{"topic":{"id":7805,"title":"bvh 加速物理碰撞检测的问题","slug":"topic","categoryId":56,"createdAt":"2023-12-12 09:38:46.905065","bumpedAt":"2023-12-12 13:59:33.913651","views":202,"postsCount":3,"highestPostNumber":3,"likeCount":0,"closed":true,"pinned":false,"pinnedGlobally":false,"pinnedAt":null,"pinnedUntil":null,"isBanner":false,"excerpt":"AABB：intersect 函数使用什么坐标系进行求交判断呢。我的理解是使用世界坐标系，但函数头缺少把 AABB 转换到世界坐标系所需的 model 矩阵，请问该怎么解决呢 AABB：intersect 函数头及其定义： bool AABB::intersect(const Ray& ray, const Vector3f& inv_dir, const std::array<int, 3>& d…","deletedAt":null,"isAnonymous":false,"category":{"id":56,"name":"计算机图形学","slug":"cg","color":"92278F"},"author":{"id":1451,"username":"canyu0","name":"canyu0","avatarUrl":"/uploads/image/32/d3/32d384d818124c8af587f11c235c5238544758c53d72a72cfac3d3603d8d5a1d.avif"},"tags":[]},"posts":[{"id":19157,"postNumber":1,"raw":"![image|677x43](/uploads/image/91/7e/917e148a1a3eaea090528167a9a95c70c6ad15bd024aae13d15b793ab3409c69.avif)\nAABB：intersect 函数使用什么坐标系进行求交判断呢。\n我的理解是使用世界坐标系，但函数头缺少把 AABB 转换到世界坐标系所需的 model 矩阵，请问该怎么解决呢\nAABB：intersect 函数头及其定义：\n```\nbool AABB::intersect(const Ray& ray, const Vector3f& inv_dir, const std::array& dir_is_neg)\n```\n![image|690x233](/uploads/image/9e/0a/9e0a697d8a64c9fddcbf4d33a88dfce52c1334a738a805605b611e951f16df1d.avif)","cooked":"

$\"image\"$
\nAABB：intersect 函数使用什么坐标系进行求交判断呢。
\n我的理解是使用世界坐标系，但函数头缺少把 AABB 转换到世界坐标系所需的 model 矩阵，请问该怎么解决呢
\nAABB：intersect 函数头及其定义：

bool AABB::intersect(const Ray& ray, const Vector3f& inv_dir, const std::array<int, 3>& dir_is_neg)\n

$\"image\"$

\n","createdAt":"2023-12-12 09:38:47.156764","updatedAt":"2023-12-12 09:38:47.156764","replyToPostNumber":null,"replyCount":0,"likeCount":0,"wordCount":86,"liked":false,"bookmarked":false,"polls":[],"reactions":[],"wiki":false,"version":1,"publicVersion":1,"deletedAt":null,"isAnonymous":false,"user":{"id":1451,"username":"canyu0","name":"canyu0","avatarUrl":"/uploads/image/32/d3/32d384d818124c8af587f11c235c5238544758c53d72a72cfac3d3603d8d5a1d.avif","admin":false,"moderator":false,"signatureRaw":null,"signatureCooked":null}},{"id":19158,"postNumber":2,"raw":"![image|478x500](/uploads/image/db/43/db43c70090a9c082d626071f04b78276f6cb5248d49908f48fcba2b248f3eb48.avif)\n让我产生疑惑的原因：\n\n> ray_triangle_intersect 是发生在 model 坐标系中的，原因在 4.2.1 中已经详细说明。但在该函数外部，我们都采用相机坐标系，于是就存在对返回结果坐标系的变换，这里同学们需要特别注意法线的从模型坐标系到相机坐标系的变换。","cooked":"

$\"image\"$
\n让我产生疑惑的原因：

\n
ray_triangle_intersect 是发生在 model 坐标系中的，原因在 4.2.1 中已经详细说明。但在该函数外部，我们都采用相机坐标系，于是就存在对返回结果坐标系的变换，这里同学们需要特别注意法线的从模型坐标系到相机坐标系的变换。
\n

\n","createdAt":"2023-12-12 10:15:01.00039","updatedAt":"2023-12-12 10:15:01.00039","replyToPostNumber":null,"replyCount":0,"likeCount":0,"wordCount":102,"liked":false,"bookmarked":false,"polls":[],"reactions":[],"wiki":false,"version":1,"publicVersion":1,"deletedAt":null,"isAnonymous":false,"user":{"id":1451,"username":"canyu0","name":"canyu0","avatarUrl":"/uploads/image/32/d3/32d384d818124c8af587f11c235c5238544758c53d72a72cfac3d3603d8d5a1d.avif","admin":false,"moderator":false,"signatureRaw":null,"signatureCooked":null}},{"id":19179,"postNumber":3,"raw":"这一段是在讲 ray_triangle_intersect 的处理，也就是说这一步返回的结果就需要转化为世界坐标系，而 AABB::intersect 应该不需要考虑这个问题。","cooked":"

这一段是在讲 ray_triangle_intersect 的处理，也就是说这一步返回的结果就需要转化为世界坐标系，而 AABB::intersect 应该不需要考虑这个问题。

\n","createdAt":"2023-12-12 13:59:33.913651","updatedAt":"2023-12-12 13:59:33.913651","replyToPostNumber":null,"replyCount":0,"likeCount":0,"wordCount":49,"liked":false,"bookmarked":false,"polls":[],"reactions":[],"wiki":false,"version":1,"publicVersion":1,"deletedAt":null,"isAnonymous":false,"user":{"id":1488,"username":"roland","name":"李昌洲","avatarUrl":null,"admin":false,"moderator":false,"signatureRaw":null,"signatureCooked":null}}],"hasMore":false,"lastReadPostNumber":3,"hasUrlPostNumber":true}