Hold to charge, let go to fire

Challenge 18 of 20

Three lines: one that fills the meter while the key is held, and two in the release that turn the charge into a speed and empty the meter again. The comments give every number.

Write all three.

Your code JavaScript

Write all three.

Console print() output

0 / 48 frames · 400×400

Target

Yours

Yours over Target — ghosted shapes are in the target but missing from yours

Results

Press Run to check your code

Penalties: none this run

Report this challenge

Lesson Make It Interactive Yourself

The scaffolding comes away here. From now on the missing part is a whole line, and the comment directly above the gap says what that line has to do:

// set x to mouseX

You write the line. Everything you need has been in the last seven topics.

A few reminders, because they are the things people get wrong when nothing is filled in for them.

A handler changes a variable. It never draws. Whatever a handler draws is thrown away before anyone sees it, so put the change in a variable and let everyFrame draw from it.

Every line ends with a semicolon and every name is spelled exactly as it is elsewhere in the sketch. mouseX has a capital X. lampColour is spelled the way it is declared at the top.

A question about a round thing measures distance to its middle and compares against half its width:

distance(mouseX, mouseY, 200, 180) < 70

A question about a box is four comparisons joined with &&, using the same numbers the rectangle is drawn with:

mouseX > 120 && mouseX < 280 && mouseY > 140 && mouseY < 240

A stretch — the button being held, a key being held — is asked about in everyFrame with mouseIsPressed or keyIsPressed. A moment — the button going down, a key coming up — gets a handler.

There is one handler here you have not used yet. whenKeyTyped runs when a character key is typed, and key holds the character. It works exactly like whenKeyPressed and is in the reference drawer with the rest of them.

If a line does not work, read the message in the results panel. It gives the line number for a misspelled name, and the picture beside yours is what you are aiming at — step through it a frame at a time and find the frame where the two stop agreeing.