let scl = 40;

let terrain = []

​

function setup() {

  createCanvas(400, 400, WEBGL);

  rows = height/scl;

  cols = width/scl;

  for (let x = 0; x < cols; x++){

    terrain[x] = []

    for (let y = 0; y < rows; y++){

      terrain[x][y] = 0 // default value

    }

  }

}

​

function draw() {

  background(0);

  fill(200, 200, 200, 50)

  let yoff = 0.0;

  for (let y = 0; y < rows; y++){

    let xoff = 0.0;

    for(let x = 0; x < cols; x++){

      terrain[x][y] = map(noise(xoff, yoff), 0, 1, -100, 100)

      xoff += 0.2

    }

    yoff += 0.2

  }

  print(terrain[5])

  rotateX(PI/3.0)

  translate(-width/2, -height/2)

  for (let y = 0; y < rows-1; y++){

    beginShape()

    for (let x = 0; x < cols-1; x++){

      vertex(x*scl, (y+1)*scl, terrain[x][y+1])

      vertex(x*scl, y*scl, terrain[x][y])

      vertex((x+1)*scl, y*scl, terrain[x+1][y])

      vertex((x+1)*scl, (y+1)*scl, terrain[x+1][y+1])

      vertex(x*scl, (y+1)*scl, terrain[x][y+1])

    }

    endShape();

  }

}