From a849dc72d2d2dd4c12cafbac7983fe2ad626a271 Mon Sep 17 00:00:00 2001 From: lmj01 Date: Sat, 4 Nov 2023 21:17:33 +0800 Subject: [PATCH 1/2] Create half-edge.md --- cg/half-edge.md | 15 +++++++++++++++ 1 file changed, 15 insertions(+) create mode 100644 cg/half-edge.md diff --git a/cg/half-edge.md b/cg/half-edge.md new file mode 100644 index 0000000..3095698 --- /dev/null +++ b/cg/half-edge.md @@ -0,0 +1,15 @@ +# Half-Edge + +> 在计算图形学中，半边结构用于描述geometric polygon meshes。它是一个连接描述，一种拓扑描述。是关于vertices、half-edges、edges和polygons的描述。 + +geometric interpretations，称为embeddings，与半边结构的关系是 +- 通常的解释是映射vertices为points，half-edges为directed line segments，edges为line segments，polygons为planar polygons。 +- 另一种解释是映射结构到sphere，vertices为points，edges为arcs，polygons为spherical polygons。 + +半边结构的重点在于它能够有效地回应邻接查询 + +- + + +## 参考 +- [Half-edge structure](https://kaba.hilvi.org/homepage/blog/halfedge/halfedge.htm) From 357520f8533c03c5b6e757ce97e0b0a0c26554e6 Mon Sep 17 00:00:00 2001 From: lmj01 Date: Sat, 4 Nov 2023 21:37:35 +0800 Subject: [PATCH 2/2] Update half-edge.md --- cg/half-edge.md | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/cg/half-edge.md b/cg/half-edge.md index 3095698..4bc7cf1 100644 --- a/cg/half-edge.md +++ b/cg/half-edge.md @@ -8,7 +8,16 @@ geometric interpretations，称为embeddings，与半边结构的关系是 半边结构的重点在于它能够有效地回应邻接查询 -- +- 那些edges与vertex相连 +- 那些polygons与vertex相连 +- 那些vertices与polygon相连 + +半边结构达到这些目的仅仅使用常量数据对每个要求。它能描述polygon meshes和所有graphs（包含带循环的多图），它能描述mixes of a polygon mesh and a wireframe mesh. + +但也存在两个很重要的限制于关系的描述 +- no non-orientalbe sureface(Moebius strip)莫比乌斯带 + + ## 参考