计算Catmull-Clark的法线

Question

在做catmull-clark迭代后，我没有正确计算法线。我不确定解决这个问题的正确方法。

现在，我首先执行细分，在draw_vertices中获取顶点，然后在draw_vertices上调用calculate normals。

如何确定每个四边形的正确方向？

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-dontwarn javax.xml.**
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-libraryjars libs/android-support-v13.jar
-libraryjars libs/google-play-services.jar


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-keepclassmembers public class com.google.code.linkedinapi.client.impl.LinkedInApiXppClient {
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-keepclassmembers class **.R$* {
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Answer 1

您正在计算每个面的法线并为每个顶点指定该法线。由于顶点连接到四个不同的面，因此将一个面的法线指定给顶点并不能提供正确的答案。您应该计算连接到顶点的每个面的法线并取平均值。另外，如果顶点以逆时钟方式设置c = b.cross（a）