// TODO: How can this be done in parallel with goroutines?
func (gm *GeoMipMap) buildQuadTreeRec(dev g3.GraphicsDevice, depth uint, x, y, w, h int, parent g3.SpatElement) (g3.SpatElement, int) {
// TODO: remove magic numbers; calc from LOD
if depth >= gm.maxDepth /*|| w <= gm.maxPatchWidth || h <= gm.maxPatchHeight*/ {
//println(w, h)
vertices, normals := createPatchVertices(gm.heightMap, x, y, w, h, gm.maxLOD, gm.whScale, gm.hScale)
bbox := g3.MakeBoundingBoxFromPoints(vertices)
center := bbox.CalculateCenter()
patch := patch{center, dev.NewVertexBufferVec3(vertices), dev.NewVertexBufferVec3(normals)}
return &g3.SpatLeaf{g3.SpatElementData{&bbox, parent, patch}}, 1
}
p := &g3.SpatNode{g3.SpatElementData{nil, parent, nil}, make([]g3.SpatElement, 4)}
c1, l1 := gm.buildQuadTreeRec(dev, depth+1, x, y, w/2, h/2, p)
c2, l2 := gm.buildQuadTreeRec(dev, depth+1, x+w/2, y, w/2, h/2, p)
c3, l3 := gm.buildQuadTreeRec(dev, depth+1, x, y+h/2, w/2, h/2, p)
c4, l4 := gm.buildQuadTreeRec(dev, depth+1, x+w/2, y+h/2, w/2, h/2, p)
bbox := g3.MakeBoundingBoxFromBoxes([]g3.BoundingBox{
*c1.GetBoundingVolume().(*g3.BoundingBox),
*c2.GetBoundingVolume().(*g3.BoundingBox),
*c3.GetBoundingVolume().(*g3.BoundingBox),
*c4.GetBoundingVolume().(*g3.BoundingBox)})
p.BVolume = &bbox
p.Children = []g3.SpatElement{c1, c2, c3, c4}
return p, l1 + l2 + l3 + l4
}
