| 1 |
#ifndef lint |
| 2 |
static const char RCSid[] = "$Id: ambcomp.c,v 2.47 2014/05/03 05:46:19 greg Exp $"; |
| 3 |
#endif |
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/* |
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* Routines to compute "ambient" values using Monte Carlo |
| 6 |
* |
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* Hessian calculations based on "Practical Hessian-Based Error Control |
| 8 |
* 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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* Added book-keeping optimization to avoid calculations that would |
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* cancel due to traversal both directions on edges that are adjacent |
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* to same-valued triangles. This cuts about half of Hessian math. |
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* |
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* Declarations of external symbols in ambient.h |
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*/ |
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|
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#include "copyright.h" |
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|
| 20 |
#include "ray.h" |
| 21 |
#include "ambient.h" |
| 22 |
#include "random.h" |
| 23 |
|
| 24 |
#ifdef NEWAMB |
| 25 |
|
| 26 |
/* #define AHEM_MARG 1.2 /* hem margin */ |
| 27 |
|
| 28 |
extern void SDsquare2disk(double ds[2], double seedx, double seedy); |
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|
| 30 |
/* vertex direction bit positions */ |
| 31 |
#define VDB_xy 0 |
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#define VDB_y 01 |
| 33 |
#define VDB_x 02 |
| 34 |
#define VDB_Xy 03 |
| 35 |
#define VDB_xY 04 |
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#define VDB_X 05 |
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#define VDB_Y 06 |
| 38 |
#define VDB_XY 07 |
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/* get opposite vertex direction bit */ |
| 40 |
#define VDB_OPP(f) (~(f) & 07) |
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/* adjacent triangle vertex flags */ |
| 42 |
static const int adjacent_trifl[8] = { |
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0, /* forbidden diagonal */ |
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1<<VDB_x|1<<VDB_y|1<<VDB_Xy, |
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1<<VDB_y|1<<VDB_x|1<<VDB_xY, |
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1<<VDB_y|1<<VDB_Xy|1<<VDB_X, |
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1<<VDB_x|1<<VDB_xY|1<<VDB_Y, |
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1<<VDB_Xy|1<<VDB_X|1<<VDB_Y, |
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1<<VDB_xY|1<<VDB_Y|1<<VDB_X, |
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0, /* forbidden diagonal */ |
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}; |
| 52 |
|
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typedef struct { |
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COLOR v; /* hemisphere sample value */ |
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float d; /* reciprocal distance (1/rt) */ |
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FVECT p; /* intersection point */ |
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} AMBSAMP; /* sample value */ |
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|
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typedef struct { |
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RAY *rp; /* originating ray sample */ |
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FVECT ux, uy; /* tangent axis unit vectors */ |
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int ns; /* number of samples per axis */ |
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COLOR acoef; /* division contribution coefficient */ |
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AMBSAMP sa[1]; /* sample array (extends struct) */ |
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} AMBHEMI; /* ambient sample hemisphere */ |
| 66 |
|
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#define ambndx(h,i,j) ((i)*(h)->ns + (j)) |
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#define ambsam(h,i,j) (h)->sa[ambndx(h,i,j)] |
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|
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typedef struct { |
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FVECT r_i, r_i1, e_i, rcp, rI2_eJ2; |
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double I1, I2; |
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int valid; |
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} FFTRI; /* vectors and coefficients for Hessian calculation */ |
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|
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|
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/* Get index for adjacent vertex */ |
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static int |
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adjacent_verti(AMBHEMI *hp, int i, int j, int dbit) |
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{ |
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int i0 = i*hp->ns + j; |
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|
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switch (dbit) { |
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case VDB_y: return(i0 - hp->ns); |
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case VDB_x: return(i0 - 1); |
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case VDB_Xy: return(i0 - hp->ns + 1); |
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case VDB_xY: return(i0 + hp->ns - 1); |
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case VDB_X: return(i0 + 1); |
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case VDB_Y: return(i0 + hp->ns); |
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/* the following should never occur */ |
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case VDB_xy: return(i0 - hp->ns - 1); |
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case VDB_XY: return(i0 + hp->ns + 1); |
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} |
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return(-1); |
