I tried to create some random points inside a boundary defined by color (RGB(100,100,100)). If each new point's relating pixel is RGB(100,100,100), then create the point; vice versa. However, I find it really hard to work with this array. anybody has an suggestion?

PImage b;
PImage c;

float envSize = 280;
int population = 1000;

color[] imgPixels = new color[parseInt(envSize*2)*parseInt(envSize)];
kVec strPt;

//setup
void setup() {
  smooth();
  b = loadImage("background.gif");
  size(b.width,b.height,P3D);

  c = loadImage("boundary.png");
  image(c,-width/2,-height/2);

  loadPixels();
  for(int i = 0; i < envSize*2*envSize; i++){
    imgPixels[i] = pixels[i];
  }

  for(int i = 0; i < population; i++) {

    strPt = new kVec(random(0,envSize),random(0,envSize/2),random(0,envSize/3));
    colorMode(RGB);
    if(pixels[parseInt(strPt.y)* width + parseInt(strPt.x)] == color(100,100,100)){
      //create the point here;
    }
  }

}