3 Vertices
Blitz3D Forums/Blitz3D Programming/3 Vertices
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| When I do a cameraPick To Get Picked Triangle, I can obviously Get The 3 Vertices That Make Up That Triangle, What I can't figure out is, How to get the Whole Square. When looking top down on a Mesh, in wireframe. The Triangles Hypotenuse matches up with another Triangle. I want that Other Triangle 3 Vertices. Make Sense? Thanks in Advance for any help, Eric |
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| But since you can have a triangle attached to _any_ of the three edges, there seems to be a greater problem - which one? Sorry. |
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| Is the mesh just a grid of squares? If it is and the triangles are all in sequential order you could just use some arbitrary math to decide which triangle shares this triangles hypot. |
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| If you can decide which 2 vertices form the hypot you could use them to find the triangle that is made of this 2 vertices and a 3rd as only 1 possible triangle can share them normally. |
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| John, There is one one Hyponeuse of a triangle. So It would be the other triangle that shares the same hypotenuse. Shambler Any Ideas on how to do that? |
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| Maybe he meant something like this. ThisTri = Pickedtriangle() If ThisTri And 1 Then OtherTri = ThisTri+1 Else OtherTri = ThisTri-1 |
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| DJ, Can you please give me just a little more Guidance, Maybe I should have posted in the beginners section. Regard, Eric |
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| DJ, in a grid, that's perfect. He needs to use the pic coords to get the domain of the quad he is in. |
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| DJ, I thanks, I got it, But I had to Change it to ThisTri = PickedTriangle() If ThisTri And 1 Then OtherTri = ThisTri(-)1 Else OtherTri = ThisTri(+)1 The Signs We backward for my program. Regards, Eric |
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| Yes, my fault, I forgot the tri index starts at 0. |
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| So I can Actually Learn something, Can you explain how this works? |
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| Basically the first 'square' will be made up of triangle 0 and 1, the second is triangle 2 and 3 and so on. So, if your pick returns an even number triangle then the other triangle that makes up the square will be the next triangle in the mesh 'ThisTri+1' but if the pick returns an odd number triangle then the other triangle making up the square will be the previous triangle 'ThisTri-1' |
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| BTW in case you are not familiar with binary stuff, ThisTri And 1 checks if bit 0 of the index number is set, as it will be for all odd numbers. In Binary, Decimal 1=1, 2=10, 3=11, 4=100, 5=101 and so on. The AND operator in blitz performs a bitwise AND which returns a result that has bits set only if those bits are set in both the operands. The if condition evaluates any non zero Integer result as true. |
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| Thanks for the explaination. Regards, ERic |
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