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} |
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|
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|
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/* Get vertex direction bit for the opposite edge to complete triangle */ |
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static int |
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vdb_edge(int db1, int db2) |
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{ |
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switch (db1) { |
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case VDB_x: return(db2==VDB_y ? VDB_Xy : VDB_Y); |
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case VDB_y: return(db2==VDB_x ? VDB_xY : VDB_X); |
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case VDB_X: return(db2==VDB_Xy ? VDB_y : VDB_xY); |
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case VDB_Y: return(db2==VDB_xY ? VDB_x : VDB_Xy); |
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case VDB_xY: return(db2==VDB_x ? VDB_y : VDB_X); |
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case VDB_Xy: return(db2==VDB_y ? VDB_x : VDB_Y); |
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} |
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error(INTERNAL, "forbidden diagonal in vdb_edge()"); |
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return(-1); |
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} |
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|
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|
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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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) |
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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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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) + sizeof(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] = 0.5 - frandom(); |
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hp->uy[1] = 0.5 - frandom(); |
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hp->uy[2] = 0.5 - frandom(); |
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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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break; |
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if (i < 0) |
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error(CONSISTENCY, "bad ray direction in inithemi"); |
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hp->uy[i] = 1.0; |
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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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|
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|
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/* Sample ambient division and apply weighting coefficient */ |
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static int |
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getambsamp(RAY *arp, AMBHEMI *hp, int i, int j, int n) |
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{ |
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int hlist[3], ii; |
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double spt[2], zd; |
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/* ambient coefficient for weight */ |
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if (ambacc > FTINY) |
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setcolor(arp->rcoef, AVGREFL, AVGREFL, AVGREFL); |
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else |
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copycolor(arp->rcoef, hp->acoef); |
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if (rayorigin(arp, AMBIENT, hp->rp, arp->rcoef) < 0) |
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return(0); |
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if (ambacc > FTINY) { |
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multcolor(arp->rcoef, hp->acoef); |
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scalecolor(arp->rcoef, 1./AVGREFL); |
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} |
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hlist[0] = hp->rp->rno; |
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hlist[1] = j; |
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hlist[2] = i; |
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multisamp(spt, 2, urand(ilhash(hlist,3)+n)); |
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if (!n) { /* avoid border samples for n==0 */ |
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if ((spt[0] < 0.1) | (spt[0] >= 0.9)) |
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spt[0] = 0.1 + 0.8*frandom(); |
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if ((spt[1] < 0.1) | (spt[1] >= 0.9)) |
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spt[1] = 0.1 + 0.8*frandom(); |
| 187 |
} |
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SDsquare2disk(spt, (j+spt[1])/hp->ns, (i+spt[0])/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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arp->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(arp->rdir); |
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dimlist[ndims++] = ambndx(hp,i,j) + 90171; |
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rayvalue(arp); /* evaluate ray */ |
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ndims--; /* apply coefficient */ |
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multcolor(arp->rcol, arp->rcoef); |
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return(1); |
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} |
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|
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|
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static AMBSAMP * |
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ambsample( /* initial ambient division sample */ |
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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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AMBSAMP *ap = &ambsam(hp,i,j); |
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RAY ar; |
