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POAveraging normals results in zero-length vector
primarykey
Id
15854462
data
AcceptedAnswerId
15855187
AnswerCount
1
ClosedDate
CommentCount
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CommunityOwnedDate
CreationDate
2013-04-06T18:24:17.737
FavoriteCount
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2013-04-06T19:38:21.073
LastEditDate
2013-04-06T18:44:39.900
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PostTypeId
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Score
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ViewCount
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LastEditorDisplayName
text
Body
<p>I have four normals which I am attempting to average by adding the x, y, and z values, then normalizing the result. However, when I add the different axis values, the resulting vector has a length of zero. I get the feeling that this issue is very easily solved, but I'm relatively new to OpenGL, and don't know vectors in and out yet.</p> <p>Code for getting the face and vertex normals, respectively.</p> <pre><code>public Vector3f getNormal(Vector3f p1, Vector3f p2, Vector3f p3){ Vector3f v = new Vector3f(); Vector3f calU = new Vector3f(p2.x - p1.x, p2.y - p1.y, p2.z - p1.z); Vector3f calV = new Vector3f(p3.x - p1.x, p3.y - p1.y, p3.z - p1.z); v.setX(calU.getY() * calV.getZ() - calU.getZ() * calV.getY()); v.setY(calU.getZ() * calV.getX() - calU.getX() * calV.getZ()); v.setZ(calU.getX() * calV.getY() - calU.getY() * calV.getX()); return (Vector3f)v.normalise(); } public Vector3f getVectorNormal(Vector3f p){ Vector3f t1 = getNormal(p, new Vector3f(p.getX() - 1, p.getY(), p.getZ()), new Vector3f(p.getX(), p.getY(), p.getZ() - 1)); Vector3f t2 = getNormal(p, new Vector3f(p.getX() + 1, p.getY(), p.getZ()), new Vector3f(p.getX(), p.getY(), p.getZ() - 1)); Vector3f t3 = getNormal(p, new Vector3f(p.getX() + 1, p.getY(), p.getZ()), new Vector3f(p.getX(), p.getY(), p.getZ() + 1)); Vector3f t4 = getNormal(p, new Vector3f(p.getX() - 1, p.getY(), p.getZ()), new Vector3f(p.getX(), p.getY(), p.getZ() + 1)); float x = t1.getX() + t2.getX() + t3.getX() + t4.getX(); float y = t1.getY() + t2.getY() + t3.getY() + t4.getY(); float z = t1.getZ() + t2.getZ() + t3.getZ() + t4.getZ(); Vector3f v = new Vector3f(x, y, z); return (Vector3f)v.normalise(); } </code></pre>
Tags
<java><opengl><lwjgl>
Title
Averaging normals results in zero-length vector
singulars
PostAcceptedAnswerId
1. PO
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  PTAnswer
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1. This table or related slice is empty.
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1. PTQuestion
UserLastEditorUserId
1. UScaseif
UserOwnerUserId
1. UScaseif
plurals
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1. PL
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PostLinksRelatedPostIdPostId
1. This table or related slice is empty.
PostsAcceptedAnswerId
1. This table or related slice is empty.
PostsParentIdCreationDate
1. PO
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  PostTypePostTypeId
  PTAnswer
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1. VO
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  POAveraging normals results in zero-length vector
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CommentsPostId

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