java - LIBGDX：如何使用 shaperenderer 绘制填充多边形？

Question

我已经使用顶点数组定义了一个形状：

float[] points =  new float[]{50,60,50,70,60,70, 60,60,50,60};

我在这里画这个：

shapeRenderer.polygon(floatNew);

这只是给出了形状的轮廓。
如何用颜色填充它？
谢谢

Answer 1

目前，ShapeRenderer 支持多边形绘制（按线）但不支持填充。

这段代码在三角形上剪裁多边形，然后分别绘制每个三角形。

像这样编辑 ShapeRenderer.java：

EarClippingTriangulator ear = new EarClippingTriangulator();

public void polygon(float[] vertices, int offset, int count)
{
    if (shapeType != ShapeType.Filled && shapeType != ShapeType.Line)
        throw new GdxRuntimeException("Must call begin(ShapeType.Filled) or begin(ShapeType.Line)");
    if (count < 6)
        throw new IllegalArgumentException("Polygons must contain at least 3 points.");
    if (count % 2 != 0)
        throw new IllegalArgumentException("Polygons must have an even number of vertices.");

    check(shapeType, null, count);

    final float firstX = vertices[0];
    final float firstY = vertices[1];
    if (shapeType == ShapeType.Line)
    {
        for (int i = offset, n = offset + count; i < n; i += 2)
        {
            final float x1 = vertices[i];
            final float y1 = vertices[i + 1];

            final float x2;
            final float y2;

            if (i + 2 >= count)
            {
                x2 = firstX;
                y2 = firstY;
            } else
            {
                x2 = vertices[i + 2];
                y2 = vertices[i + 3];
            }

            renderer.color(color);
            renderer.vertex(x1, y1, 0);
            renderer.color(color);
            renderer.vertex(x2, y2, 0);

        }
    } else
    {
        ShortArray arrRes = ear.computeTriangles(vertices);

        for (int i = 0; i < arrRes.size - 2; i = i + 3)
        {
            float x1 = vertices[arrRes.get(i) * 2];
            float y1 = vertices[(arrRes.get(i) * 2) + 1];

            float x2 = vertices[(arrRes.get(i + 1)) * 2];
            float y2 = vertices[(arrRes.get(i + 1) * 2) + 1];

            float x3 = vertices[arrRes.get(i + 2) * 2];
            float y3 = vertices[(arrRes.get(i + 2) * 2) + 1];

            this.triangle(x1, y1, x2, y2, x3, y3);
        }
    }
}

Answer 2

您还不能使用 shaperender 绘制填充的多边形。从bugtracker

看一下 你也可以在 API 中阅读。

public void polygon(float[] vertices)
在 x/y 平面上绘制一个多边形。顶点必须包含至少 3 个点（6 个浮点 x，y）。传递给 begin 的 ShapeRenderer.ShapeType 必须是 ShapeRenderer.ShapeType.Line。

API ShapeRender
当然，如果它与 ShapeType.Line 你只是得到轮廓。
在这种情况下，您需要使用三角形自己绘制。至少应该可以填充三角形。
也许从 Stackoverflow 看一下这个：drawing-filled-polygon-with-libgdx

Answer 3

编辑 ShapeRenderer.java 类，用以下代码替换 polygon() 方法：

public void polygon(float[] vertices, int offset, int count) {
    if (currType != ShapeType.Filled && currType != ShapeType.Line)
        throw new GdxRuntimeException(
                "Must call begin(ShapeType.Filled) or begin(ShapeType.Line)");
    if (count < 6)
        throw new IllegalArgumentException(
                "Polygons must contain at least 3 points.");
    if (count % 2 != 0)
        throw new IllegalArgumentException(
                "Polygons must have an even number of vertices.");

    checkDirty();
    checkFlush(count);

    final float firstX = vertices[0];
    final float firstY = vertices[1];
    if (currType == ShapeType.Line) {
        for (int i = offset, n = offset + count; i < n; i += 2) {
            final float x1 = vertices[i];
            final float y1 = vertices[i + 1];

            final float x2;
            final float y2;

            if (i + 2 >= count) {
                x2 = firstX;
                y2 = firstY;
            } else {
                x2 = vertices[i + 2];
                y2 = vertices[i + 3];
            }

            renderer.color(color);
            renderer.vertex(x1, y1, 0);
            renderer.color(color);
            renderer.vertex(x2, y2, 0);

        }
    } else {

        for (int i = offset, n = offset + count; i < n; i += 4) {

            final float x1 = vertices[i];
            final float y1 = vertices[i + 1];

            if (i + 2 >= count) {
                break;
            }

            final float x2 = vertices[i + 2];
            final float y2 = vertices[i + 3];

            final float x3;
            final float y3;

            if (i + 4 >= count) {
                x3 = firstX;
                y3 = firstY;
            } else {
                x3 = vertices[i + 4];
                y3 = vertices[i + 5];
            }

            renderer.color(color);
            renderer.vertex(x1, y1, 0);
            renderer.color(color);
            renderer.vertex(x2, y2, 0);
            renderer.color(color);
            renderer.vertex(x3, y3, 0);


        }

    }
}

用法：

    gdx_shape_renderer.begin(ShapeType.Filled);
    gdx_shape_renderer.setColor(fill_r, fill_g, fill_b, fill_a);
    gdx_shape_renderer.polygon(vertices);
    gdx_shape_renderer.end();

    gdx_shape_renderer.begin(ShapeType.Line);
    gdx_shape_renderer.setColor(border_r, border_g, border_b, border_a);
    gdx_shape_renderer.polygon(vertices);
    gdx_shape_renderer.end();