3d terrain gen triangle-strip flyover colour

void setup() {
  size(600, 500, P3D);
  fill(255);
  stroke(0);
  cols = w/res;
  rows = 300;
  terrain = new float[cols][rows];
  frameRate(60);
  smooth();
}

int cols;
int rows;
int res = 10;
float noiseStart = 0;
float[][] terrain;
int w = 600;
int h = 1200;

void draw() {
  background(255);

  translate(0, height/2);
  rotateX(PI/3);
  translate(0, -height*2);

  float xOff = noiseStart;
  for (int i = 0; i < rows; i++) {
    float yOff = 0;
    for (int j = 0; j < cols; j++) {
      terrain[j][i] = constrain(map(noise(xOff, yOff), 0, 1, -100, 100),0,200);
      yOff+=0.1;
    }
    xOff+=0.1;
  }
  noiseStart-=0.05;
  
  for (int i = 0; i < rows-1; i++) {
  beginShape(TRIANGLE_STRIP);
    for (int j = 0; j < cols; j++) {
      if(terrain[j][i] < 1){
        fill(0,0,200);
      }
      else if(terrain[j][i]>100){
        fill(255);
      }
      else{
        fill(0,200,0);
      }
      vertex(j*res,i*res, terrain[j][i]);
      vertex(j*res,(i+1)*res, terrain[j][i+1]);
    }
  endShape();
  }
  
  println(frameRate);
}