0f) \
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{ \
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ISECT(VV1,VV0,VV2,D1,D0,D2,isect0,isect1); \
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} \
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else if(D2!=0.0f) \
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{ \
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ISECT(VV2,VV0,VV1,D2,D0,D1,isect0,isect1); \
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} \
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else \
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{ \
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/* triangles are coplanar */ \
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return coplanar_tri_tri(N1,V0,V1,V2,U0,U1,U2); \
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}
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/* this edge to edge test is based on Franlin Antonio's gem:
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"Faster Line Segment Intersection", in Graphics Gems III,
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pp. 199-202 */
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#define EDGE_EDGE_TEST(V0,U0,U1) \
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Bx=U0[i0]-U1[i0]; \
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By=U0[i1]-U1[i1]; \
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Cx=V0[i0]-U0[i0]; \
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Cy=V0[i1]-U0[i1]; \
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f=Ay*Bx-Ax*By; \
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d=By*Cx-Bx*Cy; \
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if((f>0 && d>=0 && d<=f) || (f<0 && d<=0 && d>=f)) \
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{ \
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e=Ax*Cy-Ay*Cx; \
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if(f>0) \
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{ \
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if(e>=0 && e<=f) return 1; \
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} \
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else \
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{ \
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if(e<=0 && e>=f) return 1; \
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} \
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}
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#define EDGE_AGAINST_TRI_EDGES(V0,V1,U0,U1,U2) \
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{ \
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float Ax,Ay,Bx,By,Cx,Cy,e,d,f; \
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Ax=V1[i0]-V0[i0]; \
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Ay=V1[i1]-V0[i1]; \
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/* test edge U0,U1 against V0,V1 */ \
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EDGE_EDGE_TEST(V0,U0,U1); \
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/* test edge U1,U2 against V0,V1 */ \
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EDGE_EDGE_TEST(V0,U1,U2); \
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/* test edge U2,U1 against V0,V1 */ \
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EDGE_EDGE_TEST(V0,U2,U0); \
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}
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#define POINT_IN_TRI(V0,U0,U1,U2) \
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{ \
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float a,b,c,d0,d1,d2; \
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/* is T1 completly inside T2? */ \
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/* check if V0 is inside tri(U0,U1,U2) */ \
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a=U1[i1]-U0[i1]; \
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b=-(U1[i0]-U0[i0]); \
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c=-a*U0[i0]-b*U0[i1]; \
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d0=a*V0[i0]+b*V0[i1]+c; \
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\
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a=U2[i1]-U1[i1]; \
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b=-(U2[i0]-U1[i0]); \
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c=-a*U1[i0]-b*U1[i1]; \
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d1=a*V0[i0]+b*V0[i1]+c; \
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\
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a=U0[i1]-U2[i1]; \
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b=-(U0[i0]-U2[i0]); \
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c=-a*U2[i0]-b*U2[i1]; \
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d2=a*V0[i0]+b*V0[i1]+c; \
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if(d0*d1>0.0) \
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{ \
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if(d0*d2>0.0) return 1; \
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} \
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}
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qboolean coplanar_tri_tri(vec3_t N,vec3_t V0,vec3_t V1,vec3_t V2,
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vec3_t U0,vec3_t U1,vec3_t U2)
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{
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vec3_t A;
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short i0,i1;
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/* first project onto an axis-aligned plane, that maximizes the area */
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/* of the triangles, compute indices: i0,i1. */
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A[0]=fabs(N[0]);
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A[1]=fabs(N[1]);
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A[2]=fabs(N[2]);
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if(A[0]>A[1])
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{
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if(A[0]>A[2])
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{
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i0=1; /* A[0] is greatest */
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i1=2;
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}
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else
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{
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i0=0; /* A[2] is greatest */
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i1=1;
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}
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}
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else /* A[0]<=A[1] */
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{
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if(A[2]>A[1])
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{
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i0=0; /* A[2] is greatest */
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i1=1;
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}
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else
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{
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i0=0; /* A[1] is greatest */
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i1=2;
