The Slow Glass scripting language includes variables that are created automatically - you do not have to use make to create them, and their value may be different each time you use them.

I have adopted the convention that built-in variables are all upper-case and suggest that you use lower case for all other names.

The following built in variables are supported:

Current Time Information

• $SECONDS - number of seconds in the current minute (zero padded)
• $MINUTES - number of minutes in the current hour (zero padded)
• $HOURS - number of hours in the current day (24 hour, zero padded)

The following variables conatin a string either “yes” or “no” (this can be used directly in an IF statement, e.g. IF $MORNING.

• $MORNING - between 7 and 12 AM
• $AFTERNOON - between 12 and 5 PM
• $EVENING - between 6 and 9 PM
• $NIGHT - between 10 and 6 AM

(See also $SUNANGLE below)

Current Date Information

• $DAY - number of the day in the month (zero padded)
• $DAYOFMONTH - same as above
• $MONTH - number of the month (zero padded)
• $YEAR - $ digit year
• $DAYOFWEEK - number of day of the week, Sunday = 1
• $DAYOFYEAR - number of the current day in the year
• $DAYNAME - Name of the day as a string
• $MONTHNAME - Name of the month as a string
• $TIMEZONE - current timezone as a string
• $SEASON - season name for the current hemisphere as a string

Note that the season variable will be set to “autumn”, NOT “fall”.

Further “yes” / “no” variables:

• $WEEKDAY - Monday to Friday
• $WEEKEND - Saturday or Sunday
• $WINTER - calendar winter for the current hemisphere
• $SPRING - calendar spring for the current hemisphere
• $SUMMER - calendar summer for the current hemisphere
• $AUTUMN - calendar autumn for the current hemisphere
• $FALL - synonym for the above

Location Information

• $LATITUDE - current latitude, -180 to 180, East positive
• $LONGITUDE - current longitude, -90 to 90 North positive
• $LAT / $LON / $LONG - abbreviations for the above
• $SUNANGLE - a crude approximation of the angle of the sun above
  or below the horizon at this location on this date

The $SUNANGLE built-in variable can be used for instance to drive the brightness of the screen. Note that the calculation only has a resolution of 1 hour so testing it more frequently is not helpful. Instead, you can use a duration to interpolate changes over the hour, for example:

every 1 hour ` DARKEN background to ($SUNANGLE * some_factor) in 60 minutes`

Timing Information

• $ELAPSED - Number of seconds since the main scene was started
• $MILLIS - number of milliseconds since the main scene was started
• $FRAMENO - count of frames since the main scene was started
• $FINISHED - Have all the previous actions in the current set of actions completed yet?

Randomness

• $CHANCE - a random value between 0 and 1, different every time
• $PERCENT - a random value between 0 and 100, different every time
• $RANDOMX - a random location across the canvas, different every time
• $RANDOMY - a random location down the canvas, different every time
• $UNIQUE - a number guaranteed to be higher each time, but not necessarily sequential

Drawing Canvas Information

(All of this is subject to change as I’m figuring out how to best manage scaling for screen and canvas)

• $SCALEX
• $SCALEY
• $CENTREX
• $CENTREY
• $WIDTH
• $HEIGHT

Scene Information

• $SCENENAME - name of the current scene as a string
• $SCENEID - unique identifier for the current scene
• $LASTID - Unique identifier for the most recently started scene
• $LAST - name of the most recently started scene
• $PARAMETERS - space separated list of words passed to the scene
  in the start command
• $PARAMS - abbreviated version of the above
• $GRAVITY - the force of gravity for this scene, in pixels per second per second
• $GROUNDLEVEL - the assumed y coordinate of the ground for this scene

System Information

• $KEY - the key currently being pressed, or NONE if no key is in use
• $LASTKEY - the last key that was pressed by the user
• $CLICKX - coordinate of the last time the mouse was clicked (TBD)
• $CLICKY - coordinate of the last time the mouse was clicked (TBD)
• $MOUSEX - current coordinate of the pointer, or NONE
• $MOUSEY - current coordinate of the pointer, or NONE

Resource Information

All of the following contain a space separated list of resource names.

• $VARIABLES - list of all variable names in the current scene
• ${scene-name}:VARIABLES - list of all variables names in the named scene
• $VARIABLES#{tag-name} - list of all variables in the current scene with the named tag
• $SPRITES - list of all sprite names in the current scene
• ${scene-name}:SPRITES - list of all sprite names in the named scene
• $SPRITES#{tag-name} - list of all sprite in the current scene with the named tag
• $IMAGES - list of all image names in the current scene
• ${scene-name}:IMAGES - list of all image names in the named scene
• $IMAGES#{tag-name} - list of all image in the current scene with the named tag
• $SCENES - list of all scene names
• $SCENES#{tag-name} - list of all scene names with the given tag