| 1 |
#ifndef lint |
| 2 |
static const char RCSid[] = "$Id: pabopto2xml.c,v 2.2 2012/08/24 20:55:28 greg Exp $"; |
| 3 |
#endif |
| 4 |
/* |
| 5 |
* Convert PAB-Opto measurements to XML format using tensor tree representation |
| 6 |
* Employs Bonneel et al. Earth Mover's Distance interpolant. |
| 7 |
* |
| 8 |
* G.Ward |
| 9 |
*/ |
| 10 |
|
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#define _USE_MATH_DEFINES |
| 12 |
#include <stdio.h> |
| 13 |
#include <stdlib.h> |
| 14 |
#include <string.h> |
| 15 |
#include <ctype.h> |
| 16 |
#include <math.h> |
| 17 |
#include "bsdf.h" |
| 18 |
|
| 19 |
#ifndef GRIDRES |
| 20 |
#define GRIDRES 200 /* max. grid resolution per side */ |
| 21 |
#endif |
| 22 |
|
| 23 |
#define RSCA 2.7 /* radius scaling factor (empirical) */ |
| 24 |
|
| 25 |
#define R2ANG(c) (((c)+.5)*(M_PI/(1<<16))) |
| 26 |
#define ANG2R(r) (int)((r)*((1<<16)/M_PI)) |
| 27 |
|
| 28 |
typedef struct { |
| 29 |
float vsum; /* BSDF sum */ |
| 30 |
unsigned short nval; /* number of values in sum */ |
| 31 |
unsigned short crad; /* radius (coded angle) */ |
| 32 |
} GRIDVAL; /* grid value */ |
| 33 |
|
| 34 |
typedef struct { |
| 35 |
float bsdf; /* lobe value at peak */ |
| 36 |
unsigned short crad; /* radius (coded angle) */ |
| 37 |
unsigned char gx, gy; /* grid position */ |
| 38 |
} RBFVAL; /* radial basis function value */ |
| 39 |
|
| 40 |
typedef struct s_rbflist { |
| 41 |
struct s_rbflist *next; /* next in our RBF list */ |
| 42 |
FVECT invec; /* incident vector direction */ |
| 43 |
int nrbf; /* number of RBFs */ |
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RBFVAL rbfa[1]; /* RBF array (extends struct) */ |
| 45 |
} RBFLIST; /* RBF representation of BSDF @ 1 incidence */ |
| 46 |
|
| 47 |
/* our loaded grid for this incident angle */ |
| 48 |
static double theta_in_deg, phi_in_deg; |
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static GRIDVAL bsdf_grid[GRIDRES][GRIDRES]; |
| 50 |
|
| 51 |
/* processed incident BSDF measurements */ |
| 52 |
static RBFLIST *bsdf_list = NULL; |
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|
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/* Compute outgoing vector from grid position */ |
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static void |
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vec_from_pos(FVECT vec, int xpos, int ypos) |
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{ |
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double uv[2]; |
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double r2; |
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|
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SDsquare2disk(uv, (1./GRIDRES)*(xpos+.5), (1./GRIDRES)*(ypos+.5)); |
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/* uniform hemispherical projection */ |
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r2 = uv[0]*uv[0] + uv[1]*uv[1]; |
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vec[0] = vec[1] = sqrt(2. - r2); |
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vec[0] *= uv[0]; |
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vec[1] *= uv[1]; |
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vec[2] = 1. - r2; |
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} |
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|
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/* Compute grid position from normalized outgoing vector */ |
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static void |
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pos_from_vec(int pos[2], const FVECT vec) |
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{ |
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double sq[2]; /* uniform hemispherical projection */ |
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double norm = 1./sqrt(1. + vec[2]); |
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|
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SDdisk2square(sq, vec[0]*norm, vec[1]*norm); |
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|
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pos[0] = (int)(sq[0]*GRIDRES); |
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pos[1] = (int)(sq[1]*GRIDRES); |
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} |
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|
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/* Evaluate RBF for BSDF at the given normalized outgoing direction */ |
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static double |
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eval_rbfrep(const RBFLIST *rp, const FVECT outvec) |