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}
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}
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/* test all edges of triangle 1 against the edges of triangle 2 */
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EDGE_AGAINST_TRI_EDGES(V0,V1,U0,U1,U2);
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EDGE_AGAINST_TRI_EDGES(V1,V2,U0,U1,U2);
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EDGE_AGAINST_TRI_EDGES(V2,V0,U0,U1,U2);
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/* finally, test if tri1 is totally contained in tri2 or vice versa */
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POINT_IN_TRI(V0,U0,U1,U2);
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POINT_IN_TRI(U0,V0,V1,V2);
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return qfalse;
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}
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qboolean tri_tri_intersect(vec3_t V0,vec3_t V1,vec3_t V2,
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vec3_t U0,vec3_t U1,vec3_t U2)
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{
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vec3_t E1,E2;
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vec3_t N1,N2;
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float d1,d2;
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float du0,du1,du2,dv0,dv1,dv2;
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vec3_t D;
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float isect1[2], isect2[2];
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float du0du1,du0du2,dv0dv1,dv0dv2;
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short index;
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float vp0,vp1,vp2;
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float up0,up1,up2;
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float b,c,max;
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/* compute plane equation of triangle(V0,V1,V2) */
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SUB(E1,V1,V0);
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SUB(E2,V2,V0);
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CROSS(N1,E1,E2);
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d1=-DOT(N1,V0);
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/* plane equation 1: N1.X+d1=0 */
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/* put U0,U1,U2 into plane equation 1 to compute signed distances to the plane*/
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du0=DOT(N1,U0)+d1;
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du1=DOT(N1,U1)+d1;
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du2=DOT(N1,U2)+d1;
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/* coplanarity robustness check */
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#if USE_EPSILON_TEST
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if(fabs(du0)<EPSILON) du0=0.0;
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if(fabs(du1)<EPSILON) du1=0.0;
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if(fabs(du2)<EPSILON) du2=0.0;
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#endif
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du0du1=du0*du1;
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du0du2=du0*du2;
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if(du0du1>0.0f && du0du2>0.0f) /* same sign on all of them + not equal 0 ? */
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return 0; /* no intersection occurs */
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/* compute plane of triangle (U0,U1,U2) */
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SUB(E1,U1,U0);
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SUB(E2,U2,U0);
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CROSS(N2,E1,E2);
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d2=-DOT(N2,U0);
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/* plane equation 2: N2.X+d2=0 */
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/* put V0,V1,V2 into plane equation 2 */
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dv0=DOT(N2,V0)+d2;
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dv1=DOT(N2,V1)+d2;
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dv2=DOT(N2,V2)+d2;
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#if USE_EPSILON_TEST
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if(fabs(dv0)<EPSILON) dv0=0.0;
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if(fabs(dv1)<EPSILON) dv1=0.0;
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if(fabs(dv2)<EPSILON) dv2=0.0;
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#endif
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dv0dv1=dv0*dv1;
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dv0dv2=dv0*dv2;
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if(dv0dv1>0.0f && dv0dv2>0.0f) /* same sign on all of them + not equal 0 ? */
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return 0; /* no intersection occurs */
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/* compute direction of intersection line */
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CROSS(D,N1,N2);
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/* compute and index to the largest component of D */
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max=fabs(D[0]);
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index=0;
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b=fabs(D[1]);
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c=fabs(D[2]);
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if(b>max) max=b,index=1;
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if(c>max) max=c,index=2;
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/* this is the simplified projection onto L*/
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vp0=V0[index];
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vp1=V1[index];
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vp2=V2[index];
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up0=U0[index];
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up1=U1[index];
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up2=U2[index];
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/* compute interval for triangle 1 */
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COMPUTE_INTERVALS(vp0,vp1,vp2,dv0,dv1,dv2,dv0dv1,dv0dv2,isect1[0],isect1[1]);
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/* compute interval for triangle 2 */
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COMPUTE_INTERVALS(up0,up1,up2,du0,du1,du2,du0du1,du0du2,isect2[0],isect2[1]);
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SORT(isect1[0],isect1[1]);
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SORT(isect2[0],isect2[1]);
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if(isect1[1]<isect2[0] || isect2[1]<isect1[0]) return qtrue;
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return qfalse;
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}
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float LineSegmentDistance( vec3_t a, vec3_t b, vec3_t c, vec3_t d )
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{
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vec3_t v1, v2, v3, cross;
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//FIXME: what if parallel or intersect?
