Slow Glass Timing Commands

Slow Glass supports a number of ways to link actions or to synchronise their timings. The most straightforward is then, the other commands should probably be considered as advanced.

Then

This is quite straightforward, it just pauses the actions in this group until ALL the previous actions have completed. As discussed in the overview, most commands complete immediately, but some things, like loading images, moving sprites in to a location at a particular speed and so on take an indeterminate time to actually happen.

Using the then command will ensure that everything is finished before the next command is executed. Consider the example:

begin
    load truck.png as truck
    place truck at 100 100
    move truck to 800 100 at 37 pixels per second
then
    play beep-horn

Hopefully this sequence of actions is fairly readable - drive the truck across the screen, and once it arrives it beeps the horn!

Note that this command only stops the current action group (i.e. the set of actions that belong to a particular trigger). All other action groups and scenes will continue processing. You can use then as many times as you like to string together a sequence of actions.

Wait for a time

wait [for] {number} [{duration}]

This command starts a timer running for the specified duration.

The command completes when the timer expires.

The purpose of this command is to insert specific delays between actions, for example the structure here:

...do things...
wait for 3 seconds
...do more things...

Will ensure that all the first set of things complete, wait for 3 seconds and then start executing more things.

Wait for a condition

This command is similar to then but instead of waiting for previous commands to complete the conditions for restarting can be more complex.

wait (until | while) {logical-expression}

With the until keyword this command pauses execution until the logical expression evaluates to true. The while keyword does something and pauses execution for as long as the expression evaluates to true.

See the page on logic expressions for more examples of this.

Note that the built-in variable $FINISHED also provides information about the status of previous tasks, hence the then command is exactly equivalent (but much shorter) to:

wait until $FINISHED

Timing Accuracy

At present suspended actions are checked for updating at a minimum of every 500ms (twice per second), hence you should not assume a granularity better than one second.

This may change in the future.