# Solving t-junctions in geomipmapping

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Hi ! I've implemented the geomipmapping algorithm in managed directx but now i need to handle the cracks resulting from adjacent sections with diferent levels of detail. My current implementation relies on a vertex buffer per section and a global array of index buffers representing the different levels of detail. There is 4 possible situations that i need to cope to solve the cracks: - Blend Left - Blend Right - Blend Up - Blend Down * - And some mixed situations beetwen two cases, like for example Up and Left
0--1--2
| /| /|
|/ |/ |
3--4--5
| /| /|
|/ |/ |
6--7--8

IB = 0, 3, 1, 4, 2, 5, |5|, |3|, 3, 6, 4, 7, 5, 8 I'm using one single triangle strip to draw the sections as illustrated... The index buffer connects the two strips in the figure above using degenerate triangles, created by the addition of |5| and |3|. My problem is how do i build my index buffer for all the blending situations mencioned. I don't even know if this is possible since there is some strange cases like blending down and right that i'm not totally sure... =========LEFT=========
0-----2       0--1--2   0-----2 0-----1--2
|    /|       | /| /|   |    /| |    /| /|
|   / |       |/ |/ |   |   / | |   / |/ |
|  /  | blend 3--4--5 = |  /  | |  /  4--5
| /   | left  | /| /|   | /   | | / / | /|
|/    |       |/ |/ |   |/    | |//   |/ |
6-----8       6--7--8   6-----8 6-----7--8

IB = 0, 6, 1, 4, 2, 5, |5|, |4|, 4, 7, 5, 8 Is this right ? ======================= =========RIGHT=========
0--1--2       0-----2    0--1-----2 0-----2
| /| /|       |    /|    | /|    /| |    /|
|/ |/ |       |   / |    |/ |  // | |   / |
3--4--5 blend |  /  | =  3--4/ /  | |  /  |
| /| /| right | /   |    | /| /   | | /   |
|/ |/ |       |/    |    |/ |/    | |/    |
6--7--8       6-----8    6--7-----8 6-----8

IB = ? ====================== =========TOP==========
0-----2
|    /|   0-----2
|   / |   |    /|
|  /  |   |   / |
| /   |   |  /  |
|/    |   | /   |
6-----8   |/    |
6-----8
blend  =
top      0-----2
|   / |
0--1--2   |  // |
| /| /|   | / / |
|/ |/ |   |/ /  |
3--4--5   3--4--5
| /| /|   | /| /|
|/ |/ |   |/ |/ |
6--7--8   6--7--8

IB = ? ====================== =========DOWN=========
          0--1--2
0--1--2   | /| /|
| /| /|   |/ |/ |
|/ |/ |   3--4--5
3--4--5   |  / /|
| /| /|   | / / |
|/ |/ |   |/ /  |
6--7--8   |/    |
6-----8
blend  =
down     0-----2
|    /|
0-----2   |   / |
|    /|   |  /  |
|   / |   | /   |
|  /  |   |/    |
| /   |   6-----8
|/    |
6-----8

IB = ? ====================== Tnks for any help [Edited by - i24021 on July 26, 2005 4:18:56 AM]

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