zhangman523 首页归档标签分类关于
手把手教你写蛇蛇大作战(二)
|libgdxgame

这篇我们主要实现游戏的主要框架 并且绘制一条蛇 让它动起来

首先我们看看那本篇完成的最终效果图吧

snakeIo

配置工程

如果你没有配置运行工程的话，会报错。

配置destop工程

在菜单栏找到Run 选择 Edit Configurations 然后配置Working directory 配置工作区域选择 android 工程下的assets 目录 重新运行，OK！

编写代码框架

在core工程下的src 目录下新建 WorldController.java(控制游戏)和WorldRenderer.java(渲染游戏)

在 WorldController.java 添加update 方法

1
2
3
public void update(float deltaTime) {
    //用于更新 游戏对象
}

在WorldRenderer.java 添加 render方法

1
2
3
public void render() {
    //绘制游戏对象    
}

WorldRenderer.java 修改为下面一样

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
public class WorldRenderer implements Disposable {

    private WorldController worldController;
    private SpriteBatch spriteBatch;


    public WorldRenderer(WorldController worldController) {
        this.worldController = worldController;
        init();
    }

    private void init() {
        spriteBatch = new SpriteBatch();
    }

    public void render() {
        spriteBatch.begin();
        //绘制对象
        spriteBatch.end();
    }


    @Override
    public void dispose() {
        spriteBatch.dispose();
    }
}

然后修改SnakeIo.java

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
public class SnakeIo extends ApplicationAdapter {
    private WorldController worldController;
    private WorldRenderer worldRenderer;

    @Override
    public void create() {
        worldController = new WorldController();
        worldRenderer = new WorldRenderer(worldController);
    }

    @Override
    public void render() {
        worldController.update(Gdx.graphics.getDeltaTime());//更新worldController
        Gdx.gl.glClearColor(1, 1, 1, 1);
        Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT);
        worldRenderer.render();//绘制
    }

    @Override
    public void dispose() {
        worldRenderer.dispose();
        worldController.dispose();
    }
}

这个很简单 将WorldController 和WorldRenderer 实例化
然后在render 方法里面调用更新和绘制方法

编写蛇对象

在这之前我们需要准备两张图片
eyes

body

一张是眼睛图片，一张是身体的图片 将图片copy 进destop工程
目录下的images下

我们先把图片打包
在DesktopLauncher.java 添加如下代码

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
public static void main(String[] arg) {
        if (true) {
            TexturePacker.Settings settings = new TexturePacker.Settings();
            settings.maxHeight = 1024;
            settings.maxWidth = 1024;
            settings.duplicatePadding = false;
            settings.debug = false;
            TexturePacker.process(settings, "../../desktop/images",
                    "../../android/assets/images", "snake");
        }
        LwjglApplicationConfiguration config = new LwjglApplicationConfiguration();
        config.width = 800;
        config.height = 480;
        config.samples = 3;
        new LwjglApplication(new SnakeIo(), config);
}

运行下工程 就会在android 工程下的 assets/images 目录下生成 snake.png 和 snake.atlas 把两张图打包成一张图片

我们在core工程的src 目录下新建objects 包
然后新建AbstractGameObject.java和Snake.java
AbstractGameObject 为 基础的抽象游戏对象
具体实现

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
public abstract class AbstractGameObject {
    public Vector2 position;
    public Vector2 dimension;
    public Vector2 origin;
    public Vector2 scale;
    public float rotation;

    public Vector2 velocity;//This is the object's current speed in m/s.
    //This is the object's positive and negative maximum speed in m/s.
    public Vector2 terminalVelocity;
    public Vector2 friction;

    public Vector2 acceleration;//This is the object's constant acceleration in m/s2.
    public Rectangle bounds;

    public Body body;

    public float stateTime;
    public Animation<TextureRegion> animation;

    public AbstractGameObject() {
        position = new Vector2();
        dimension = new Vector2(1, 1);
        origin = new Vector2();
        scale = new Vector2(1, 1);
        rotation = 0;

        velocity = new Vector2();
        terminalVelocity = new Vector2();
        friction = new Vector2();
        acceleration = new Vector2();
        bounds = new Rectangle();
    }

    public void update(float deltaTime) {
        stateTime += deltaTime;
        if (body == null) {
            updateMotionX(deltaTime);
            updateMotionY(deltaTime);
            //move to new position
            position.x += velocity.x * deltaTime;
            position.y += velocity.y * deltaTime;
        } else {
            position.set(body.getPosition());
            rotation = body.getAngle() * MathUtils.radiansToDegrees;
        }
    }

    protected void updateMotionX(float deltaTime) {
        if (velocity.x != 0) {
            //Apply friction
            if (velocity.x > 0) {
                velocity.x = Math.max(velocity.x - friction.x * deltaTime, 0);
            } else {
                velocity.x = Math.min(velocity.x + friction.x * deltaTime, 0);
            }
        }
        //Apply acceleration
        velocity.x += acceleration.x * deltaTime;
        // Make sure the object's velocity does not exceed the
        // positive or negative terminal velocity
        velocity.x = MathUtils.clamp(velocity.x, -terminalVelocity.x, terminalVelocity.x);
    }