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/* generate hemispherical sample */ |
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if (!getambsamp(&ar, hp, i, j, 0) || ar.rt <= FTINY) { |
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memset(ap, 0, sizeof(AMBSAMP)); |
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return(NULL); |
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} |
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ap->d = 1.0/ar.rt; /* 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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VSUM(ap->p, ar.rorg, ar.rdir, ar.rt); |
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copycolor(ap->v, ar.rcol); |
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return(ap); |
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} |
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|
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|
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/* Estimate errors based on ambient division differences */ |
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static float * |
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getambdiffs(AMBHEMI *hp) |
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{ |
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float *earr = (float *)calloc(hp->ns*hp->ns, sizeof(float)); |
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float *ep; |
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AMBSAMP *ap; |
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double b, d2; |
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int i, j; |
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|
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if (earr == NULL) /* out of memory? */ |
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return(NULL); |
| 238 |
/* compute squared neighbor diffs */ |
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for (ap = hp->sa, ep = earr, i = 0; i < hp->ns; i++) |
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for (j = 0; j < hp->ns; j++, ap++, ep++) { |
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b = bright(ap[0].v); |
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if (i) { /* from above */ |
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d2 = b - bright(ap[-hp->ns].v); |
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d2 *= d2; |
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ep[0] += d2; |
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ep[-hp->ns] += d2; |
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} |
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if (j) { /* from behind */ |
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d2 = b - bright(ap[-1].v); |
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d2 *= d2; |
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ep[0] += d2; |
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ep[-1] += d2; |
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} |
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} |
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/* correct for number of neighbors */ |
| 256 |
earr[0] *= 2.f; |
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earr[hp->ns-1] *= 2.f; |
| 258 |
earr[(hp->ns-1)*hp->ns] *= 2.f; |
| 259 |
earr[(hp->ns-1)*hp->ns + hp->ns-1] *= 2.f; |
| 260 |
for (i = 1; i < hp->ns-1; i++) { |
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earr[i*hp->ns] *= 4./3.; |
| 262 |
earr[i*hp->ns + hp->ns-1] *= 4./3.; |
| 263 |
} |
| 264 |
for (j = 1; j < hp->ns-1; j++) { |
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earr[j] *= 4./3.; |
| 266 |
earr[(hp->ns-1)*hp->ns + j] *= 4./3.; |
| 267 |
} |
| 268 |
return(earr); |
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} |
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|
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|
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/* Perform super-sampling on hemisphere (introduces bias) */ |
| 273 |
static void |
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ambsupersamp(double acol[3], AMBHEMI *hp, int cnt) |
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{ |
| 276 |
float *earr = getambdiffs(hp); |
| 277 |
double e2sum = 0; |
| 278 |
AMBSAMP *ap; |
| 279 |
RAY ar; |
| 280 |
COLOR asum; |
| 281 |
float *ep; |
| 282 |
int i, j, n; |
| 283 |
|
| 284 |
if (earr == NULL) /* just skip calc. if no memory */ |
| 285 |
return; |
| 286 |
/* add up estimated variances */ |
| 287 |
for (ep = earr + hp->ns*hp->ns; ep-- > earr; ) |
| 288 |
e2sum += *ep; |
| 289 |
ep = earr; /* perform super-sampling */ |
| 290 |
for (ap = hp->sa, i = 0; i < hp->ns; i++) |
| 291 |
for (j = 0; j < hp->ns; j++, ap++) { |
| 292 |
int nss = *ep/e2sum*cnt + frandom(); |
| 293 |
setcolor(asum, 0., 0., 0.); |
| 294 |
for (n = 1; n <= nss; n++) { |
| 295 |
if (!getambsamp(&ar, hp, i, j, n)) { |
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nss = n-1; |
| 297 |
break; |
| 298 |
} |
| 299 |
addcolor(asum, ar.rcol); |
| 300 |
} |
| 301 |
if (nss) { /* update returned ambient value */ |
| 302 |
const double ssf = 1./(nss + 1); |
| 303 |
for (n = 3; n--; ) |
| 304 |
acol[n] += ssf*colval(asum,n) + |
| 305 |
(ssf - 1.)*colval(ap->v,n); |
| 306 |
} |
| 307 |
e2sum -= *ep++; /* update remainders */ |
| 308 |
cnt -= nss; |
| 309 |
} |
| 310 |
free(earr); |
| 311 |
} |
| 312 |
|
| 313 |
|
| 314 |
/* Compute vertex flags, indicating farthest in each direction */ |
| 315 |
static uby8 * |
| 316 |
vertex_flags(AMBHEMI *hp) |
| 317 |
{ |
| 318 |
uby8 *vflags = (uby8 *)calloc(hp->ns*hp->ns, sizeof(uby8)); |
| 319 |
uby8 *vf; |
| 320 |
AMBSAMP *ap; |
| 321 |
int i, j; |
| 322 |
|
| 323 |
if (vflags == NULL) |
| 324 |
error(SYSTEM, "out of memory in vertex_flags()"); |
| 325 |
vf = vflags; |
| 326 |
ap = hp->sa; /* compute farthest along first row */ |
| 327 |
for (j = 0; j < hp->ns-1; j++, vf++, ap++) |
| 328 |
if (ap[0].d <= ap[1].d) |
| 329 |
vf[0] |= 1<<VDB_X; |
| 330 |
else |
| 331 |
vf[1] |= 1<<VDB_x; |
| 332 |
++vf; ++ap; |
| 333 |
/* flag subsequent rows */ |
| 334 |
for (i = 1; i < hp->ns; i++) { |
| 335 |
for (j = 0; j < hp->ns-1; j++, vf++, ap++) { |
| 336 |
if (ap[0].d <= ap[-hp->ns].d) /* row before */ |
| 337 |
vf[0] |= 1<<VDB_y; |
| 338 |
else |
| 339 |
vf[-hp->ns] |= 1<<VDB_Y; |
| 340 |
if (ap[0].d <= ap[1-hp->ns].d) /* diagonal we care about */ |
