| 1 |
#ifndef lint
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static const char RCSid[] = "$Id: ambcomp.c,v 2.35 2014/04/25 18:39:22 greg Exp $";
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#endif
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/*
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* Routines to compute "ambient" values using Monte Carlo
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*
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* Hessian calculations based on "Practical Hessian-Based Error Control
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* for Irradiance Caching" by Schwarzhaupt, Wann Jensen, & Jarosz
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* from ACM SIGGRAPH Asia 2012 conference proceedings.
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*
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| 11 |
* Declarations of external symbols in ambient.h
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*/
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#include "copyright.h"
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#include "ray.h"
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#include "ambient.h"
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#include "random.h"
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| 20 |
#ifdef NEWAMB
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| 22 |
extern void SDsquare2disk(double ds[2], double seedx, double seedy);
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| 23 |
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| 24 |
typedef struct {
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| 25 |
RAY *rp; /* originating ray sample */
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| 26 |
FVECT ux, uy; /* tangent axis unit vectors */
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| 27 |
int ns; /* number of samples per axis */
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COLOR acoef; /* division contribution coefficient */
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struct s_ambsamp {
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COLOR v; /* hemisphere sample value */
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FVECT p; /* intersection point */
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| 32 |
} sa[1]; /* sample array (extends struct) */
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} AMBHEMI; /* ambient sample hemisphere */
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| 35 |
#define ambsamp(h,i,j) (h)->sa[(i)*(h)->ns + (j)]
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| 36 |
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| 37 |
typedef struct {
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| 38 |
FVECT r_i, r_i1, e_i, rcp, rI2_eJ2;
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| 39 |
double I1, I2;
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| 40 |
} FFTRI; /* vectors and coefficients for Hessian calculation */
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static AMBHEMI *
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inithemi( /* initialize sampling hemisphere */
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COLOR ac,
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RAY *r,
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double wt
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| 48 |
)
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{
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AMBHEMI *hp;
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double d;
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int n, i;
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/* set number of divisions */
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| 54 |
if (ambacc <= FTINY &&
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wt > (d = 0.8*intens(ac)*r->rweight/(ambdiv*minweight)))
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wt = d; /* avoid ray termination */
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n = sqrt(ambdiv * wt) + 0.5;
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i = 1 + 5*(ambacc > FTINY); /* minimum number of samples */
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if (n < i)
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n = i;
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/* allocate sampling array */
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hp = (AMBHEMI *)malloc(sizeof(AMBHEMI) +
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sizeof(struct s_ambsamp)*(n*n - 1));
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if (hp == NULL)
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return(NULL);
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hp->rp = r;
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hp->ns = n;
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/* assign coefficient */
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copycolor(hp->acoef, ac);
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d = 1.0/(n*n);
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scalecolor(hp->acoef, d);
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/* make tangent plane axes */
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hp->uy[0] = hp->uy[1] = hp->uy[2] = 0;
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for (i = 3; i--; )
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if ((0.6 < r->ron[i]) & (r->ron[i] < 0.6))
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hp->uy[i] = 0.1+frandom();
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if (DOT(hp->uy,hp->uy) <= FTINY)
