/** Statistics class for ray tracer performance numbers
 * Not a part of ray tracer, report generation only
 * Provides a single place for stats, rather than in several classes
 * Static for simplicity and global stats
 * TBD: stats per frame, camera?
 * @author: Phil Gage
 */
public class Statistics {

    // Pixel draw count for statistics
    static long pixelCount = 0;        // Primary Rays
    // Ray count for statistics
    static long rayCount = 0;          // Total Rays
    /** Intersection count for statistics,
        every object's intersect method must increment this */
    // (could be per camera?)
    static long intersectionCount = 0; // Intersections
    static long totalStart = System.currentTimeMillis();
    static long frameStart;

/**
 * Start report for each frame.
 * @param frame input frame number
 */
    public static void beginFrame (int frame) {
        frameStart = System.currentTimeMillis();
//tbd zero frame stats...
    }

/**
 * Print report for each frame.
 * @param frame input frame number
 */
    public static void endFrame (int frame) {
        double secs = (System.currentTimeMillis() - frameStart)/1000.0;
        System.out.println("Frame "+ frame + " secs: " + secs);
//tbd print frame stats...
    }

/**
 * Print report for total run.
 * @param world input World object
 */
    public static void report (World world) {
        System.out.println ("Ray Tracing Report");

        // Print stats
        double secs = (System.currentTimeMillis() - totalStart)/1000.0;
        System.out.println("Total secs: " + secs);
        if (world.grid != null) {
            System.out.println("Grid size= " + world.grid.size);
//            if (camera.bitmap != null)
//                System.out.println("Bitmap size=" + world.grid.size);
//            else
//                System.out.println("No bitmap");
        }
        else
            System.out.println("No grid");
        System.out.println("Primary Rays:  " + pixelCount);
        System.out.println("Total Rays:    " + rayCount);
        System.out.println("Intersections: " + intersectionCount);
    }

}