| 341 |
vf[0] |= 1<<VDB_Xy; |
| 342 |
else |
| 343 |
vf[1-hp->ns] |= 1<<VDB_xY; |
| 344 |
if (ap[0].d <= ap[1].d) /* column after */ |
| 345 |
vf[0] |= 1<<VDB_X; |
| 346 |
else |
| 347 |
vf[1] |= 1<<VDB_x; |
| 348 |
} |
| 349 |
if (ap[0].d <= ap[-hp->ns].d) /* final column edge */ |
| 350 |
vf[0] |= 1<<VDB_y; |
| 351 |
else |
| 352 |
vf[-hp->ns] |= 1<<VDB_Y; |
| 353 |
++vf; ++ap; |
| 354 |
} |
| 355 |
return(vflags); |
| 356 |
} |
| 357 |
|
| 358 |
|
| 359 |
/* Return brightness of farthest ambient sample */ |
| 360 |
static double |
| 361 |
back_ambval(AMBHEMI *hp, int i, int j, int dbit1, int dbit2, const uby8 *vflags) |
| 362 |
{ |
| 363 |
const int v0 = ambndx(hp,i,j); |
| 364 |
const int tflags = (1<<dbit1 | 1<<dbit2); |
| 365 |
int v1, v2; |
| 366 |
|
| 367 |
if ((vflags[v0] & tflags) == tflags) /* is v0 the farthest? */ |
| 368 |
return(colval(hp->sa[v0].v,CIEY)); |
| 369 |
v1 = adjacent_verti(hp, i, j, dbit1); |
| 370 |
if (vflags[v0] & 1<<dbit2) /* v1 farthest if v0>v2 */ |
| 371 |
return(colval(hp->sa[v1].v,CIEY)); |
| 372 |
v2 = adjacent_verti(hp, i, j, dbit2); |
| 373 |
if (vflags[v0] & 1<<dbit1) /* v2 farthest if v0>v1 */ |
| 374 |
return(colval(hp->sa[v2].v,CIEY)); |
| 375 |
/* else check if v1>v2 */ |
| 376 |
if (vflags[v1] & 1<<vdb_edge(dbit1,dbit2)) |
| 377 |
return(colval(hp->sa[v1].v,CIEY)); |
| 378 |
return(colval(hp->sa[v2].v,CIEY)); |
| 379 |
} |
| 380 |
|
| 381 |
|
| 382 |
/* Compute vectors and coefficients for Hessian/gradient calcs */ |
| 383 |
static void |
| 384 |
comp_fftri(FFTRI *ftp, AMBHEMI *hp, int i, int j, int dbit, const uby8 *vflags) |
| 385 |
{ |
| 386 |
const int i0 = ambndx(hp,i,j); |
| 387 |
double rdot_cp, dot_e, dot_er, rdot_r, rdot_r1, J2; |
| 388 |
int i1, ii; |
| 389 |
|
| 390 |
ftp->valid = 0; /* check if we can skip this edge */ |
| 391 |
ii = adjacent_trifl[dbit]; |
| 392 |
if ((vflags[i0] & ii) == ii) /* cancels if vertex used as value */ |
| 393 |
return; |
| 394 |
i1 = adjacent_verti(hp, i, j, dbit); |
| 395 |
ii = adjacent_trifl[VDB_OPP(dbit)]; |
| 396 |
if ((vflags[i1] & ii) == ii) /* on either end (for both triangles) */ |
| 397 |
return; |
| 398 |
/* else go ahead with calculation */ |
| 399 |
VSUB(ftp->r_i, hp->sa[i0].p, hp->rp->rop); |
| 400 |
VSUB(ftp->r_i1, hp->sa[i1].p, hp->rp->rop); |
| 401 |
VSUB(ftp->e_i, hp->sa[i1].p, hp->sa[i0].p); |
| 402 |
VCROSS(ftp->rcp, ftp->r_i, ftp->r_i1); |
| 403 |
rdot_cp = 1.0/DOT(ftp->rcp,ftp->rcp); |
| 404 |
dot_e = DOT(ftp->e_i,ftp->e_i); |
| 405 |
dot_er = DOT(ftp->e_i, ftp->r_i); |
| 406 |
rdot_r = 1.0/DOT(ftp->r_i,ftp->r_i); |
| 407 |
rdot_r1 = 1.0/DOT(ftp->r_i1,ftp->r_i1); |
| 408 |
ftp->I1 = acos( DOT(ftp->r_i, ftp->r_i1) * sqrt(rdot_r*rdot_r1) ) * |
| 409 |
sqrt( rdot_cp ); |
| 410 |
ftp->I2 = ( DOT(ftp->e_i, ftp->r_i1)*rdot_r1 - dot_er*rdot_r + |
| 411 |
dot_e*ftp->I1 )*0.5*rdot_cp; |
| 412 |
J2 = ( 0.5*(rdot_r - rdot_r1) - dot_er*ftp->I2 ) / dot_e; |
| 413 |
for (ii = 3; ii--; ) |
| 414 |
ftp->rI2_eJ2[ii] = ftp->I2*ftp->r_i[ii] + J2*ftp->e_i[ii]; |
| 415 |
ftp->valid++; |
| 416 |
} |
| 417 |
|
| 418 |
|
| 419 |
/* Compose 3x3 matrix from two vectors */ |
| 420 |
static void |
| 421 |
compose_matrix(FVECT mat[3], FVECT va, FVECT vb) |
| 422 |
{ |
| 423 |
mat[0][0] = 2.0*va[0]*vb[0]; |
| 424 |
mat[1][1] = 2.0*va[1]*vb[1]; |
| 425 |
mat[2][2] = 2.0*va[2]*vb[2]; |
| 426 |
mat[0][1] = mat[1][0] = va[0]*vb[1] + va[1]*vb[0]; |
| 427 |
mat[0][2] = mat[2][0] = va[0]*vb[2] + va[2]*vb[0]; |
| 428 |
mat[1][2] = mat[2][1] = va[1]*vb[2] + va[2]*vb[1]; |
| 429 |
} |
| 430 |
|
| 431 |
|
| 432 |
/* Compute partial 3x3 Hessian matrix for edge */ |
| 433 |
static void |
| 434 |
comp_hessian(FVECT hess[3], FFTRI *ftp, FVECT nrm) |
| 435 |
{ |
| 436 |
FVECT ncp; |
| 437 |
FVECT m1[3], m2[3], m3[3], m4[3]; |
| 438 |
double d1, d2, d3, d4; |
| 439 |
double I3, J3, K3; |
| 440 |
int i, j; |
| 441 |
|
| 442 |
if (!ftp->valid) { /* preemptive test */ |
| 443 |
memset(hess, 0, sizeof(FVECT)*3); |
| 444 |
return; |
| 445 |
} |
| 446 |
/* compute intermediate coefficients */ |
| 447 |
d1 = 1.0/DOT(ftp->r_i,ftp->r_i); |
| 448 |
d2 = 1.0/DOT(ftp->r_i1,ftp->r_i1); |
| 449 |
d3 = 1.0/DOT(ftp->e_i,ftp->e_i); |
| 450 |
d4 = DOT(ftp->e_i, ftp->r_i); |
| 451 |
I3 = ( DOT(ftp->e_i, ftp->r_i1)*d2*d2 - d4*d1*d1 + 3.0/d3*ftp->I2 ) |
| 452 |
/ ( 4.0*DOT(ftp->rcp,ftp->rcp) ); |
| 453 |
J3 = 0.25*d3*(d1*d1 - d2*d2) - d4*d3*I3; |
| 454 |
K3 = d3*(ftp->I2 - I3/d1 - 2.0*d4*J3); |
| 455 |
/* intermediate matrices */ |
| 456 |
VCROSS(ncp, nrm, ftp->e_i); |
| 457 |
compose_matrix(m1, ncp, ftp->rI2_eJ2); |
| 458 |
compose_matrix(m2, ftp->r_i, ftp->r_i); |
| 459 |
compose_matrix(m3, ftp->e_i, ftp->e_i); |
| 460 |
compose_matrix(m4, ftp->r_i, ftp->e_i); |
| 461 |
d1 = DOT(nrm, ftp->rcp); |
| 462 |
d2 = -d1*ftp->I2; |
| 463 |
d1 *= 2.0; |
| 464 |
for (i = 3; i--; ) /* final matrix sum */ |
| 465 |
for (j = 3; j--; ) { |
| 466 |
hess[i][j] = m1[i][j] + d1*( I3*m2[i][j] + K3*m3[i][j] + |
| 467 |
2.0*J3*m4[i][j] ); |
| 468 |
hess[i][j] += d2*(i==j); |
| 469 |
hess[i][j] *= -1.0/PI; |
| 470 |
} |
| 471 |
} |
| 472 |
|
| 473 |
|
| 474 |
/* Reverse hessian calculation result for edge in other direction */ |
| 475 |
static void |
| 476 |
rev_hessian(FVECT hess[3]) |
| 477 |
{ |
| 478 |
int i; |
| 479 |
|
| 480 |
for (i = 3; i--; ) { |
| 481 |
hess[i][0] = -hess[i][0]; |
| 482 |
hess[i][1] = -hess[i][1]; |
| 483 |
hess[i][2] = -hess[i][2]; |
| 484 |
} |
| 485 |
} |
| 486 |
|
| 487 |
|
| 488 |
/* Add to radiometric Hessian from the given triangle */ |
| 489 |
static void |
| 490 |
add2hessian(FVECT hess[3], FVECT ehess1[3], |
| 491 |
FVECT ehess2[3], FVECT ehess3[3], double v) |
| 492 |
{ |
| 493 |
int i, j; |
| 494 |
|
| 495 |
for (i = 3; i--; ) |
| 496 |
for (j = 3; j--; ) |
| 497 |
hess[i][j] += v*( ehess1[i][j] + ehess2[i][j] + ehess3[i][j] ); |
| 498 |
} |
| 499 |
|
| 500 |
|
| 501 |
/* Compute partial displacement form factor gradient for edge */ |
| 502 |
static void |
| 503 |
comp_gradient(FVECT grad, FFTRI *ftp, FVECT nrm) |
| 504 |
{ |
| 505 |
FVECT ncp; |
| 506 |
double f1; |
| 507 |
int i; |
| 508 |
|
| 509 |
if (!ftp->valid) { /* preemptive test */ |
| 510 |
memset(grad, 0, sizeof(FVECT)); |
| 511 |
return; |
| 512 |
} |
| 513 |
f1 = 2.0*DOT(nrm, ftp->rcp); |
| 514 |
VCROSS(ncp, nrm, ftp->e_i); |
| 515 |
for (i = 3; i--; ) |
| 516 |
grad[i] = (0.5/PI)*( ftp->I1*ncp[i] + f1*ftp->rI2_eJ2[i] ); |
| 517 |
} |
