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POV-Ray defines a variety of built-in functions for manipulating floats, vectors and strings. Function calls consist of a keyword which specifies the name of the function followed by a parameter list enclosed in parentheses. Parameters are separated by commas. For example:
keyword(param1,param2)
The following are the functions which return float values. They take one or more float, integer, vector, or string parameters. Assume that A and B are any valid expression that evaluates to a float; I is a float which is truncated to integer internally, S, S1, S2 etc. are strings, and V, V1, V2 etc. are any vector expressions.
abs(A)
A. If A is negative, returns -A otherwise returns A.
acos(A)
A. Returns the angle, measured in radians, whose cosine is A.
asc(S)
S. For example asc("ABC") is 65 because that is the value of the character "A".
asin(A)
A. Returns the angle, measured in radians, whose sine is A.
atan2(A,B)
(A/B). Returns the angle, measured in radians, whose tangent is (A/B). Returns appropriate value even if B is zero. Use atan2(A,1) to compute usual atan(A) function.
ceil(A)
A. Returns the smallest integer greater than A. Rounds up to the next higher integer.
cos(A)
A. Returns the cosine of the angle A, where A is measured in radians.
defined(
) Returns true if the identifier is currently defined, false otherwise. This is especially useful for detecting end-of-file after a #read directive because the file identifer is automatically undefined when end-of-file is reached. See "The #read Directive" for details.
degrees(A)
A. Formula is degrees=A/pi*180.0.
dimensions(
) Returns the number of dimensions of a previously declared array identifier. For example if you do #declare MyArray=array[6][10] then dimensions(MyArray) returns the value 2.
dimension_size(
) Returns the size of a given dimension of a previously declared array identifier. Dimensions are numbered left-to-right starting with 1. For example if you do #declare MyArray=array[6][10] then dimension_size(MyArray,2) returns the value 10.
div(A,B)
(A/B).
exp(A)
A. Returns the value of e raised to the power A where e is the base of the natural logarithm, i.e. the non-repeating value approximately equal to 2.71828182846.
file_exists(S)
S. The current directory and all library directories specified by the Library_Path or +L options are also searched. See "Library Paths" for details. Returns 1 if successful and 0 if unsuccessful.
floor(A)
A. Returns the largest integer less than A. Rounds down to the next lower integer.
int(A)
A. Returns the truncated integer part of A. Rounds towards zero.
log(A)
A. Returns the natural logarithm base e of the value A.
max(A,B)
A and B. Returns A if A larger than B. Otherwise returns B.
min(A,B)
A and B. Returns A if A smaller than B. Otherwise returns B.
mod(A,B)
A modulo B. Returns the remainder after the integer division of A/B. Formula is mod=((A/B)-int(A/B))*B.
pow(A,B)
A raised to the power B.
radians(A)
A. Formula is radians=A*pi/180.0.
rand(I)
I. You must call seed() to initialize a random stream before calling rand(). The numbers are uniformly distributed, and have values between 0.0 and 1.0, inclusively. The numbers generated by separate streams are independent random variables.
seed(A)
A. The number corresponding to this random stream is returned. Any number of pseudo-random streams may be used as shown in the example below:
#declare R1 = seed(0);
#declare R2 = seed(12345);
#sphere { <rand(R1), rand(R1), rand(R1)>, rand(R2) }
Multiple random generators are very useful in situations where you use rand() to place a group of objects, and then decide to use rand() in another location earlier in the file to set some colors or place another group of objects. Without separate rand() streams, all of your objects would move when you added more calls to rand(). This is very annoying.
sin(A)
A. Returns the sine of the angle A, where A is measured in radians.
strcmp(S1,S2)
S1 to S2. Returns a float value zero if the strings are equal, a positive number if S1 comes after S2 in the ASCII collating sequence, else a negative number.
strlen(S)
S. Returns an integer value that is the number of characters in the string S.
sqrt(A)
A. Returns the value whose square is A.
tan(A)
A. Returns the tangent of the angle A, where A is measured in radians.
val(S)
S to float. Returns a float value that is represented by the text in string S. For example val("123.45") is 123.45 as a float.
vdot(V1,V2)
V1 and V2. Returns a float value that is the dot product (sometimes called scalar product of V1 with V2. Formula is vdot=V1.x*V2.x + V1.y*V2.y + V1.z*V2.z. See the animated demo scene VECT2.POV for an illustration.
vlength(V)
V. Returns a float value that is the length of vector V. Formula is vlength=sqrt(vdot(A,A)). Can be used to compute the distance between two points. Dist=vlength(V2-V1).
See section "Vector Functions" and section "String Functions" for other functions which are somewhat float-related but which return vectors and strings. In addition to the above built-in functions, you may also define your own functions using the new #macro directive. See the section "User Defined Macros" for more details.
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