Greyhound bounds scale/offset

point-cloud-bounds.js

var PointCloudBounds = function(serverInfo) {
    var bounds = serverInfo.bounds;
    var preScale = serverInfo.scale || [1, 1, 1];
    var preOffset = serverInfo.offset || [0, 0, 0];

    console.log('From:', serverInfo);

    if (!preScale.length) preScale = [preScale, preScale, preScale];

    bounds = bounds.map((v, i) => v * preScale[i % 3] + preOffset[i % 3]);

    // Default to scale of 0.01, or the highest-resolution scale available in
    // the resource.
    var minScale = Math.min(preScale[0], preScale[1], preScale[2], 0.01);
    var effectiveScale = [minScale, minScale, minScale];
    var effectiveOffset = [
        bounds[0] + (bounds[3] - bounds[0]) / 2,
        bounds[1] + (bounds[4] - bounds[1]) / 2,
        bounds[2] + (bounds[5] - bounds[2]) / 2
    ];

    bounds = bounds.map((v, i) => (v - effectiveOffset[i % 3]) / effectiveScale[i % 3]);
    var scale = preScale.map((v, i) => 1 / v * effectiveScale[i]);
    var offset = preOffset.map((v, i) => -v + effectiveOffset[i]);

    this.effectiveScale = effectiveScale;
    this.effectiveOffset = effectiveOffset;

    this.bounds = bounds;
    this.scale = scale;
    this.offset = offset;

    console.log('Our bounds', bounds);
    console.log('To-native scale', effectiveScale);
    console.log('To-native offset', effectiveOffset);
    console.log('Query param scale', scale);
    console.log('Query param offset', offset);
    console.log('Native:', this.nativeBounds());    // This will be equal to serverInfo.nativeBounds
    console.log();
};

PointCloudBounds.prototype.nativeBounds = function(b) {
    if (!b) b = this.bounds;
    return b.map((v, i) => v * this.effectiveScale[i % 3] + this.effectiveOffset[i % 3]);
};

var a = new PointCloudBounds({
    bounds: [50, 50, 50, 150, 150, 150]
});

var b = new PointCloudBounds({
    bounds: [-50, -50, -50, 50, 50, 50],
    offset: [100, 100, 100]
});

var c = new PointCloudBounds({
    bounds: [-5000, -5000, -5000, 5000, 5000, 5000],
    offset: [100, 100, 100],
    scale: 0.01
});

var d = new PointCloudBounds({
    bounds: [-5000, -5000, -50000, 5000, 5000, 50000],
    offset: [100, 100, 100],
    scale: [0.01, 0.01, 0.001]
});