| 518 |
|
| 519 |
|
| 520 |
/* Reverse gradient calculation result for edge in other direction */ |
| 521 |
static void |
| 522 |
rev_gradient(FVECT grad) |
| 523 |
{ |
| 524 |
grad[0] = -grad[0]; |
| 525 |
grad[1] = -grad[1]; |
| 526 |
grad[2] = -grad[2]; |
| 527 |
} |
| 528 |
|
| 529 |
|
| 530 |
/* Add to displacement gradient from the given triangle */ |
| 531 |
static void |
| 532 |
add2gradient(FVECT grad, FVECT egrad1, FVECT egrad2, FVECT egrad3, double v) |
| 533 |
{ |
| 534 |
int i; |
| 535 |
|
| 536 |
for (i = 3; i--; ) |
| 537 |
grad[i] += v*( egrad1[i] + egrad2[i] + egrad3[i] ); |
| 538 |
} |
| 539 |
|
| 540 |
|
| 541 |
/* Compute anisotropic radii and eigenvector directions */ |
| 542 |
static int |
| 543 |
eigenvectors(FVECT uv[2], float ra[2], FVECT hessian[3]) |
| 544 |
{ |
| 545 |
double hess2[2][2]; |
| 546 |
FVECT a, b; |
| 547 |
double evalue[2], slope1, xmag1; |
| 548 |
int i; |
| 549 |
/* project Hessian to sample plane */ |
| 550 |
for (i = 3; i--; ) { |
| 551 |
a[i] = DOT(hessian[i], uv[0]); |
| 552 |
b[i] = DOT(hessian[i], uv[1]); |
| 553 |
} |
| 554 |
hess2[0][0] = DOT(uv[0], a); |
| 555 |
hess2[0][1] = DOT(uv[0], b); |
| 556 |
hess2[1][0] = DOT(uv[1], a); |
| 557 |
hess2[1][1] = DOT(uv[1], b); |
| 558 |
/* compute eigenvalue(s) */ |
| 559 |
i = quadratic(evalue, 1.0, -hess2[0][0]-hess2[1][1], |
| 560 |
hess2[0][0]*hess2[1][1]-hess2[0][1]*hess2[1][0]); |
| 561 |
if (i == 1) /* double-root (circle) */ |
| 562 |
evalue[1] = evalue[0]; |
| 563 |
if (!i || ((evalue[0] = fabs(evalue[0])) <= FTINY*FTINY) | |
| 564 |
((evalue[1] = fabs(evalue[1])) <= FTINY*FTINY) ) |
| 565 |
error(INTERNAL, "bad eigenvalue calculation"); |
| 566 |
|
| 567 |
if (evalue[0] > evalue[1]) { |
| 568 |
ra[0] = sqrt(sqrt(4.0/evalue[0])); |
| 569 |
ra[1] = sqrt(sqrt(4.0/evalue[1])); |
| 570 |
slope1 = evalue[1]; |
| 571 |
} else { |
| 572 |
ra[0] = sqrt(sqrt(4.0/evalue[1])); |
| 573 |
ra[1] = sqrt(sqrt(4.0/evalue[0])); |
| 574 |
slope1 = evalue[0]; |
| 575 |
} |
| 576 |
/* compute unit eigenvectors */ |
| 577 |
if (fabs(hess2[0][1]) <= FTINY) |
| 578 |
return; /* uv OK as is */ |
| 579 |
slope1 = (slope1 - hess2[0][0]) / hess2[0][1]; |
| 580 |
xmag1 = sqrt(1.0/(1.0 + slope1*slope1)); |
| 581 |
for (i = 3; i--; ) { |
| 582 |
b[i] = xmag1*uv[0][i] + slope1*xmag1*uv[1][i]; |
| 583 |
a[i] = slope1*xmag1*uv[0][i] - xmag1*uv[1][i]; |
| 584 |
} |
| 585 |
VCOPY(uv[0], a); |
| 586 |
VCOPY(uv[1], b); |
| 587 |
} |
| 588 |
|
| 589 |
|
| 590 |
static void |
| 591 |
ambHessian( /* anisotropic radii & pos. gradient */ |
| 592 |
AMBHEMI *hp, |
| 593 |
FVECT uv[2], /* returned */ |
| 594 |
float ra[2], /* returned (optional) */ |
| 595 |
float pg[2] /* returned (optional) */ |
| 596 |
) |
| 597 |
{ |
| 598 |
static char memerrmsg[] = "out of memory in ambHessian()"; |
| 599 |
FVECT (*hessrow)[3] = NULL; |
| 600 |
FVECT *gradrow = NULL; |
| 601 |
uby8 *vflags; |
| 602 |
FVECT hessian[3]; |
| 603 |
FVECT gradient; |
| 604 |
FFTRI fftr; |
| 605 |
int i, j; |
| 606 |
/* be sure to assign unit vectors */ |
| 607 |
VCOPY(uv[0], hp->ux); |
| 608 |
VCOPY(uv[1], hp->uy); |
| 609 |
/* clock-wise vertex traversal from sample POV */ |
| 610 |
if (ra != NULL) { /* initialize Hessian row buffer */ |
| 611 |
hessrow = (FVECT (*)[3])malloc(sizeof(FVECT)*3*(hp->ns-1)); |
| 612 |
if (hessrow == NULL) |
| 613 |
error(SYSTEM, memerrmsg); |
| 614 |
memset(hessian, 0, sizeof(hessian)); |
| 615 |
} else if (pg == NULL) /* bogus call? */ |
| 616 |
return; |
| 617 |
if (pg != NULL) { /* initialize form factor row buffer */ |
| 618 |
gradrow = (FVECT *)malloc(sizeof(FVECT)*(hp->ns-1)); |
| 619 |
if (gradrow == NULL) |
| 620 |
error(SYSTEM, memerrmsg); |
| 621 |
memset(gradient, 0, sizeof(gradient)); |
| 622 |
} |
| 623 |
/* get vertex position flags */ |
| 624 |
vflags = vertex_flags(hp); |
| 625 |
/* compute first row of edges */ |
| 626 |
for (j = 0; j < hp->ns-1; j++) { |
| 627 |
comp_fftri(&fftr, hp, 0, j, VDB_X, vflags); |
| 628 |
if (hessrow != NULL) |
| 629 |
comp_hessian(hessrow[j], &fftr, hp->rp->ron); |
| 630 |
if (gradrow != NULL) |
| 631 |
comp_gradient(gradrow[j], &fftr, hp->rp->ron); |
| 632 |
} |
| 633 |
/* sum each row of triangles */ |
| 634 |
for (i = 0; i < hp->ns-1; i++) { |
| 635 |
FVECT hesscol[3]; /* compute first vertical edge */ |
| 636 |
FVECT gradcol; |
| 637 |
comp_fftri(&fftr, hp, i, 0, VDB_Y, vflags); |
| 638 |
if (hessrow != NULL) |
| 639 |
comp_hessian(hesscol, &fftr, hp->rp->ron); |
| 640 |
if (gradrow != NULL) |
| 641 |
comp_gradient(gradcol, &fftr, hp->rp->ron); |
| 642 |
for (j = 0; j < hp->ns-1; j++) { |
| 643 |
FVECT hessdia[3]; /* compute triangle contributions */ |
| 644 |
FVECT graddia; |
| 645 |
double backg; |
| 646 |
backg = back_ambval(hp, i, j, VDB_X, VDB_Y, vflags); |
| 647 |
/* diagonal (inner) edge */ |
| 648 |
comp_fftri(&fftr, hp, i, j+1, VDB_xY, vflags); |
| 649 |
if (hessrow != NULL) { |
| 650 |
comp_hessian(hessdia, &fftr, hp->rp->ron); |
| 651 |
rev_hessian(hesscol); |
| 652 |
add2hessian(hessian, hessrow[j], hessdia, hesscol, backg); |
| 653 |
} |
| 654 |
if (gradrow != NULL) { |
| 655 |
comp_gradient(graddia, &fftr, hp->rp->ron); |
| 656 |
rev_gradient(gradcol); |
| 657 |
add2gradient(gradient, gradrow[j], graddia, gradcol, backg); |
| 658 |
} |
| 659 |
/* initialize edge in next row */ |
| 660 |
comp_fftri(&fftr, hp, i+1, j+1, VDB_x, vflags); |
| 661 |
if (hessrow != NULL) |
| 662 |
comp_hessian(hessrow[j], &fftr, hp->rp->ron); |
| 663 |
if (gradrow != NULL) |
| 664 |
comp_gradient(gradrow[j], &fftr, hp->rp->ron); |
| 665 |
/* new column edge & paired triangle */ |
| 666 |
backg = back_ambval(hp, i+1, j+1, VDB_x, VDB_y, vflags); |
| 667 |
comp_fftri(&fftr, hp, i, j+1, VDB_Y, vflags); |
| 668 |
if (hessrow != NULL) { |
| 669 |
comp_hessian(hesscol, &fftr, hp->rp->ron); |
| 670 |
rev_hessian(hessdia); |
| 671 |
add2hessian(hessian, hessrow[j], hessdia, hesscol, backg); |
| 672 |
if (i < hp->ns-2) |
| 673 |
rev_hessian(hessrow[j]); |
| 674 |
} |
| 675 |
if (gradrow != NULL) { |
| 676 |
comp_gradient(gradcol, &fftr, hp->rp->ron); |
| 677 |
rev_gradient(graddia); |
| 678 |
add2gradient(gradient, gradrow[j], graddia, gradcol, backg); |
| 679 |
if (i < hp->ns-2) |
| 680 |
rev_gradient(gradrow[j]); |
| 681 |
} |
| 682 |
} |
| 683 |
} |
| 684 |
/* release row buffers */ |
| 685 |
if (hessrow != NULL) free(hessrow); |
| 686 |
if (gradrow != NULL) free(gradrow); |
| 687 |
free(vflags); |
