| 1 |
greg |
2.1 |
#ifndef lint |
| 2 |
greg |
2.20 |
static const char RCSid[] = "$Id: bsdfrbf.c,v 2.19 2014/03/02 01:56:03 greg Exp $"; |
| 3 |
greg |
2.1 |
#endif |
| 4 |
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/* |
| 5 |
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* Radial basis function representation for BSDF data. |
| 6 |
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* |
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* G. Ward |
| 8 |
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*/ |
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| 10 |
greg |
2.13 |
/**************************************************************** |
| 11 |
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1) Collect samples into a grid using the Shirley-Chiu |
| 12 |
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angular mapping from a hemisphere to a square. |
| 13 |
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| 14 |
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2) Compute an adaptive quadtree by subdividing the grid so that |
| 15 |
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each leaf node has at least one sample up to as many |
| 16 |
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samples as fit nicely on a plane to within a certain |
| 17 |
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MSE tolerance. |
| 18 |
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| 19 |
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3) Place one Gaussian lobe at each leaf node in the quadtree, |
| 20 |
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sizing it to have a radius equal to the leaf size and |
| 21 |
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a volume equal to the energy in that node. |
| 22 |
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*****************************************************************/ |
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| 24 |
greg |
2.1 |
#define _USE_MATH_DEFINES |
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#include <stdio.h> |
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#include <stdlib.h> |
| 27 |
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#include <string.h> |
| 28 |
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#include <math.h> |
| 29 |
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#include "bsdfrep.h" |
| 30 |
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| 31 |
greg |
2.12 |
#ifndef RSCA |
| 32 |
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#define RSCA 2.2 /* radius scaling factor (empirical) */ |
| 33 |
greg |
2.9 |
#endif |
| 34 |
greg |
2.12 |
#ifndef SMOOTH_MSE |
| 35 |
greg |
2.19 |
#define SMOOTH_MSE 5e-5 /* acceptable mean squared error */ |
| 36 |
greg |
2.1 |
#endif |
| 37 |
greg |
2.12 |
#ifndef SMOOTH_MSER |
| 38 |
greg |
2.18 |
#define SMOOTH_MSER 0.03 /* acceptable relative MSE */ |
| 39 |
greg |
2.7 |
#endif |
| 40 |
greg |
2.12 |
#define MAX_RAD (GRIDRES/8) /* maximum lobe radius */ |
| 41 |
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| 42 |
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#define RBFALLOCB 10 /* RBF allocation block size */ |
| 43 |
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| 44 |
greg |
2.20 |
/* our loaded grid or comparison DSFs */ |
| 45 |
greg |
2.1 |
GRIDVAL dsf_grid[GRIDRES][GRIDRES]; |
| 46 |
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| 47 |
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/* Start new DSF input grid */ |
| 48 |
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void |
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new_bsdf_data(double new_theta, double new_phi) |
| 50 |
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{ |
| 51 |
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if (!new_input_direction(new_theta, new_phi)) |
| 52 |
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exit(1); |
| 53 |
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memset(dsf_grid, 0, sizeof(dsf_grid)); |
| 54 |
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} |
| 55 |
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| 56 |
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/* Add BSDF data point */ |
| 57 |
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void |
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add_bsdf_data(double theta_out, double phi_out, double val, int isDSF) |
| 59 |
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{ |
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FVECT ovec; |
| 61 |
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int pos[2]; |
| 62 |
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| 63 |
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if (!output_orient) /* check output orientation */ |
| 64 |
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output_orient = 1 - 2*(theta_out > 90.); |
| 65 |
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else if (output_orient > 0 ^ theta_out < 90.) { |
| 66 |
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fputs("Cannot handle output angles on both sides of surface\n", |
| 67 |
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stderr); |
| 68 |
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exit(1); |
| 69 |
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} |
| 70 |
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ovec[2] = sin((M_PI/180.)*theta_out); |
| 71 |
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ovec[0] = cos((M_PI/180.)*phi_out) * ovec[2]; |
| 72 |
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ovec[1] = sin((M_PI/180.)*phi_out) * ovec[2]; |
| 73 |
