416 lines
17 KiB
JavaScript
416 lines
17 KiB
JavaScript
/**
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* Cesium - https://github.com/CesiumGS/cesium
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*
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* Copyright 2011-2020 Cesium Contributors
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*
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* Columbus View (Pat. Pend.)
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*
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* Portions licensed separately.
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* See https://github.com/CesiumGS/cesium/blob/master/LICENSE.md for full licensing details.
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*/
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define(['exports', './when-8d13db60', './Check-70bec281', './Math-61ede240', './Cartographic-f2a06374', './Cartesian2-16a61632'], function (exports, when, Check, _Math, Cartographic, Cartesian2) { 'use strict';
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var RIGHT_SHIFT = 1.0 / 256.0;
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var LEFT_SHIFT = 256.0;
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/**
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* Attribute compression and decompression functions.
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*
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* @exports AttributeCompression
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*
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* @private
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*/
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var AttributeCompression = {};
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/**
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* Encodes a normalized vector into 2 SNORM values in the range of [0-rangeMax] following the 'oct' encoding.
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*
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* Oct encoding is a compact representation of unit length vectors.
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* The 'oct' encoding is described in "A Survey of Efficient Representations of Independent Unit Vectors",
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* Cigolle et al 2014: {@link http://jcgt.org/published/0003/02/01/}
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*
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* @param {Cartesian3} vector The normalized vector to be compressed into 2 component 'oct' encoding.
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* @param {Cartesian2} result The 2 component oct-encoded unit length vector.
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* @param {Number} rangeMax The maximum value of the SNORM range. The encoded vector is stored in log2(rangeMax+1) bits.
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* @returns {Cartesian2} The 2 component oct-encoded unit length vector.
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*
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* @exception {DeveloperError} vector must be normalized.
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*
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* @see AttributeCompression.octDecodeInRange
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*/
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AttributeCompression.octEncodeInRange = function(vector, rangeMax, result) {
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//>>includeStart('debug', pragmas.debug);
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Check.Check.defined('vector', vector);
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Check.Check.defined('result', result);
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var magSquared = Cartographic.Cartesian3.magnitudeSquared(vector);
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if (Math.abs(magSquared - 1.0) > _Math.CesiumMath.EPSILON6) {
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throw new Check.DeveloperError('vector must be normalized.');
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}
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//>>includeEnd('debug');
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result.x = vector.x / (Math.abs(vector.x) + Math.abs(vector.y) + Math.abs(vector.z));
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result.y = vector.y / (Math.abs(vector.x) + Math.abs(vector.y) + Math.abs(vector.z));
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if (vector.z < 0) {
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var x = result.x;
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var y = result.y;
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result.x = (1.0 - Math.abs(y)) * _Math.CesiumMath.signNotZero(x);
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result.y = (1.0 - Math.abs(x)) * _Math.CesiumMath.signNotZero(y);
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}
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result.x = _Math.CesiumMath.toSNorm(result.x, rangeMax);
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result.y = _Math.CesiumMath.toSNorm(result.y, rangeMax);
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return result;
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};
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/**
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* Encodes a normalized vector into 2 SNORM values in the range of [0-255] following the 'oct' encoding.
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*
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* @param {Cartesian3} vector The normalized vector to be compressed into 2 byte 'oct' encoding.
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* @param {Cartesian2} result The 2 byte oct-encoded unit length vector.
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* @returns {Cartesian2} The 2 byte oct-encoded unit length vector.
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*
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* @exception {DeveloperError} vector must be normalized.
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*
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* @see AttributeCompression.octEncodeInRange
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* @see AttributeCompression.octDecode
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*/
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AttributeCompression.octEncode = function(vector, result) {
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return AttributeCompression.octEncodeInRange(vector, 255, result);
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};
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var octEncodeScratch = new Cartesian2.Cartesian2();
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var uint8ForceArray = new Uint8Array(1);
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function forceUint8(value) {
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uint8ForceArray[0] = value;
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return uint8ForceArray[0];
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}
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/**
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* @param {Cartesian3} vector The normalized vector to be compressed into 4 byte 'oct' encoding.