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error(CONSISTENCY, "bad ray direction in inithemi()");
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VCROSS(hp->ux, hp->uy, r->ron);
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normalize(hp->ux);
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VCROSS(hp->uy, r->ron, hp->ux);
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/* we're ready to sample */
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return(hp);
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}
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static struct s_ambsamp *
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ambsample( /* sample an ambient direction */
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AMBHEMI *hp,
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int i,
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int j
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)
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{
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struct s_ambsamp *ap = &ambsamp(hp,i,j);
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RAY ar;
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double spt[2], zd;
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int ii;
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/* ambient coefficient for weight */
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if (ambacc > FTINY)
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setcolor(ar.rcoef, AVGREFL, AVGREFL, AVGREFL);
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else
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copycolor(ar.rcoef, hp->acoef);
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if (rayorigin(&ar, AMBIENT, hp->rp, ar.rcoef) < 0)
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goto badsample;
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if (ambacc > FTINY) {
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multcolor(ar.rcoef, hp->acoef);
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scalecolor(ar.rcoef, 1./AVGREFL);
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}
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/* generate hemispherical sample */
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SDsquare2disk(spt, (i+.1+.8*frandom())/hp->ns,
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(j+.1+.8*frandom())/hp->ns );
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zd = sqrt(1. - spt[0]*spt[0] - spt[1]*spt[1]);
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for (ii = 3; ii--; )
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ar.rdir[ii] = spt[0]*hp->ux[ii] +
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spt[1]*hp->uy[ii] +
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zd*hp->rp->ron[ii];
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checknorm(ar.rdir);
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dimlist[ndims++] = i*hp->ns + j + 90171;
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rayvalue(&ar); /* evaluate ray */
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ndims--;
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/* limit vertex distance */
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if (ar.rt > 10.0*thescene.cusize)
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ar.rt = 10.0*thescene.cusize;
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else if (ar.rt <= FTINY) /* should never happen! */
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goto badsample;
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VSUM(ap->p, ar.rorg, ar.rdir, ar.rt);
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multcolor(ar.rcol, ar.rcoef); /* apply coefficient */
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copycolor(ap->v, ar.rcol);
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return(ap);
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badsample:
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setcolor(ap->v, 0., 0., 0.);
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VCOPY(ap->p, hp->rp->rop);
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return(NULL);
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}
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/* Compute vectors and coefficients for Hessian/gradient calcs */
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static void
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comp_fftri(FFTRI *ftp, FVECT ap0, FVECT ap1, FVECT rop)
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{
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double rdot_cp, dot_e, dot_er, rdot_r, rdot_r1, J2;
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int i;
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VSUB(ftp->r_i, ap0, rop);
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VSUB(ftp->r_i1, ap1, rop);
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VSUB(ftp->e_i, ap1, ap0);
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VCROSS(ftp->rcp, ftp->r_i, ftp->r_i1);
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rdot_cp = 1.0/DOT(ftp->rcp,ftp->rcp);
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dot_e = DOT(ftp->e_i,ftp->e_i);
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dot_er = DOT(ftp->e_i, ftp->r_i);
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rdot_r = 1.0/DOT(ftp->r_i,ftp->r_i);
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rdot_r1 = 1.0/DOT(ftp->r_i1,ftp->r_i1);
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ftp->I1 = acos( DOT(ftp->r_i, ftp->r_i1) * sqrt(rdot_r*rdot_r1) ) *
