import java.lang.Double;

/**
 * The DepthBuffer class implements a DepthBuffer and its pass test.
 */
public class DepthBuffer {
    private double[] buffer;
    int width;
    int height;

    /**
     * Constructs a DepthBuffer of size width x height.
     * The buffer is initially cleared.
     */
    public DepthBuffer(int width, int height) {
        buffer = new double[width * height];
        this.width = width;
        this.height = height;
        clear();
    }

    /**
     * Clears the buffer to infinite depth for all fragments.
     */
    public void clear() {
        for (int i = 0; i < height; i++) {
            for (int j = 0; j < width; j++) {
                buffer[i * width + j] = Double.POSITIVE_INFINITY;
                // buffer[i * width + j] = 0;
            }
        }

    }

    /**
     * Test if a fragment passes the DepthBuffer test, i.e. is the fragment the
     * closest at its position.
     */
    public boolean testFragment(Fragment fragment) {
        if ((fragment.getX() >= 0) && (fragment.getX() < width) && (fragment.getY() >= 0)
                && (fragment.getY() < height)) {

            if (fragment.getDepth() < this.buffer[fragment.getY() * width + fragment.getX()]) {
                return true;
            }

            // if (fragment.getDepth() > this.buffer[fragment.getY() * width +
            // fragment.getX()]) {
            // return true;
            // }

            return false;
        } else {
            return false;
        }
    }

    /**
     * Writes the fragment depth to the buffer
     */
    public void writeFragment(Fragment fragment) {
        if (testFragment(fragment)) {
            this.buffer[fragment.getY() * width + fragment.getX()] = fragment.getDepth();
        }
    }
}