如何绘制由四个三角形组成的正方形？ （libgdx）

Question

我有一个案例，我需要画出由四个三角形组成的正方形，如下图所示：

三角形参数存储在JDBC中，我知道如何在Libgdx中绘制形状，但这种形状对我来说似乎有点棘手，任何帮助或任何关于如何做到这一点的想法将不胜感激。 （我不是要求为我编写代码）

Answer 1

这是一个简单的例子，我不能呃测试，因为我现在无法访问libgdx，但我认为，作为一个想法，你可以提供帮助。

void draw(float x, float y, float width, float height, Color color) {


    if (idx==verts.length)
        flush();

    //assuming (0, 0) is lower left, and Y is up

    //bottom left vertex
    verts[idx++] = x;           //Position(x, y) 
    verts[idx++] = y;
    verts[idx++] = color.r;             //Color(r, g, b, a)
    verts[idx++] = color.g;
    verts[idx++] = color.b;
    verts[idx++] = color.a;

    //top left vertex
    verts[idx++] = x;           //Position(x, y) 
    verts[idx++] = y + height;
    verts[idx++] = color.r;             //Color(r, g, b, a)
    verts[idx++] = color.g;
    verts[idx++] = color.b;
    verts[idx++] = color.a;

    //bottom right vertex
    verts[idx++] = x + (width / 2);         //Position(x, y) 
    verts[idx++] = y + (height / 2);
    verts[idx++] = color.r;             //Color(r, g, b, a)
    verts[idx++] = color.g;
    verts[idx++] = color.b;
    verts[idx++] = color.a;
            //2
            //|\
            //| \ 3
            //| /
            //|/
            //1

    //
    verts[idx++] = x + width;       //Position(x, y) 
    verts[idx++] = y + height;
    verts[idx++] = color.r;             //Color(r, g, b, a)
    verts[idx++] = color.g;
    verts[idx++] = color.b;
    verts[idx++] = color.a;

    //
    verts[idx++] = x;           //Position(x, y) 
    verts[idx++] = y + height;
    verts[idx++] = color.r;             //Color(r, g, b, a)
    verts[idx++] = color.g;
    verts[idx++] = color.b;
    verts[idx++] = color.a;

    //
    verts[idx++] = x + (width / 2);         //Position(x, y) 
    verts[idx++] = y + (height / 2);
    verts[idx++] = color.r;             //Color(r, g, b, a)
    verts[idx++] = color.g;
    verts[idx++] = color.b;
    verts[idx++] = color.a;

            //2_____1
            // \   /
            //  \ /
            //   3
            //
            //

            //
    verts[idx++] = x + width;       //Position(x, y) 
    verts[idx++] = y;
    verts[idx++] = color.r;             //Color(r, g, b, a)
    verts[idx++] = color.g;
    verts[idx++] = color.b;
    verts[idx++] = color.a;

    //
    verts[idx++] = x + width;       //Position(x, y) 
    verts[idx++] = y + height;
    verts[idx++] = color.r;             //Color(r, g, b, a)
    verts[idx++] = color.g;
    verts[idx++] = color.b;
    verts[idx++] = color.a;

    //
    verts[idx++] = x + (width / 2);         //Position(x, y) 
    verts[idx++] = y + (height / 2);
    verts[idx++] = color.r;             //Color(r, g, b, a)
    verts[idx++] = color.g;
    verts[idx++] = color.b;
    verts[idx++] = color.a;

            //      2
            //     /|
            //   3/ |
            //    \ |
            //     \|
            //      1

    //
    verts[idx++] = x;                   //Position(x, y) 
    verts[idx++] = y;
    verts[idx++] = color.r;             //Color(r, g, b, a)
    verts[idx++] = color.g;
    verts[idx++] = color.b;
    verts[idx++] = color.a;

    //
    verts[idx++] = x + width;       //Position(x, y) 
    verts[idx++] = y;
    verts[idx++] = color.r;             //Color(r, g, b, a)
    verts[idx++] = color.g;
    verts[idx++] = color.b;
    verts[idx++] = color.a;

    //
    verts[idx++] = x + (width / 2);         //Position(x, y) 
    verts[idx++] = y + (height / 2);
    verts[idx++] = color.r;             //Color(r, g, b, a)
    verts[idx++] = color.g;
    verts[idx++] = color.b;
    verts[idx++] = color.a;

            //   3
            //  /\
            // /__\
            // 1  2 
    flush();
}

注意：当我写作时，答案没有被记住，这个例子是针对libgdx的网格。

只有您必须调整代码才能在每个三角形中绘制纹理，或者为您的外观绘制颜色。

如果您需要，可以使用更多代码使其发挥作用，发表评论，以及我是否可以说你。

如果没有，它适合你，评论，我会删除

Answer 2

使用四次调用ShapeRenderer.triangle（）

示例（未经测试）......

// Assumes you set a shapes roperty in your create method
// e.g. this.shapes = new ShapeRenderer();

public void square(float x, float y, float width, float height, Color color) {

    float centerX = width / 2;
    float centerY = height / 2;
    float x2 = x + width;
    float y2 = y + height;

    shapes.begin(ShapeRenderer.ShapeType.Filled);
    shapes.triangle(x, y, centerX, centerY, x2, y, color, color, color);
    shapes.triangle(x2, y, centerX, centerY, x2, y2, color, color, color);
    shapes.triangle(x2, y2, centerX, centerY, x, y2, color, color, color);
    shapes.triangle(x, y2, centerX, centerY, x, y, color, color, color);
}

我希望这会有所帮助