android - 画一条流畅的线

Question

我正在使用 libgdx 开发游戏，我想使用形状渲染器绘制一条平滑的线。

        shaperenderer.begin(ShapeType.Line);
        shaperenderer.line(fisrstVec2,secondVec2);
        shaperenderer.end();

我试过了Multi Sample anti aliasing来自 libgdx 博客。我也经历过Anti aliased filed shape in libgdx但不幸的是，这些行不在最新版本的 libgdx 中。

   Gdx.gl.glEnable(GL10.GL_LINE_SMOOTH);
   Gdx.gl.glEnable(GL10.GL_POINT_SMOOTH); 

Answer 1

在配置中启用抗锯齿:

对于桌面:

    LwjglApplicationConfiguration config = new LwjglApplicationConfiguration();
    config.samples = 2;
    new LwjglApplication(new MyGdxGame(Helper.arrayList(arg)), config);

对于安卓:

    AndroidApplicationConfiguration config = new AndroidApplicationConfiguration();
    config.numSamples = 2;
    initialize(new MyGdxGame(null), config);

或者您可以创建一个 1x1 的白色像素图并使用它来创建 Sprite 并使用该 Sprite 绘制线条，我个人更喜欢这种方法而不是 ShapeRenderer(请注意此方法中没有旋转):

/**
 * draws a line on the given axis between given points
 *
 * @param batch       spriteBatch
 * @param axis        axis of the line, vertical or horizontal
 * @param x          x position of the start of the line
 * @param y          y position of the start of the line
 * @param widthHeight width or height of the line according to the axis
 * @param thickness thickness of the line
 * @param color       color of the line, if the color is null, color will not be changed.
 */
public static void line(SpriteBatch batch, Axis axis, float x, float y, float widthHeight, float thickness, Color color, float alpha) {
    if (color != null) sprite.setColor(color);
    sprite.setAlpha(alpha);
    if (axis == Axis.vertical) {
        sprite.setSize(thickness, widthHeight);
    } else if (axis == Axis.horizontal) {
        sprite.setSize(widthHeight, 1);
    }
    sprite.setPosition(x,y);
    sprite.draw(batch);
    sprite.setAlpha(1);
}

对之前的方法进行一些修改，你可以想出这个方法来画一条旋转的线。

public static void rotationLine(SpriteBatch batch, float x1, float y1, float x2, float y2, float thickness, Color color, float alpha) {
    // set color and alpha
    if (color != null) sprite.setColor(color);
    sprite.setAlpha(alpha);
    // set origin and rotation
    sprite.setOrigin(0,0);
    sprite.setRotation(getDegree(x2,y2, x1, y1));
    // set position and dimension
    sprite.setSize(distance(x1,y1,x2,y2),thickness);
    sprite.setPosition(x1, y1);
    // draw
    sprite.draw(batch);
    // reset rotation
    sprite.rotate(0);
}

public static float getDegree(float x, float y, float originX, float originY) {
    float angle = (float) Math.toDegrees(Math.atan2(y - originY, x - originX));
    while (angle < 0 || angle > 360)
        if (angle < 0) angle += 360;
        else if (angle > 360) angle -= 360;
    return angle;
}

public static float distance(float x, float y, float x2, float y2) {
    return (float) Math.sqrt(Math.pow((x2 - x), 2) + Math.pow((y2 - y), 2));
}