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sqrt( rdot_cp );
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ftp->I2 = ( DOT(ftp->e_i, ftp->r_i1)*rdot_r1 - dot_er*rdot_r +
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dot_e*ftp->I1 )*0.5*rdot_cp;
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J2 = ( 0.5*(rdot_r - rdot_r1) - dot_er*ftp->I2 ) / dot_e;
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for (i = 3; i--; )
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ftp->rI2_eJ2[i] = ftp->I2*ftp->r_i[i] + J2*ftp->e_i[i];
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}
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/* Compose 3x3 matrix from two vectors */
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static void
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compose_matrix(FVECT mat[3], FVECT va, FVECT vb)
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{
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mat[0][0] = 2.0*va[0]*vb[0];
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mat[1][1] = 2.0*va[1]*vb[1];
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mat[2][2] = 2.0*va[2]*vb[2];
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mat[0][1] = mat[1][0] = va[0]*vb[1] + va[1]*vb[0];
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mat[0][2] = mat[2][0] = va[0]*vb[2] + va[2]*vb[0];
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mat[1][2] = mat[2][1] = va[1]*vb[2] + va[2]*vb[1];
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}
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/* Compute partial 3x3 Hessian matrix for edge */
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static void
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comp_hessian(FVECT hess[3], FFTRI *ftp, FVECT nrm)
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{
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FVECT ncp;
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FVECT m1[3], m2[3], m3[3], m4[3];
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double d1, d2, d3, d4;
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double I3, J3, K3;
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int i, j;
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/* compute intermediate coefficients */
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d1 = 1.0/DOT(ftp->r_i,ftp->r_i);
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d2 = 1.0/DOT(ftp->r_i1,ftp->r_i1);
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d3 = 1.0/DOT(ftp->e_i,ftp->e_i);
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d4 = DOT(ftp->e_i, ftp->r_i);
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I3 = ( DOT(ftp->e_i, ftp->r_i1)*d2*d2 - d4*d1*d1 + 3.0/d3*ftp->I2 )
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/ ( 4.0*DOT(ftp->rcp,ftp->rcp) );
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J3 = 0.25*d3*(d1*d1 - d2*d2) - d4*d3*I3;
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K3 = d3*(ftp->I2 - I3/d1 - 2.0*d4*J3);
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/* intermediate matrices */
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VCROSS(ncp, nrm, ftp->e_i);
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compose_matrix(m1, ncp, ftp->rI2_eJ2);
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compose_matrix(m2, ftp->r_i, ftp->r_i);
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compose_matrix(m3, ftp->e_i, ftp->e_i);
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compose_matrix(m4, ftp->r_i, ftp->e_i);
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d1 = DOT(nrm, ftp->rcp);
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d2 = -d1*ftp->I2;
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d1 *= 2.0;
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for (i = 3; i--; ) /* final matrix sum */
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for (j = 3; j--; ) {
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hess[i][j] = m1[i][j] + d1*( I3*m2[i][j] + K3*m3[i][j] +
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2.0*J3*m4[i][j] );
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hess[i][j] += d2*(i==j);
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hess[i][j] *= 1.0/PI;
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}
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}
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/* Reverse hessian calculation result for edge in other direction */
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static void
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rev_hessian(FVECT hess[3])
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{
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int i;
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for (i = 3; i--; ) {
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hess[i][0] = -hess[i][0];
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hess[i][1] = -hess[i][1];
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hess[i][2] = -hess[i][2];
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}
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}
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/* Add to radiometric Hessian from the given triangle */
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static void
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add2hessian(FVECT hess[3], FVECT ehess1[3],
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FVECT ehess2[3], FVECT ehess3[3], COLORV v)
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{
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| 232 |
int i, j;
