Workshop › Missile Command-style Defense › Step 14 of 35

Interceptors fly

What we are doing

Interceptors fly like enemy missiles, only much faster (7 pixels per frame), and are drawn as green lines from the base.

```js
const SHOT_SPEED = 7

  for (const s of shots) {
    if (stepTowards(s, SHOT_SPEED)) {
      s.done = true
    }
  }
  shots = shots.filter((s) => !s.done)

  ctx.strokeStyle = '#a3e635'
  for (const s of shots) {
    ctx.beginPath()
    ctx.moveTo(BASE.x, BASE.y)
    ctx.lineTo(s.x, s.y)
    ctx.stroke()
  }
```

What it means

SHOT_SPEED is the interceptors' speed.
In update, the same mark-then-filter pattern as the missiles. The { } stay: the next steps add more inside.
In draw, each interceptor is a green line from the base to where it is.

Your turn

Under const CITY_XS = ... write const SHOT_SPEED = 7.
In update, between the countdown block and the missile loop, write the shots loop and its filter (empty line above).
In draw, under the missile trail loop, write the green lines.

Skills: Velocity and gravity, Drawing on a canvas

← Click the sky An explosion that grows and shrinks →

All steps