Babylon.js/Babylon/Culling/Octrees/babylon.octree.js

var BABYLON = BABYLON || {};

(function () {
    BABYLON.Octree = function () {
        this.blocks = [];
        this._selection = new BABYLON.Tools.SmartArray(256);
    };
    
    // Methods
    BABYLON.Octree.prototype.update = function (worldMin, worldMax, meshes) {
        this.blocks = [];
        var blockSize = new BABYLON.Vector3((worldMax.x - worldMin.x) / 2, (worldMax.y - worldMin.y) / 2, (worldMax.z - worldMin.z) / 2);

        // Segmenting space
        for (var x = 0; x < 2; x++) {
            for (var y = 0; y < 2; y++) {
                for (var z = 0; z < 2; z++) {
                    var localMin = worldMin.add(blockSize.multiplyByFloats(x, y, z));
                    var localMax = worldMin.add(blockSize.multiplyByFloats(x + 1, y + 1, z + 1));

                    var block = new BABYLON.OctreeBlock(x, y, z, localMin, localMax);
                    block.addEntries(meshes);
                    this.blocks.push(block);
                }
            }
        }
    };

    BABYLON.Octree.prototype.select = function (frustumPlanes) {
        this._selection.reset();

        for (var index = 0; index < this.blocks.length; index++) {
            var block = this.blocks[index];
            if (block.intersects(frustumPlanes)) {                
                this._selection.push(block);
            }
        }

        return this._selection;
    };
})();