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| 233 |
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for (i = 3; i--; )
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| 235 |
for (j = 3; j--; )
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hess[i][j] += v*( ehess1[i][j] + ehess2[i][j] + ehess3[i][j] );
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}
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/* Compute partial displacement form factor gradient for edge */
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static void
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comp_gradient(FVECT grad, FFTRI *ftp, FVECT nrm)
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{
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FVECT ncp;
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double f1;
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int i;
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| 247 |
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f1 = 2.0*DOT(nrm, ftp->rcp);
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VCROSS(ncp, nrm, ftp->e_i);
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for (i = 3; i--; )
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grad[i] = (-0.5/PI)*( ftp->I1*ncp[i] + f1*ftp->rI2_eJ2[i] );
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}
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/* Reverse gradient calculation result for edge in other direction */
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static void
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rev_gradient(FVECT grad)
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{
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| 259 |
grad[0] = -grad[0];
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grad[1] = -grad[1];
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grad[2] = -grad[2];
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}
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| 264 |
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/* Add to displacement gradient from the given triangle */
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static void
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add2gradient(FVECT grad, FVECT egrad1, FVECT egrad2, FVECT egrad3, COLORV v)
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| 268 |
{
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| 269 |
int i;
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| 270 |
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| 271 |
for (i = 3; i--; )
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| 272 |
grad[i] += v*( egrad1[i] + egrad2[i] + egrad3[i] );
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| 273 |
}
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| 274 |
|
| 275 |
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| 276 |
/* Return brightness of furthest ambient sample */
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| 277 |
static COLORV
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back_ambval(struct s_ambsamp *ap1, struct s_ambsamp *ap2,
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| 279 |
struct s_ambsamp *ap3, FVECT orig)
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| 280 |
{
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| 281 |
COLORV vback;
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| 282 |
FVECT vec;
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| 283 |
double d2, d2best;
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| 284 |
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| 285 |
VSUB(vec, ap1->p, orig);
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| 286 |
d2best = DOT(vec,vec);
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| 287 |
vback = colval(ap1->v,CIEY);
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| 288 |
VSUB(vec, ap2->p, orig);
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| 289 |
d2 = DOT(vec,vec);
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| 290 |
if (d2 > d2best) {
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| 291 |
d2best = d2;
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| 292 |
vback = colval(ap2->v,CIEY);
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| 293 |
}
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| 294 |
VSUB(vec, ap3->p, orig);
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| 295 |
d2 = DOT(vec,vec);
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| 296 |
if (d2 > d2best)
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| 297 |
return(colval(ap3->v,CIEY));
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| 298 |
return(vback);
|
| 299 |
}
|
| 300 |
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| 301 |
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| 302 |
/* Compute anisotropic radii and eigenvector directions */
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| 303 |
static int
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| 304 |
eigenvectors(FVECT uv[2], float ra[2], FVECT hessian[3])
|
| 305 |
{
|
| 306 |
double hess2[2][2];
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| 307 |
FVECT a, b;
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| 308 |
double evalue[2], slope1, xmag1;
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| 309 |
int i;
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| 310 |
/* project Hessian to sample plane */
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| 311 |
for (i = 3; i--; ) {
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| 312 |
a[i] = DOT(hessian[i], uv[0]);
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| 313 |