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ovec[2] = sqrt(1. - ovec[2]*ovec[2]); |
| 74 |
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| 75 |
greg |
2.8 |
if (val <= 0) /* truncate to zero */ |
| 76 |
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val = 0; |
| 77 |
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else if (!isDSF) |
| 78 |
greg |
2.1 |
val *= ovec[2]; /* convert from BSDF to DSF */ |
| 79 |
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| 80 |
greg |
2.4 |
/* update BSDF histogram */ |
| 81 |
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if (val < BSDF2BIG*ovec[2] && val > BSDF2SML*ovec[2]) |
| 82 |
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++bsdf_hist[histndx(val/ovec[2])]; |
| 83 |
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| 84 |
greg |
2.1 |
pos_from_vec(pos, ovec); |
| 85 |
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| 86 |
greg |
2.20 |
dsf_grid[pos[0]][pos[1]].sum.v += val; |
| 87 |
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dsf_grid[pos[0]][pos[1]].sum.n++; |
| 88 |
greg |
2.1 |
} |
| 89 |
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| 90 |
greg |
2.11 |
/* Compute minimum BSDF from histogram (does not clear) */ |
| 91 |
greg |
2.5 |
static void |
| 92 |
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comp_bsdf_min() |
| 93 |
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{ |
| 94 |
greg |
2.17 |
unsigned long cnt, target; |
| 95 |
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int i; |
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greg |
2.5 |
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| 97 |
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cnt = 0; |
| 98 |
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for (i = HISTLEN; i--; ) |
| 99 |
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cnt += bsdf_hist[i]; |
| 100 |
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if (!cnt) { /* shouldn't happen */ |
| 101 |
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bsdf_min = 0; |
| 102 |
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return; |
| 103 |
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} |
| 104 |
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target = cnt/100; /* ignore bottom 1% */ |
| 105 |
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cnt = 0; |
| 106 |
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for (i = 0; cnt <= target; i++) |
| 107 |
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cnt += bsdf_hist[i]; |
| 108 |
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bsdf_min = histval(i-1); |
| 109 |
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} |
| 110 |
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| 111 |
greg |
2.12 |
/* Determine if the given region is empty of grid samples */ |
| 112 |
greg |
2.6 |
static int |
| 113 |
greg |
2.12 |
empty_region(int x0, int x1, int y0, int y1) |
| 114 |
greg |
2.6 |
{ |
| 115 |
greg |
2.12 |
int x, y; |
| 116 |
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| 117 |
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for (x = x0; x < x1; x++) |
| 118 |
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for (y = y0; y < y1; y++) |
| 119 |
greg |
2.20 |
if (dsf_grid[x][y].sum.n) |
| 120 |
greg |
2.12 |
return(0); |
| 121 |
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return(1); |
| 122 |
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} |
| 123 |
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| 124 |
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/* Determine if the given region is smooth enough to be a single lobe */ |
| 125 |
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static int |
| 126 |
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smooth_region(int x0, int x1, int y0, int y1) |
| 127 |
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{ |
| 128 |
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RREAL rMtx[3][3]; |
| 129 |
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FVECT xvec; |
| 130 |
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double A, B, C, nvs, sqerr; |
| 131 |
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int x, y, n; |
| 132 |
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/* compute planar regression */ |
| 133 |
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memset(rMtx, 0, sizeof(rMtx)); |
| 134 |
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memset(xvec, 0, sizeof(xvec)); |
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for (x = x0; x < x1; x++) |
| 136 |
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for (y = y0; y < y1; y++) |
| 137 |
greg |
2.20 |
if ((n = dsf_grid[x][y].sum.n) > 0) { |
| 138 |
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double z = dsf_grid[x][y].sum.v; |
| 139 |
greg |
2.13 |
rMtx[0][0] += x*x*(double)n; |
| 140 |
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rMtx[0][1] += x*y*(double)n; |
| 141 |
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rMtx[0][2] += x*(double)n; |
| 142 |
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rMtx[1][1] += y*y*(double)n; |
| 143 |
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rMtx[1][2] += y*(double)n; |
| 144 |
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rMtx[2][2] += (double)n; |
| 145 |
greg |
2.12 |
xvec[0] += x*z; |
| 146 |
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xvec[1] += y*z; |
| 147 |
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xvec[2] += z; |
| 148 |
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} |
| 149 |
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rMtx[1][0] = rMtx[0][1]; |
| 150 |
greg |
2.15 |
