figure.java

tetris是一款用java编写的小游戏--俄罗斯方块

/*
 * @(#)Figure.java
 *
 * This work is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of
 * the License, or (at your option) any later version.
 *
 * This work is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * Copyright (c) 2003 Per Cederberg. All rights reserved.
 */

package net.percederberg.tetris;

import java.awt.Color;

/**
 * A class representing a Tetris square figure. Each figure consists 
 * of four connected squares in one of seven possible constellations. 
 * The figures may be rotated in 90 degree steps and have sideways and 
 * downwards movability.<p>
 * 
 * Each figure instance can have two states, either attached to a 
 * square board or not. When attached, all move and rotation 
 * operations are checked so that collisions do not occur with other
 * squares on the board. When not attached, any rotation can be made 
 * (and will be kept when attached to a new board).
 *
 * @version  1.2
 * @author   Per Cederberg, [e-mail]
 */
public class Figure extends Object {

    /**
     * A figure constant used to create a figure forming a square.
     */
    public static final int SQUARE_FIGURE = 1;

    /**
     * A figure constant used to create a figure forming a line.
     */
    public static final int LINE_FIGURE = 2;

    /**
     * A figure constant used to create a figure forming an "S".
     */
    public static final int S_FIGURE = 3;

    /**
     * A figure constant used to create a figure forming a "Z".
     */
    public static final int Z_FIGURE = 4;

    /**
     * A figure constant used to create a figure forming a right angle.
     */
    public static final int RIGHT_ANGLE_FIGURE = 5;

    /**
     * A figure constant used to create a figure forming a left angle.
     */
    public static final int LEFT_ANGLE_FIGURE = 6;

    /**
     * A figure constant used to create a figure forming a triangle.
     */
    public static final int TRIANGLE_FIGURE = 7;

    /**
     * The square board to which the figure is attached. If this 
     * variable is set to null, the figure is not attached.
     */
    private SquareBoard board = null;

    /**
     * The horizontal figure position on the board. This value has no
     * meaning when the figure is not attached to a square board.
     */
    private int xPos = 0;

    /**
     * The vertical figure position on the board. This value has no
     * meaning when the figure is not attached to a square board.
     */
    private int yPos = 0;

    /**
     * The figure orientation (or rotation). This value is normally 
     * between 0 and 3, but must also be less than the maxOrientation 
     * value.
     * 
     * @see #maxOrientation
     */
    private int orientation = 0;

    /**
     * The maximum allowed orientation number. This is used to reduce 
     * the number of possible rotations for some figures, such as the
     * square figure. If this value is not used, the square figure 
     * will be possible to rotate around one of its squares, which 
     * gives an erroneous effect.
     * 
     * @see #orientation
     */
    private int maxOrientation = 4;

    /**
     * The horizontal coordinates of the figure shape. The coordinates 
     * are relative to the current figure position and orientation.
     */
    private int[] shapeX = new int[4];

    /**
     * The vertical coordinates of the figure shape. The coordinates 
     * are relative to the current figure position and orientation.
     */
    private int[] shapeY = new int[4];

    /**
     * The figure color.
     */
    private Color color = Color.white;

    /**
     * Creates a new figure of one of the seven predefined types. The
     * figure will not be attached to any square board and default
     * colors and orientations will be assigned.
     *
     * @param type      the figure type (one of the figure constants)
     * 
     * @see #SQUARE_FIGURE
     * @see #LINE_FIGURE
     * @see #S_FIGURE
     * @see #Z_FIGURE
     * @see #RIGHT_ANGLE_FIGURE
     * @see #LEFT_ANGLE_FIGURE
     * @see #TRIANGLE_FIGURE
     * 
     * @throws IllegalArgumentException if the figure type specified
     *             is not recognized
     */
    public Figure(int type) throws IllegalArgumentException {
        initialize(type);
    }
    
    /**
     * Initializes the instance variables for a specified figure type.
     * 
     * @param type      the figure type (one of the figure constants)
     * 
     * @see #SQUARE_FIGURE
     * @see #LINE_FIGURE
     * @see #S_FIGURE
     * @see #Z_FIGURE
     * @see #RIGHT_ANGLE_FIGURE
     * @see #LEFT_ANGLE_FIGURE
     * @see #TRIANGLE_FIGURE
     * 
     * @throws IllegalArgumentException if the figure type specified
     *             is not recognized
     */
    private void initialize(int type) throws IllegalArgumentException {
        
        // Initialize default variables
        board = null;
        xPos = 0;
        yPos = 0;
        orientation = 0;

