LibGdx 有没有办法将着色器应用于 sprite 批处理的一部分以获得水效果？

Question

所以我将水效果应用于我的水的矩形图像，以便在其上应用正弦波函数。它仅适用于此 TextureRegion:

Water.java

public  void updateshaders(){

    float dt = Gdx.graphics.getDeltaTime();

    if(waterShader != null){

        time += dt ;
        float angle = time * (2 * MathUtils.PI);
        if (angle > (2 * MathUtils.PI))
            angle -= (2 * MathUtils.PI);

        Gdx.gl20.glBlendFunc(GL20.GL_SRC_ALPHA, GL20.GL_ONE_MINUS_SRC_ALPHA);
        Gdx.gl20.glEnable(GL20.GL_BLEND);
        waterShader.setUniformMatrix("u_projTrans",  gs.cam.combined);

        waterShader.begin();
        waterShader.setUniformf("timedelta", -angle);
        waterShader.end();
    }
}
@Override
public void draw(SpriteBatch g) {
    g.end();
    updateshaders();
    g.setProjectionMatrix(gs.cam.combined);
    g.setShader(waterShader);
    g.begin();
    g.draw(gs.gsm.rm.water_top, x, y + height - gs.gsm.rm.water_top.getRegionHeight(), width, gs.gsm.rm.water_top.getRegionHeight());
    g.draw(gs.gsm.rm.water, x, y, width, height - gs.gsm.rm.water_top.getRegionHeight());
    g.end();
    g.setShader(null);
    g.begin();
}

我想将此效果添加到红色矩形中的所有内容。我正在考虑刷新 SpriteBatch 并剪切出该区域的图像，应用失真然后在原始图像上重新绘制它，然后完成我的渲染线程的其余部分。

更新：所以我的解决方案奏效了……有点。它非常慢。它看起来是正确的，但会使游戏无法播放且速度缓慢。（在 gif 中可能有点难以注意到，但在游戏中看起来不错。）

新代码：

Water.java

public void draw(SpriteBatch g) {
    g.end();
    updateshaders();
    //Distortion
    coords = gs.cam.project(new Vector3(x,y,0));
    if(scr != null){scr.getTexture().dispose();}
    scr = ScreenUtils.getFrameBufferTexture(
            (int)coords.x,(int)coords.y,
            (int)(width * scaleX),(int)((height - gs.gsm.rm.water_top.getRegionHeight() / 4) * scaleY));

    if(scr != null){
        g.setShader(waterShader2);
        g.begin();
        g.draw(scr,
            x,y,
            width,height- gs.gsm.rm.water_top.getRegionHeight() / 4);
        g.end();
    }
    //SURFACE WAVES
    g.setShader(waterShader);
    g.begin();
    g.draw(gs.gsm.rm.water_top, x, y + height - gs.gsm.rm.water_top.getRegionHeight(), width, gs.gsm.rm.water_top.getRegionHeight());
    g.end();
    //BACK TO NORMAL
    g.setShader(null);
    g.begin();
    g.draw(gs.gsm.rm.water, x, y, width, height - gs.gsm.rm.water_top.getRegionHeight());
}

更新：我尝试了 Tenfour04 的解决方案并且它有效......有点。虽然存在失真效果，并且游戏以全 FPS 运行，但失真会使背景显示出来。这是因为着色器正在应用于纹理，而不仅仅是在我抓取的区域范围内：

    scr = new TextureRegion(((PlayGameState) gs).frameBuffer.getColorBufferTexture(),
            (int)coords.x, (int)coords.y,
            (int)(width * scaleX),(int)((height - gs.gsm.rm.water_top.getRegionHeight() / 4) * scaleY));

Answer 1

在每一帧上，您都在丢弃并重新创建像素图和纹理，然后将屏幕捕获到该纹理。这是一次又一次重复的极其缓慢的操作。

相反，您可以将游戏直接渲染到持久的屏幕外帧缓冲区。

private FrameBuffer frameBuffer;
private final Matrix4 idt = new Matrix4();

public void render() {
    if (frameBuffer == null){
        //Normally this would go in the resize method, but that causes issues on iOS 
        //because resize isn't always called on the GL thread in iOS. So lazy load here.
        try {
            frameBuffer = new FrameBuffer(Format.RGBA8888, Gdx.graphics.getWidth(), Gdx.graphics.getHeight(), false);
        } catch (GdxRuntimeException e){ 
            frameBuffer = new FrameBuffer(Format.RGB565, Gdx.graphics.getWidth(), Gdx.graphics.getHeight(), false);
            //RGBA8888 not supported on all devices. You might instead want to turn off 
            //the water effect if it's not supported, because 565 is kinda ugly.
        }
    }

    frameBuffer.begin();
    Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT);
    //draw everything that is behind the water layer here
    frameBuffer.end();

    Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT);
    //Draw the frame buffer texture to the screen:
    spriteBatch.setProjectionMatrix(idt);
    spriteBatch.begin();
    spriteBatch.draw(frameBuffer.getColorBufferTexture(), -1, 1, 2, -2); //IIRC, you need to vertically flip it. If I remembered wrong, then do -1, -1, 2, 2
    spriteBatch.end();

    water.draw(spriteBatch, frameBuffer.getColorBufferTexture());

    //draw stuff that is in front of the water here
}

然后修改你的水class如下。如果我没记错的话，屏幕纹理是颠倒的，所以你可能需要翻转你的一些数学。我没有在下面检查你的数学以了解你是否已经考虑到这一点。

public void draw(SpriteBatch g, Texture scr) {
    updateshaders();
    //Distortion
    coords = gs.cam.project(new Vector3(x,y,0));

    if(scr != null){
        g.setShader(waterShader2);
        g.begin();
        g.draw(scr,
            x,y,
            width,height- gs.gsm.rm.water_top.getRegionHeight() / 4);
        g.end();
    }
    //SURFACE WAVES
    g.setShader(waterShader);
    g.begin();
    g.draw(gs.gsm.rm.water_top, x, y + height - gs.gsm.rm.water_top.getRegionHeight(), width, gs.gsm.rm.water_top.getRegionHeight());
    g.end();
    //BACK TO NORMAL
    g.setShader(null);
    g.begin();
    g.draw(gs.gsm.rm.water, x, y, width, height - gs.gsm.rm.water_top.getRegionHeight());
}

在此过程中未优化的一件事是您最终将水层后面的所有像素绘制至少两次。一次将其绘制在帧缓冲区上，然后第二次将帧缓冲区绘制到屏幕上。这可以在以后进行优化（如果您受填充率限制），方法是仅在视图中被水覆盖的区域绘制水后的东西，然后将帧缓冲区纹理绘制到屏幕的步骤替换为绘制背景的东西通常。如果您成功构建了 RGBA8888 帧缓冲区，这看起来不错，但并非所有 Android 都支持。

LibGdx 有没有办法将着色器应用于 sprite 批处理的一部分以获得水效果？

LibGdx Is there a way to apply shader to a section of the sprite batch for a water effect?

java

opengl

libgdx