我有一个简单的算法来计算顶点法线。对于大量顶点，算法太慢而无法使用。我的问题是，是否有更好的计算顶点法线的方法。（已经计算了面顶点）
我正在使用的代码如下：
curl --compressed -v -o /dev/null design.cdn.getsprk.com/icons/space/flat/11-neil-armstrong.svg
* About to connect() to design.cdn.getsprk.com port 80 (#0)
* Trying 54.192.144.164...
% Total % Received % Xferd Average Speed Time Time Time Current
Dload Upload Total Spent Left Speed
0 0 0 0 0 0 0 0 --:--:-- --:--:-- --:--:-- 0* connected
* Connected to design.cdn.getsprk.com (54.192.144.164) port 80 (#0)
> GET /icons/space/flat/11-neil-armstrong.svg HTTP/1.1
> User-Agent: curl/7.26.0
> Host: design.cdn.getsprk.com
> Accept: */*
> Accept-Encoding: deflate, gzip
>
* additional stuff not fine transfer.c:1037: 0 0
* HTTP 1.1 or later with persistent connection, pipelining supported
< HTTP/1.1 200 OK
< Content-Type: image/svg+xml
< Content-Length: 7702
< Connection: keep-alive
< Date: Wed, 18 Nov 2015 00:43:12 GMT
< Last-Modified: Tue, 10 Nov 2015 23:59:32 GMT
< ETag: "746b7f4bce35cf3e6a8c965207087631"
< Accept-Ranges: bytes
< Server: AmazonS3
< Age: 9094
< **X-Cache: Hit from cloudfront**
< Via: 1.1 43ff408868c37128de942a235a1225f2.cloudfront.net (CloudFront)
< X-Amz-Cf-Id: G7VwUZ3l15YnxjbZaeZmeeqSaj_E4OszrsS2sSfFjqkh1ZlTOXoKEg==
<
{ [data not shown]
100 7702 100 7702 0 0 70606 0 --:--:-- --:--:-- --:--:-- 104k
* Connection #0 to host design.cdn.getsprk.com left intact
* Closing connection #0