gltf-pipeline/lib/getAccessorByteStride.js

Content pipeline tools for optimizing glTF assets.

'use strict';
const Cesium = require('cesium');
const numberOfComponentsForType = require('./numberOfComponentsForType');

const ComponentDatatype = Cesium.ComponentDatatype;
const defined = Cesium.defined;

module.exports = getAccessorByteStride;

/**
 * Returns the byte stride of the provided accessor.
 * If the byteStride is 0, it is calculated based on type and componentType
 *
 * @param {Object} gltf A javascript object containing a glTF asset.
 * @param {Object} accessor The accessor.
 * @returns {Number} The byte stride of the accessor.
 *
 * @private
 */
function getAccessorByteStride(gltf, accessor) {
    const bufferViewId = accessor.bufferView;
    if (defined(bufferViewId)) {
        const bufferView = gltf.bufferViews[bufferViewId];
        if (defined(bufferView.byteStride) && bufferView.byteStride > 0) {
            return bufferView.byteStride;
        }
    }
    return ComponentDatatype.getSizeInBytes(accessor.componentType) * numberOfComponentsForType(accessor.type);
}