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Complete program listing
A complete listing of the program discussed in this module is provided in Listing 11 .
| Listing 11 . Source code for Slick0190. |
|---|
/*Slick0190.java
Copyright 2013, R.G.BaldwinFairly complex animation using a sprite sheet.
Sprite moves to right during first third of theanimation. Sprite remains stationary during second third
of the animation. Sprite moves to the left back to thestarting point during the last third of the animation.
Much more complicated than Slick0180 for several reasonsincluding the following:
The sprite is moved horizontally during a portion but notall of the animation. Movement must be synchronized with
the animation frame counter.The sprite sheet contains only images of the dog facing
to the left. However, images of the dog facing to theright are also required. This requires that each image
on the sprite sheet be extracted and flipped horizontallybefore being fed to the Animation object for half of
the animation sequence.The display duration for images from the first row is
shorter than for images from the second row.Tested using JDK 1.7 under WinXP
*********************************************************/import org.newdawn.slick.AppGameContainer;
import org.newdawn.slick.BasicGame;import org.newdawn.slick.GameContainer;
import org.newdawn.slick.Graphics;import org.newdawn.slick.Image;
import org.newdawn.slick.SlickException;import org.newdawn.slick.SpriteSheet;
import org.newdawn.slick.Animation;import org.newdawn.slick.Color;
public class Slick0190 extends BasicGame{Image spriteSheetImage = null;
float spriteSheetWidth;float spriteSheetHeight;
int spritesPerRow = 5;int spritesPerColumn = 2;
int spriteWidth;int spriteHeight;
int targetDelta = 16;//msecSpriteSheet spriteSheet;
Animation animation = new Animation();//Horizontal and vertical drawing coordinates.
float spriteX = 0;float spriteY = 0;
//----------------------------------------------------//public Slick0190(){
//Call to superclass constructor is required.super("Slick0190, Baldwin.");
}//end constructor//----------------------------------------------------//
public static void main(String[]args)
throws SlickException{AppGameContainer app = new AppGameContainer(
new Slick0190(),450,120,false);app.start();//this statement is required
}//end main//----------------------------------------------------//
@Overridepublic void init(GameContainer gc)
throws SlickException {//Create a SpriteSheet object
spriteSheetImage = new Image("Slick0190a1.png");//Enlarge the sprite sheet.Image temp = spriteSheetImage.getScaledCopy(580,224);
spriteSheetImage = temp;spriteSheetWidth = spriteSheetImage.getWidth();
spriteSheetHeight = spriteSheetImage.getHeight();spriteWidth = (int)(spriteSheetWidth/spritesPerRow);
spriteHeight =(int)(spriteSheetHeight/spritesPerColumn);
//Instantiate a new spriteSheet object based on the// width and height of the individual tiles on the
// sheet.spriteSheet = new SpriteSheet(spriteSheetImage,
spriteWidth,spriteHeight);
//Populate the Animation object//Begin by adding four sets of five sprites from the
// top row with the images flipped to face right.for(int cntr = 0;cntr<4;cntr++){
for(int cnt = 0;cnt<5;cnt++){
animation.addFrame(spriteSheet.getSprite(cnt,0).getFlippedCopy(
true,false),100);}//end inner loop
}//end outer loop//Add two sets of five sprites from the bottom row// with the images flipped to face right.
for(int cntr = 0;cntr<2;cntr++){
for(int cnt = 0;cnt<5;cnt++){
animation.addFrame(spriteSheet.getSprite(cnt,1).getFlippedCopy(
true,false),400);}//end inner loop
}//end outer loop//Add two sets of five sprites from the bottom row
// with the images facing left.for(int cntr = 0;cntr<2;cntr++){
for(int cnt = 0;cnt<5;cnt++){
animation.addFrame(spriteSheet.getSprite(cnt,1),400);
}//end inner loop}//end outer loop//Add four sets of five sprites from the top row with
// the images facing leftfor(int cntr = 0;cntr<4;cntr++){
for(int cnt = 0;cnt<5;cnt++){
animation.addFrame(spriteSheet.getSprite(cnt,0),100);
}//end for loop}//end for loop
gc.setShowFPS(true);//display FPS//Set frame rate
gc.setTargetFrameRate((int)(1000/targetDelta));}//end init
//----------------------------------------------------//@Override
public void update(GameContainer gc, int delta)throws SlickException{
int stepSize = 15;//Distance the sprite movesint frame = animation.getFrame();//animation frame
int oneThird = animation.getFrameCount()/3;//Treat the entire animation in thirds with regard// to sprite movement. Move to the right during first
// third. Stay stationary during second third. Move// to left back to starting point during last third.
if(frame<oneThird){
//Sprite is moving to the right. Compute the new// position.
spriteX = frame*stepSize;}else if(frame<2*oneThird){
//Sprite is stationary. Don't change position}else if(frame<3*oneThird){
//Cause the sprite to turn around and start// moving to the left toward the starting point.
//Reduce frame count by number of frames during// which the sprite wasn't moving.
frame -= oneThird;//Compute the new position.
spriteX = (2*oneThird - frame)*stepSize;}//end else if}//end update
//----------------------------------------------------//public void render(GameContainer gc, Graphics g)
throws SlickException{g.setDrawMode(g.MODE_NORMAL);
g.setBackground(Color.gray);animation.draw(spriteX,spriteY);
}//end render}//end class Slick0190 |
-end-
Read also:
OpenStax, Anatomy of a game engine. OpenStax CNX. Feb 07, 2013 Download for free at https://legacy.cnx.org/content/col11489/1.13
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