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#ifndef lint |
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static const char RCSid[] = "$Id: lampcolor.c,v 2.10 2004/03/18 05:22:00 greg Exp $"; |
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#endif |
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/* |
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* Program to convert lamp color from table and compute radiance. |
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*/ |
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|
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#include <math.h> |
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|
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#include "rtmath.h" |
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#include "rtio.h" |
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#include "color.h" |
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|
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/* lamp parameters */ |
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#define LTYPE 0 |
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#define LUNIT 1 |
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#define LGEOM 2 |
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#define LOUTP 3 |
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#define NPARAMS 4 |
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|
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static int typecheck(char *s); |
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static int unitcheck(char *s); |
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static int geomcheck(char *s); |
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static int outpcheck(char *s); |
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static void compute(void); |
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static int getpolygon(void), getsphere(void), getcylinder(void), getring(void); |
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static int getd(char *name, double *dp, char *help); |
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|
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|
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float *lampcolor; /* the lamp color (RGB) */ |
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double unit2meter; /* conversion from units to meters */ |
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double area; /* radiating area for this geometry */ |
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double lumens; /* total lamp lumens */ |
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|
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struct { |
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char *name; |
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char value[64]; |
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int (*check)(); |
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char *help; |
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} param[NPARAMS] = { |
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{ "lamp type", "WHITE", typecheck, |
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"The lamp type is a string which corresponds to one of the types registered\n\ |
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in the lamp table file. A value of \"WHITE\" means an uncolored source,\n\ |
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which may be preferable because it results in a color balanced image." }, |
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{ "length unit", "meter", unitcheck, |
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"Unit must be one of: \"meter\", \"centimeter\", \"foot\", or \"inch\".\n\ |
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These may be abbreviated as a single letter." }, |
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{ "lamp geometry", "polygon", geomcheck, |
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"The lamp geometry must be one of: \"polygon\", \"sphere\", \"cylinder\"\n\ |
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or \"ring\". These may be abbreviated as a single letter." }, |
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{ "total lamp lumens", "0", outpcheck, |
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"This is the overall light output of the lamp and its fixture. If you do\n\ |
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not know this value explicitly, you can compute the approximate lumens\n\ |
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by multiplying the input wattage by 14 for incandescent fixtures or 70\n\ |
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for fluorescent fixtures." }, |
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}; |
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|
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|
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int |
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main( |
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int argc, |
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char *argv[] |
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) |
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{ |
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char *lamptab = "lamp.tab"; |
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char buf[64]; |
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int i; |
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|
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if (argc > 1) lamptab = argv[1]; |
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if (loadlamps(lamptab) == 0) { |
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fprintf(stderr, "%s: no such lamp table\n", lamptab); |
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exit(1); |
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} |
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printf("Program to compute lamp radiance. Enter '?' for help.\n"); |
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for ( ; ; ) { |
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i = 0; |
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while (i < NPARAMS) { |
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printf("Enter %s [%s]: ", param[i].name, |
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param[i].value); |
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if (fgetline(buf, sizeof(buf), stdin) == NULL) |
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exit(0); |
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if (buf[0] == '?') { |
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puts(param[i].help); |
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continue; |
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} |
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if (buf[0]) |
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strcpy(param[i].value, buf); |
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if (!(*param[i].check)(param[i].value)) { |
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fprintf(stderr, "%s: bad value for %s\n", |
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param[i].value, param[i].name); |
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continue; |
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} |
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i++; |
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} |
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compute(); |
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} |
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} |
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|
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|
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static int |
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typecheck( /* check lamp type */ |
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char *s |
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) |
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{ |
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lampcolor = matchlamp(s); |
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return(lampcolor != NULL); |
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} |
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|
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|
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static int |
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unitcheck( /* compute conversion to meters */ |
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char *s |
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) |
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{ |
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int len = strlen(s); |
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|
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switch (*s) { |
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case 'm': |
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if (strncmp(s, "meters", len)) |
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return(0); |
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unit2meter = 1.0; |
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return(1); |
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case 'c': |
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if (strncmp(s, "centimeters", len) && strncmp(s, "cms", len)) |
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return(0); |
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unit2meter = 0.01; |
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return(1); |
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case 'f': |
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if (strncmp(s, "foot", len) && strncmp(s, "feet", len)) |
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return(0); |