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{ |
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double res = .0; |
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const RBFVAL *rbfp; |
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FVECT odir; |
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double sig2; |
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int n; |
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|
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rbfp = rp->rbfa; |
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for (n = rp->nrbf; n--; rbfp++) { |
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vec_from_pos(odir, rbfp->gx, rbfp->gy); |
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sig2 = R2ANG(rbfp->crad); |
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sig2 = (DOT(odir,outvec) - 1.) / (sig2*sig2); |
| 98 |
if (sig2 > -19.) |
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res += rbfp->bsdf * exp(sig2); |
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} |
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return(res); |
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} |
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|
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/* Count up filled nodes and build RBF representation from current grid */ |
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static RBFLIST * |
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make_rbfrep(void) |
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{ |
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int niter = 4; |
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int nn; |
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RBFLIST *newnode; |
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int i, j; |
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|
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nn = 0; /* count selected bins */ |
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for (i = 0; i < GRIDRES; i++) |
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for (j = 0; j < GRIDRES; j++) |
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nn += (bsdf_grid[i][j].nval > 0); |
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/* allocate RBF array */ |
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newnode = (RBFLIST *)malloc(sizeof(RBFLIST) + sizeof(RBFVAL)*(nn-1)); |
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if (newnode == NULL) { |
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fputs("Out of memory in make_rbfrep\n", stderr); |
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exit(1); |
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} |
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newnode->next = NULL; |
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newnode->invec[2] = sin(M_PI/180.*theta_in_deg); |
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newnode->invec[0] = cos(M_PI/180.*phi_in_deg)*newnode->invec[2]; |
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newnode->invec[1] = sin(M_PI/180.*phi_in_deg)*newnode->invec[2]; |
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newnode->invec[2] = sqrt(1. - newnode->invec[2]*newnode->invec[2]); |
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newnode->nrbf = nn; |
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nn = 0; /* fill RBF array */ |
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for (i = 0; i < GRIDRES; i++) |
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for (j = 0; j < GRIDRES; j++) |
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if (bsdf_grid[i][j].nval) { |
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newnode->rbfa[nn].bsdf = |
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bsdf_grid[i][j].vsum /= |
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(double)bsdf_grid[i][j].nval; |
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bsdf_grid[i][j].nval = 1; |
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newnode->rbfa[nn].crad = RSCA*bsdf_grid[i][j].crad + .5; |
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newnode->rbfa[nn].gx = i; |
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newnode->rbfa[nn].gy = j; |
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++nn; |
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} |
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/* iterate for better convergence */ |
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while (niter--) { |
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nn = 0; |
