| 1 |
#ifndef lint
|
| 2 |
static const char RCSid[] = "$Id: pf2.c,v 2.6 2003/02/22 02:07:27 greg Exp $";
|
| 3 |
#endif
|
| 4 |
/*
|
| 5 |
* pf2.c - routines used by pfilt.
|
| 6 |
*/
|
| 7 |
|
| 8 |
#include <stdio.h>
|
| 9 |
#include <stdlib.h>
|
| 10 |
#include <math.h>
|
| 11 |
|
| 12 |
#include "rterror.h"
|
| 13 |
#include "random.h"
|
| 14 |
#include "color.h"
|
| 15 |
#include "pfilt.h"
|
| 16 |
|
| 17 |
#define PI 3.14159265359
|
| 18 |
#define FTINY (1e-6)
|
| 19 |
|
| 20 |
#define AVGLVL 0.5 /* target mean brightness */
|
| 21 |
|
| 22 |
double avgbrt; /* average picture brightness */
|
| 23 |
long npix; /* # pixels in average */
|
| 24 |
|
| 25 |
typedef struct hotpix { /* structure for avgbrt pixels */
|
| 26 |
struct hotpix *next; /* next in list */
|
| 27 |
COLOR val; /* pixel color */
|
| 28 |
short x, y; /* pixel position */
|
| 29 |
float slope; /* random slope for diffraction */
|
| 30 |
} HOTPIX;
|
| 31 |
|
| 32 |
HOTPIX *head; /* head of avgbrt pixel list */
|
| 33 |
|
| 34 |
double sprdfact; /* computed spread factor */
|
| 35 |
|
| 36 |
static void starpoint(COLOR fcol, int x, int y, HOTPIX *hp);
|
| 37 |
|
| 38 |
|
| 39 |
extern void
|
| 40 |
pass1init(void) /* prepare for first pass */
|
| 41 |
{
|
| 42 |
avgbrt = 0.0;
|
| 43 |
npix = 0;
|
| 44 |
head = NULL;
|
| 45 |
}
|
| 46 |
|
| 47 |
|
| 48 |
extern void
|
| 49 |
pass1default(void) /* for single pass */
|
| 50 |
{
|
| 51 |
avgbrt = AVGLVL;
|
| 52 |
npix = 1;
|
| 53 |
head = NULL;
|
| 54 |
}
|
| 55 |
|
| 56 |
|
| 57 |
extern void
|
| 58 |
pass1scan( /* process first pass scanline */
|
| 59 |
register COLOR *scan,
|
| 60 |
int y
|
| 61 |
)
|
| 62 |
{
|
| 63 |
double cbrt;
|
| 64 |
register int x;
|
| 65 |
register HOTPIX *hp;
|
| 66 |
|
| 67 |
for (x = 0; x < xres; x++) {
|
| 68 |
|
| 69 |
cbrt = (*ourbright)(scan[x]);
|
| 70 |
|
| 71 |
if (cbrt <= 0)
|
| 72 |
continue;
|
| 73 |
|
| 74 |
if (avghot || cbrt < hotlvl) {
|
| 75 |
avgbrt += cbrt;
|
| 76 |
npix++;
|
| 77 |
}
|
| 78 |
if (npts && cbrt >= hotlvl) {
|
| 79 |
hp = (HOTPIX *)malloc(sizeof(HOTPIX));
|
| 80 |
if (hp == NULL) {
|
| 81 |
fprintf(stderr, "%s: out of memory\n",
|
| 82 |
progname);
|
| 83 |
quit(1);
|
| 84 |
}
|
| 85 |
copycolor(hp->val, scan[x]);
|
| 86 |
hp->x = x;
|
| 87 |
hp->y = y;
|
| 88 |
hp->slope = tan(PI*(0.5-(random()%npts+0.5)/npts));
|
| 89 |
hp->next = head;
|
| 90 |
head = hp;
|
| 91 |
}
|
| 92 |
}
|
| 93 |
}
|
| 94 |
|
| 95 |
|
| 96 |
extern void
|
| 97 |
pass2init(void) /* prepare for final pass */
|
| 98 |
{
|
| 99 |
if (!npix) {
|
| 100 |
fprintf(stderr, "%s: picture too dark or too bright\n",
|
| 101 |
progname);
|
| 102 |
quit(1);
|
| 103 |
}
|
| 104 |
avgbrt /= (double)npix;
|
| 105 |
|
| 106 |
scalecolor(exposure, AVGLVL/avgbrt);
|
| 107 |
|
| 108 |
sprdfact = spread / (hotlvl * (*ourbright)(exposure))
|
| 109 |
* ((double)xres*xres + (double)yres*yres) / 4.0;
|
| 110 |
}
|
| 111 |
|
| 112 |
|
| 113 |
extern void
|
| 114 |
pass2scan( /* process final pass scanline */
|
| 115 |
register COLOR *scan,
|
| 116 |
int y
|
| 117 |
)
|
| 118 |
{
|
| 119 |
int xmin, xmax;
|
| 120 |
register int x;
|
| 121 |
register HOTPIX *hp;
|
| 122 |
|
| 123 |
for (hp = head; hp != NULL; hp = hp->next) {
|
| 124 |
if (hp->slope > FTINY) {
|
| 125 |
xmin = (y - hp->y - 0.5)/hp->slope + hp->x;
|
| 126 |
xmax = (y - hp->y + 0.5)/hp->slope + hp->x;
|
| 127 |
} else if (hp->slope < -FTINY) {
|
| 128 |
xmin = (y - hp->y + 0.5)/hp->slope + hp->x;
|
| 129 |
xmax = (y - hp->y - 0.5)/hp->slope + hp->x;
|
| 130 |
} else if (y == hp->y) {
|
| 131 |
xmin = 0;
|
| 132 |
xmax = xres-1;
|
| 133 |
} else {
|
| 134 |
xmin = 1;
|
| 135 |
xmax = 0;
|
| 136 |
}
|
| 137 |
if (xmin < 0)
|
| 138 |
xmin = 0;
|
| 139 |
if (xmax >= xres)
|
| 140 |
xmax = xres-1;
|
| 141 |
for (x = xmin; x <= xmax; x++)
|
| 142 |
starpoint(scan[x], x, y, hp);
|
| 143 |
}
|
| 144 |
for (x = 0; x < xres; x++)
|
| 145 |
multcolor(scan[x], exposure);
|
| 146 |
}
|
| 147 |
|
| 148 |
|
| 149 |
static void
|
| 150 |
starpoint( /* pixel is on the star's point */
|
| 151 |
COLOR fcol,
|
| 152 |
int x,
|
| 153 |
int y,
|
| 154 |
register HOTPIX *hp
|
| 155 |
)
|
| 156 |
{
|
| 157 |
COLOR ctmp;
|
| 158 |
double d2;
|
| 159 |
|
| 160 |
d2 = (double)(x - hp->x)*(x - hp->x) + (double)(y - hp->y)*(y - hp->y);
|
| 161 |
if (d2 > sprdfact) {
|
| 162 |
d2 = sprdfact / d2;
|
| 163 |
if (d2 < FTINY)
|
| 164 |
return;
|
| 165 |
copycolor(ctmp, hp->val);
|
| 166 |
scalecolor(ctmp, d2);
|
| 167 |
addcolor(fcol, ctmp);
|
| 168 |
} else if (d2 > FTINY) {
|
| 169 |
addcolor(fcol, hp->val);
|
| 170 |
}
|
| 171 |
}
|
