Unity Ply網格讀取
阿新 • • 發佈：2020-11-24
Unity Ply網格讀取
Ply格式說明
The version 1.0 PLY format, 詳細參見：https://ww2.mathworks.cn/help/vision/ug/the-ply-format.html
File Header
檔案頭示例’{}‘為說明：
ply {檔案頭} format binary_big_endian 1.0 {資料格式以及版本} element vertex 9200 {定義vertex元素} property float x {定義屬性} property float y property float z element face 18000 {定義面元素} property list uchar int vertex_indices end_header {這行後面就是資料了}
其中，format <data format> <PLY version> 中的<data format>支援（little/big endian refers to the byte ordering of multi-byte data）：
- ascii
- binary_little_endian
- binary_big_endian
元素定義方式如下：
element <element name> <number in file> property <data type> <property name 1> property <data type> <property name 2> property <data type> <property name 3> ...
其中對應的<data type>有：
| Name | Type |
|---|---|
| char | (8-bit) character |
| uchar | (8-bit) unsigned character |
| short | (16-bit) short integer |
| ushort | (16-bit) unsigned short integer |
| int | (32-bit) integer |
| uint | (32-bit) unsigned integer |
| float | (32-bit) single-precision float |
| double | (64-bit) double-precision float |
對於list的屬性為：
property list <count data type> <data type> <property name>
在檔案頭裡面還可以添加註釋，具體格式如下：
comment <comment text>
Data
header之後存資料。按照之前約定的元素順序和屬性型別，依次儲存。
Common Elements and Properties
常見元素和屬性為：
| Required Core Property | Element | Property | Data Type | Property Description |
|---|---|---|---|---|
| ✓ | vertex | x | float |
x,y,z coordinates |
| ✓ | y | float |
||
| ✓ | z | float |
||
| nx | float |
x,y,z of normal | ||
| ny | float |
|||
| nz | float |
|||
| red | uchar |
vertex color | ||
| green | uchar |
|||
| blue | uchar |
|||
| alpha | uchar |
amount of transparency | ||
| material_index | int |
index to list of materials | ||
| face | vertex_indices | list of int | indices to vertices | |
| back_red | uchar |
backside color | ||
| back_green | uchar |
|||
| back_blue | uchar |
|||
| edge | vertex1 | int |
index to vertex | |
| vertex2 | int |
index to other vertex | ||
| crease_tag | uchar |
crease in subdivision surface | ||
| material | red | uchar |
material color | |
| green | uchar |
|||
| blue | uchar |
|||
| alpha | uchar |
amount of transparency | ||
| reflect_coeff | float |
amount of light reflected | ||
| refract_coeff | float |
amount of light refracted | ||
| refract_index | float |
index of refraction | ||
| extinct_coeff | float |
extinction coefficent |
Unity Ply Reader
附上專案路徑：https://github.com/grassofsky/PlyImporter
PlyImporter
原始專案的說明見：https://github.com/3DBear/PlyImporter
在原來基礎上的改動主要有
- 增加了PlyElement基類，專門用來處理不同的element，方便後期進行擴充套件，目前支援PlyFaceElement，PlyVertexElement；
- 增加了PlyProperty基類，處理不同的屬性，按照屬性的功能又分為PlyMultiProperty，用來支援單個property定義；PlyListProperty支援property list定義。
TODO
- 支援PlyEdgeElement；
- 考慮到Unity中的shader基本沒有用到頂點的顏色，增加PlyMaterialElement用來設定材質顏色；
- 通常對於載入的檔案，需要知道該檔案對應的網格名稱，擴充套件comment支援更多的選項；
- Support for Binary Big Endian
- PLY exporting