64 lines
1.4 KiB
Markdown
64 lines
1.4 KiB
Markdown
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# Box
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带变换的有向包围盒 (OBB) 结构体。
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## 头文件
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```cpp
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#include <XCEngine/Math/Box.h>
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```
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## 命名空间
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`XCEngine::Math`
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## 结构体定义
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```cpp
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struct Box {
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Vector3 center = Vector3::Zero();
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Vector3 extents = Vector3::Zero(); // 半长
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Matrix4x4 transform = Matrix4x4::Identity();
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};
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```
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OBB 由中心点、半长向量和变换矩阵定义。
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## 构造函数
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- `Box()` - 默认构造
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- `Box(const Vector3& center, const Vector3& extents)` - 从中心和半长构造
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## 实例方法
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| 方法 | 返回值 | 描述 |
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|------|--------|------|
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| `GetMin()` | `Vector3` | 局部空间最小点 (-extents) |
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| `GetMax()` | `Vector3` | 局部空间最大点 (+extents) |
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| `Contains(point)` | `bool` | 点是否在盒内（变换到局部空间检测） |
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| `Intersects(Sphere)` | `bool` | 与球体相交 |
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| `Intersects(Box)` | `bool` | 与另一个 OBB 相交（SAT 算法） |
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| `Intersects(Ray, t)` | `bool` | 与射线相交，输出距离 t |
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## 使用示例
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```cpp
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Box box(Vector3(0.0f), Vector3(1.0f)); // 2x2x2 盒子
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box.transform = Matrix4::TRS(position, rotation, scale);
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// 点检测
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if (box.Contains(testPoint)) { ... }
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// 球体相交
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if (box.Intersects(sphere)) { ... }
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// OBB 相交
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if (box.Intersects(otherBox)) { ... }
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// 射线相交
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float t;
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if (box.Intersects(ray, t)) {
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Vector3 hit = ray.GetPoint(t);
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}
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```
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