| 688 |
|
| 689 |
if (ra != NULL) /* extract eigenvectors & radii */ |
| 690 |
eigenvectors(uv, ra, hessian); |
| 691 |
if (pg != NULL) { /* tangential position gradient */ |
| 692 |
pg[0] = DOT(gradient, uv[0]); |
| 693 |
pg[1] = DOT(gradient, uv[1]); |
| 694 |
} |
| 695 |
} |
| 696 |
|
| 697 |
|
| 698 |
/* Compute direction gradient from a hemispherical sampling */ |
| 699 |
static void |
| 700 |
ambdirgrad(AMBHEMI *hp, FVECT uv[2], float dg[2]) |
| 701 |
{ |
| 702 |
AMBSAMP *ap; |
| 703 |
double dgsum[2]; |
| 704 |
int n; |
| 705 |
FVECT vd; |
| 706 |
double gfact; |
| 707 |
|
| 708 |
dgsum[0] = dgsum[1] = 0.0; /* sum values times -tan(theta) */ |
| 709 |
for (ap = hp->sa, n = hp->ns*hp->ns; n--; ap++) { |
| 710 |
/* use vector for azimuth + 90deg */ |
| 711 |
VSUB(vd, ap->p, hp->rp->rop); |
| 712 |
/* brightness over cosine factor */ |
| 713 |
gfact = colval(ap->v,CIEY) / DOT(hp->rp->ron, vd); |
| 714 |
/* sine = proj_radius/vd_length */ |
| 715 |
dgsum[0] -= DOT(uv[1], vd) * gfact; |
| 716 |
dgsum[1] += DOT(uv[0], vd) * gfact; |
| 717 |
} |
| 718 |
dg[0] = dgsum[0] / (hp->ns*hp->ns); |
| 719 |
dg[1] = dgsum[1] / (hp->ns*hp->ns); |
| 720 |
} |
| 721 |
|
| 722 |
|
| 723 |
/* Make sure radii don't extend beyond what we see in our periphery */ |
| 724 |
static int |
| 725 |
hem_radii(AMBHEMI *hp, FVECT uv[2], float ra[2]) |
| 726 |
{ |
| 727 |
#ifdef AHEM_MARG |
| 728 |
#define MAXDACCUM 47 |
| 729 |
const double hemarg = AHEM_MARG*ambacc; /* hem margin */ |
| 730 |
float radivisor2[MAXDACCUM+1]; |
| 731 |
int i, j, k = hp->ns/10 + 1; /* around 5%ile */ |
| 732 |
const int n2accum = (k < MAXDACCUM) ? k : MAXDACCUM ; |
| 733 |
int na = 0; |
| 734 |
double d; |
| 735 |
/* circle around perimeter */ |
| 736 |
for (i = 0; i < hp->ns; i++) |
| 737 |
for (j = 0; j < hp->ns; j += !i|(i==hp->ns-1) ? 1 : hp->ns-1) { |
| 738 |
AMBSAMP *ap = &ambsam(hp,i,j); |
| 739 |
double radiv2 = 0; |
| 740 |
FVECT vec; |
| 741 |
if (ap->d <= FTINY) |
| 742 |
continue; |
| 743 |
VSUB(vec, ap->p, hp->rp->rop); |
| 744 |
for (k = 2; k--; ) { |
| 745 |
d = ap->d * DOT(vec, uv[k]) * ra[k]; |
| 746 |
radiv2 += d*d; |
| 747 |
} |
| 748 |
radiv2 *= hemarg*hemarg * ap->d * ap->d; |
| 749 |
if (radiv2 <= 1.0) |
| 750 |
continue; |
| 751 |
/* insert in percentile list */ |
| 752 |
for (k = na; k && radiv2 > radivisor2[k-1]; k--) |
| 753 |
radivisor2[k] = radivisor2[k-1]; |
| 754 |
radivisor2[k] = radiv2; |
| 755 |
na += (na < n2accum); |
| 756 |
} |
| 757 |
if (na < n2accum) /* current radii are OK? */ |
| 758 |
return(0); |
| 759 |
/* else apply divisor */ |
| 760 |
d = 1.0/sqrt(radivisor2[na-1]); |
| 761 |
ra[0] *= d; |
| 762 |
ra[1] *= d; |
| 763 |
return(1); |
| 764 |
#undef MAXDACCUM |
| 765 |
#else |
| 766 |
return(0); |
| 767 |
#endif |
| 768 |
} |
| 769 |
|
| 770 |
|
| 771 |
int |
| 772 |
doambient( /* compute ambient component */ |
| 773 |
COLOR rcol, /* input/output color */ |
| 774 |
RAY *r, |
| 775 |
double wt, |
| 776 |
FVECT uv[2], /* returned (optional) */ |
| 777 |
float ra[2], /* returned (optional) */ |
| 778 |
float pg[2], /* returned (optional) */ |
| 779 |
float dg[2] /* returned (optional) */ |
| 780 |
) |
| 781 |
{ |
| 782 |
AMBHEMI *hp = inithemi(rcol, r, wt); |
| 783 |
int cnt; |
| 784 |
FVECT my_uv[2]; |
| 785 |
double d, K, acol[3]; |
| 786 |
AMBSAMP *ap; |
| 787 |
int i, j; |
| 788 |
/* check/initialize */ |
| 789 |
if (hp == NULL) |
| 790 |
return(0); |
| 791 |
if (uv != NULL) |
| 792 |
memset(uv, 0, sizeof(FVECT)*2); |
| 793 |
if (ra != NULL) |
| 794 |
ra[0] = ra[1] = 0.0; |
| 795 |
if (pg != NULL) |
| 796 |
pg[0] = pg[1] = 0.0; |
| 797 |
if (dg != NULL) |
| 798 |
dg[0] = dg[1] = 0.0; |
| 799 |
/* sample the hemisphere */ |
| 800 |
acol[0] = acol[1] = acol[2] = 0.0; |
| 801 |
cnt = 0; |
| 802 |
for (i = hp->ns; i--; ) |
| 803 |
for (j = hp->ns; j--; ) |
| 804 |
if ((ap = ambsample(hp, i, j)) != NULL) { |
| 805 |
addcolor(acol, ap->v); |
| 806 |
++cnt; |
| 807 |
} |
| 808 |
if (!cnt) { |
| 809 |
setcolor(rcol, 0.0, 0.0, 0.0); |
| 810 |
free(hp); |
| 811 |
return(0); /* no valid samples */ |
| 812 |
} |
| 813 |
if (cnt < hp->ns*hp->ns) { /* incomplete sampling? */ |
| 814 |
copycolor(rcol, acol); |
| 815 |
free(hp); |
| 816 |
return(-1); /* return value w/o Hessian */ |
| 817 |
} |
| 818 |
cnt = ambssamp*wt + 0.5; /* perform super-sampling? */ |
| 819 |
if (cnt > 0) |
| 820 |
ambsupersamp(acol, hp, cnt); |
| 821 |
copycolor(rcol, acol); /* final indirect irradiance/PI */ |
| 822 |
if ((ra == NULL) & (pg == NULL) & (dg == NULL)) { |
| 823 |
free(hp); |
| 824 |
return(-1); /* no radius or gradient calc. */ |
| 825 |
} |
| 826 |
if ((d = bright(acol)) > FTINY) { /* normalize Y values */ |
| 827 |
d = 0.99*(hp->ns*hp->ns)/d; |
| 828 |
K = 0.01; |
| 829 |
} else { /* or fall back on geometric Hessian */ |
| 830 |
K = 1.0; |
| 831 |
pg = NULL; |
| 832 |
dg = NULL; |
| 833 |
} |
| 834 |
ap = hp->sa; /* relative Y channel from here on... */ |
| 835 |
for (i = hp->ns*hp->ns; i--; ap++) |
| 836 |
colval(ap->v,CIEY) = bright(ap->v)*d + K; |
| 837 |
|
| 838 |
if (uv == NULL) /* make sure we have axis pointers */ |
| 839 |
uv = my_uv; |
| 840 |
/* compute radii & pos. gradient */ |
| 841 |
ambHessian(hp, uv, ra, pg); |
| 842 |
|
| 843 |
if (dg != NULL) /* compute direction gradient */ |
| 844 |
ambdirgrad(hp, uv, dg); |
| 845 |
|
| 846 |
if (ra != NULL) { /* scale/clamp radii */ |
| 847 |
if (pg != NULL) { |
| 848 |
if (ra[0]*(d = fabs(pg[0])) > 1.0) |
| 849 |
ra[0] = 1.0/d; |
| 850 |
if (ra[1]*(d = fabs(pg[1])) > 1.0) |
| 851 |
ra[1] = 1.0/d; |
| 852 |
if (ra[0] > ra[1]) |
| 853 |
ra[0] = ra[1]; |
| 854 |
} |
| 855 |
hem_radii(hp, uv, ra); |
| 856 |
if (ra[0] < minarad) { |
| 857 |
ra[0] = minarad; |
| 858 |
if (ra[1] < minarad) |
| 859 |
ra[1] = minarad; |
| 860 |
} |
| 861 |
ra[0] *= d = 1.0/sqrt(sqrt(wt)); |
| 862 |
if ((ra[1] *= d) > 2.0*ra[0]) |
| 863 |
ra[1] = 2.0*ra[0]; |
| 864 |
if (ra[1] > maxarad) { |
| 865 |
ra[1] = maxarad; |
| 866 |
if (ra[0] > maxarad) |
| 867 |
ra[0] = maxarad; |
| 868 |
} |
| 869 |
if (pg != NULL) { /* cap gradient if necessary */ |
| 870 |
d = pg[0]*pg[0]*ra[0]*ra[0] + pg[1]*pg[1]*ra[1]*ra[1]; |
| 871 |
if (d > 1.0) { |
| 872 |
d = 1.0/sqrt(d); |
| 873 |
pg[0] *= d; |
| 874 |
pg[1] *= d; |
| 875 |
} |
| 876 |
} |
| 877 |
} |
| 878 |
free(hp); /* clean up and return */ |
| 879 |
return(1); |
| 880 |
} |
| 881 |
|
| 882 |
|
| 883 |
#else /* ! NEWAMB */ |
| 884 |
