使用渲染器 (world space) 在游戏对象周围绘制边界矩形 (screen space) (Unity)

Question

我的场景中有一个游戏对象存在于世界 space 中。我想在屏幕 space 中获取此游戏对象的渲染器的边界矩形角的坐标，因为我有 UI 个元素想要围绕此框定位。

上下文：我正在制作一个教程，我正在使用面板使所有内容变暗，但游戏对象除外，该对象将不变暗。我可以使用已经存在于屏幕 space 中并对其进行矩形变换的按钮轻松地做到这一点，但我不知道如何围绕世界 space 中的游戏对象做到这一点。我们正在使用具有正交投影的相机并且正在使用 Unity版本2019.2.17f1.

这是我试过的方法：

public void FocusOnRenderer(Renderer renderer) {

        // left, top, right, and bottom are Panels whose pivots are set as follows:
        // top: (1, 0)
        // right: (0, 0)
        // bottom: (0, 1)
        // left: (1, 1)
        // so when their positions are set to be the corners of the target bounding box, they will fit together nicely.

        left.gameObject.SetActive(true);
        top.gameObject.SetActive(true);
        right.gameObject.SetActive(true);
        bottom.gameObject.SetActive(true);

        Vector3 center = HandleUtility.WorldToGUIPoint(renderer.bounds.center); // center of bounding box
        Vector3 halfSize = HandleUtility.WorldToGUIPoint(renderer.bounds.extents)); // half size of bounding box

        Vector3 topRight = center + halfSize;
        Vector3 topLeft = center  + new Vector3(-halfSize.x, halfSize.y, halfSize.z);
        Vector3 bottomRight = center  + new Vector3(halfSize.x, -halfSize.y, halfSize.z);
        Vector3 bottomLeft = center  + new Vector3(-halfSize.x, -halfSize.y, halfSize.z);

        left.position = topLeft;
        top.position = topRight;
        right.position = bottomRight;
        bottom.position = bottomLeft;
    }

我认为这是错误的，因为我使用渲染器的边界来计算 halfSize 和 center 并没有给我一个边界矩形。我希望有一种简单的内置方法可以做到这一点，但到目前为止我还没有找到任何东西。

感谢您的帮助！

Answer 1

我找到了答案（来自 @SparrowsNest on the Unity Forum)! Here's the video starting at the relevant timestamp: https://youtu.be/2Tgqr1_ajqE?t=1061

的视频建议

步骤：

从渲染器的边界获取边界框的角
将这些角转换成屏幕 space
获取最小和最大 x 和 y 值
使用那些最小和最大 x 和 y 值设置我的面板的位置

这是我的代码：

    public void FocusOnBounds(Bounds bounds) {
        
        // left, top, right, and bottom are Panels whose pivots are set as follows:
        // top: (1, 0)
        // right: (0, 0)
        // bottom: (0, 1)
        // left: (1, 1)
        // so when their positions are set to be the corners of the target bounding box, they will fit together nicely.

        left.gameObject.SetActive(true);
        top.gameObject.SetActive(true);
        right.gameObject.SetActive(true);
        bottom.gameObject.SetActive(true);

        Vector3 c = bounds.center;
        Vector3 e = bounds.extents;

        Vector3[] worldCorners = new [] {
            new Vector3( c.x + e.x, c.y + e.y, c.z + e.z ),
            new Vector3( c.x + e.x, c.y + e.y, c.z - e.z ),
            new Vector3( c.x + e.x, c.y - e.y, c.z + e.z ),
            new Vector3( c.x + e.x, c.y - e.y, c.z - e.z ),
            new Vector3( c.x - e.x, c.y + e.y, c.z + e.z ),
            new Vector3( c.x - e.x, c.y + e.y, c.z - e.z ),
            new Vector3( c.x - e.x, c.y - e.y, c.z + e.z ),
            new Vector3( c.x - e.x, c.y - e.y, c.z - e.z ),
        };

        IEnumerable<Vector3> screenCorners = worldCorners.Select(corner => Camera.main.WorldToScreenPoint(corner));
        float maxX = screenCorners.Max(corner => corner.x);
        float minX = screenCorners.Min(corner => corner.x);
        float maxY = screenCorners.Max(corner => corner.y);
        float minY = screenCorners.Min(corner => corner.y);