b[i] = DOT(hessian[i], uv[1]);
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| 314 |
}
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| 315 |
hess2[0][0] = DOT(uv[0], a);
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| 316 |
hess2[0][1] = DOT(uv[0], b);
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| 317 |
hess2[1][0] = DOT(uv[1], a);
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| 318 |
hess2[1][1] = DOT(uv[1], b);
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| 319 |
/* compute eigenvalues */
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| 320 |
if ( quadratic(evalue, 1.0, -hess2[0][0]-hess2[1][1],
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| 321 |
hess2[0][0]*hess2[1][1]-hess2[0][1]*hess2[1][0]) != 2 ||
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| 322 |
((evalue[0] = fabs(evalue[0])) <= FTINY*FTINY) |
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| 323 |
((evalue[1] = fabs(evalue[1])) <= FTINY*FTINY) )
|
| 324 |
error(INTERNAL, "bad eigenvalue calculation");
|
| 325 |
|
| 326 |
if (evalue[0] > evalue[1]) {
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| 327 |
ra[0] = sqrt(sqrt(4.0/evalue[0]));
|
| 328 |
ra[1] = sqrt(sqrt(4.0/evalue[1]));
|
| 329 |
slope1 = evalue[1];
|
| 330 |
} else {
|
| 331 |
ra[0] = sqrt(sqrt(4.0/evalue[1]));
|
| 332 |
ra[1] = sqrt(sqrt(4.0/evalue[0]));
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| 333 |
slope1 = evalue[0];
|
| 334 |
}
|
| 335 |
/* compute unit eigenvectors */
|
| 336 |
if (fabs(hess2[0][1]) <= FTINY)
|
| 337 |
return; /* uv OK as is */
|
| 338 |
slope1 = (slope1 - hess2[0][0]) / hess2[0][1];
|
| 339 |
xmag1 = sqrt(1.0/(1.0 + slope1*slope1));
|
| 340 |
for (i = 3; i--; ) {
|
| 341 |
b[i] = xmag1*uv[0][i] + slope1*xmag1*uv[1][i];
|
| 342 |
a[i] = slope1*xmag1*uv[0][i] - xmag1*uv[1][i];
|
| 343 |
}
|
| 344 |
VCOPY(uv[0], a);
|
| 345 |
VCOPY(uv[1], b);
|
| 346 |
}
|
| 347 |
|
| 348 |
|
| 349 |
static void
|
| 350 |
ambHessian( /* anisotropic radii & pos. gradient */
|
| 351 |
AMBHEMI *hp,
|
| 352 |
FVECT uv[2], /* returned */
|
| 353 |
float ra[2], /* returned (optional) */
|
| 354 |
float pg[2] /* returned (optional) */
|
| 355 |
)
|
| 356 |
{
|
| 357 |
static char memerrmsg[] = "out of memory in ambHessian()";
|
| 358 |
FVECT (*hessrow)[3] = NULL;
|
| 359 |
FVECT *gradrow = NULL;
|
| 360 |
FVECT hessian[3];
|
| 361 |
FVECT gradient;
|
| 362 |
FFTRI fftr;
|
| 363 |
int i, j;
|
| 364 |
/* be sure to assign unit vectors */
|
| 365 |
VCOPY(uv[0], hp->ux);
|
| 366 |
VCOPY(uv[1], hp->uy);
|
| 367 |
/* clock-wise vertex traversal from sample POV */
|
| 368 |
if (ra != NULL) { /* initialize Hessian row buffer */
|
| 369 |
hessrow = (FVECT (*)[3])malloc(sizeof(FVECT)*3*(hp->ns-1));
|
| 370 |
if (hessrow == NULL)
|
| 371 |
error(SYSTEM, memerrmsg);
|
| 372 |
memset(hessian, 0, sizeof(hessian));
|
| 373 |
} else if (pg == NULL) /* bogus call? */
|
| 374 |
return;
|
| 375 |
if (pg != NULL) { /* initialize form factor row buffer */
|
| 376 |
gradrow = (FVECT *)malloc(sizeof(FVECT)*(hp->ns-1));
|
| 377 |
if (gradrow == NULL)
|
| 378 |
error(SYSTEM, memerrmsg);
|
| 379 |
memset(gradient, 0, sizeof(gradient));
|
| 380 |
}
|
| 381 |
/* compute first row of edges */
|
| 382 |
for (j = 0; j < hp->ns-1; j++) {
|
| 383 |
comp_fftri(&fftr, ambsamp(hp,0,j).p,
|
| 384 |
ambsamp(hp,0,j+1).p, hp->rp->rop);
|
| 385 |
if (hessrow != NULL)
|
| 386 |
comp_hessian(hessrow[j], &fftr, hp->rp->ron);
|
| 387 |
if (gradrow != NULL)
|
| 388 |
comp_gradient(gradrow[j], &fftr, hp->rp->ron);
|
| 389 |
}
|
| 390 |
/* sum each row of triangles */
|
| 391 |
for (i = 0; i < hp->ns-1; i++) {
|
| 392 |
FVECT hesscol[3]; /* compute first vertical edge */
|
| 393 |
FVECT gradcol;
|
| 394 |
comp_fftri(&fftr, ambsamp(hp,i,0).p,
|
| 395 |
ambsamp(hp,i+1,0).p, hp->rp->rop);
|
| 396 |
if (hessrow != NULL)
|
| 397 |
comp_hessian(hesscol, &fftr, hp->rp->ron);
|
| 398 |
if (gradrow != NULL)
|
| 399 |
comp_gradient(gradcol, &fftr, hp->rp->ron);
|
| 400 |
for (j = 0; j < hp->ns-1; j++) {
|
| 401 |
FVECT hessdia[3]; /* compute triangle contributions */
|
| 402 |
FVECT graddia;
|
| 403 |
COLORV backg;
|
| 404 |
backg = back_ambval(&ambsamp(hp,i,j), &ambsamp(hp,i,j+1),
|
| 405 |
&ambsamp(hp,i+1,j), hp->rp->rop);
|
| 406 |
/* diagonal (inner) edge */
|
| 407 |
comp_fftri(&fftr, ambsamp(hp,i,j+1).p,
|
| 408 |
ambsamp(hp,i+1,j).p, hp->rp->rop);
|
| 409 |
if (hessrow != NULL) {
|
| 410 |
comp_hessian(hessdia, &fftr, hp->rp->ron);
|
| 411 |
rev_hessian(hesscol);
|
| 412 |
add2hessian(hessian, hessrow[j], hessdia, hesscol, backg);
|
| 413 |
}
|
| 414 |
if (gradient != NULL) {
|
| 415 |
comp_gradient(graddia, &fftr, hp->rp->ron);
|
| 416 |
rev_gradient(gradcol);
|
| 417 |
add2gradient(gradient, gradrow[j], graddia, gradcol, backg);
|
| 418 |
}
|
| 419 |
/* initialize edge in next row */
|
| 420 |
comp_fftri(&fftr, ambsamp(hp,i+1,j+1).p,
|
| 421 |
ambsamp(hp,i+1,j).p, hp->rp->rop);
|
| 422 |
if (hessrow != NULL)
|
| 423 |
comp_hessian(hessrow[j], &fftr, hp->rp->ron);
|
| 424 |
if (gradrow != NULL)
|
| 425 |
comp_gradient(gradrow[j], &fftr, hp->rp->ron);
|
| 426 |
/* new column edge & paired triangle */
|
| 427 |
backg = back_ambval(&ambsamp(hp,i,j+1), &ambsamp(hp,i+1,j+1),
|
| 428 |
&ambsamp(hp,i+1,j), hp->rp->rop);
|
| 429 |
comp_fftri(&fftr, ambsamp(hp,i,j+1).p, ambsamp(hp,i+1,j+1).p,
|
| 430 |
hp->rp->rop);
|
| 431 |
if (hessrow != NULL) {
|
| 432 |
comp_hessian(hesscol, &fftr, hp->rp->ron);
|
| 433 |
rev_hessian(hessdia);
|
| 434 |
add2hessian(hessian, hessrow[j], hessdia, hesscol, backg);
|
| 435 |
if (i < hp->ns-2)
|
| 436 |
rev_hessian(hessrow[j]);
|
| 437 |
}
|
| 438 |
if (gradrow != NULL) {
|
| 439 |
comp_gradient(gradcol, &fftr, hp->rp->ron);
|
| 440 |