rMtx[2][0] = rMtx[0][2]; |
| 151 |
greg |
2.12 |
rMtx[2][1] = rMtx[1][2]; |
| 152 |
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nvs = rMtx[2][2]; |
| 153 |
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if (SDinvXform(rMtx, rMtx) != SDEnone) |
| 154 |
greg |
2.16 |
return(1); /* colinear values */ |
| 155 |
greg |
2.12 |
A = DOT(rMtx[0], xvec); |
| 156 |
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B = DOT(rMtx[1], xvec); |
| 157 |
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C = DOT(rMtx[2], xvec); |
| 158 |
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sqerr = 0.0; /* compute mean squared error */ |
| 159 |
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for (x = x0; x < x1; x++) |
| 160 |
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for (y = y0; y < y1; y++) |
| 161 |
greg |
2.20 |
if ((n = dsf_grid[x][y].sum.n) > 0) { |
| 162 |
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double d = A*x + B*y + C - dsf_grid[x][y].sum.v/n; |
| 163 |
greg |
2.12 |
sqerr += n*d*d; |
| 164 |
greg |
2.6 |
} |
| 165 |
greg |
2.12 |
if (sqerr <= nvs*SMOOTH_MSE) /* below absolute MSE threshold? */ |
| 166 |
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return(1); |
| 167 |
greg |
2.13 |
/* OR below relative MSE threshold? */ |
| 168 |
greg |
2.12 |
return(sqerr*nvs <= xvec[2]*xvec[2]*SMOOTH_MSER); |
| 169 |
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} |
| 170 |
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| 171 |
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/* Create new lobe based on integrated samples in region */ |
| 172 |
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static void |
| 173 |
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create_lobe(RBFVAL *rvp, int x0, int x1, int y0, int y1) |
| 174 |
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{ |
| 175 |
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double vtot = 0.0; |
| 176 |
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int nv = 0; |
| 177 |
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double rad; |
| 178 |
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int x, y; |
| 179 |
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/* compute average for region */ |
| 180 |
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for (x = x0; x < x1; x++) |
| 181 |
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for (y = y0; y < y1; y++) { |
| 182 |
greg |
2.20 |
vtot += dsf_grid[x][y].sum.v; |
| 183 |
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nv += dsf_grid[x][y].sum.n; |
| 184 |
greg |
2.12 |
} |
| 185 |
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if (!nv) { |
| 186 |
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fprintf(stderr, "%s: internal - missing samples in create_lobe\n", |
| 187 |
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progname); |
| 188 |
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exit(1); |
| 189 |
greg |
2.6 |
} |
| 190 |
greg |
2.12 |
/* peak value based on integral */ |
| 191 |
|
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vtot *= (x1-x0)*(y1-y0)*(2.*M_PI/GRIDRES/GRIDRES)/(double)nv; |
| 192 |
|
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rad = (RSCA/(double)GRIDRES)*(x1-x0); |
| 193 |
|
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rvp->peak = vtot / ((2.*M_PI) * rad*rad); |
| 194 |
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rvp->crad = ANG2R(rad); |
| 195 |
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rvp->gx = (x0+x1)>>1; |
| 196 |
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rvp->gy = (y0+y1)>>1; |
| 197 |
greg |
2.6 |
} |
| 198 |
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| 199 |
greg |
2.12 |
/* Recursive function to build radial basis function representation */ |
| 200 |
greg |
2.6 |
static int |
| 201 |
greg |
2.12 |
build_rbfrep(RBFVAL **arp, int *np, int x0, int x1, int y0, int y1) |
| 202 |
greg |
2.6 |
{ |
| 203 |
greg |
2.12 |
int xmid = (x0+x1)>>1; |
| 204 |
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int ymid = (y0+y1)>>1; |
| 205 |
|
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int branched[4]; |
| 206 |
|
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int nadded, nleaves; |
| 207 |
|
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/* need to make this a leaf? */ |
| 208 |
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if (empty_region(x0, xmid, y0, ymid) || |
| 209 |
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empty_region(xmid, x1, y0, ymid) || |
| 210 |
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empty_region(x0, xmid, ymid, y1) || |
| 211 |
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empty_region(xmid, x1, ymid, y1)) |
| 212 |
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return(0); |
| 213 |
|
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/* add children (branches+leaves) */ |
| 214 |
|
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if ((branched[0] = build_rbfrep(arp, np, x0, xmid, y0, ymid)) < 0) |
| 215 |
|
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return(-1); |
| 216 |
|
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if ((branched[1] = build_rbfrep(arp, np, xmid, x1, y0, ymid)) < 0) |
| 217 |
|
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return(-1); |
| 218 |
|
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if ((branched[2] = build_rbfrep(arp, np, x0, xmid, ymid, y1)) < 0) |
| 219 |
|
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return(-1); |
| 220 |
|
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if ((branched[3] = build_rbfrep(arp, np, xmid, x1, ymid, y1)) < 0) |
| 221 |
|
