TrainSprite.java

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// This file is part of MicropolisJ.
// Copyright (C) 2013 Jason Long
// Portions Copyright (C) 1989-2007 Electronic Arts Inc.
//
// MicropolisJ is free software; you can redistribute it and/or modify
// it under the terms of the GNU GPLv3, with additional terms.
// See the README file, included in this distribution, for details.

package micropolisj.engine;

import static micropolisj.engine.TileConstants.*;

public class TrainSprite extends Sprite
{
        static int [] Cx = { 0, 16, 0, -16 };
        static int [] Cy = { -16, 0, 16, 0 };
        static int [] Dx = { 0, 4, 0, -4, 0 };
        static int [] Dy = { -4, 0, 4, 0, 0 };
        static int [] TrainPic2 = { 1, 2, 1, 2, 5 };
        static final int TRA_GROOVE_X = 8;
        static final int TRA_GROOVE_Y = 8;

        static final int FRAME_NORTHSOUTH = 1;
        static final int FRAME_EASTWEST = 2;
        static final int FRAME_NW_SE = 3;
        static final int FRAME_SW_NE = 4;
        static final int FRAME_UNDERWATER = 5;

        static final int DIR_NORTH = 0;
        static final int DIR_EAST = 1;
        static final int DIR_SOUTH = 2;
        static final int DIR_WEST = 3;
        static final int DIR_NONE = 4; //not moving

        public TrainSprite(Micropolis engine, int xpos, int ypos)
        {
                super(engine, SpriteKind.TRA);
                this.x = xpos * 16 + TRA_GROOVE_X;
                this.y = ypos * 16 + TRA_GROOVE_Y;
                this.offx = -16;
                this.offy = -16;
                this.dir = DIR_NONE;   //not moving
        }

        @Override
        public void moveImpl()
        {
                if (frame == 3 || frame == 4) {
                        frame = TrainPic2[this.dir];
                }
                x += Dx[this.dir];
                y += Dy[this.dir];
                if (city.acycle % 4 == 0) {
                        // should be at the center of a cell, if not, correct it
                        x = (x/16) * 16 + TRA_GROOVE_X;
                        y = (y/16) * 16 + TRA_GROOVE_Y;
                        int d1 = city.PRNG.nextInt(4);
                        for (int z = d1; z < d1 + 4; z++) {
                                int d2 = z % 4;
                                if (this.dir != DIR_NONE) { //impossible?
                                        if (d2 == (this.dir + 2) % 4)
                                                continue;
                                }

                                int c = getChar(this.x + Cx[d2], this.y + Cy[d2]);
                                if (((c >= RAILBASE) && (c <= LASTRAIL)) || //track?
                                        (c == RAILVPOWERH) ||
                                        (c == RAILHPOWERV))
                                {
                                        if ((this.dir != d2) && (this.dir != DIR_NONE)) {
                                                if (this.dir + d2 == 3)
                                                        this.frame = FRAME_NW_SE;
                                                else
                                                        this.frame = FRAME_SW_NE;
                                        }
                                        else {
                                                this.frame = TrainPic2[d2];
                                        }

                                        if ((c == RAILBASE) || (c == (RAILBASE+1))) {
                                                //underwater
                                                this.frame = FRAME_UNDERWATER;
                                        }
                                        this.dir = d2;
                                        return;
                                }
                        }
                        if (this.dir == DIR_NONE) {
                                // train has nowhere to go, so retire
                                this.frame = 0;
                                return;
                        }
                        this.dir = DIR_NONE;
                }
        }
}