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#ifndef lint
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static const char RCSid[] = "$Id: cone.c,v 2.6 2003/02/25 02:47:21 greg Exp $";
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#endif
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/*
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* cone.c - routines for making cones
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*/
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#include "copyright.h"
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#include "standard.h"
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#include "object.h"
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#include "otypes.h"
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#include "cone.h"
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/*
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* In general, a cone may be any one of a cone, a cylinder, a ring,
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* a cup (inverted cone), or a tube (inverted cylinder).
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* Most cones are specified with a starting point and radius and
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* an ending point and radius. In the cases of a cylinder or tube,
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* only one radius is needed. In the case of a ring, a normal direction
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* is specified instead of a second endpoint.
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*
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* mtype (cone|cup) name
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* 0
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* 0
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* 8 P0x P0y P0z P1x P1y P1z R0 R1
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*
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* mtype (cylinder|tube) name
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* 0
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* 0
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* 7 P0x P0y P0z P1x P1y P1z R
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*
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* mtype ring name
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* 0
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* 0
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* 8 Px Py Pz Nx Ny Nz R0 R1
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*/
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CONE *
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getcone(o, getxf) /* get cone structure */
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register OBJREC *o;
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int getxf;
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{
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int sgn0, sgn1;
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register CONE *co;
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if ((co = (CONE *)o->os) == NULL) {
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co = (CONE *)malloc(sizeof(CONE));
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if (co == NULL)
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error(SYSTEM, "out of memory in makecone");
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co->ca = o->oargs.farg;
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/* get radii */
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if (o->otype == OBJ_CYLINDER | o->otype == OBJ_TUBE) {
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if (o->oargs.nfargs != 7)
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goto argcerr;
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if (co->ca[6] < -FTINY) {
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objerror(o, WARNING, "negative radius");
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o->otype = o->otype == OBJ_CYLINDER ?
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OBJ_TUBE : OBJ_CYLINDER;
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co->ca[6] = -co->ca[6];
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} else if (co->ca[6] <= FTINY)
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goto raderr;
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co->p0 = 0; co->p1 = 3;
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co->r0 = co->r1 = 6;
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} else {
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if (o->oargs.nfargs != 8)
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goto argcerr;
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if (co->ca[6] < -FTINY) sgn0 = -1;
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else if (co->ca[6] > FTINY) sgn0 = 1;
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else sgn0 = 0;
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if (co->ca[7] < -FTINY) sgn1 = -1;
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else if (co->ca[7] > FTINY) sgn1 = 1;
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else sgn1 = 0;
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if (sgn0+sgn1 == 0)
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goto raderr;
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if (sgn0 < 0 | sgn1 < 0) {
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objerror(o, o->otype==OBJ_RING?USER:WARNING,
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"negative radii");
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o->otype = o->otype == OBJ_CONE ?
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OBJ_CUP : OBJ_CONE;
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}
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co->ca[6] = co->ca[6]*sgn0;
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co->ca[7] = co->ca[7]*sgn1;
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if (co->ca[7] - co->ca[6] > FTINY) {
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if (o->otype == OBJ_RING)
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co->p0 = co->p1 = 0;
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else {
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co->p0 = 0; co->p1 = 3;
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}
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co->r0 = 6; co->r1 = 7;
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} else if (co->ca[6] - co->ca[7] > FTINY) {
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if (o->otype == OBJ_RING)
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co->p0 = co->p1 = 0;
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else {
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co->p0 = 3; co->p1 = 0;
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}
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co->r0 = 7; co->r1 = 6;
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} else {
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if (o->otype == OBJ_RING)
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goto raderr;
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o->otype = o->otype == OBJ_CONE ?
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OBJ_CYLINDER : OBJ_TUBE;
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o->oargs.nfargs = 7;
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co->p0 = 0; co->p1 = 3;
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co->r0 = co->r1 = 6;
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}
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}
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/* get axis orientation */
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if (o->otype == OBJ_RING)
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VCOPY(co->ad, o->oargs.farg+3);
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else {
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co->ad[0] = CO_P1(co)[0] - CO_P0(co)[0];
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co->ad[1] = CO_P1(co)[1] - CO_P0(co)[1];
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co->ad[2] = CO_P1(co)[2] - CO_P0(co)[2];
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}
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co->al = normalize(co->ad);
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if (co->al == 0.0)
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objerror(o, USER, "zero orientation");
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/* compute axis and side lengths */
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if (o->otype == OBJ_RING) {
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co->al = 0.0;
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co->sl = CO_R1(co) - CO_R0(co);
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} else if (o->otype == OBJ_CONE | o->otype == OBJ_CUP) {
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co->sl = co->ca[7] - co->ca[6];
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co->sl = sqrt(co->sl*co->sl + co->al*co->al);
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} else { /* OBJ_CYLINDER or OBJ_TUBE */
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co->sl = co->al;
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}
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co->tm = NULL;
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o->os = (char *)co;
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}
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if (getxf && co->tm == NULL)
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conexform(co);
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return(co);
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argcerr:
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objerror(o, USER, "bad # arguments");
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raderr:
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objerror(o, USER, "illegal radii");
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return NULL; /* pro forma return */
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}
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void
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freecone(o) /* free memory associated with cone */
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OBJREC *o;
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{
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register CONE *co = (CONE *)o->os;
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if (co == NULL)
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return;
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if (co->tm != NULL)
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free((void *)co->tm);
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free((void *)co);
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o->os = NULL;
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}
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void
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conexform(co) /* get cone transformation matrix */
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register CONE *co;
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{
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MAT4 m4;
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register double d;
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register int i;
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co->tm = (FLOAT (*)[4])malloc(sizeof(MAT4));
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if (co->tm == NULL)
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error(SYSTEM, "out of memory in conexform");
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/* translate to origin */
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setident4(co->tm);
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if (co->r0 == co->r1)
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d = 0.0;
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else
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d = CO_R0(co) / (CO_R1(co) - CO_R0(co));
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for (i = 0; i < 3; i++)
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co->tm[3][i] = d*(CO_P1(co)[i] - CO_P0(co)[i])
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- CO_P0(co)[i];
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/* rotate to positive z-axis */
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setident4(m4);
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d = co->ad[1]*co->ad[1] + co->ad[2]*co->ad[2];
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if (d <= FTINY*FTINY) {
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m4[0][0] = 0.0;
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m4[0][2] = co->ad[0];
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m4[2][0] = -co->ad[0];
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m4[2][2] = 0.0;
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} else {
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d = sqrt(d);
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m4[0][0] = d;
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m4[1][0] = -co->ad[0]*co->ad[1]/d;
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m4[2][0] = -co->ad[0]*co->ad[2]/d;
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m4[1][1] = co->ad[2]/d;
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m4[2][1] = -co->ad[1]/d;
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m4[0][2] = co->ad[0];
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m4[1][2] = co->ad[1];
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m4[2][2] = co->ad[2];
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}
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multmat4(co->tm, co->tm, m4);
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/* scale z-axis */
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if (co->p0 != co->p1 & co->r0 != co->r1) {
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setident4(m4);
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m4[2][2] = (CO_R1(co) - CO_R0(co)) / co->al;
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multmat4(co->tm, co->tm, m4);
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}
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}
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