        Vector3 topRight = new Vector3(maxX, maxY, 0);
        Vector3 topLeft = new Vector3(minX, maxY, 0);
        Vector3 bottomRight = new Vector3(maxX, minY, 0);
        Vector3 bottomLeft = new Vector3(minX, minY, 0);

        left.position = topLeft;
        top.position = topRight;
        right.position = bottomRight;
        bottom.position = bottomLeft;
    }

Answer 2

如果上面的代码不起作用，下面是从

中提取的代码

http://quill18.com/unity_tutorials/unit_selection/

函数输入：任何呈现在屏幕上的可见内容。

输出：可用于 canvas

的二维矩形边界

static Rect RendererBoundsInScreenSpace(Renderer r) {
        // This is the space occupied by the object's visuals
        // in WORLD space.
        Bounds bigBounds = r.bounds;

        if(screenSpaceCorners == null)
            screenSpaceCorners = new Vector3[8];

        Camera theCamera = Camera.main;

        // For each of the 8 corners of our renderer's world space bounding box,
        // convert those corners into screen space.
        screenSpaceCorners[0] = theCamera.WorldToScreenPoint( new Vector3( bigBounds.center.x + bigBounds.extents.x, bigBounds.center.y + bigBounds.extents.y, bigBounds.center.z + bigBounds.extents.z ) );
        screenSpaceCorners[1] = theCamera.WorldToScreenPoint( new Vector3( bigBounds.center.x + bigBounds.extents.x, bigBounds.center.y + bigBounds.extents.y, bigBounds.center.z - bigBounds.extents.z ) );
        screenSpaceCorners[2] = theCamera.WorldToScreenPoint( new Vector3( bigBounds.center.x + bigBounds.extents.x, bigBounds.center.y - bigBounds.extents.y, bigBounds.center.z + bigBounds.extents.z ) );
        screenSpaceCorners[3] = theCamera.WorldToScreenPoint( new Vector3( bigBounds.center.x + bigBounds.extents.x, bigBounds.center.y - bigBounds.extents.y, bigBounds.center.z - bigBounds.extents.z ) );
        screenSpaceCorners[4] = theCamera.WorldToScreenPoint( new Vector3( bigBounds.center.x - bigBounds.extents.x, bigBounds.center.y + bigBounds.extents.y, bigBounds.center.z + bigBounds.extents.z ) );
        screenSpaceCorners[5] = theCamera.WorldToScreenPoint( new Vector3( bigBounds.center.x - bigBounds.extents.x, bigBounds.center.y + bigBounds.extents.y, bigBounds.center.z - bigBounds.extents.z ) );
        screenSpaceCorners[6] = theCamera.WorldToScreenPoint( new Vector3( bigBounds.center.x - bigBounds.extents.x, bigBounds.center.y - bigBounds.extents.y, bigBounds.center.z + bigBounds.extents.z ) );
        screenSpaceCorners[7] = theCamera.WorldToScreenPoint( new Vector3( bigBounds.center.x - bigBounds.extents.x, bigBounds.center.y - bigBounds.extents.y, bigBounds.center.z - bigBounds.extents.z ) );

        // Now find the min/max X & Y of these screen space corners.
        float min_x = screenSpaceCorners[0].x;
        float min_y = screenSpaceCorners[0].y;
        float max_x = screenSpaceCorners[0].x;
        float max_y = screenSpaceCorners[0].y;

        for (int i = 1; i < 8; i++) {
            if(screenSpaceCorners[i].x < min_x) {
                min_x = screenSpaceCorners[i].x;
            }
            if(screenSpaceCorners[i].y < min_y) {
                min_y = screenSpaceCorners[i].y;
            }
            if(screenSpaceCorners[i].x > max_x) {
                max_x = screenSpaceCorners[i].x;
            }
            if(screenSpaceCorners[i].y > max_y) {
                max_y = screenSpaceCorners[i].y;
            }
        }

        return Rect.MinMaxRect( min_x, min_y, max_x, max_y );

    }

使用渲染器 (world space) 在游戏对象周围绘制边界矩形 (screen space) (Unity)

Draw bounding rectangle (screen space) around a game object with a renderer (world space) (Unity)

c#

unity3d

unity-ui