    protected void updateMotionY(float deltaTime) {
        if (velocity.y != 0) {
            //Apply friction
            if (velocity.y > 0) {
                velocity.y = Math.max(velocity.y - friction.y * deltaTime, 0);
            } else {
                velocity.y = Math.min(velocity.y + friction.y * deltaTime, 0);
            }
        }
        //Apply acceleration
        velocity.y += acceleration.y * deltaTime;
        // Make sure the object's velocity does not exceed the
        // positive or negative terminal velocity
        velocity.y = MathUtils.clamp(velocity.y, -terminalVelocity.y, terminalVelocity.y);
    }

    public void setAnimation(Animation<TextureRegion> animation) {
        this.animation = animation;
        stateTime = 0;
    }

    public abstract void render(SpriteBatch batch);
}

Snake.java

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
public class Snake extends AbstractGameObject implements Disposable {
    private static final String TAG = Snake.class.getSimpleName();
    TextureRegion eyes;//眼睛
    TextureRegion body;//身体
    private AssetManager assetManager;

    private int length = 100 * 80;//长度
    private float speed = 8 * 10;//速度
    public Array<Movement> movements;//运动path


    public Snake() {
        initRegion();
        init();
    }

    private void init() {
        dimension.set(20, 20);
        origin.set(dimension.x / 2, dimension.y / 2);
        terminalVelocity.set(100, 100);
        position.set(50, 120);
        rotation = -90;
        scale.set(0.7f, 0.7f);
        bounds.set(0, 0, dimension.x, dimension.y);
        movements = new Array<Movement>();
        velocity.set(speed, 0);
    }

    private void initRegion() {
        assetManager = new AssetManager();
        assetManager.setErrorListener(new AssetErrorListener() {
            @Override
            public void error(AssetDescriptor asset, Throwable throwable) {
                Gdx.app.error(TAG, "Couldn't load asset '"
                        + asset.fileName + "'", throwable);
            }
        });
        assetManager.load("images/snake.atlas", TextureAtlas.class);
    
        assetManager.finishLoading();
        TextureAtlas atlas = assetManager.get("images/snake.atlas");
        // enable texture filtering for pixel smoothing;
        for (Texture texture : atlas.getTextures()) {
            texture.setFilter(Texture.TextureFilter.Linear, Texture.TextureFilter.Linear);
        }
        eyes = atlas.findRegion("eyes");
        body = atlas.findRegion("body");
    }

    @Override
    public void render(SpriteBatch batch) {
        float snakeLength = this.length;
        for (int i = movements.size - 1; i >= 0; i--) {
            Movement movement = movements.get(i);
            float x = movement.position.x;
            float y = movement.position.y;
            if (snakeLength > 0 && snakeLength < movement.speed) {
                if (i != movements.size - 1) {
                    Movement lm = movements.get(i + 1);
                    float ratio = snakeLength / movement.speed;
                    x = lm.position.x - (lm.position.x - x) * ratio;
                    y = lm.position.y - (lm.position.y - y) * ratio;
                }
            } else if (snakeLength < 0) {
                break;
            }
            snakeLength -= movement.speed;
            TextureRegion reg = body;
            batch.setColor(Color.valueOf("#F65454"));//set snake body color
            batch.draw(reg.getTexture(), x,
                    y, origin.x, origin.y, dimension.x,
                    dimension.y, scale.x, scale.y, rotation, reg.getRegionX(),
                    reg.getRegionY(), reg.getRegionWidth(), reg.getRegionHeight(),
                    false, false);
        }
        TextureRegion reg = eyes;
        batch.setColor(Color.WHITE.toFloatBits());//reset  color
        batch.draw(reg.getTexture(), position.x,
                position.y, origin.x, origin.y, dimension.x - 0.1f,
                dimension.y - 0.1f, scale.x, scale.y, rotation, reg.getRegionX(),
                reg.getRegionY(), reg.getRegionWidth(), reg.getRegionHeight(),
                false, false);
    }

    @Override
    public void update(float deltaTime) {
        movements.add(new Movement(new Vector2(position), speed));
        if (movements.size > length) {
            movements.removeValue(movements.first(), true);
        }
        super.update(deltaTime);
    }

    @Override
    public void dispose() {
        assetManager.dispose();
    }

    public class Movement {
        public Vector2 position;
        public float speed;

        public Movement(Vector2 position, float speed) {
            this.position = position;
            this.speed = speed;
        }
    }
}

在WorldController.java 添加Snake属性

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
public class WorldController extends InputAdapter implements Disposable {

    Snake snake;

    public WorldController() {
        snake = new Snake();
    }

    public void update(float deltaTime) {
        snake.update(deltaTime);
    }

    @Override
    public void dispose() {
        snake.dispose();
    }
}

运行工程 就可以看到结果了

代码已经放在GITHUB
可以切换到tag1 来查看本篇文章代码

使用 git checkout tag1

文章作者: zhangman523
文章链接: http://blog.zhangman523.cn/2018/09/20/snake_second/
版权声明: 本博客所有文章除特别声明外，均采用 CC BY-NC-SA 4.0 许可协议。转载请注明来自 zhangman523！
libgdxgame
支付宝打赏
微信打赏