rev_gradient(graddia);
|
| 441 |
add2gradient(gradient, gradrow[j], graddia, gradcol, backg);
|
| 442 |
if (i < hp->ns-2)
|
| 443 |
rev_gradient(gradrow[j]);
|
| 444 |
}
|
| 445 |
}
|
| 446 |
}
|
| 447 |
/* release row buffers */
|
| 448 |
if (hessrow != NULL) free(hessrow);
|
| 449 |
if (gradrow != NULL) free(gradrow);
|
| 450 |
|
| 451 |
if (ra != NULL) /* extract eigenvectors & radii */
|
| 452 |
eigenvectors(uv, ra, hessian);
|
| 453 |
if (pg != NULL) { /* tangential position gradient */
|
| 454 |
pg[0] = DOT(gradient, uv[0]);
|
| 455 |
pg[1] = DOT(gradient, uv[1]);
|
| 456 |
}
|
| 457 |
}
|
| 458 |
|
| 459 |
|
| 460 |
/* Compute direction gradient from a hemispherical sampling */
|
| 461 |
static void
|
| 462 |
ambdirgrad(AMBHEMI *hp, FVECT uv[2], float dg[2])
|
| 463 |
{
|
| 464 |
struct s_ambsamp *ap;
|
| 465 |
double dgsum[2];
|
| 466 |
int n;
|
| 467 |
FVECT vd;
|
| 468 |
double gfact;
|
| 469 |
|
| 470 |
dgsum[0] = dgsum[1] = 0.0; /* sum values times -tan(theta) */
|
| 471 |
for (ap = hp->sa, n = hp->ns*hp->ns; n--; ap++) {
|
| 472 |
/* use vector for azimuth + 90deg */
|
| 473 |
VSUB(vd, ap->p, hp->rp->rop);
|
| 474 |
/* brightness over cosine factor */
|
| 475 |
gfact = colval(ap->v,CIEY) / DOT(hp->rp->ron, vd);
|
| 476 |
/* -sine = -proj_radius/vd_length */
|
| 477 |
dgsum[0] += DOT(uv[1], vd) * gfact;
|
| 478 |
dgsum[1] -= DOT(uv[0], vd) * gfact;
|
| 479 |
}
|
| 480 |
dg[0] = dgsum[0] / (hp->ns*hp->ns);
|
| 481 |
dg[1] = dgsum[1] / (hp->ns*hp->ns);
|
| 482 |
}
|
| 483 |
|
| 484 |
|
| 485 |
int
|
| 486 |
doambient( /* compute ambient component */
|
| 487 |
COLOR rcol, /* input/output color */
|
| 488 |
RAY *r,
|
| 489 |
double wt,
|
| 490 |
FVECT uv[2], /* returned (optional) */
|
| 491 |
float ra[2], /* returned (optional) */
|
| 492 |
float pg[2], /* returned (optional) */
|
| 493 |
float dg[2] /* returned (optional) */
|
| 494 |
)
|
| 495 |
{
|
| 496 |
AMBHEMI *hp = inithemi(rcol, r, wt);
|
| 497 |
int cnt = 0;
|
| 498 |
FVECT my_uv[2];
|
| 499 |
double d, acol[3];
|
| 500 |
struct s_ambsamp *ap;
|
| 501 |
int i, j;
|
| 502 |
/* check/initialize */
|
| 503 |
if (hp == NULL)
|
| 504 |
return(0);
|
| 505 |
if (uv != NULL)
|
| 506 |
memset(uv, 0, sizeof(FVECT)*2);
|
| 507 |
if (ra != NULL)
|
| 508 |
ra[0] = ra[1] = 0.0;
|
| 509 |
if (pg != NULL)
|
| 510 |
pg[0] = pg[1] = 0.0;
|
| 511 |
if (dg != NULL)
|
| 512 |
dg[0] = dg[1] = 0.0;
|
| 513 |
/* sample the hemisphere */
|
| 514 |
acol[0] = acol[1] = acol[2] = 0.0;
|
| 515 |
for (i = hp->ns; i--; )
|
| 516 |
for (j = hp->ns; j--; )
|
| 517 |
if ((ap = ambsample(hp, i, j)) != NULL) {
|
| 518 |
addcolor(acol, ap->v);
|
| 519 |
++cnt;
|
| 520 |
}
|
| 521 |
if (!cnt) {
|
| 522 |
setcolor(rcol, 0.0, 0.0, 0.0);
|
| 523 |
free(hp);
|
| 524 |
return(0); /* no valid samples */
|
| 525 |
}
|
| 526 |
copycolor(rcol, acol); /* final indirect irradiance/PI */
|
| 527 |
if (cnt < hp->ns*hp->ns || /* incomplete sampling? */
|
| 528 |
(ra == NULL) & (pg == NULL) & (dg == NULL)) {
|
| 529 |
free(hp);
|
| 530 |
return(-1); /* no radius or gradient calc. */
|
| 531 |
}
|
| 532 |
if (bright(acol) > FTINY) /* normalize Y values */
|
| 533 |
d = cnt/bright(acol);
|
| 534 |
else
|
| 535 |
d = 0.0;
|
| 536 |
ap = hp->sa; /* relative Y channel from here on... */
|
| 537 |
for (i = hp->ns*hp->ns; i--; ap++)
|
| 538 |
colval(ap->v,CIEY) = bright(ap->v)*d + 0.01;
|
| 539 |
|
| 540 |
if (uv == NULL) /* make sure we have axis pointers */
|
| 541 |
uv = my_uv;
|
| 542 |
/* compute radii & pos. gradient */
|
| 543 |
ambHessian(hp, uv, ra, pg);
|
| 544 |
|
| 545 |
if (dg != NULL) /* compute direction gradient */
|
| 546 |
ambdirgrad(hp, uv, dg);
|
| 547 |
|
| 548 |
if (ra != NULL) { /* scale/clamp radii */
|
| 549 |
if (pg != NULL) {
|
| 550 |
if (ra[0]*(d = fabs(pg[0])) > 1.0)
|
| 551 |
ra[0] = 1.0/d;
|
| 552 |
if (ra[1]*(d = fabs(pg[1])) > 1.0)
|
| 553 |
ra[1] = 1.0/d;
|
| 554 |
if (ra[0] > ra[1])
|
| 555 |
ra[0] = ra[1];
|
| 556 |
}
|
| 557 |
if (ra[0] < minarad) {
|
| 558 |
ra[0] = minarad;
|
| 559 |
if (ra[1] < minarad)
|
| 560 |
ra[1] = minarad;
|
| 561 |
}
|
| 562 |
ra[0] *= d = 1.0/sqrt(sqrt(wt));
|
| 563 |
if ((ra[1] *= d) > 2.0*ra[0])
|
| 564 |
ra[1] = 2.0*ra[0];
|
| 565 |
if (ra[1] > maxarad) {
|
| 566 |
ra[1] = maxarad;
|
| 567 |
if (ra[0] > maxarad)
|
| 568 |
ra[0] = maxarad;
|
| 569 |
}
|
| 570 |
if (pg != NULL) { /* cap gradient if necessary */
|
| 571 |
d = pg[0]*pg[0]*ra[0]*ra[0] + pg[1]*pg[1]*ra[1]*ra[1];
|
| 572 |
if (d > 1.0) {
|
| 573 |
d = 1.0/sqrt(d);
|
| 574 |
pg[0] *= d;
|
| 575 |
pg[1] *= d;
|
| 576 |
}
|
| 577 |
}
|
| 578 |
}
|
| 579 |
free(hp); /* clean up and return */
|
| 580 |
return(1);
|
| 581 |
}
|
| 582 |
|
| 583 |
|
| 584 |
#else /* ! NEWAMB */
|
| 585 |
|
| 586 |
|
| 587 |
void
|
| 588 |
inithemi( /* initialize sampling hemisphere */
|
| 589 |
AMBHEMI *hp,
|
| 590 |
COLOR ac,
|
| 591 |
RAY *r,
|
| 592 |
double wt
|
| 593 |
)
|
| 594 |
{
|
| 595 |
double d;
|
| 596 |
int i;
|
| 597 |
/* set number of divisions */
|
| 598 |
if (ambacc <= FTINY &&
|
| 599 |
wt > (d = 0.8*intens(ac)*r->rweight/(ambdiv*minweight)))
|
| 600 |
wt = d; /* avoid ray termination */
|
| 601 |
hp->nt = sqrt(ambdiv * wt / PI) + 0.5;
|
| 602 |
i = ambacc > FTINY ? 3 : 1; /* minimum number of samples */
|
| 603 |
if (hp->nt < i)
|
| 604 |
hp->nt = i;
|
| 605 |
hp->np = PI * hp->nt + 0.5;
|
| 606 |
/* set number of super-samples */
|
| 607 |
hp->ns = ambssamp * wt + 0.5;
|
| 608 |
/* assign coefficient */
|
| 609 |
copycolor(hp->acoef, ac);
|
| 610 |
d = 1.0/(hp->nt*hp->np);
|
| 611 |
scalecolor(hp->acoef, d);
|
| 612 |
/* make axes */
|
| 613 |
VCOPY(hp->uz, r->ron);
|
| 614 |
hp->uy[0] = hp->uy[1] = hp->uy[2] = 0.0;
|
| 615 |
for (i = 0; i < 3; i++)
|
| 616 |
if (hp->uz[i] < 0.6 && hp->uz[i] > -0.6)
