--- ray/src/cv/lampcolor.c	1991/03/14 13:55:03	1.1
+++ ray/src/cv/lampcolor.c	1991/09/05 15:09:08	1.2
@@ -5,35 +5,246 @@ static char SCCSid[] = "$SunId$ LBL";
 #endif
 
 /*
- * Do dah program to convert lamp color from table.
+ * Program to convert lamp color from table and compute radiance.
  */
 
 #include <stdio.h>
 
+#define PI	3.14159265358979323846
+
+extern char	*gets(), *strcpy();
+extern double	atof();
 extern float	*matchlamp();
 
+				/* lamp parameters */
+#define LTYPE		0
+#define LUNIT		1
+#define LGEOM		2
+#define LOUTP		3
+#define NPARAMS		4
 
+int	typecheck(), unitcheck(), geomcheck(), outpcheck();
+
+float	*lampcolor;		/* the lamp color (RGB) */
+double	unit2meter;		/* conversion from units to meters */
+double	projarea;		/* projected area for this geometry */
+double	lumens;			/* total lamp lumens */
+
+struct {
+	char	*name;
+	char	value[64];
+	int	(*check)();
+	char	*help;
+} param[NPARAMS] = {
+	{ "lamp type", "white", typecheck,
+"The lamp type is a string which corresponds to one of the types registered\n\
+in the lamp table file.  A value of \"white\" means an uncolored source,\n\
+which may be preferable because it results in a color balanced image." },
+	{ "length unit", "meter", unitcheck,
+"Unit must be one of:  \"meter\", \"centimeter\", \"foot\", or \"inch\".\n\
+These may be abbreviated as a single letter." },
+	{ "lamp geometry", "polygon", geomcheck,
+"The lamp geometry must be one of:  \"polygon\", \"sphere\", \"cylinder\"\n\
+or \"ring\".  These may be abbreviated as a single letter." },
+	{ "total lamp lumens", "0", outpcheck,
+"This is the overall light output of the lamp and its fixture.  If you do\n\
+not know this value explicitly, you can compute the approximate lumens\n\
+by multiplying the input wattage by 15 for incandescent fixtures or 40\n\
+for fluorescent fixtures." },
+};
+
+
 main(argc, argv)
 int	argc;
 char	*argv[];
 {
 	char	*lamptab = "lamp.tab";
-	float	*lcol;
-	char	buf[80];
+	char	buf[64];
+	int	i;
 
 	if (argc > 1) lamptab = argv[1];
 	if (loadlamps(lamptab) == 0) {
-		perror(lamptab);
+		fprintf(stderr, "%s: no such lamp table\n", lamptab);
 		exit(1);
 	}
+	printf("Program to compute lamp radiance.  Enter '?' for help.\n");
 	for ( ; ; ) {
-		printf("Enter lamp type: ");
-		buf[0] = '\0';
-		gets(buf);
-		if (!buf[0]) exit(0);
-		if ((lcol = matchlamp(buf)) == NULL)
-			printf("No match in table\n");
-		else
-			printf("RGB = (%f,%f,%f)\n", lcol[0], lcol[1], lcol[2]);
+		i = 0;
+		while (i < NPARAMS) {
+			printf("Enter %s [%s]: ", param[i].name,
+					param[i].value);
+			if (gets(buf) == NULL)
+				exit(0);
+			if (buf[0] == '?') {
+				puts(param[i].help);
+				continue;
+			}
+			if (buf[0])
+				strcpy(param[i].value, buf);
+			if (!(*param[i].check)(param[i].value)) {
+				fprintf(stderr, "%s: bad value for %s\n",
+						param[i].value, param[i].name);
+				continue;
+			}
+			i++;
+		}
+		compute();
 	}
+}
+
+
+typecheck(s)			/* check lamp type */
+char	*s;
+{
+	lampcolor = matchlamp(s);
+	return(lampcolor != NULL);
+}
+
+
+unitcheck(s)			/* compute conversion to meters */
+char	*s;
+{
+	int	len = strlen(s);
+
+	switch (*s) {
+	case 'm':
+		if (strncmp(s, "meters", len))
+			return(0);
+		unit2meter = 1.0;
+		return(1);
+	case 'c':
+		if (strncmp(s, "centimeters", len) && strncmp(s, "cms", len))
+			return(0);
+		unit2meter = 0.01;
+		return(1);
+	case 'f':
+		if (strncmp(s, "foot", len) && strncmp(s, "feet", len))
+			return(0);
+		unit2meter = 0.3048;
+		return(1);
+	case 'i':
+		if (strncmp(s, "inches", len))
+			return(0);
+		unit2meter = 0.0254;
+		return(1);
+	}
+	return(0);
+}
+
+
+geomcheck(s)			/* check/set lamp geometry */
+char	*s;
+{
+	int	len = strlen(s);
+
+	switch (*s) {
+	case 'p':
+		if (strncmp(s, "polygonal", len))
+			return(0);
+		return(getpolygon());
+	case 's':
+		if (strncmp(s, "sphere", len) && strncmp(s, "spherical", len))
+			return(0);
+		return(getsphere());
+	case 'c':
+		if (strncmp(s,"cylinder",len) && strncmp(s,"cylindrical",len))
+			return(0);
+		return(getcylinder());
+	case 'r':
+		if (strncmp(s, "ring", len) && strncmp(s, "disk", len))
+			return(0);
+		return(getring());
+	}
+	return(0);
+}
+
+
+outpcheck(s)			/* check lumen output value */
+register char	*s;
+{
+	if ((*s < '0' || *s > '9') && *s != '.')
+		return(0);
+	lumens = atof(s);
+	return(1);
+}
+
+
+compute()			/* compute lamp radiance */
+{
+	double	whiteval;
+
+	whiteval = lumens/470./projarea;
+
+	printf("Lamp color (RGB) = %f %f %f\n",
+			lampcolor[0]*whiteval,
+			lampcolor[1]*whiteval,
+			lampcolor[2]*whiteval);
+}
+
+
+getd(dp)			/* get a positive double from stdin */
+double	*dp;
+{
+	char	buf[32];
+
+	if (gets(buf) == NULL)
+		return(0);
+	if ((buf[0] < '0' || buf[0] > '9') && buf[0] != '.')
+		return(0);
+	*dp = atof(buf);
+	return(1);
+}
+
+
+getpolygon()			/* get projected area for a polygon */
+{
+	printf("Enter area of polygon: ");
+	if (!getd(&projarea))
+		return(0);
+	projarea *= unit2meter*unit2meter;
+	projarea *= PI;
+	return(1);
+}
+
+
+getsphere()			/* get projected area for a sphere */
+{
+	double	radius;
+
+	printf("Enter sphere radius: ");
+	if (!getd(&radius))
+		return(0);
+	radius *= unit2meter;
+	projarea = 4.*PI*PI*radius*radius;
+	return(1);
+}
+
+
+getcylinder()			/* get projected area for a cylinder */
+{
+	double	length, radius;
+
+	printf("Enter cylinder length: ");
+	if (!getd(&length))
+		return(0);
+	length *= unit2meter;
+	printf("Enter cylinder radius: ");
+	if (!getd(&radius))
+		return(0);
+	radius *= unit2meter;
+	projarea = PI*PI*2.*PI*radius*length;
+	return(1);
+}
+
+
+getring()			/* get projected area for a ring */
+{
+	double	radius;
+
+	printf("Enter disk radius: ");
+	if (!getd(&radius))
+		return(0);
+	radius *= unit2meter;
+	projarea = PI*PI*radius*radius;
+	return(1);
 }