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//FIXME: this doesn't take into account the endpoints...
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//get the two lines
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VectorSubtract( b, a, v1 );
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VectorSubtract( c, d, v2 );
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//get their normalized cross product
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CrossProduct( v1, v2, cross );
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/*
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float crossLength = VectorLength( cross );
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if ( crossLength == 0 )
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{//intersect! Or... parallel?
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return 0;
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}
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VectorScale( cross, 1/crossLength, cross );
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*/
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VectorNormalize( cross );
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//now get a vector from v1 to v2
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VectorSubtract( d, a, v3 );
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//distance is dot product of that new vector and the normalized cross product
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float dist = fabs( DotProduct( v3, cross ) );
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return dist;
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}
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extern qboolean G_FindClosestPointOnLineSegment( const vec3_t start, const vec3_t end, const vec3_t from, vec3_t result );
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float ShortestLineSegBewteen2LineSegs( vec3_t start1, vec3_t end1, vec3_t start2, vec3_t end2, vec3_t close_pnt1, vec3_t close_pnt2 )
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{
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float current_dist, new_dist;
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vec3_t new_pnt;
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//start1, end1 : the first segment
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//start2, end2 : the second segment
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//output, one point on each segment, the closest two points on the segments.
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//compute some temporaries:
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//vec start_dif = start2 - start1
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vec3_t start_dif;
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VectorSubtract( start2, start1, start_dif );
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//vec v1 = end1 - start1
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vec3_t v1;
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VectorSubtract( end1, start1, v1 );
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//vec v2 = end2 - start2
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vec3_t v2;
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VectorSubtract( end2, start2, v2 );
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//
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float v1v1 = DotProduct( v1, v1 );
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float v2v2 = DotProduct( v2, v2 );
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float v1v2 = DotProduct( v1, v2 );
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//the main computation
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float denom = (v1v2 * v1v2) - (v1v1 * v2v2);
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//if denom is small, then skip all this and jump to the section marked below
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if ( fabs(denom) > 0.001f )
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{
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float s = -( (v2v2*DotProduct( v1, start_dif )) - (v1v2*DotProduct( v2, start_dif )) ) / denom;
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float t = ( (v1v1*DotProduct( v2, start_dif )) - (v1v2*DotProduct( v1, start_dif )) ) / denom;
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qboolean done = qtrue;
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if ( s < 0 )
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{
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done = qfalse;
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s = 0;// and see note below
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}
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if ( s > 1 )
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{
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done = qfalse;
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s = 1;// and see note below
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}
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if ( t < 0 )
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{
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done = qfalse;
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t = 0;// and see note below
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}
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if ( t > 1 )
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{
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done = qfalse;
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t = 1;// and see note below
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}
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//vec close_pnt1 = start1 + s * v1
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VectorMA( start1, s, v1, close_pnt1 );
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//vec close_pnt2 = start2 + t * v2
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VectorMA( start2, t, v2, close_pnt2 );
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current_dist = Distance( close_pnt1, close_pnt2 );
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//now, if none of those if's fired, you are done.
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if ( done )
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{
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return current_dist;
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}
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||||
//If they did fire, then we need to do some additional tests.
|
||||
|
||||
//What we are gonna do is see if we can find a shorter distance than the above
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//involving the endpoints.
