BufferUtils.js•1.56 kB
import { GPU_CHUNK_BYTES } from './Constants.js';
/** @module BufferUtils **/
/**
* This function is usually called with the length in bytes of an array buffer.
* It returns an padded value which ensure chunk size alignment according to STD140 layout.
*
* @function
* @param {Number} floatLength - The buffer length.
* @return {Number} The padded length.
*/
function getFloatLength( floatLength ) {
// ensure chunk size alignment (STD140 layout)
return floatLength + ( ( GPU_CHUNK_BYTES - ( floatLength % GPU_CHUNK_BYTES ) ) % GPU_CHUNK_BYTES );
}
/**
* Given the count of vectors and their vector length, this function computes
* a total length in bytes with buffer alignment according to STD140 layout.
*
* @function
* @param {Number} count - The number of vectors.
* @param {Number} [vectorLength=4] - The vector length.
* @return {Number} The padded length.
*/
function getVectorLength( count, vectorLength = 4 ) {
const strideLength = getStrideLength( vectorLength );
const floatLength = strideLength * count;
return getFloatLength( floatLength );
}
/**
* This function is called with a vector length and ensure the computed length
* matches a predefined stride (in this case `4`).
*
* @function
* @param {Number} vectorLength - The vector length.
* @return {Number} The padded length.
*/
function getStrideLength( vectorLength ) {
const strideLength = 4;
return vectorLength + ( ( strideLength - ( vectorLength % strideLength ) ) % strideLength );
}
export {
getFloatLength,
getVectorLength,
getStrideLength
};