Effect file

.effect

Resources::GetEffect

File format

Param

These are values that can be sent to the effect and used in the effect expressions, for example these are used to send in an angle to most projectiles and rotate their sprites accordingly.

   <param name="angle" default="0" />

Expression language

This is a simple language for creating dynamic values that can change over time for the effect components, for example if you want a sprite to fade out during the effect you might do something like

   color-a="1 - t"

or if you want it to pulse during the effect you could do

   color-a="sin(t) / 2 + 0.5"

Parameters

There are four built in parameters for effects,

t	time	0-1
l	loop	0+
u	unit	Not 0
i	index	0+

The time parameter says where in the effect "timeline" you are, so it goes from 0 to 1 over the length of the effect, if the effect is looping then when time hits 1 it will reset to 0 and loop will increase by 1. So an expression like,

   t + l

will simply start at 0 and go up forever until the effect is stopped.

The unit parameter simply contains the unit id for the unit that is currently playing the effect, this is fairly unique but can be reused for future effects getting played.

And the index parameter only exists inside a trail effect component and simply contains the id of the current segment in the trail.

More parameters can be added to an effect using the <param> tag and has to be filled with values by scripts.

Functions

sin	Simple sine function, takes radians
cos	Simple cosine function, takes radians
abs	The absolute value, basically just turns negative values in to positive ones
ceil	Rounds a value up to the next or current integer
floor	Rounds a value down to the previous or current integer
exp	Returns e raised to the specified power
log	Returns the natural (base e) logarithm of a specified number
saturate	Clamps a number to 0-1
sign	The sign of the number (-1, 0 or 1)
sqrt	Square root
clamp	clamp(v, min, max) - Clamps v so it is not lower than min or higher than max
lerp	lerp(t, a, b) - Linearly interpolates from a to b using t (0-1)
smoothstep	smoothstep(t, a, b) - Smoothly interpolates from a to b using t (0-1)
min	Returns the smallest of two values
max	Returns the largest of two values
pow	pow(a, b) - Returns a to the power of b
rand	Returns a random value based on an input value, for example rand(t) returns a new value every frame while rand(l) returns a new value every time the effect loops
wposx	wposx(n) - Returns the x coordinate of where this unit was n frames ago relative to their current position
wposy	wposy(n) - Returns the y coordinate of where this unit was n frames ago relative to their current position