----------------------------------

Based on Photon text motion illustration by Erik Van Blokland:

https://www.youtube.com/watch?v=WFYTGlLeUfY

​

+ Based on 3D Black Hole by Juan Carlos Ponce Campuzano:

https://github.com/jcponce/jcponce.github.io/tree/master/sketches/blackhole

​

++ ^Based on the Coding Train Challenge #144:

https://thecodingtrain.com/CodingChallenges/144-black-hole-visualization.html

​

with The p5.EasyCam library

https://github.com/diwi/p5.EasyCam

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*/

​

​

let myText = "Goodbye World"

let pg // offscreen drawing canvas

​

const c = 30 // "Speed of Light" constant

const G = 6 // "Universal Gravitational" constant

const m = 5000 // "Mass"

​

let camdist = 350 // Camera distance

let dt = .25 // Delta time step

​

let photons = []

let m87;

​

function setup() { 

  createCanvas(500, 500, WEBGL);

  createEasyCam({distance:camdist});  

  // Set up offscreen text setting

  pg = createGraphics(500,500)

  pg.textSize(70)

  pg.textAlign(CENTER, CENTER)

  pg.background(123)

  pg.text(myText, width/2, height/2)

  // Push a photon if the offscreen pixel has text

  // ---------------------------------------------

  for (let i = 0; i < pg.width; i++) {

    for (let j = 0; j < pg.height; j++) {

      let pixRGBA = pg.get(i, j)

      if (pixRGBA[0] < 120) {

        photons.push(new Photon(i-width/2, j-height/2, camdist*1.25))

      }

    }

  }

}

​

function draw() {

  background(30);

  m87 = new Blackhole(0, 0, 0, m);

  m87.display();

  for (let k = 0; k < photons.length; k++) {

    let p = photons[k];

    m87.pull(p)

    p.update()

    p.display()

  }

}