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for (i = 0; i < GRIDRES; i++) |
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for (j = 0; j < GRIDRES; j++) |
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if (bsdf_grid[i][j].nval) { |
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FVECT odir; |
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vec_from_pos(odir, i, j); |
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newnode->rbfa[nn++].bsdf *= |
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bsdf_grid[i][j].vsum / |
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eval_rbfrep(newnode, odir); |
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} |
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} |
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newnode->next = bsdf_list; |
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return(bsdf_list = newnode); |
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} |
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|
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/* Load a set of measurements corresponding to a particular incident angle */ |
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static int |
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load_bsdf_meas(const char *fname) |
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{ |
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FILE *fp = fopen(fname, "r"); |
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int inp_is_DSF = -1; |
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double theta_out, phi_out, val; |
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char buf[2048]; |
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int n, c; |
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|
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if (fp == NULL) { |
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fputs(fname, stderr); |
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fputs(": cannot open\n", stderr); |
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return(0); |
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} |
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memset(bsdf_grid, 0, sizeof(bsdf_grid)); |
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/* read header information */ |
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while ((c = getc(fp)) == '#' || c == EOF) { |
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if (fgets(buf, sizeof(buf), fp) == NULL) { |
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fputs(fname, stderr); |
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fputs(": unexpected EOF\n", stderr); |
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fclose(fp); |
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return(0); |
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} |
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if (!strcmp(buf, "format: theta phi DSF\n")) { |
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inp_is_DSF = 1; |
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continue; |
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} |
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if (!strcmp(buf, "format: theta phi BSDF\n")) { |
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inp_is_DSF = 0; |
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continue; |
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} |
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if (sscanf(buf, "intheta %lf", &theta_in_deg) == 1) |
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continue; |
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if (sscanf(buf, "inphi %lf", &phi_in_deg) == 1) |
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continue; |
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if (sscanf(buf, "incident_angle %lf %lf", |
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&theta_in_deg, &phi_in_deg) == 2) |
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continue; |
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} |
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if (inp_is_DSF < 0) { |
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fputs(fname, stderr); |
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fputs(": unknown format\n", stderr); |
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fclose(fp); |
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return(0); |
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} |
