Question

我只是想绘制背景，用0.5f透明黑色覆盖它以使其变暗并在暂停菜单上呈现。

我试过了：

    Gdx.gl.glClearColor(0f, 0f, 0f, 0.5f);
    Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT);

并没有任何效果。我也无法在网上找到任何解决方案。我的另一个选择是覆盖黑色精灵，但我不想这样做。无论如何用GL来画它？

Answer 1

好吧，我会画一个透明的矩形

    Gdx.gl.glEnable(GL20.GL_BLEND);
    Gdx.gl.glBlendFunc(GL20.GL_SRC_ALPHA, GL20.GL_ONE_MINUS_SRC_ALPHA);
    shapeRenderer.begin(ShapeRenderer.ShapeType.Filled);
    shapeRenderer.setColor(new Color(0, 0, 0, 0.5f));
    shapeRenderer.rect(0, 0, screenWidth, screenHeight);
    shapeRenderer.end();
    Gdx.gl.glDisable(GL20.GL_BLEND);

希望这有帮助

Answer 2

您唯一的解决方案是覆盖黑色精灵。是最有效率和最有效的。

根据文件：

Alpha function, blend function, logical operation, stenciling, 
texture mapping, and depth-buffering are ignored by glClear.

glClear takes a single argument that is the bitwise OR of several
values indicating which buffer is to be cleared.

The values are as follows:

GL_COLOR_BUFFER_BIT
    Indicates the buffers currently enabled for color writing.

运行glClear后，“under”下面没有更多颜色

Libgdx使用glClearColor调暗屏幕

2 个答案: