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César, Newbie
Posted: 16 February 2013 02:49 PM Total Posts: 11
Hello,
I am trying to add UV on two polygons, but I don’t understand why I can’t move the vertex UV as I want…
I add 4 points.
I add two triangles.
I add one vertice UV per triangle point, so 6 UV points.
And then the 6 index.
But instead of have the two polygon with the same UV unwraping, the second have somthing I don’t explain (see image).
var points:Vector.<Number> = new Vector.<Number>();
points.push(0,0,0);
points.push(50,0,0);
points.push(50,0,50);
points.push(0,0,50);
var uvs:Vector.<Number> = new Vector.<Number>();
uvs.push(0,0);
uvs.push(0,1);
uvs.push(1,1);
uvs.push(0,0);
uvs.push(0,1);
uvs.push(1,1);
var indices:Vector.<uint> = Vector.<uint>([0,1,2, 0,2,3]);
var sousGeometrie:SubGeometry = new SubGeometry();
sousGeometrie.updateVertexData(points);
sousGeometrie.updateIndexData(indices);
sousGeometrie.updateUVData(uvs);
var geometrie:Geometry = new Geometry();
geometrie.addSubGeometry(sousGeometrie);
modele = new Mesh(geometrie, matSel);
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Fabrice Closier, Administrator
Posted: 16 February 2013 09:31 PM Total Posts: 1265
[ # 1 ]
From what I see, you have a wrong winding and you have inverted the v values. Make sure that the shared side at 0-1 and 0-0 is indeed the one
you think it is…
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César, Newbie
Posted: 16 February 2013 09:59 PM Total Posts: 11
[ # 2 ]
I am not sure to understand how it works, I have the same result with only 4 points UV, it’s not very logical, the number of UV points depend of the number of polygons × 3 and not of the vertices number, isn’t it ?
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Fabrice Closier, Administrator
Posted: 16 February 2013 11:54 PM Total Posts: 1265
[ # 3 ]
k, let me put it this way. Make just one triangle. invert the v value.
looking at your image, you have one right.
Now instead of sharing the index, make it unique, and make the second triangle. Once you have the second mapped correctly, compair with your original code. you will see that the coordinates expected at shared line are incorrect. To give you a hint: if u values goes from left to right. how come your second triangle as 2 0’s for u in your code?
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César, Newbie
Posted: 17 February 2013 10:58 AM Total Posts: 11
[ # 4 ]
I think I understand. : )
I make the two triangles independally like you said and the texture display fine :
var points:Vector.<Number> = new Vector.<Number>();
points.push(0,0,0);
points.push(50,0,0);
points.push(50,0,50);
points.push(0,0,0);
points.push(50,0,50);
points.push(0,0,50);
var uvs:Vector.<Number> = new Vector.<Number>();
uvs.push(0,0);
uvs.push(1,0);
uvs.push(1,1);
uvs.push(0,0);
uvs.push(1,1);
uvs.push(0,1);
var indices:Vector.<uint> = Vector.<uint>([0,1,2, 3,4,5]);
But I have now 6 vertexes with two identical, it’s not very economic, is it necessary to have UV coordinates independally ?
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Fabrice Closier, Administrator
Posted: 17 February 2013 12:33 PM Total Posts: 1265
[ # 5 ]
of course its not economical.the goal was to help you fix your original buffer. Now you can easylly find and share the side propperly. because now there is only one index combo possible and your uvs are correct.
You just need to respect the face winding and set the indices where vertex values are identical.
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