code: package org.sunflow.core;
  
  /**
   * Represents a mapping from the 3D scene onto the final image. A camera lens is
   * responsible for determining what ray to cast through each pixel.
   */
  public interface CameraLens extends RenderObject {
      /**
       * Create a new {@link Ray ray}to be cast through pixel (x,y) on the image
       * plane. Two sampling parameters are provided for lens sampling. They are
       * guarenteed to be in the interval [0,1). They can be used to perturb the
       * position of the source of the ray on the lens of the camera for DOF
       * effects. A third sampling parameter is provided for motion blur effects.
       * Note that the {@link Camera} class already handles camera movement motion
       * blur. Rays should be generated in camera space - that is, with the eye at
       * the origin, looking down the -Z axis, with +Y pointing up.
       * 
       * @param x x coordinate of the (sub)pixel
       * @param y y coordinate of the (sub)pixel
       * @param imageWidth image width in pixels
       * @param imageHeight image height in pixels
       * @param lensX x lens sampling parameter
       * @param lensY y lens sampling parameter
       * @param time time sampling parameter
       * @return a new ray passing through the given pixel
       */
      public Ray getRay(float x, float y, int imageWidth, int imageHeight, double lensX, double lensY, double time);
  }