Expression Operator

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DmeExpressionOperator is a DmeOperator that writes to its "value" float attribute the evaluated expression stored in its "expr" string attribute. The expression can read other float attributes on the DmeExpressionOperator, and can nest arbitrarily deep. For example, the expression "clamp(distance * cos(angle), 0, 10)" will cause the DmeExpressionOperator to write a value between 0 and 10 into its "value" attribute, depending upon the value of its "distance" and "angle" float attributes.

Operator Precedence

  • unary operators: + - ! func var
  • * / %
  • + -
  • < > <= >=
  • == !=
  • &&
  • ||
  •  ?:

Functions

dtor(d) 
converts degrees to radians
rtod(r) 
converts radians to degrees
abs(a)  
absolute value
floor(a)  
rounds down to the nearest integer
ceiling(a) 
rounds up to the nearest integer
round(a)  
rounds to the nearest integer
sgn(a)  
if a < 0 returns -1 else 1
sqr(a)  
returns a * a
sqrt(a)  
returns sqrt(a)
sin(a)  
sin(a), a is in degrees
asin(a)  
asin(a) returns degrees
cos(a)  
cos(a), a is in degrees
acos(a)  
acos(a) returns degrees
tan(a)  
tan(a), a is in degrees
exp(a)  
returns the exponential function of a
log(a)  
returns the natural logarithm of a
min(a,b)  
if a < b returns a else b
max(a,b)  
if a > b returns a else b
atan2(a,b) 
atan(a/b) returns radians (it's Arg(b+ia) actually)
pow(a,b) 
function returns a raised to the power of b
inrange(x,a,b) 
if x is between a and b, returns 1 else returns 0
clamp(x,a,b)  
if x < a returns a else if x > b returns b else returns x
ramp(value,a,b)  
returns 0 -> 1 as value goes from a to b
lerp(factor,a,b)  
returns a -> b as factor goes from 0 to 1
cramp(value,a,b)  
clamp(ramp(value,a,b),0,1)
clerp(factor,a,b)  
clamp(lerp(factor,a,b),a,b)
elerp(x,a,b)  
ramp( 3*x*x - 2*x*x*x, a, b)
noise(a,b,c) 
{ solid noise pattern (improved perlin noise) indexed with three numbers }
rescale (X,Xa,Xb,Ya,Yb) 
lerp(ramp(X,Xa,Xb),Ya,Yb)
crescale(X,Xa,Xb,Ya,Yb) 
clamp(rescale(X,Xa,Xb,Ya,Yb),Ya,Yb)
  • Note : arithmetic priorites may not work as intended (for instance, 0-0+3 = -3), so adding brackets might be needed.