|
| 617 |
break;
|
| 618 |
if (i >= 3)
|
| 619 |
error(CONSISTENCY, "bad ray direction in inithemi");
|
| 620 |
hp->uy[i] = 1.0;
|
| 621 |
fcross(hp->ux, hp->uy, hp->uz);
|
| 622 |
normalize(hp->ux);
|
| 623 |
fcross(hp->uy, hp->uz, hp->ux);
|
| 624 |
}
|
| 625 |
|
| 626 |
|
| 627 |
int
|
| 628 |
divsample( /* sample a division */
|
| 629 |
AMBSAMP *dp,
|
| 630 |
AMBHEMI *h,
|
| 631 |
RAY *r
|
| 632 |
)
|
| 633 |
{
|
| 634 |
RAY ar;
|
| 635 |
int hlist[3];
|
| 636 |
double spt[2];
|
| 637 |
double xd, yd, zd;
|
| 638 |
double b2;
|
| 639 |
double phi;
|
| 640 |
int i;
|
| 641 |
/* ambient coefficient for weight */
|
| 642 |
if (ambacc > FTINY)
|
| 643 |
setcolor(ar.rcoef, AVGREFL, AVGREFL, AVGREFL);
|
| 644 |
else
|
| 645 |
copycolor(ar.rcoef, h->acoef);
|
| 646 |
if (rayorigin(&ar, AMBIENT, r, ar.rcoef) < 0)
|
| 647 |
return(-1);
|
| 648 |
if (ambacc > FTINY) {
|
| 649 |
multcolor(ar.rcoef, h->acoef);
|
| 650 |
scalecolor(ar.rcoef, 1./AVGREFL);
|
| 651 |
}
|
| 652 |
hlist[0] = r->rno;
|
| 653 |
hlist[1] = dp->t;
|
| 654 |
hlist[2] = dp->p;
|
| 655 |
multisamp(spt, 2, urand(ilhash(hlist,3)+dp->n));
|
| 656 |
zd = sqrt((dp->t + spt[0])/h->nt);
|
| 657 |
phi = 2.0*PI * (dp->p + spt[1])/h->np;
|
| 658 |
xd = tcos(phi) * zd;
|
| 659 |
yd = tsin(phi) * zd;
|
| 660 |
zd = sqrt(1.0 - zd*zd);
|
| 661 |
for (i = 0; i < 3; i++)
|
| 662 |
ar.rdir[i] = xd*h->ux[i] +
|
| 663 |
yd*h->uy[i] +
|
| 664 |
zd*h->uz[i];
|
| 665 |
checknorm(ar.rdir);
|
| 666 |
dimlist[ndims++] = dp->t*h->np + dp->p + 90171;
|
| 667 |
rayvalue(&ar);
|
| 668 |
ndims--;
|
| 669 |
multcolor(ar.rcol, ar.rcoef); /* apply coefficient */
|
| 670 |
addcolor(dp->v, ar.rcol);
|
| 671 |
/* use rt to improve gradient calc */
|
| 672 |
if (ar.rt > FTINY && ar.rt < FHUGE)
|
| 673 |
dp->r += 1.0/ar.rt;
|
| 674 |
/* (re)initialize error */
|
| 675 |
if (dp->n++) {
|
| 676 |
b2 = bright(dp->v)/dp->n - bright(ar.rcol);
|
| 677 |
b2 = b2*b2 + dp->k*((dp->n-1)*(dp->n-1));
|
| 678 |
dp->k = b2/(dp->n*dp->n);
|
| 679 |
} else
|
| 680 |
dp->k = 0.0;
|
| 681 |
return(0);
|
| 682 |
}
|
| 683 |
|
| 684 |
|
| 685 |
static int
|
| 686 |
ambcmp( /* decreasing order */
|
| 687 |
const void *p1,
|
| 688 |
const void *p2
|
| 689 |
)
|
| 690 |
{
|
| 691 |
const AMBSAMP *d1 = (const AMBSAMP *)p1;
|
| 692 |
const AMBSAMP *d2 = (const AMBSAMP *)p2;
|
| 693 |
|
| 694 |
if (d1->k < d2->k)
|
| 695 |
return(1);
|
| 696 |
if (d1->k > d2->k)
|
| 697 |
return(-1);
|
| 698 |
return(0);
|
| 699 |
}
|
| 700 |
|
| 701 |
|
| 702 |
static int
|
| 703 |
ambnorm( /* standard order */
|
| 704 |
const void *p1,
|
| 705 |
const void *p2
|
| 706 |
)
|
| 707 |
{
|
| 708 |
const AMBSAMP *d1 = (const AMBSAMP *)p1;
|
| 709 |
const AMBSAMP *d2 = (const AMBSAMP *)p2;
|
| 710 |
int c;
|
| 711 |
|
| 712 |
if ( (c = d1->t - d2->t) )
|
| 713 |
return(c);
|
| 714 |
return(d1->p - d2->p);
|
| 715 |
}
|
| 716 |
|
| 717 |
|
| 718 |
double
|
| 719 |
doambient( /* compute ambient component */
|
| 720 |
COLOR rcol,
|
| 721 |
RAY *r,
|
| 722 |
double wt,
|
| 723 |
FVECT pg,
|
| 724 |
FVECT dg
|
| 725 |
)
|
| 726 |
{
|
| 727 |
double b, d=0;
|
| 728 |
AMBHEMI hemi;
|
| 729 |
AMBSAMP *div;
|
| 730 |
AMBSAMP dnew;
|
| 731 |
double acol[3];
|
| 732 |
AMBSAMP *dp;
|
| 733 |
double arad;
|
| 734 |
int divcnt;
|
| 735 |
int i, j;
|
| 736 |
/* initialize hemisphere */
|
| 737 |
inithemi(&hemi, rcol, r, wt);
|
| 738 |
divcnt = hemi.nt * hemi.np;
|
| 739 |
/* initialize */
|
| 740 |
if (pg != NULL)
|
| 741 |
pg[0] = pg[1] = pg[2] = 0.0;
|
| 742 |
if (dg != NULL)
|
| 743 |
dg[0] = dg[1] = dg[2] = 0.0;
|
| 744 |
setcolor(rcol, 0.0, 0.0, 0.0);
|
| 745 |
if (divcnt == 0)
|
| 746 |
return(0.0);
|
| 747 |
/* allocate super-samples */
|
| 748 |
if (hemi.ns > 0 || pg != NULL || dg != NULL) {
|
| 749 |
div = (AMBSAMP *)malloc(divcnt*sizeof(AMBSAMP));
|
| 750 |
if (div == NULL)
|
| 751 |
error(SYSTEM, "out of memory in doambient");
|
| 752 |
} else
|
| 753 |
div = NULL;
|
| 754 |
/* sample the divisions */
|
| 755 |
arad = 0.0;
|
| 756 |
acol[0] = acol[1] = acol[2] = 0.0;
|
| 757 |
if ((dp = div) == NULL)
|
| 758 |
dp = &dnew;
|
| 759 |
divcnt = 0;
|
| 760 |
for (i = 0; i < hemi.nt; i++)
|
| 761 |
for (j = 0; j < hemi.np; j++) {
|
| 762 |
dp->t = i; dp->p = j;
|
| 763 |
setcolor(dp->v, 0.0, 0.0, 0.0);
|
| 764 |
dp->r = 0.0;
|
| 765 |
dp->n = 0;
|
| 766 |
if (divsample(dp, &hemi, r) < 0) {
|
| 767 |
if (div != NULL)
|
| 768 |
dp++;
|
| 769 |
continue;
|
| 770 |
}
|
| 771 |
arad += dp->r;
|
| 772 |
divcnt++;
|
| 773 |
if (div != NULL)
|
| 774 |
dp++;
|
| 775 |
else
|
| 776 |
addcolor(acol, dp->v);
|
| 777 |
}
|
| 778 |
if (!divcnt) {
|
| 779 |
if (div != NULL)
|
| 780 |
free((void *)div);
|
| 781 |
return(0.0); /* no samples taken */
|
| 782 |
}
|
| 783 |
if (divcnt < hemi.nt*hemi.np) {
|
| 784 |
pg = dg = NULL; /* incomplete sampling */
|
| 785 |
hemi.ns = 0;
|
| 786 |
} else if (arad > FTINY && divcnt/arad < minarad) {
|
| 787 |
hemi.ns = 0; /* close enough */
|
| 788 |
} else if (hemi.ns > 0) { /* else perform super-sampling? */
|
| 789 |
comperrs(div, &hemi); /* compute errors */
|
| 790 |
qsort(div, divcnt, sizeof(AMBSAMP), ambcmp); /* sort divs */
|
| 791 |
/* super-sample */
|
| 792 |
for (i = hemi.ns; i > 0; i--) {
|
| 793 |
dnew = *div;
|
| 794 |
if (divsample(&dnew, &hemi, r) < 0) {
|
| 795 |
dp++;
|
| 796 |
continue;
|
| 797 |
}
|
| 798 |
dp = div; /* reinsert */
|
| 799 |
j = divcnt < i ? divcnt : i;
|
| 800 |
while (--j > 0 && dnew.k < dp[1].k) {
|
| 801 |
*dp = *(dp+1);
|
| 802 |
dp++;
|
| 803 |
}
|
| 804 |
*dp = dnew;
|
| 805 |
}
|
| 806 |
if (pg != NULL || dg != NULL) /* restore order */
|
| 807 |
qsort(div, divcnt, sizeof(AMBSAMP), ambnorm);
|
| 808 |
}
|
| 809 |
/* compute returned values */
|
| 810 |
if (div != NULL) {
|
| 811 |
