java - 渲染图像不显示 Java Libgdx

Question

我正在尝试渲染图像，但是当我作为桌面启动器运行游戏时，看不到图像，但是我相信图像正在渲染，因为它与另一个 Sprite 重叠以提供输出。

if (chicken.overlaps(farmer)){
                System.out.print("GameOver");
                gameOver();

我没有收到任何错误。

相机

OrthographicCamera camera;
camera = new OrthographicCamera();
camera.setToOrtho(false, 1920, 1080);
camera.update();
inputUpdate(touch, camera);
batch.setProjectionMatrix(camera.combined);

代码:

public void render(float delta) {


    camera.update();
    inputUpdate(touch, camera);
    batch.setProjectionMatrix(camera.combined);



    Iterator<Rectangle> iter = chickens.iterator();
    while(iter.hasNext()){      
        Rectangle chicken = iter.next();
        if(farmerX < (chicken.x - 85/2)) chicken.x -= 2.5;
        if(farmerX > (chicken.x - 85/2))chicken.x += 2.5;
        if (farmerY < (chicken.y - 66/2))chicken.y -= 2.5;
        if(farmerY > (chicken.y - 66/2))chicken.y += 2.5;

        float diffYchick;
        float diffXchick;
        float angleDegreeschick;

        diffYchick = (float) (farmerY - chicken.y);
        diffXchick = (float) (farmerX - chicken.x);

        angleDegreeschick = (float) Math.toDegrees(Math.atan2(diffYchick, diffXchick));


        game.batch.begin();
            game.batch.draw(chickenImage, (float)chicken.x, (float)chicken.y, (float)42.5, (float)33, (float)85, (float)66, (float)1, (float)1, (float)angleDegreeschick);

        game.batch.end();


        int stop;
        stop = 0;
        switch(stop){
        case 0:
            if (chicken.overlaps(farmer)){
            System.out.print("GameOver");
            gameOver();

            stop +=1;
                break;
            }
        }



    }

    float diffY;
    float diffX;
    diffY = (float) (touch.y - farmerY);
    diffX = (float) (touch.x - farmerX);

    float angleDegrees;

    angleDegrees = (float) Math.toDegrees(Math.atan2(diffY, diffX));

    if(TimeUtils.nanoTime() - lastSpawnTime > 1000000000) spawnChicken();       

    Gdx.gl.glClearColor(0, 1, 0.2f, 1);
    Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT);

    camera.update();
    inputUpdate(touch, camera);
    batch.setProjectionMatrix(camera.combined);





    FarmerAsset.stateTime += Gdx.graphics.getDeltaTime();
    FarmerAsset.currentFrame = FarmerAsset.walkAnimation.getKeyFrame(FarmerAsset.stateTime, true);

    game.batch.begin();
    game.batch.draw(FarmerAsset.currentFrame, farmerX, farmerY, (float)85, (float)85, (float)170, (float)170, (float)1, (float)1, (float)angleDegrees + 270);
    game.font.draw(game.batch, "Chickens Running: " + runningChickens, 0, 1080);
    game.batch.end();

    if(Gdx.input.isTouched()){
        touch.set(Gdx.input.getX(), Gdx.input.getY(), 0);
        camera.unproject(touch);


        if(farmerY <=  touch.y && touch.y<= farmerY + 170 && 
                farmerX  <=  touch.x && touch. x <= farmerX + 170){
        }else{
            if (touch.x - 85 > farmerX){
                farmerX +=5;
            }
            if (touch.x - 85 < farmerX){
                farmerX -=5;
            }
            if (touch.y - 85 > farmerY){
                farmerY +=5;
            }
            if (touch.y - 85 < farmerY){
                farmerY -=5;
            }
        }


    }

    if(Gdx.input.isKeyPressed(Keys.A)||Gdx.input.isKeyPressed(Keys.LEFT)){
        farmerX -= 10;
    }
    else if(Gdx.input.isKeyPressed(Keys.D)||Gdx.input.isKeyPressed(Keys.RIGHT)){
        farmerX += 10;  
    }
    else if(Gdx.input.isKeyPressed(Keys.W)||Gdx.input.isKeyPressed(Keys.UP)){
        farmerY += 10;
    }
    else if(Gdx.input.isKeyPressed(Keys.S)||Gdx.input.isKeyPressed(Keys.DOWN)){
        farmerY -= 10;  
    }

    if(farmerX < 0) farmerX = 0;
    if(farmerX > 1920-170) farmerX = 1920-170;
    if(farmerY < 0) farmerY = 0;
    if(farmerY > 1080-170) farmerY = 1080-170;
    farmer.x = farmerX;
    farmer.y = farmerY;



}

农民

game.batch.draw(FarmerAsset.currentFrame, farmerX, farmerY, (float)85, (float)85, (float)170, (float)170, (float)1, (float)1, (float)angleDegrees + 270);

Answer 1

我在渲染方法中发现了一些问题:

• 多次重复更新相机和触摸。 render 方法中的前三行将进一步向下重复。他们应该只被调用一次。如果您不移动相机，则没有理由更新它，但通常如果您要移动它，则在处理可能导致其移动的任何触摸逻辑后，您会希望移动并更新它。
• 在画小鸡之前没有清除屏幕。在使用 Sprite 批处理之前，您必须调用 Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT);。
• 不将所有鸡分批在一起。您为每只鸡调用 batch.begin 和 batch.end，这是 CPU 密集型操作，如果鸡数量较多，很快就会成为游戏性能的瓶颈。您应该将 batch.begin 移至 while 循环之前，将 batch.end 移至 while 循环之后。
• 混淆了更新游戏状态和绘图的顺序。在绘制这些对象之前，您应该处理所有触摸逻辑和对象位置更新。 (这不会导致您的问题，但会导致用户输入出现一帧延迟。)

最有可能的是，由于在更新相机和调用 glClear 之前使用 Sprite 批处理绘制鸡，因此鸡未正确渲染。

这大致就是我重新排序的方式。但如果这是我的项目，我会做更多的工作来分离逻辑和渲染。例如，我会使用 Sprite 对象来表示鸡，而不仅仅是矩形。然后，我会在渲染方法开始时适当移动所有 Sprite ，然后再对所有 Sprite 进行一次循环，以在最后将它们提交给 SpriteBatch。这将使您的代码不易出现错误。

public void render(float delta) {

    inputUpdate(touch, camera);

    if(TimeUtils.nanoTime() - lastSpawnTime > 1000000000) spawnChicken();  

    if(Gdx.input.isTouched()){
        touch.set(Gdx.input.getX(), Gdx.input.getY(), 0);
        camera.unproject(touch);


        if(farmerY <=  touch.y && touch.y<= farmerY + 170 && 
            farmerX  <=  touch.x && touch. x <= farmerX + 170){
        }else{
        if (touch.x - 85 > farmerX){
            farmerX +=5;
        }
        if (touch.x - 85 < farmerX){
            farmerX -=5;
        }
        if (touch.y - 85 > farmerY){
            farmerY +=5;
        }
        if (touch.y - 85 < farmerY){
            farmerY -=5;
        }
        }


    }

    if(Gdx.input.isKeyPressed(Keys.A)||Gdx.input.isKeyPressed(Keys.LEFT)){
        farmerX -= 10;
    }
    else if(Gdx.input.isKeyPressed(Keys.D)||Gdx.input.isKeyPressed(Keys.RIGHT)){
        farmerX += 10;  
    }
    else if(Gdx.input.isKeyPressed(Keys.W)||Gdx.input.isKeyPressed(Keys.UP)){
        farmerY += 10;
    }
    else if(Gdx.input.isKeyPressed(Keys.S)||Gdx.input.isKeyPressed(Keys.DOWN)){
        farmerY -= 10;  
    }

    if(farmerX < 0) farmerX = 0;
    if(farmerX > 1920-170) farmerX = 1920-170;
    if(farmerY < 0) farmerY = 0;
    if(farmerY > 1080-170) farmerY = 1080-170;
    farmer.x = farmerX;
    farmer.y = farmerY;

    camera.update();
    batch.setProjectionMatrix(camera.combined);

    Gdx.gl.glClearColor(0, 1, 0.2f, 1);
    Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT);

    game.batch.begin();

    Iterator<Rectangle> iter = chickens.iterator();
    while(iter.hasNext()){  
        Rectangle chicken = iter.next();
        if(farmerX < (chicken.x - 85/2)) chicken.x -= 2.5;
        if(farmerX > (chicken.x - 85/2))chicken.x += 2.5;
        if (farmerY < (chicken.y - 66/2))chicken.y -= 2.5;
        if(farmerY > (chicken.y - 66/2))chicken.y += 2.5;

        float diffYchick;
        float diffXchick;
        float angleDegreeschick;

        diffYchick = (float) (farmerY - chicken.y);
        diffXchick = (float) (farmerX - chicken.x);

        angleDegreeschick = (float) Math.toDegrees(Math.atan2(diffYchick, diffXchick));

        game.batch.draw(chickenImage, (float)chicken.x, (float)chicken.y, (float)42.5, (float)33, (float)85, (float)66, (float)1, (float)1, (float)angleDegreeschick);

        int stop;
        stop = 0;
        switch(stop){
        case 0:
        if (chicken.overlaps(farmer)){
            System.out.print("GameOver");
            gameOver();

            stop +=1;
            break;
        }
        }

    }

    game.batch.end();

    float diffY = (float) (touch.y - farmerY);
    float diffX = (float) (touch.x - farmerX);

    float angleDegrees = (float) Math.toDegrees(Math.atan2(diffY, diffX));

    FarmerAsset.stateTime += Gdx.graphics.getDeltaTime();
    FarmerAsset.currentFrame = FarmerAsset.walkAnimation.getKeyFrame(FarmerAsset.stateTime, true);

    game.batch.begin();
    game.batch.draw(FarmerAsset.currentFrame, farmerX, farmerY, (float)85, (float)85, (float)170, (float)170, (float)1, (float)1, (float)angleDegrees + 270);
    game.font.draw(game.batch, "Chickens Running: " + runningChickens, 0, 1080);
    game.batch.end();

    }

除此之外，您的 switch 语句有一个错误...break 应该在 if 语句之外调用。现在不是问题，但稍后当您添加到 switch 语句时就会出现问题。我没有更正上面的问题。

仅供引用，您不必在 float 字之前继续输入 (float) 。只需在它们后面输入 f 即可。