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}
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else
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{
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//******start here for paralell lines with current_dist = infinity****
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current_dist = Q3_INFINITE;
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}
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//test 2 close_pnts first
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/*
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G_FindClosestPointOnLineSegment( start1, end1, close_pnt2, new_pnt );
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new_dist = Distance( close_pnt2, new_pnt );
|
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if ( new_dist < current_dist )
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||||
{//then update close_pnt1 close_pnt2 and current_dist
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||||
VectorCopy( new_pnt, close_pnt1 );
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||||
VectorCopy( close_pnt2, close_pnt2 );
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current_dist = new_dist;
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||||
}
|
||||
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||||
G_FindClosestPointOnLineSegment( start2, end2, close_pnt1, new_pnt );
|
||||
new_dist = Distance( close_pnt1, new_pnt );
|
||||
if ( new_dist < current_dist )
|
||||
{//then update close_pnt1 close_pnt2 and current_dist
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||||
VectorCopy( close_pnt1, close_pnt1 );
|
||||
VectorCopy( new_pnt, close_pnt2 );
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||||
current_dist = new_dist;
|
||||
}
|
||||
*/
|
||||
//test all the endpoints
|
||||
new_dist = Distance( start1, start2 );
|
||||
if ( new_dist < current_dist )
|
||||
{//then update close_pnt1 close_pnt2 and current_dist
|
||||
VectorCopy( start1, close_pnt1 );
|
||||
VectorCopy( start2, close_pnt2 );
|
||||
current_dist = new_dist;
|
||||
}
|
||||
|
||||
new_dist = Distance( start1, end2 );
|
||||
if ( new_dist < current_dist )
|
||||
{//then update close_pnt1 close_pnt2 and current_dist
|
||||
VectorCopy( start1, close_pnt1 );
|
||||
VectorCopy( end2, close_pnt2 );
|
||||
current_dist = new_dist;
|
||||
}
|
||||
|
||||
new_dist = Distance( end1, start2 );
|
||||
if ( new_dist < current_dist )
|
||||
{//then update close_pnt1 close_pnt2 and current_dist
|
||||
VectorCopy( end1, close_pnt1 );
|
||||
VectorCopy( start2, close_pnt2 );
|
||||
current_dist = new_dist;
|
||||
}
|
||||
|
||||
new_dist = Distance( end1, end2 );
|
||||
if ( new_dist < current_dist )
|
||||
{//then update close_pnt1 close_pnt2 and current_dist
|
||||
VectorCopy( end1, close_pnt1 );
|
||||
VectorCopy( end2, close_pnt2 );
|
||||
current_dist = new_dist;
|
||||
}
|
||||
|
||||
//Then we have 4 more point / segment tests
|
||||
|
||||
G_FindClosestPointOnLineSegment( start2, end2, start1, new_pnt );
|
||||
new_dist = Distance( start1, new_pnt );
|
||||
if ( new_dist < current_dist )
|
||||
{//then update close_pnt1 close_pnt2 and current_dist
|
||||
VectorCopy( start1, close_pnt1 );
|
||||
VectorCopy( new_pnt, close_pnt2 );
|
||||
current_dist = new_dist;
|
||||
}
|
||||
|
||||
G_FindClosestPointOnLineSegment( start2, end2, end1, new_pnt );
|
||||
new_dist = Distance( end1, new_pnt );
|
||||
if ( new_dist < current_dist )
|
||||
{//then update close_pnt1 close_pnt2 and current_dist
|
||||
VectorCopy( end1, close_pnt1 );
|
||||
VectorCopy( new_pnt, close_pnt2 );
|
||||
current_dist = new_dist;
|
||||
}
|
||||
|
||||
G_FindClosestPointOnLineSegment( start1, end1, start2, new_pnt );
|
||||
new_dist = Distance( start2, new_pnt );
|
||||
if ( new_dist < current_dist )
|
||||
{//then update close_pnt1 close_pnt2 and current_dist
|
||||
VectorCopy( new_pnt, close_pnt1 );
|
||||
VectorCopy( start2, close_pnt2 );
|
||||
current_dist = new_dist;
|
||||
}
|
||||
|
||||
G_FindClosestPointOnLineSegment( start1, end1, end2, new_pnt );
|
||||
new_dist = Distance( end2, new_pnt );
|
||||
if ( new_dist < current_dist )
|
||||
{//then update close_pnt1 close_pnt2 and current_dist
|
||||
VectorCopy( new_pnt, close_pnt1 );
|
||||
VectorCopy( end2, close_pnt2 );
|
||||
current_dist = new_dist;
|
||||
}
|
||||
|
||||
return current_dist;
|
||||
}
|
||||
Reference in New Issue
Block a user