使用 libGDX 绘制填充多边形

问题描述

我想用 libGDX 绘制一些(填充的)多边形.它不应该填充图形/纹理.我只有多边形的顶点(闭合路径)并尝试使用网格进行可视化，但在某些时候这不是最好的解决方案，我认为.

I want to draw some (filled) polygons with libGDX. It shoudn't be filled with a graphic/texture. I have only the vertices of the polygon (closed path) and tried to visualize with meshes but at some point this is not the best solution, I think.

我的矩形代码是:

private Mesh mesh;

@Override
public void create() {
    if (mesh == null) {
        mesh = new Mesh(
            true, 4, 0,
            new VertexAttribute(Usage.Position, 3, "a_position")
        );
        mesh.setVertices(new float[] {
            -0.5f, -0.5f, 0
            0.5f, -0.5f, 0,
            -0.5f, 0.5f, 0,
            0.5f, 0.5f, 0
        });
    }
}

// ...

@Override
public void render() {
    Gdx.gl.glClear(GL10.GL_COLOR_BUFFER_BIT);
    mesh.render(GL10.GL_TRIANGLE_STRIP, 0, 4);
}

有什么功能可以更简单地绘制填充多边形吗?

is there a function or something to draw filled polygons in an easier way?

推荐答案

这是一个绘制 2D 凹多边形的 libGDX 示例.

Here is a libGDX example which draws a 2D concave polygon.

为 PolygonSprite 定义类成员 PolygonSpriteBatch

PolygonSprite poly;
PolygonSpriteBatch polyBatch;
Texture textureSolid;

创建实例，使用红色像素作为解决方法的 1x1 大小纹理.一个坐标数组 (x, y) 用于多边形的初始化.

Create instances, 1x1 size texture used with red pixel as workaround. An array of coordinates (x, y) is used for initialization of the polygon.

ctor() {
    textureSolid = makeTextureBox(1, 0xFFFF0000, 0, 0);
    float a = 100;
    float b = 100;
    PolygonRegion polyReg = new PolygonRegion(new TextureRegion(textureSolid),
      new float[] {
        a*0, b*0,
        a*0, b*2,
        a*3, b*2,
        a*3, b*0,
        a*2, b*0,
        a*2, b*1,
        a*1, b*1,
        a*1, b*0,
    });
    poly = new PolygonSprite(polyReg);
    poly.setOrigin(a, b);
    polyBatch = new PolygonSpriteBatch();
}

绘制和旋转多边形

void draw() {
    super.draw();
    polyBatch.begin();
    poly.draw(polyBatch);
    polyBatch.end();
    poly.rotate(1.1f);
}

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