|
| 885 |
|
| 886 |
void |
| 887 |
inithemi( /* initialize sampling hemisphere */ |
| 888 |
AMBHEMI *hp, |
| 889 |
COLOR ac, |
| 890 |
RAY *r, |
| 891 |
double wt |
| 892 |
) |
| 893 |
{ |
| 894 |
double d; |
| 895 |
int i; |
| 896 |
/* set number of divisions */ |
| 897 |
if (ambacc <= FTINY && |
| 898 |
wt > (d = 0.8*intens(ac)*r->rweight/(ambdiv*minweight))) |
| 899 |
wt = d; /* avoid ray termination */ |
| 900 |
hp->nt = sqrt(ambdiv * wt / PI) + 0.5; |
| 901 |
i = ambacc > FTINY ? 3 : 1; /* minimum number of samples */ |
| 902 |
if (hp->nt < i) |
| 903 |
hp->nt = i; |
| 904 |
hp->np = PI * hp->nt + 0.5; |
| 905 |
/* set number of super-samples */ |
| 906 |
hp->ns = ambssamp * wt + 0.5; |
| 907 |
/* assign coefficient */ |
| 908 |
copycolor(hp->acoef, ac); |
| 909 |
d = 1.0/(hp->nt*hp->np); |
| 910 |
scalecolor(hp->acoef, d); |
| 911 |
/* make axes */ |
| 912 |
VCOPY(hp->uz, r->ron); |
| 913 |
hp->uy[0] = hp->uy[1] = hp->uy[2] = 0.0; |
| 914 |
for (i = 0; i < 3; i++) |
| 915 |
if (hp->uz[i] < 0.6 && hp->uz[i] > -0.6) |
| 916 |
break; |
| 917 |
if (i >= 3) |
| 918 |
error(CONSISTENCY, "bad ray direction in inithemi"); |
| 919 |
hp->uy[i] = 1.0; |
| 920 |
fcross(hp->ux, hp->uy, hp->uz); |
| 921 |
normalize(hp->ux); |
| 922 |
fcross(hp->uy, hp->uz, hp->ux); |
| 923 |
} |
| 924 |
|
| 925 |
|
| 926 |
int |
| 927 |
divsample( /* sample a division */ |
| 928 |
AMBSAMP *dp, |
| 929 |
AMBHEMI *h, |
| 930 |
RAY *r |
| 931 |
) |
| 932 |
{ |
| 933 |
RAY ar; |
| 934 |
int hlist[3]; |
| 935 |
double spt[2]; |
| 936 |
double xd, yd, zd; |
| 937 |
double b2; |
| 938 |
double phi; |
| 939 |
int i; |
| 940 |
/* ambient coefficient for weight */ |
| 941 |
if (ambacc > FTINY) |
| 942 |
setcolor(ar.rcoef, AVGREFL, AVGREFL, AVGREFL); |
| 943 |
else |
| 944 |
copycolor(ar.rcoef, h->acoef); |
| 945 |
if (rayorigin(&ar, AMBIENT, r, ar.rcoef) < 0) |
| 946 |
return(-1); |
| 947 |
if (ambacc > FTINY) { |
| 948 |
multcolor(ar.rcoef, h->acoef); |
| 949 |
scalecolor(ar.rcoef, 1./AVGREFL); |
| 950 |
} |
| 951 |
hlist[0] = r->rno; |
| 952 |
hlist[1] = dp->t; |
| 953 |
hlist[2] = dp->p; |
| 954 |
multisamp(spt, 2, urand(ilhash(hlist,3)+dp->n)); |
| 955 |
zd = sqrt((dp->t + spt[0])/h->nt); |
| 956 |
phi = 2.0*PI * (dp->p + spt[1])/h->np; |
| 957 |
xd = tcos(phi) * zd; |
| 958 |
yd = tsin(phi) * zd; |
| 959 |
zd = sqrt(1.0 - zd*zd); |
| 960 |
for (i = 0; i < 3; i++) |
| 961 |
ar.rdir[i] = xd*h->ux[i] + |
| 962 |
yd*h->uy[i] + |
| 963 |
zd*h->uz[i]; |
| 964 |
checknorm(ar.rdir); |
| 965 |
dimlist[ndims++] = dp->t*h->np + dp->p + 90171; |
| 966 |
rayvalue(&ar); |
| 967 |
ndims--; |
| 968 |
multcolor(ar.rcol, ar.rcoef); /* apply coefficient */ |
| 969 |
addcolor(dp->v, ar.rcol); |
| 970 |
/* use rt to improve gradient calc */ |
| 971 |
if (ar.rt > FTINY && ar.rt < FHUGE) |
| 972 |
dp->r += 1.0/ar.rt; |
| 973 |
/* (re)initialize error */ |
| 974 |
if (dp->n++) { |
| 975 |
b2 = bright(dp->v)/dp->n - bright(ar.rcol); |
| 976 |
b2 = b2*b2 + dp->k*((dp->n-1)*(dp->n-1)); |
| 977 |
dp->k = b2/(dp->n*dp->n); |
| 978 |
} else |
| 979 |
dp->k = 0.0; |
| 980 |
return(0); |
| 981 |
} |
| 982 |
|
| 983 |
|
| 984 |
static int |
| 985 |
ambcmp( /* decreasing order */ |
| 986 |
const void *p1, |
| 987 |
const void *p2 |
| 988 |
) |
| 989 |
{ |
| 990 |
const AMBSAMP *d1 = (const AMBSAMP *)p1; |
| 991 |
const AMBSAMP *d2 = (const AMBSAMP *)p2; |
| 992 |
|
| 993 |
if (d1->k < d2->k) |
| 994 |
return(1); |
| 995 |
if (d1->k > d2->k) |
| 996 |
return(-1); |
| 997 |
return(0); |
| 998 |
} |
| 999 |
|
| 1000 |
|
| 1001 |
static int |
| 1002 |
ambnorm( /* standard order */ |
| 1003 |
const void *p1, |
| 1004 |
const void *p2 |
| 1005 |
) |
| 1006 |
{ |
| 1007 |
const AMBSAMP *d1 = (const AMBSAMP *)p1; |
| 1008 |
const AMBSAMP *d2 = (const AMBSAMP *)p2; |
| 1009 |
int c; |
| 1010 |
|
| 1011 |
if ( (c = d1->t - d2->t) ) |
| 1012 |
return(c); |
| 1013 |
return(d1->p - d2->p); |
| 1014 |
} |
| 1015 |
|
| 1016 |
|
| 1017 |
double |
| 1018 |
doambient( /* compute ambient component */ |
| 1019 |
COLOR rcol, |
| 1020 |
RAY *r, |
| 1021 |
double wt, |
| 1022 |
FVECT pg, |
| 1023 |
FVECT dg |
| 1024 |
) |
| 1025 |
{ |
| 1026 |
double b, d=0; |
| 1027 |
AMBHEMI hemi; |
| 1028 |
AMBSAMP *div; |
| 1029 |
AMBSAMP dnew; |
| 1030 |
double acol[3]; |
| 1031 |
AMBSAMP *dp; |
| 1032 |
double arad; |
| 1033 |
int divcnt; |
| 1034 |
int i, j; |
| 1035 |
/* initialize hemisphere */ |
| 1036 |
inithemi(&hemi, rcol, r, wt); |
| 1037 |
divcnt = hemi.nt * hemi.np; |
| 1038 |
/* initialize */ |
| 1039 |
if (pg != NULL) |
| 1040 |
pg[0] = pg[1] = pg[2] = 0.0; |
| 1041 |
if (dg != NULL) |
| 1042 |
dg[0] = dg[1] = dg[2] = 0.0; |
| 1043 |
setcolor(rcol, 0.0, 0.0, 0.0); |
| 1044 |
if (divcnt == 0) |
| 1045 |
return(0.0); |
| 1046 |
/* allocate super-samples */ |
| 1047 |
if (hemi.ns > 0 || pg != NULL || dg != NULL) { |
| 1048 |
div = (AMBSAMP *)malloc(divcnt*sizeof(AMBSAMP)); |
| 1049 |
if (div == NULL) |
| 1050 |
error(SYSTEM, "out of memory in doambient"); |
| 1051 |
} else |
| 1052 |
div = NULL; |
| 1053 |
/* sample the divisions */ |
| 1054 |
arad = 0.0; |
| 1055 |
acol[0] = acol[1] = acol[2] = 0.0; |
| 1056 |
if ((dp = div) == NULL) |
| 1057 |
dp = &dnew; |
| 1058 |
divcnt = 0; |
| 1059 |
for (i = 0; i < hemi.nt; i++) |
| 1060 |
for (j = 0; j < hemi.np; j++) { |
| 1061 |
dp->t = i; dp->p = j; |
| 1062 |
setcolor(dp->v, 0.0, 0.0, 0.0); |
| 1063 |
dp->r = 0.0; |
| 1064 |
dp->n = 0; |
| 1065 |
if (divsample(dp, &hemi, r) < 0) { |
| 1066 |
if (div != NULL) |
| 1067 |
dp++; |
| 1068 |
continue; |
| 1069 |
} |
| 1070 |
arad += dp->r; |
| 1071 |
divcnt++; |
| 1072 |
if (div != NULL) |
| 1073 |
dp++; |
| 1074 |
else |
| 1075 |
addcolor(acol, dp->v); |
| 1076 |
} |
| 1077 |
if (!divcnt) { |
| 1078 |
if (div != NULL) |
| 1079 |
free((void *)div); |
| 1080 |
return(0.0); /* no samples taken */ |
| 1081 |
} |
| 1082 |
if (divcnt < hemi.nt*hemi.np) { |
| 1083 |
pg = dg = NULL; /* incomplete sampling */ |
| 1084 |
hemi.ns = 0; |
| 1085 |
} else if (arad > FTINY && divcnt/arad < minarad) { |
| 1086 |
hemi.ns = 0; /* close enough */ |
| 1087 |
} else if (hemi.ns > 0) { /* else perform super-sampling? */ |
| 1088 |
comperrs(div, &hemi); /* compute errors */ |
| 1089 |
qsort(div, divcnt, sizeof(AMBSAMP), ambcmp); /* sort divs */ |
| 1090 |
/* super-sample */ |
| 1091 |
for (i = hemi.ns; i > 0; i--) { |
| 1092 |
dnew = *div; |
| 1093 |
if (divsample(&dnew, &hemi, r) < 0) { |
| 1094 |