arad = 0.0; /* note: divcnt may be < nt*np */
|
| 812 |
for (i = hemi.nt*hemi.np, dp = div; i-- > 0; dp++) {
|
| 813 |
arad += dp->r;
|
| 814 |
if (dp->n > 1) {
|
| 815 |
b = 1.0/dp->n;
|
| 816 |
scalecolor(dp->v, b);
|
| 817 |
dp->r *= b;
|
| 818 |
dp->n = 1;
|
| 819 |
}
|
| 820 |
addcolor(acol, dp->v);
|
| 821 |
}
|
| 822 |
b = bright(acol);
|
| 823 |
if (b > FTINY) {
|
| 824 |
b = 1.0/b; /* compute & normalize gradient(s) */
|
| 825 |
if (pg != NULL) {
|
| 826 |
posgradient(pg, div, &hemi);
|
| 827 |
for (i = 0; i < 3; i++)
|
| 828 |
pg[i] *= b;
|
| 829 |
}
|
| 830 |
if (dg != NULL) {
|
| 831 |
dirgradient(dg, div, &hemi);
|
| 832 |
for (i = 0; i < 3; i++)
|
| 833 |
dg[i] *= b;
|
| 834 |
}
|
| 835 |
}
|
| 836 |
free((void *)div);
|
| 837 |
}
|
| 838 |
copycolor(rcol, acol);
|
| 839 |
if (arad <= FTINY)
|
| 840 |
arad = maxarad;
|
| 841 |
else
|
| 842 |
arad = (divcnt+hemi.ns)/arad;
|
| 843 |
if (pg != NULL) { /* reduce radius if gradient large */
|
| 844 |
d = DOT(pg,pg);
|
| 845 |
if (d*arad*arad > 1.0)
|
| 846 |
arad = 1.0/sqrt(d);
|
| 847 |
}
|
| 848 |
if (arad < minarad) {
|
| 849 |
arad = minarad;
|
| 850 |
if (pg != NULL && d*arad*arad > 1.0) { /* cap gradient */
|
| 851 |
d = 1.0/arad/sqrt(d);
|
| 852 |
for (i = 0; i < 3; i++)
|
| 853 |
pg[i] *= d;
|
| 854 |
}
|
| 855 |
}
|
| 856 |
if ((arad /= sqrt(wt)) > maxarad)
|
| 857 |
arad = maxarad;
|
| 858 |
return(arad);
|
| 859 |
}
|
| 860 |
|
| 861 |
|
| 862 |
void
|
| 863 |
comperrs( /* compute initial error estimates */
|
| 864 |
AMBSAMP *da, /* assumes standard ordering */
|
| 865 |
AMBHEMI *hp
|
| 866 |
)
|
| 867 |
{
|
| 868 |
double b, b2;
|
| 869 |
int i, j;
|
| 870 |
AMBSAMP *dp;
|
| 871 |
/* sum differences from neighbors */
|
| 872 |
dp = da;
|
| 873 |
for (i = 0; i < hp->nt; i++)
|
| 874 |
for (j = 0; j < hp->np; j++) {
|
| 875 |
#ifdef DEBUG
|
| 876 |
if (dp->t != i || dp->p != j)
|
| 877 |
error(CONSISTENCY,
|
| 878 |
"division order in comperrs");
|
| 879 |
#endif
|
| 880 |
b = bright(dp[0].v);
|
| 881 |
if (i > 0) { /* from above */
|
| 882 |
b2 = bright(dp[-hp->np].v) - b;
|
| 883 |
b2 *= b2 * 0.25;
|
| 884 |
dp[0].k += b2;
|
| 885 |
dp[-hp->np].k += b2;
|
| 886 |
}
|
| 887 |
if (j > 0) { /* from behind */
|
| 888 |
b2 = bright(dp[-1].v) - b;
|
| 889 |
b2 *= b2 * 0.25;
|
| 890 |
dp[0].k += b2;
|
| 891 |
dp[-1].k += b2;
|
| 892 |
} else { /* around */
|
| 893 |
b2 = bright(dp[hp->np-1].v) - b;
|
| 894 |
b2 *= b2 * 0.25;
|
| 895 |
dp[0].k += b2;
|
| 896 |
dp[hp->np-1].k += b2;
|
| 897 |
}
|
| 898 |
dp++;
|
| 899 |
}
|
| 900 |
/* divide by number of neighbors */
|
| 901 |
dp = da;
|
| 902 |
for (j = 0; j < hp->np; j++) /* top row */
|
| 903 |
(dp++)->k *= 1.0/3.0;
|
| 904 |
if (hp->nt < 2)
|
| 905 |
return;
|
| 906 |
for (i = 1; i < hp->nt-1; i++) /* central region */
|
| 907 |
for (j = 0; j < hp->np; j++)
|
| 908 |
(dp++)->k *= 0.25;
|
| 909 |
for (j = 0; j < hp->np; j++) /* bottom row */
|
| 910 |
(dp++)->k *= 1.0/3.0;
|
| 911 |
}
|
| 912 |
|
| 913 |
|
| 914 |
void
|
| 915 |
posgradient( /* compute position gradient */
|
| 916 |
FVECT gv,
|
| 917 |
AMBSAMP *da, /* assumes standard ordering */
|
| 918 |
AMBHEMI *hp
|
| 919 |
)
|
| 920 |
{
|
| 921 |
int i, j;
|
| 922 |
double nextsine, lastsine, b, d;
|
| 923 |
double mag0, mag1;
|
| 924 |
double phi, cosp, sinp, xd, yd;
|
| 925 |
AMBSAMP *dp;
|
| 926 |
|
| 927 |
xd = yd = 0.0;
|
| 928 |
for (j = 0; j < hp->np; j++) {
|
| 929 |
dp = da + j;
|
| 930 |
mag0 = mag1 = 0.0;
|
| 931 |
lastsine = 0.0;
|
| 932 |
for (i = 0; i < hp->nt; i++) {
|
| 933 |
#ifdef DEBUG
|
| 934 |
if (dp->t != i || dp->p != j)
|
| 935 |
error(CONSISTENCY,
|
| 936 |
"division order in posgradient");
|
| 937 |
#endif
|
| 938 |
b = bright(dp->v);
|
| 939 |
if (i > 0) {
|
| 940 |
d = dp[-hp->np].r;
|
| 941 |
if (dp[0].r > d) d = dp[0].r;
|
| 942 |
/* sin(t)*cos(t)^2 */
|
| 943 |
d *= lastsine * (1.0 - (double)i/hp->nt);
|
| 944 |
mag0 += d*(b - bright(dp[-hp->np].v));
|
| 945 |
}
|
| 946 |
nextsine = sqrt((double)(i+1)/hp->nt);
|
| 947 |
if (j > 0) {
|
| 948 |
d = dp[-1].r;
|
| 949 |
if (dp[0].r > d) d = dp[0].r;
|
| 950 |
mag1 += d * (nextsine - lastsine) *
|
| 951 |
(b - bright(dp[-1].v));
|
| 952 |
} else {
|
| 953 |
d = dp[hp->np-1].r;
|
| 954 |
if (dp[0].r > d) d = dp[0].r;
|
| 955 |
mag1 += d * (nextsine - lastsine) *
|
| 956 |
(b - bright(dp[hp->np-1].v));
|
| 957 |
}
|
| 958 |
dp += hp->np;
|
| 959 |
lastsine = nextsine;
|
| 960 |
}
|
| 961 |
mag0 *= 2.0*PI / hp->np;
|
| 962 |
phi = 2.0*PI * (double)j/hp->np;
|
| 963 |
cosp = tcos(phi); sinp = tsin(phi);
|
| 964 |
xd += mag0*cosp - mag1*sinp;
|
| 965 |
yd += mag0*sinp + mag1*cosp;
|
| 966 |
}
|
| 967 |
for (i = 0; i < 3; i++)
|
| 968 |
gv[i] = (xd*hp->ux[i] + yd*hp->uy[i])*(hp->nt*hp->np)/PI;
|
| 969 |
}
|
| 970 |
|
| 971 |
|
| 972 |
void
|
| 973 |
dirgradient( /* compute direction gradient */
|
| 974 |
FVECT gv,
|
| 975 |
AMBSAMP *da, /* assumes standard ordering */
|
| 976 |
AMBHEMI *hp
|
| 977 |
)
|
| 978 |
{
|
| 979 |
int i, j;
|
| 980 |
double mag;
|
| 981 |
double phi, xd, yd;
|
| 982 |
AMBSAMP *dp;
|
| 983 |
|
| 984 |
xd = yd = 0.0;
|
| 985 |
for (j = 0; j < hp->np; j++) {
|
| 986 |
dp = da + j;
|
| 987 |
mag = 0.0;
|
| 988 |
for (i = 0; i < hp->nt; i++) {
|
| 989 |
#ifdef DEBUG
|
| 990 |
if (dp->t != i || dp->p != j)
|
| 991 |
error(CONSISTENCY,
|
| 992 |
"division order in dirgradient");
|
| 993 |
#endif
|
| 994 |
/* tan(t) */
|
| 995 |
mag += bright(dp->v)/sqrt(hp->nt/(i+.5) - 1.0);
|
| 996 |
dp += hp->np;
|
| 997 |
}
|
| 998 |
phi = 2.0*PI * (j+.5)/hp->np + PI/2.0;
|
| 999 |
xd += mag * tcos(phi);
|
| 1000 |
yd += mag * tsin(phi);
|
| 1001 |
}
|
| 1002 |
for (i = 0; i < 3; i++)
|
| 1003 |
gv[i] = xd*hp->ux[i] + yd*hp->uy[i];
|
| 1004 |
}
|
| 1005 |
|
| 1006 |
#endif /* ! NEWAMB */
|