        // Initialize figure type variables
        switch (type) {
        case SQUARE_FIGURE :
            maxOrientation = 1;
            color = Configuration.getColor("figure.square", "#ffd8b1");
            shapeX[0] = -1;
            shapeY[0] = 0;
            shapeX[1] = 0;
            shapeY[1] = 0;
            shapeX[2] = -1;
            shapeY[2] = 1;
            shapeX[3] = 0;
            shapeY[3] = 1;
            break;
        case LINE_FIGURE :
            maxOrientation = 2;
            color = Configuration.getColor("figure.line", "#ffb4b4");
            shapeX[0] = -2;
            shapeY[0] = 0;
            shapeX[1] = -1;
            shapeY[1] = 0;
            shapeX[2] = 0;
            shapeY[2] = 0;
            shapeX[3] = 1;
            shapeY[3] = 0;
            break;
        case S_FIGURE :
            maxOrientation = 2;
            color = Configuration.getColor("figure.s", "#a3d5ee");
            shapeX[0] = 0;
            shapeY[0] = 0;
            shapeX[1] = 1;
            shapeY[1] = 0;
            shapeX[2] = -1;
            shapeY[2] = 1;
            shapeX[3] = 0;
            shapeY[3] = 1;
            break;
        case Z_FIGURE :
            maxOrientation = 2;
            color = Configuration.getColor("figure.z", "#f4adff");
            shapeX[0] = -1;
            shapeY[0] = 0;
            shapeX[1] = 0;
            shapeY[1] = 0;
            shapeX[2] = 0;
            shapeY[2] = 1;
            shapeX[3] = 1;
            shapeY[3] = 1;
            break;
        case RIGHT_ANGLE_FIGURE :
            maxOrientation = 4;
            color = Configuration.getColor("figure.right", "#c0b6fa");
            shapeX[0] = -1;
            shapeY[0] = 0;
            shapeX[1] = 0;
            shapeY[1] = 0;
            shapeX[2] = 1;
            shapeY[2] = 0;
            shapeX[3] = 1;
            shapeY[3] = 1;
            break;
        case LEFT_ANGLE_FIGURE :
            maxOrientation = 4;
            color = Configuration.getColor("figure.left", "#f5f4a7");
            shapeX[0] = -1;
            shapeY[0] = 0;
            shapeX[1] = 0;
            shapeY[1] = 0;
            shapeX[2] = 1;
            shapeY[2] = 0;
            shapeX[3] = -1;
            shapeY[3] = 1;
            break;
        case TRIANGLE_FIGURE :
            maxOrientation = 4;
            color = Configuration.getColor("figure.triangle", "#a4d9b6");
            shapeX[0] = -1;
            shapeY[0] = 0;
            shapeX[1] = 0;
            shapeY[1] = 0;
            shapeX[2] = 1;
            shapeY[2] = 0;
            shapeX[3] = 0;
            shapeY[3] = 1;
            break;
        default :
            throw new IllegalArgumentException("No figure constant: " + 
                                               type);
        }
    }

    /**
     * Checks if this figure is attached to a square board.
     * 
     * @return true if the figure is already attached, or
     *         false otherwise
     */
    public boolean isAttached() {
        return board != null;
    }

    /**
     * Attaches the figure to a specified square board. The figure 
     * will be drawn either at the absolute top of the board, with 
     * only the bottom line visible, or centered onto the board. In 
     * both cases, the squares on the new board are checked for 
     * collisions. If the squares are already occupied, this method
     * returns false and no attachment is made.<p>
     *
     * The horizontal and vertical coordinates will be reset for the 
     * figure, when centering the figure on the new board. The figure
     * orientation (rotation) will be kept, however. If the figure was
     * previously attached to another board, it will be detached from
     * that board before attaching to the new board.
     *
     * @param board     the square board to attach to
     * @param center    the centered position flag
     * 
     * @return true if the figure could be attached, or
     *         false otherwise
     */
    public boolean attach(SquareBoard board, boolean center) {
        int  newX;
        int  newY;
        int  i;

        // Check for previous attachment
        if (isAttached()) {
            detach();
        }

        // Reset position (for correct controls)
        xPos = 0;
        yPos = 0;

        // Calculate position
        newX = board.getBoardWidth() / 2;
        if (center) {
            newY = board.getBoardHeight() / 2;
        } else {
            newY = 0;
            for (i = 0; i < shapeX.length; i++) {
                if (getRelativeY(i, orientation) - newY > 0) {
                    newY = -getRelativeY(i, orientation);
                }
            }
        }

        // Check position