dp++; |
| 1095 |
continue; |
| 1096 |
} |
| 1097 |
dp = div; /* reinsert */ |
| 1098 |
j = divcnt < i ? divcnt : i; |
| 1099 |
while (--j > 0 && dnew.k < dp[1].k) { |
| 1100 |
*dp = *(dp+1); |
| 1101 |
dp++; |
| 1102 |
} |
| 1103 |
*dp = dnew; |
| 1104 |
} |
| 1105 |
if (pg != NULL || dg != NULL) /* restore order */ |
| 1106 |
qsort(div, divcnt, sizeof(AMBSAMP), ambnorm); |
| 1107 |
} |
| 1108 |
/* compute returned values */ |
| 1109 |
if (div != NULL) { |
| 1110 |
arad = 0.0; /* note: divcnt may be < nt*np */ |
| 1111 |
for (i = hemi.nt*hemi.np, dp = div; i-- > 0; dp++) { |
| 1112 |
arad += dp->r; |
| 1113 |
if (dp->n > 1) { |
| 1114 |
b = 1.0/dp->n; |
| 1115 |
scalecolor(dp->v, b); |
| 1116 |
dp->r *= b; |
| 1117 |
dp->n = 1; |
| 1118 |
} |
| 1119 |
addcolor(acol, dp->v); |
| 1120 |
} |
| 1121 |
b = bright(acol); |
| 1122 |
if (b > FTINY) { |
| 1123 |
b = 1.0/b; /* compute & normalize gradient(s) */ |
| 1124 |
if (pg != NULL) { |
| 1125 |
posgradient(pg, div, &hemi); |
| 1126 |
for (i = 0; i < 3; i++) |
| 1127 |
pg[i] *= b; |
| 1128 |
} |
| 1129 |
if (dg != NULL) { |
| 1130 |
dirgradient(dg, div, &hemi); |
| 1131 |
for (i = 0; i < 3; i++) |
| 1132 |
dg[i] *= b; |
| 1133 |
} |
| 1134 |
} |
| 1135 |
free((void *)div); |
| 1136 |
} |
| 1137 |
copycolor(rcol, acol); |
| 1138 |
if (arad <= FTINY) |
| 1139 |
arad = maxarad; |
| 1140 |
else |
| 1141 |
arad = (divcnt+hemi.ns)/arad; |
| 1142 |
if (pg != NULL) { /* reduce radius if gradient large */ |
| 1143 |
d = DOT(pg,pg); |
| 1144 |
if (d*arad*arad > 1.0) |
| 1145 |
arad = 1.0/sqrt(d); |
| 1146 |
} |
| 1147 |
if (arad < minarad) { |
| 1148 |
arad = minarad; |
| 1149 |
if (pg != NULL && d*arad*arad > 1.0) { /* cap gradient */ |
| 1150 |
d = 1.0/arad/sqrt(d); |
| 1151 |
for (i = 0; i < 3; i++) |
| 1152 |
pg[i] *= d; |
| 1153 |
} |
| 1154 |
} |
| 1155 |
if ((arad /= sqrt(wt)) > maxarad) |
| 1156 |
arad = maxarad; |
| 1157 |
return(arad); |
| 1158 |
} |
| 1159 |
|
| 1160 |
|
| 1161 |
void |
| 1162 |
comperrs( /* compute initial error estimates */ |
| 1163 |
AMBSAMP *da, /* assumes standard ordering */ |
| 1164 |
AMBHEMI *hp |
| 1165 |
) |
| 1166 |
{ |
| 1167 |
double b, b2; |
| 1168 |
int i, j; |
| 1169 |
AMBSAMP *dp; |
| 1170 |
/* sum differences from neighbors */ |
| 1171 |
dp = da; |
| 1172 |
for (i = 0; i < hp->nt; i++) |
| 1173 |
for (j = 0; j < hp->np; j++) { |
| 1174 |
#ifdef DEBUG |
| 1175 |
if (dp->t != i || dp->p != j) |
| 1176 |
error(CONSISTENCY, |
| 1177 |
"division order in comperrs"); |
| 1178 |
#endif |
| 1179 |
b = bright(dp[0].v); |
| 1180 |
if (i > 0) { /* from above */ |
| 1181 |
b2 = bright(dp[-hp->np].v) - b; |
| 1182 |
b2 *= b2 * 0.25; |
| 1183 |
dp[0].k += b2; |
| 1184 |
dp[-hp->np].k += b2; |
| 1185 |
} |
| 1186 |
if (j > 0) { /* from behind */ |
| 1187 |
b2 = bright(dp[-1].v) - b; |
| 1188 |
b2 *= b2 * 0.25; |
| 1189 |
dp[0].k += b2; |
| 1190 |
dp[-1].k += b2; |
| 1191 |
} else { /* around */ |
| 1192 |
b2 = bright(dp[hp->np-1].v) - b; |
| 1193 |
b2 *= b2 * 0.25; |
| 1194 |
dp[0].k += b2; |
| 1195 |
dp[hp->np-1].k += b2; |
| 1196 |
} |
| 1197 |
dp++; |
| 1198 |
} |
| 1199 |
/* divide by number of neighbors */ |
| 1200 |
dp = da; |
| 1201 |
for (j = 0; j < hp->np; j++) /* top row */ |
| 1202 |
(dp++)->k *= 1.0/3.0; |
| 1203 |
if (hp->nt < 2) |
| 1204 |
return; |
| 1205 |
for (i = 1; i < hp->nt-1; i++) /* central region */ |
| 1206 |
for (j = 0; j < hp->np; j++) |
| 1207 |
(dp++)->k *= 0.25; |
| 1208 |
for (j = 0; j < hp->np; j++) /* bottom row */ |
| 1209 |
(dp++)->k *= 1.0/3.0; |
| 1210 |
} |
| 1211 |
|
| 1212 |
|
| 1213 |
void |
| 1214 |
posgradient( /* compute position gradient */ |
| 1215 |
FVECT gv, |
| 1216 |
AMBSAMP *da, /* assumes standard ordering */ |
| 1217 |
AMBHEMI *hp |
| 1218 |
) |
| 1219 |
{ |
| 1220 |
int i, j; |
| 1221 |
double nextsine, lastsine, b, d; |
| 1222 |
double mag0, mag1; |
| 1223 |
double phi, cosp, sinp, xd, yd; |
| 1224 |
AMBSAMP *dp; |
| 1225 |
|
| 1226 |
xd = yd = 0.0; |
| 1227 |
for (j = 0; j < hp->np; j++) { |
| 1228 |
dp = da + j; |
| 1229 |
mag0 = mag1 = 0.0; |
| 1230 |
lastsine = 0.0; |
| 1231 |
for (i = 0; i < hp->nt; i++) { |
| 1232 |
#ifdef DEBUG |
| 1233 |
if (dp->t != i || dp->p != j) |
| 1234 |
error(CONSISTENCY, |
| 1235 |
"division order in posgradient"); |
| 1236 |
#endif |
| 1237 |
b = bright(dp->v); |
| 1238 |
if (i > 0) { |
| 1239 |
d = dp[-hp->np].r; |
| 1240 |
if (dp[0].r > d) d = dp[0].r; |
| 1241 |
/* sin(t)*cos(t)^2 */ |
| 1242 |
d *= lastsine * (1.0 - (double)i/hp->nt); |
| 1243 |
mag0 += d*(b - bright(dp[-hp->np].v)); |
| 1244 |
} |
| 1245 |
nextsine = sqrt((double)(i+1)/hp->nt); |
| 1246 |
if (j > 0) { |
| 1247 |
d = dp[-1].r; |
| 1248 |
if (dp[0].r > d) d = dp[0].r; |
| 1249 |
mag1 += d * (nextsine - lastsine) * |
| 1250 |
(b - bright(dp[-1].v)); |
| 1251 |
} else { |
| 1252 |
d = dp[hp->np-1].r; |
| 1253 |
if (dp[0].r > d) d = dp[0].r; |
| 1254 |
mag1 += d * (nextsine - lastsine) * |
| 1255 |
(b - bright(dp[hp->np-1].v)); |
| 1256 |
} |
| 1257 |
dp += hp->np; |
| 1258 |
lastsine = nextsine; |
| 1259 |
} |
| 1260 |
mag0 *= 2.0*PI / hp->np; |
| 1261 |
phi = 2.0*PI * (double)j/hp->np; |
| 1262 |
cosp = tcos(phi); sinp = tsin(phi); |
| 1263 |
xd += mag0*cosp - mag1*sinp; |
| 1264 |
yd += mag0*sinp + mag1*cosp; |
| 1265 |
} |
| 1266 |
for (i = 0; i < 3; i++) |
| 1267 |
gv[i] = (xd*hp->ux[i] + yd*hp->uy[i])*(hp->nt*hp->np)/PI; |
| 1268 |
} |
| 1269 |
|
| 1270 |
|
| 1271 |
void |
| 1272 |
dirgradient( /* compute direction gradient */ |
| 1273 |
FVECT gv, |
| 1274 |
AMBSAMP *da, /* assumes standard ordering */ |
| 1275 |
AMBHEMI *hp |
| 1276 |
) |
| 1277 |
{ |
| 1278 |
int i, j; |
| 1279 |
double mag; |
| 1280 |
double phi, xd, yd; |
| 1281 |
AMBSAMP *dp; |
| 1282 |
|
| 1283 |
xd = yd = 0.0; |
| 1284 |
for (j = 0; j < hp->np; j++) { |
| 1285 |
dp = da + j; |
| 1286 |
mag = 0.0; |
| 1287 |
for (i = 0; i < hp->nt; i++) { |
| 1288 |
#ifdef DEBUG |
| 1289 |
if (dp->t != i || dp->p != j) |
| 1290 |
error(CONSISTENCY, |
| 1291 |
"division order in dirgradient"); |
| 1292 |
#endif |
| 1293 |
/* tan(t) */ |
| 1294 |
mag += bright(dp->v)/sqrt(hp->nt/(i+.5) - 1.0); |
| 1295 |
dp += hp->np; |
| 1296 |
} |
| 1297 |
phi = 2.0*PI * (j+.5)/hp->np + PI/2.0; |
| 1298 |
xd += mag * tcos(phi); |
| 1299 |
yd += mag * tsin(phi); |
| 1300 |
} |
| 1301 |
for (i = 0; i < 3; i++) |
| 1302 |
gv[i] = xd*hp->ux[i] + yd*hp->uy[i]; |
| 1303 |
} |
| 1304 |
|
| 1305 |
#endif /* ! NEWAMB */ |
