runnerserpent.java

来自「Position.java ：辅助类 SerpentGameCanvas.jav」· Java 代码 · 共 73 行

import javax.microedition.midlet.*;
import javax.microedition.lcdui.*;
import java.util.*;

class RunnerSerpent extends GreedySerpent
{
	private static int count=0;
	
	RunnerSerpent(SerpentGameCanvas canv, Maze m, Position initPos, int len) {
		super(canv, m, initPos, len);
		direction=MOVE_UP;
		type=RUNNER;
	}

	protected boolean moveAhead()
	{
		synchronized(gameCanvas.npc) {
			if( !bLive ) return false;
			DirectionHelper helper=new DirectionHelper(maze, head);
			int choices=helper.numOfChoices();
			switch( choices ) {
				case 1:		//	掉头
					direction=helper.getChoice(0);
					break;
				case 2:		//	单向
					helper.kickChoiceByValue( helper.reverseDirection(direction) );
					direction=helper.getChoice(0);
					break;
				case 3:
				case 4:	//	路口
					helper.kickChoiceByValue( helper.reverseDirection(direction) );
					choices--;
					int randNumber=Math.abs( gameCanvas.rand.nextInt() % choices );
					direction=helper.getChoice(randNumber);
					break;
				case 0:
					System.err.println("no direction to follow -- impossible!");
					break;
				default:
					System.err.println("above 4 direction to select -- impossible!");
			}
	
			Position posDiff=new Position();
			switch(direction) {
				case MOVE_UP: 
					posDiff.setValue(0,-1);
					break;			
				case MOVE_DOWN:
					posDiff.setValue(0,1);
					break;			
				case MOVE_LEFT:
					posDiff.setValue(-1,0);
					break;			
				case MOVE_RIGHT:
					posDiff.setValue(1,0);
					break;			
				default:
			}
			if( conflictWithWall(posDiff)) {
				System.err.println("hit wall after direction selection -- impossible!");
				return false;
			}
			
			for( int i=body.size()-1;i>=1;i-- ) {
				((Position)body.elementAt(i)).setValue( (Position)body.elementAt(i-1) );
			}
			((Position)body.elementAt(0)).setValue(head);
			head.add(posDiff);
		}
		return true;
	}
}