CEG:Operators

Source: https://spring.clan-sy.com/svn/spring/trunk/rts/Sim/Projectiles/ExplosionGenerator.cpp

Introduction

You are not limited to using fixed numbers in CEGs for positions, speeds, and so forth. Instead, you can use operators to change the CEG based on a variety of things.

Syntax

Operators are read left to right. The operand is always to the right of the operator. Spaces are ignored, except to separate numbers. A number with no operator defaults to addition.

The Buffer

CEG provides you with a buffer in which you can store numbers using the yank ('y') operator. This buffer can store 16 values, numbered 0 to 15.

Operators

These are listed in the format "Operator Name (operator)".

Index (i)

Multiplies the operand by the current count index. This index starts at 0 and increments every time the spawn is run, until the spawn has run a number of times equal to its count.

Suggested use: Spawning things in a line.

Rand (r)

Multiplies the operand by a random float between 0 and 1.

Suggested use: Keeping explosions from looking too "perfect", making explosions look different every time.

Damage ('d')

Multiplies the operand by damage.

Sawtooth ('m')

Calculates the floating-point remainder of the operand.

Discrete ('k')

Calculates the floor of the operand.

Sine ('s')

Calculates the sine of the operand.

Yank ('y')

Saves the running result into buffer[operand], and resets the running result to zero.

Multiply ('x')

Multiplies the running result by buffer[operand].

Add Buffer ('a')

Adds buffer[operand] to the running result.

Power ('p')

Raises the running result to the operandth power

Power Buffer ('q')

Raises the running result to the buffer[operand]th power.

Add (default)

Adds the operand to the running result. This operator is used if no other operator is given.

Example

i0.03125y0 -0.2x0x0

This multiplies the index by 0.03125 and saves it to buffer[0]. It then multiplies -0.2 by buffer[0] twice. The result is then -0.2 (i * 0.03125)^2.