Expression Components and Instructions

Components

The component portion of an expression is what will be affected. For example,

= 0 [Instructions]

will take the value of the [Instructions] portion, and push it onto the X position of the Expression bone, while;

= 4 [Instructions]

will take the value of the [Instructions] portion, and push it onto the Y rotation of the bone.

Component	Value
0	X Position
1	Y Position
2	Z Position
3	X Rotation
4	Y Rotation
5	Z Rotation
6	X Scale
7	Y Scale
8	Z Scale

*Component info from Skyth

Instructions

Instructions are the math portion of expressions. The following operations are allowed:

Number

n [value] 

The n instruction pushes a number to the stack, for example:

= 6 n 1

sets the X Scale of the bone to 1

Variable

v [variable]

The v instruction gets a variable, then pushes it to the stack. The variable can either be:

[Component].[Bone] (eg, 4.j_kao_wj, 2.kl_mune_b_wj, 6.j_ude_l_wj)

or

the t instruction (time elapsed)

For example:

= 1 v 4.j_kao_wj

This would set the Y position of the bone to the Y rotation of j_kao_wj, or:

= 2 v t

This would set the Z position of the bone to the value of time elapsed

Function

f [function]

The f instruction gets the value on the stack, applies the function, then pushes the value. The function used can be:

neg	Negate the value
sin	Sine function (in degrees)
cos	Cosine function (in degrees)
tan	Tangent function (in degrees)
abs	Absolute Value function
sqrt	Square Root
av	Multiplies value by 0.1
floor	Outputs the floor (lowest integer) of a value
ceil	Outputs the ceiling (highest integer) of a value
round	Roundsthe value
asin	Inverse Sine function
acos	Inverse Cosine function
atan	Inverse Tangent function
log	Logarithm function
exp	Exponentation function
rand_0_1	Unimplemented, makes value 0. (It is meant to randomly generate between 0 and 1)

Function info from Skyth

For example:

= 0 v 1 f av

would set the X position of the bone to 0.1 (since the 1 is multiplied by 0.1)

Secondary Functions

g [function]

The g instruction gets two values from the stack, applies the function provided, then pushes the result. The function used can be:

+	Adds the values
-	Subtracts X from Y
*	Multiplies the values
/	Divides X by Y
%	Takes a portion of X by Y
==	Outputs 1 if values are equal, else 0
>	Outputs 1 if X is greater, else 0
>=	Outputs 1 if X is greater or equal, else 0
<	Outputs 1 if X is lesser, else 0
<=	Outputs 1 if X is lesser or equal, else 0
!=	Outputs 1 if values are not equal, else 0
&&	Outputs 1 if both values are 1, else 0
||	Outputs 1 if one value is 1, else 0
min	Outputs the lowest value
max	Outputs the highest value
fmod	Divides X by Y, and outputs the remainder
pow	X to the power of Y

*Function info from Skyth

For example:

= 6 n 1 n 3 g +

would set the X scale of the bone to 4 (since it adds 3 and 1)

Tertiary Functions

h [function]

The h instruction gets three values from the stack, applies the function provided, then pushes the result. The function used can be:

cond	Returns second value if first is non-zero, otherwise third value is returned
rand	Unimplemented, acts as cond

*Function info from Korenkonder

For example:

= 6 n 2 n 1 n 0 h cond

would set the X scale of the bone to 2 (since the third value is 2 and the first value is 0)