refreshBackground = function() {
      if (!curSketch.options.isTransparent) {
        if (p.use3DContext) {
          // fill background default opaque gray
          curContext.clearColor(204 / 255, 204 / 255, 204 / 255, 1.0);
          curContext.clear(curContext.COLOR_BUFFER_BIT | curContext.DEPTH_BUFFER_BIT);
        } else {
          // fill background default opaque gray
          curContext.fillStyle = "rgb(204, 204, 204)";
          curContext.fillRect(0, 0, p.width, p.height);
          isFillDirty = true;
        }
      }
    }
Sets the seed value for noise(). By default, noise() produces different results each
time the program is run. Set the value parameter to a constant to return the same
pseudo-random numbers each time the software is run.

@param {int} seed         int

@returns {float}

@see random
@see radomSeed
@see noise
@see noiseDetail