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/* Copyright (c) 1994 Regents of the University of California */ |
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|
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#ifndef lint |
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static char SCCSid[] = "$SunId$ LBL"; |
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#endif |
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|
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/* |
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* Compute and print barycentric coordinates for triangle meshes |
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*/ |
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|
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#include <stdio.h> |
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|
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#include "fvect.h" |
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|
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#include "tmesh.h" |
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|
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#define ABS(x) ((x) >= 0 ? (x) : -(x)) |
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|
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|
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int |
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flat_tri(v1, v2, v3, n1, n2, n3) /* determine if triangle is flat */ |
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FVECT v1, v2, v3, n1, n2, n3; |
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{ |
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double d1, d2, d3; |
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FVECT vt1, vt2, vn; |
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/* compute default normal */ |
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vt1[0] = v2[0] - v1[0]; vt1[1] = v2[1] - v1[1]; vt1[2] = v2[2] - v1[2]; |
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vt2[0] = v3[0] - v2[0]; vt2[1] = v3[1] - v2[1]; vt2[2] = v3[2] - v2[2]; |
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fcross(vn, vt1, vt2); |
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if (normalize(vn) == 0.0) |
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return(DEGEN); |
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/* compare to supplied normals */ |
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d1 = DOT(vn, n1); d2 = DOT(vn, n2); d3 = DOT(vn, n3); |
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if (d1 < 0 && d2 < 0 && d3 < 0) { |
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if (d1 > -COSTOL || d2 > -COSTOL || d3 > -COSTOL) |
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return(RVBENT); |
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return(RVFLAT); |
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} |
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if (d1 < COSTOL || d2 < COSTOL || d3 < COSTOL) |
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return(ISBENT); |
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return(ISFLAT); |
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} |
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|
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|
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int |
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comp_baryc(bcm, v1, v2, v3) /* compute barycentric vectors */ |
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register BARYCCM *bcm; |
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FLOAT *v1, *v2, *v3; |
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{ |
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FLOAT *vt; |
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FVECT va, vab, vcb; |
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double d; |
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int ax0, ax1; |
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register int i, j; |
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/* compute major axis */ |
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for (i = 0; i < 3; i++) { |
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vab[i] = v1[i] - v2[i]; |
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vcb[i] = v3[i] - v2[i]; |
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} |
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fcross(va, vab, vcb); |
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bcm->ax = ABS(va[0]) > ABS(va[1]) ? 0 : 1; |
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bcm->ax = ABS(va[bcm->ax]) > ABS(va[2]) ? bcm->ax : 2; |
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ax0 = (bcm->ax + 1) % 3; |
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ax1 = (bcm->ax + 2) % 3; |
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for (j = 0; j < 2; j++) { |
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vab[0] = v1[ax0] - v2[ax0]; |
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vcb[0] = v3[ax0] - v2[ax0]; |
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vab[1] = v1[ax1] - v2[ax1]; |
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vcb[1] = v3[ax1] - v2[ax1]; |
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d = vcb[0]*vcb[0] + vcb[1]*vcb[1]; |
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if (d <= FTINY) |
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return(-1); |
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d = (vcb[0]*vab[0]+vcb[1]*vab[1])/d; |
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va[0] = vab[0] - vcb[0]*d; |
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va[1] = vab[1] - vcb[1]*d; |
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d = va[0]*va[0] + va[1]*va[1]; |
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if (d <= FTINY) |
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return(-1); |
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bcm->tm[j][0] = va[0] /= d; |
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bcm->tm[j][1] = va[1] /= d; |
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bcm->tm[j][2] = -(v2[ax0]*va[0]+v2[ax1]*va[1]); |
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/* rotate vertices */ |
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vt = v1; |
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v1 = v2; |
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v2 = v3; |
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v3 = vt; |
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} |
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return(0); |
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} |
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|
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|
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put_baryc(bcm, com, n) /* put barycentric coord. vectors */ |
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register BARYCCM *bcm; |
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register FLOAT com[][3]; |
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int n; |
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{ |
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double a, b; |
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register int i, j; |
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|
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printf("%d\t%d\n", 1+3*n, bcm->ax); |
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for (i = 0; i < n; i++) { |
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a = com[i][0] - com[i][2]; |
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b = com[i][1] - com[i][2]; |
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printf("%14.8f %14.8f %14.8f\n", |
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bcm->tm[0][0]*a + bcm->tm[1][0]*b, |
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bcm->tm[0][1]*a + bcm->tm[1][1]*b, |
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bcm->tm[0][2]*a + bcm->tm[1][2]*b + com[i][2]); |
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} |
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} |