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unit2meter = 0.3048; |
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return(1); |
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case 'i': |
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if (strncmp(s, "inches", len)) |
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return(0); |
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unit2meter = 0.0254; |
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return(1); |
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} |
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return(0); |
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} |
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|
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|
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static int |
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geomcheck( /* check/set lamp geometry */ |
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char *s |
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) |
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{ |
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int len = strlen(s); |
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|
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switch (*s) { |
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case 'p': |
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if (strncmp(s, "polygonal", len)) |
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return(0); |
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return(getpolygon()); |
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case 's': |
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if (strncmp(s, "sphere", len) && strncmp(s, "spherical", len)) |
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return(0); |
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return(getsphere()); |
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case 'c': |
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if (strncmp(s,"cylinder",len) && strncmp(s,"cylindrical",len)) |
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return(0); |
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return(getcylinder()); |
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case 'r': |
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if (strncmp(s, "ring", len) && strncmp(s, "disk", len)) |
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return(0); |
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return(getring()); |
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} |
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return(0); |
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} |
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|
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|
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static int |
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outpcheck( /* check lumen output value */ |
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register char *s |
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) |
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{ |
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if ((*s < '0' || *s > '9') && *s != '.') |
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return(0); |
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lumens = atof(s); |
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return(1); |
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} |
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|
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|
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static void |
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compute(void) /* compute lamp radiance */ |
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{ |
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double whiteval; |
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|
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whiteval = lumens/area/(WHTEFFICACY*PI); |
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|
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printf("Lamp color (RGB) = %f %f %f\n", |
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lampcolor[0]*whiteval, |
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lampcolor[1]*whiteval, |
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lampcolor[2]*whiteval); |
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} |
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|
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|
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static int |
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getd( /* get a positive double from stdin */ |
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char *name, |
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double *dp, |
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char *help |
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) |
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{ |
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char buf[32]; |
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again: |
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printf("%s [%g]: ", name, *dp); |
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if (fgets(buf, sizeof(buf), stdin) == NULL) |
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return(0); |
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if (buf[0] == '?') { |
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puts(help); |
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goto again; |
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} |
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if ((buf[0] < '0' || buf[0] > '9') && buf[0] != '.') |
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return(0); |
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*dp = atof(buf); |
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return(1); |
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} |
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|
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|
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static int |
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getpolygon(void) /* get projected area for a polygon */ |
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{ |
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static double parea = 1.0; |
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|
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getd("Polygon area", &parea, |
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"Enter the total radiating area of the polygon."); |
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area = unit2meter*unit2meter * parea; |
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return(1); |
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} |
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|
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|
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static int |
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getsphere(void) /* get projected area for a sphere */ |
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{ |
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static double radius = 1.0; |
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|
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getd("Sphere radius", &radius, |
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"Enter the distance from the sphere's center to its surface."); |
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area = 4.*PI*unit2meter*unit2meter * radius*radius; |
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return(1); |
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} |
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|
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|
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static int |
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getcylinder(void) /* get projected area for a cylinder */ |
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{ |
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static double length = 1.0, radius = 0.1; |
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|
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getd("Cylinder length", &length, |
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"Enter the length of the cylinder."); |
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getd("Cylinder radius", &radius, |
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"Enter the distance from the cylinder's axis to its surface."); |
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area = 2.*PI*unit2meter*unit2meter * radius*length; |
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return(1); |
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} |
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|
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|
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static int |
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getring(void) /* get projected area for a ring */ |
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{ |
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static double radius = 1.0; |
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|
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getd("Disk radius", &radius, |
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"Enter the distance from the ring's center to its outer edge.\n\ |
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The inner radius must be zero."); |
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area = PI*unit2meter*unit2meter * radius*radius; |
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return(1); |
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} |