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ungetc(c, fp); /* read actual data */ |
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while (fscanf(fp, "%lf %lf %lf\n", &theta_out, &phi_out, &val) == 3) { |
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FVECT ovec; |
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int pos[2]; |
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|
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ovec[2] = sin(M_PI/180.*theta_out); |
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ovec[0] = cos(M_PI/180.*phi_out) * ovec[2]; |
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ovec[1] = sin(M_PI/180.*phi_out) * ovec[2]; |
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ovec[2] = sqrt(1. - ovec[2]*ovec[2]); |
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|
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if (inp_is_DSF) |
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val /= ovec[2]; /* convert from DSF to BSDF */ |
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|
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pos_from_vec(pos, ovec); |
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|
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bsdf_grid[pos[0]][pos[1]].vsum += val; |
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bsdf_grid[pos[0]][pos[1]].nval++; |
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} |
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n = 0; |
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while ((c = getc(fp)) != EOF) |
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n += !isspace(c); |
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if (n) |
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fprintf(stderr, |
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"%s: warning: %d unexpected characters past EOD\n", |
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fname, n); |
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fclose(fp); |
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return(1); |
| 232 |
} |
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|
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/* Compute radii for non-empty bins */ |
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/* (distance to furthest empty bin for which non-empty bin is the closest) */ |
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static void |
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compute_radii(void) |
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{ |
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unsigned short fill_grid[GRIDRES][GRIDRES]; |
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FVECT ovec0, ovec1; |
| 241 |
double ang2, lastang2; |
| 242 |
int r2, lastr2; |
| 243 |
int r, i, j, jn, ii, jj, inear, jnear; |
| 244 |
|
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r = GRIDRES/2; /* proceed in zig-zag */ |
| 246 |
for (i = 0; i < GRIDRES; i++) |
| 247 |
for (jn = 0; jn < GRIDRES; jn++) { |
| 248 |
j = (i&1) ? jn : GRIDRES-1-jn; |
| 249 |
if (bsdf_grid[i][j].nval) /* find empty grid pos. */ |
| 250 |
continue; |
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vec_from_pos(ovec0, i, j); |
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inear = jnear = -1; /* find nearest non-empty */ |
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lastang2 = M_PI*M_PI; |
| 254 |
for (ii = i-r; ii <= i+r; ii++) { |
| 255 |
if (ii < 0) continue; |
| 256 |
if (ii >= GRIDRES) break; |
| 257 |
for (jj = j-r; jj <= j+r; jj++) { |
| 258 |
if (jj < 0) continue; |
| 259 |
if (jj >= GRIDRES) break; |
| 260 |
if (!bsdf_grid[ii][jj].nval) |
| 261 |
continue; |
| 262 |
vec_from_pos(ovec1, ii, jj); |
| 263 |
ang2 = 2. - 2.*DOT(ovec0,ovec1); |
| 264 |
if (ang2 >= lastang2) |
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continue; |
| 266 |
lastang2 = ang2; |
| 267 |
inear = ii; jnear = jj; |
| 268 |
} |
| 269 |
} |
| 270 |
if (inear < 0) { |
| 271 |
fputs("Could not find non-empty neighbor!\n", stderr); |
| 272 |
exit(1); |
| 273 |
} |
| 274 |
ang2 = sqrt(lastang2); |
| 275 |
r = ANG2R(ang2); /* record if > previous */ |
| 276 |
if (r > bsdf_grid[inear][jnear].crad) |
| 277 |
bsdf_grid[inear][jnear].crad = r; |
| 278 |
/* next search radius */ |
| 279 |
r = ang2*(2.*GRIDRES/M_PI) + 1; |
| 280 |
} |
| 281 |
/* fill in neighbors */ |
| 282 |
memset(fill_grid, 0, sizeof(fill_grid)); |
| 283 |
for (i = 0; i < GRIDRES; i++) |
| 284 |
for (j = 0; j < GRIDRES; j++) { |
| 285 |
if (!bsdf_grid[i][j].nval) |
| 286 |
continue; /* no value -- skip */ |
| 287 |
if (bsdf_grid[i][j].crad) |
| 288 |
