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ichor

VertexArrays and Octrees (screenshots included)

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I''m having some issues with my octree coupled with my indexed vertex array. First, I create an indexed vertex array (one implemented with GL_TRIANGLE_STRIP and another with GL_TRIANGLES), and am able to render this easily with glDrawElements(). A screenshot of this is at: http://www.websamba.com/ichor/array_by_itself.jpg However, when I go from the large vertex array to the smaller vertex arrays in an octree, all the triangles are screwed up. A screenshot here: http://www.websamba.com/ichor/array_in_octree.jpg Now, since I''ve done the same steps using GL_TRIANGLE_STRIPS and GL_TRIANGLES, I''ve come to realize that the problem is with the octee (rather than the shared vertices in the STRIPS.) So, without posting all the code (the octree code I created is quite large...), here''s what''s going on when I call createNode()... 1. I set the width, center, minBounds, and maxBounds in the node. 2. If the number of vertices in that node is larger than my set number, I start the major process...first, setting hasChildren to true. (This pretty much only comes into play for my render function.) 3. I go through each vertex in the vertex array, and allocate memory for the 8 smaller arrays that the node is being split into. 4. I have an "if" for each possible (8) nodes to be created; if the node has memory allocated for it, then I create a new node (now a child node.) 5. This is where I _think_ something is getting all screwed up. I cycle through all the vertices again, and depending on the coordinates of the vertex, I assign it to one of the children nodes, and immediately thereafter, I assign the index for that node. Example:
octreeNodes[TOP_LEFT_BACK]->nodeVertArray.verts[tlb] = vertArray.verts[h];
octreeNodes[TOP_LEFT_BACK]->nodeVertArray.indices[tlb] = tlb;
tlb++; 
6. After that, I calculate the node, min/maxBounds of the node, and call createNode() again with this new information. Not the nicest of coding, but here''s an example:
octreeNodes[TOP_LEFT_FRONT]->nodeCenter = getNodeCenter(octreeNodes[TOP_LEFT_FRONT]->nodeVertArray);
octreeNodes[TOP_LEFT_FRONT]->maxBounds = getMaxBounds(octreeNodes[TOP_LEFT_FRONT]->nodeVertArray);
octreeNodes[TOP_LEFT_FRONT]->minBounds = getMinBounds(octreeNodes[TOP_LEFT_FRONT]->nodeVertArray); 
And that''s it. And the result doesn''t work. What am I doing wrong? Should I be traversing through my vertices in INDEXED order, rather than 0-n? I''ve been at this a while and can''t figure it out...

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