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return(-1); |
| 222 |
|
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nadded = branched[0] + branched[1] + branched[2] + branched[3]; |
| 223 |
|
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nleaves = !branched[0] + !branched[1] + !branched[2] + !branched[3]; |
| 224 |
|
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if (!nleaves) /* nothing but branches? */ |
| 225 |
|
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return(nadded); |
| 226 |
|
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/* combine 4 leaves into 1? */ |
| 227 |
greg |
2.14 |
if ((nleaves == 4) & (x1-x0 <= MAX_RAD) && |
| 228 |
|
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smooth_region(x0, x1, y0, y1)) |
| 229 |
greg |
2.12 |
return(0); |
| 230 |
|
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/* need more array space? */ |
| 231 |
|
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if ((*np+nleaves-1)>>RBFALLOCB != (*np-1)>>RBFALLOCB) { |
| 232 |
|
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*arp = (RBFVAL *)realloc(*arp, |
| 233 |
|
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sizeof(RBFVAL)*(*np+nleaves-1+(1<<RBFALLOCB))); |
| 234 |
|
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if (*arp == NULL) |
| 235 |
|
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return(-1); |
| 236 |
greg |
2.6 |
} |
| 237 |
greg |
2.12 |
/* create lobes for leaves */ |
| 238 |
|
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if (!branched[0]) |
| 239 |
|
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create_lobe(*arp+(*np)++, x0, xmid, y0, ymid); |
| 240 |
|
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if (!branched[1]) |
| 241 |
|
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create_lobe(*arp+(*np)++, xmid, x1, y0, ymid); |
| 242 |
|
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if (!branched[2]) |
| 243 |
|
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create_lobe(*arp+(*np)++, x0, xmid, ymid, y1); |
| 244 |
|
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if (!branched[3]) |
| 245 |
|
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create_lobe(*arp+(*np)++, xmid, x1, ymid, y1); |
| 246 |
|
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nadded += nleaves; |
| 247 |
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return(nadded); |
| 248 |
greg |
2.6 |
} |
| 249 |
|
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|
| 250 |
greg |
2.1 |
/* Count up filled nodes and build RBF representation from current grid */ |
| 251 |
|
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RBFNODE * |
| 252 |
greg |
2.12 |
make_rbfrep() |
| 253 |
greg |
2.1 |
{ |
| 254 |
greg |
2.12 |
RBFNODE *newnode; |
| 255 |
|
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RBFVAL *rbfarr; |
| 256 |
greg |
2.1 |
int nn; |
| 257 |
greg |
2.5 |
/* compute minimum BSDF */ |
| 258 |
|
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comp_bsdf_min(); |
| 259 |
greg |
2.12 |
/* create RBF node list */ |
| 260 |
|
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rbfarr = NULL; nn = 0; |
| 261 |
|
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if (build_rbfrep(&rbfarr, &nn, 0, GRIDRES, 0, GRIDRES) <= 0) |
| 262 |
|
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goto memerr; |
| 263 |
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/* (re)allocate RBF array */ |
| 264 |
|
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newnode = (RBFNODE *)realloc(rbfarr, |
| 265 |
|
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sizeof(RBFNODE) + sizeof(RBFVAL)*(nn-1)); |
| 266 |
greg |
2.2 |
if (newnode == NULL) |
| 267 |
|
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goto memerr; |
| 268 |
greg |
2.12 |
/* copy computed lobes into RBF node */ |
| 269 |
|
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memmove(newnode->rbfa, newnode, sizeof(RBFVAL)*nn); |
| 270 |
greg |
2.1 |
newnode->ord = -1; |
| 271 |
|
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newnode->next = NULL; |
| 272 |
|
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newnode->ejl = NULL; |
| 273 |
|
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newnode->invec[2] = sin((M_PI/180.)*theta_in_deg); |
| 274 |
|
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newnode->invec[0] = cos((M_PI/180.)*phi_in_deg)*newnode->invec[2]; |
| 275 |
|
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newnode->invec[1] = sin((M_PI/180.)*phi_in_deg)*newnode->invec[2]; |
| 276 |
|
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newnode->invec[2] = input_orient*sqrt(1. - newnode->invec[2]*newnode->invec[2]); |
| 277 |
greg |
2.12 |
newnode->vtotal = .0; |
| 278 |
greg |
2.1 |
newnode->nrbf = nn; |
| 279 |
greg |
2.12 |
/* compute sum for normalization */ |
| 280 |
|
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while (nn-- > 0) |
| 281 |
|
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newnode->vtotal += rbf_volume(&newnode->rbfa[nn]); |
| 282 |
greg |
2.3 |
#ifdef DEBUG |
| 283 |
greg |
2.12 |
fprintf(stderr, "Built RBF with %d lobes\n", newnode->nrbf); |
| 284 |
greg |
2.3 |
fprintf(stderr, "Integrated DSF at (%.1f,%.1f) deg. is %.2f\n", |
| 285 |
|
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get_theta180(newnode->invec), get_phi360(newnode->invec), |
| 286 |
|
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newnode->vtotal); |
| 287 |
|
|
#endif |
| 288 |
greg |
2.1 |
insert_dsf(newnode); |
| 289 |
|
|
|
| 290 |
|
|
return(newnode); |
| 291 |
greg |
2.2 |
memerr: |
| 292 |
|
|
fprintf(stderr, "%s: Out of memory in make_rbfrep()\n", progname); |
| 293 |
|
|
exit(1); |
| 294 |
greg |
2.1 |
} |