SCRIPT-8

README.md

This is a SCRIPT-8 cassette. Click here to boot it.

code.js

// title: Projectiles

const sin = x => Math.sin(x)
const cos = x => Math.cos(x)
const exp = x => Math.exp(x)

const x0 = 0
const y0 = 0
const g = 9.8 // gravity (m/s2)
const v = 48 // exit velocity (m/s)
const a = 0.6
const deg = a * 180 / Math.PI // launch angle (degrees)
//const a = deg * Math.PI / 180 // launch angle (radians)
const R = 121 // desired final distance
const k = 0.2

// calculate vt given R
const vt = R * g / (v * cos(a))
// 0.266

initialState = { x: 0, y: 0 }

update = state => {}

const project = p => ([p[0], 127 - p[1]])

draw = state => {
  clear()

  // axes and labels
  line(0, 0, 0, 127, 6)
  line(0, 127, 127, 127, 6)
  print(2, 0, 'baseball path simulator', 2)
  print(2, 30, `exit velocity: ${Math.round(v)} m/s`, 3)
  print(2, 40, `launch angle: ${Math.round(deg)} degrees`, 3)
  print(2, 50, 'estimated distance', 2)
  circFill(78, 52, 4, 2)
  print(2, 60, 'realistic distance', 0)
  circFill(78, 62, 4, 0)

  // create points
  const points = range(0, 10, 0.25)
    .map(t => {
      let x = 1
      let y = 1
x = (v * cos(a)/k)*(1 - exp(-k*t))
y = (1/k)*(v*sin(a)-g*t)+(1/(k*k))*(g - exp(-k*t)*(g + k*v*sin(a)))
//x = v * vt * cos(a) * (1 - exp(-g*t/vt)) / g
      return [x, y]
    })
    .filter(p => p[1] >= 0)
  
  // draw line...
  points.forEach((p, i, a) => {
    circFill(...project(p), 1, 0)
    if (i < a.length - 1) {
      const next = a[i + 1]
      line(...project(p), ...project(next), 3)
    }

    // and last circle
    if (i === a.length - 1) {
      circFill(...project(p), 2, 0)
      print(85, 60, `(${Math.round(p[0])} m)`, 0)
    }
  })
  
  circFill(...project([R, 0]), 4, 0)
  print(85, 50, `(${Math.round(R)} m)`, 2)
}