continue; /* has distance already */ |
| 289 |
r = GRIDRES/20; |
| 290 |
lastr2 = 2*r*r + 1; |
| 291 |
for (ii = i-r; ii <= i+r; ii++) { |
| 292 |
if (ii < 0) continue; |
| 293 |
if (ii >= GRIDRES) break; |
| 294 |
for (jj = j-r; jj <= j+r; jj++) { |
| 295 |
if (jj < 0) continue; |
| 296 |
if (jj >= GRIDRES) break; |
| 297 |
if (!bsdf_grid[ii][jj].crad) |
| 298 |
continue; |
| 299 |
/* OK to use approx. closest */ |
| 300 |
r2 = (ii-i)*(ii-i) + (jj-j)*(jj-j); |
| 301 |
if (r2 >= lastr2) |
| 302 |
continue; |
| 303 |
fill_grid[i][j] = bsdf_grid[ii][jj].crad; |
| 304 |
lastr2 = r2; |
| 305 |
} |
| 306 |
} |
| 307 |
} |
| 308 |
/* copy back filled entries */ |
| 309 |
for (i = 0; i < GRIDRES; i++) |
| 310 |
for (j = 0; j < GRIDRES; j++) |
| 311 |
if (fill_grid[i][j]) |
| 312 |
bsdf_grid[i][j].crad = fill_grid[i][j]; |
| 313 |
} |
| 314 |
|
| 315 |
/* Cull points for more uniform distribution */ |
| 316 |
static void |
| 317 |
cull_values(void) |
| 318 |
{ |
| 319 |
FVECT ovec0, ovec1; |
| 320 |
double maxang, maxang2; |
| 321 |
int i, j, ii, jj, r; |
| 322 |
/* simple greedy algorithm */ |
| 323 |
for (i = 0; i < GRIDRES; i++) |
| 324 |
for (j = 0; j < GRIDRES; j++) { |
| 325 |
if (!bsdf_grid[i][j].nval) |
| 326 |
continue; |
| 327 |
if (!bsdf_grid[i][j].crad) |
| 328 |
continue; /* shouldn't happen */ |
| 329 |
vec_from_pos(ovec0, i, j); |
| 330 |
maxang = 2.*R2ANG(bsdf_grid[i][j].crad); |
| 331 |
if (maxang > ovec0[2]) /* clamp near horizon */ |
| 332 |
maxang = ovec0[2]; |
| 333 |
r = maxang*(2.*GRIDRES/M_PI) + 1; |
| 334 |
maxang2 = maxang*maxang; |
| 335 |
for (ii = i-r; ii <= i+r; ii++) { |
| 336 |
if (ii < 0) continue; |
| 337 |
if (ii >= GRIDRES) break; |
| 338 |
for (jj = j-r; jj <= j+r; jj++) { |
| 339 |
if (jj < 0) continue; |
| 340 |
if (jj >= GRIDRES) break; |
| 341 |
if (!bsdf_grid[ii][jj].nval) |
| 342 |
continue; |
| 343 |
if ((ii == i) & (jj == j)) |
| 344 |
continue; /* don't get self-absorbed */ |
| 345 |
vec_from_pos(ovec1, ii, jj); |
| 346 |
if (2. - 2.*DOT(ovec0,ovec1) >= maxang2) |
| 347 |
continue; |
| 348 |
/* absorb sum */ |
| 349 |
bsdf_grid[i][j].vsum += bsdf_grid[ii][jj].vsum; |
| 350 |
bsdf_grid[i][j].nval += bsdf_grid[ii][jj].nval; |
| 351 |
/* keep value, though */ |
| 352 |
bsdf_grid[ii][jj].vsum /= (double)bsdf_grid[ii][jj].nval; |
| 353 |
bsdf_grid[ii][jj].nval = 0; |
| 354 |
} |
| 355 |
} |
| 356 |
} |
| 357 |
} |
| 358 |
|
| 359 |
|
| 360 |
#if 1 |
| 361 |
/* Test main produces a Radiance model from the given input file */ |
| 362 |
int |
| 363 |
main(int argc, char *argv[]) |
| 364 |
{ |
| 365 |
char buf[128]; |
| 366 |
FILE *pfp; |
| 367 |
double bsdf; |
| 368 |
FVECT dir; |
| 369 |
int i, j, n; |
| 370 |
|
| 371 |
if (argc != 2) { |
| 372 |
fprintf(stderr, "Usage: %s input.dat > output.rad\n", argv[0]); |
| 373 |
return(1); |
| 374 |
} |
| 375 |
if (!load_bsdf_meas(argv[1])) |
| 376 |
return(1); |
| 377 |
|
| 378 |
compute_radii(); |
| 379 |
cull_values(); |
| 380 |
make_rbfrep(); |
| 381 |
/* produce spheres at meas. */ |
| 382 |
puts("void plastic yellow\n0\n0\n5 .6 .4 .01 .04 .08\n"); |
| 383 |
puts("void plastic pink\n0\n0\n5 .5 .05 .9 .04 .08\n"); |
| 384 |
n = 0; |
| 385 |
for (i = 0; i < GRIDRES; i++) |
| 386 |
for (j = 0; j < GRIDRES; j++) |
| 387 |
if (bsdf_grid[i][j].vsum > .0f) { |
| 388 |
bsdf = bsdf_grid[i][j].vsum; |
| 389 |
vec_from_pos(dir, i, j); |
| 390 |
if (bsdf_grid[i][j].nval) { |
| 391 |
printf("pink cone c%04d\n0\n0\n8\n", ++n); |
| 392 |
printf("\t%.6g %.6g %.6g\n", |
| 393 |
dir[0]*bsdf, dir[1]*bsdf, dir[2]*bsdf); |
| 394 |
printf("\t%.6g %.6g %.6g\n", |
| 395 |
dir[0]*(bsdf+.005), dir[1]*(bsdf+.005), |
| 396 |
dir[2]*(bsdf+.005)); |
| 397 |
puts("\t.003\t0\n"); |
| 398 |
} else { |
| 399 |
vec_from_pos(dir, i, j); |
| 400 |
printf("yellow sphere s%04d\n0\n0\n", ++n); |
| 401 |
printf("4 %.6g %.6g %.6g .0015\n\n", |
| 402 |
dir[0]*bsdf, dir[1]*bsdf, dir[2]*bsdf); |
| 403 |
} |
| 404 |
} |
| 405 |
/* output continuous surface */ |
| 406 |
puts("void trans tgreen\n0\n0\n7 .7 1 .7 .04 .04 .9 .9\n"); |
| 407 |
fflush(stdout); |
| 408 |
sprintf(buf, "gensurf tgreen bsdf - - - %d %d", GRIDRES, GRIDRES); |
| 409 |
pfp = popen(buf, "w"); |
| 410 |
if (pfp == NULL) { |
| 411 |
fputs(buf, stderr); |
| 412 |
fputs(": cannot start command\n", stderr); |
| 413 |
return(1); |
| 414 |
} |
| 415 |
for (i = 0; i < GRIDRES; i++) |
| 416 |
for (j = 0; j < GRIDRES; j++) { |
| 417 |
vec_from_pos(dir, i, j); |
| 418 |
bsdf = eval_rbfrep(bsdf_list, dir); |
| 419 |
fprintf(pfp, "%.8e %.8e %.8e\n", |
| 420 |
dir[0]*bsdf, dir[1]*bsdf, dir[2]*bsdf); |
| 421 |
} |
| 422 |
return(pclose(pfp)==0 ? 0 : 1); |
| 423 |
} |
| 424 |
#endif |