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* @param {Cartesian4} result The 4 byte oct-encoded unit length vector.
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* @returns {Cartesian4} The 4 byte oct-encoded unit length vector.
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*
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* @exception {DeveloperError} vector must be normalized.
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*
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* @see AttributeCompression.octEncodeInRange
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* @see AttributeCompression.octDecodeFromCartesian4
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*/
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AttributeCompression.octEncodeToCartesian4 = function(vector, result) {
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AttributeCompression.octEncodeInRange(vector, 65535, octEncodeScratch);
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result.x = forceUint8(octEncodeScratch.x * RIGHT_SHIFT);
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result.y = forceUint8(octEncodeScratch.x);
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result.z = forceUint8(octEncodeScratch.y * RIGHT_SHIFT);
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result.w = forceUint8(octEncodeScratch.y);
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return result;
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};
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/**
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* Decodes a unit-length vector in 'oct' encoding to a normalized 3-component vector.
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*
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* @param {Number} x The x component of the oct-encoded unit length vector.
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* @param {Number} y The y component of the oct-encoded unit length vector.
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* @param {Number} rangeMax The maximum value of the SNORM range. The encoded vector is stored in log2(rangeMax+1) bits.
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* @param {Cartesian3} result The decoded and normalized vector
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* @returns {Cartesian3} The decoded and normalized vector.
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*
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* @exception {DeveloperError} x and y must be unsigned normalized integers between 0 and rangeMax.
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*
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* @see AttributeCompression.octEncodeInRange
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*/
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AttributeCompression.octDecodeInRange = function(x, y, rangeMax, result) {
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//>>includeStart('debug', pragmas.debug);
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Check.Check.defined('result', result);
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if (x < 0 || x > rangeMax || y < 0 || y > rangeMax) {
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throw new Check.DeveloperError('x and y must be unsigned normalized integers between 0 and ' + rangeMax);
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}
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//>>includeEnd('debug');
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result.x = _Math.CesiumMath.fromSNorm(x, rangeMax);
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result.y = _Math.CesiumMath.fromSNorm(y, rangeMax);
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result.z = 1.0 - (Math.abs(result.x) + Math.abs(result.y));
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if (result.z < 0.0)
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{
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var oldVX = result.x;
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result.x = (1.0 - Math.abs(result.y)) * _Math.CesiumMath.signNotZero(oldVX);
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result.y = (1.0 - Math.abs(oldVX)) * _Math.CesiumMath.signNotZero(result.y);
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}
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return Cartographic.Cartesian3.normalize(result, result);
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};
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/**
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* Decodes a unit-length vector in 2 byte 'oct' encoding to a normalized 3-component vector.
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*
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* @param {Number} x The x component of the oct-encoded unit length vector.
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* @param {Number} y The y component of the oct-encoded unit length vector.
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* @param {Cartesian3} result The decoded and normalized vector.
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* @returns {Cartesian3} The decoded and normalized vector.
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*
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* @exception {DeveloperError} x and y must be an unsigned normalized integer between 0 and 255.
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*
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* @see AttributeCompression.octDecodeInRange
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*/
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AttributeCompression.octDecode = function(x, y, result) {
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return AttributeCompression.octDecodeInRange(x, y, 255, result);
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};
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/**
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* Decodes a unit-length vector in 4 byte 'oct' encoding to a normalized 3-component vector.
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*
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* @param {Cartesian4} encoded The oct-encoded unit length vector.
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* @param {Cartesian3} result The decoded and normalized vector.
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* @returns {Cartesian3} The decoded and normalized vector.
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*
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* @exception {DeveloperError} x, y, z, and w must be unsigned normalized integers between 0 and 255.
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*
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* @see AttributeCompression.octDecodeInRange
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* @see AttributeCompression.octEncodeToCartesian4
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*/
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AttributeCompression.octDecodeFromCartesian4 = function(encoded, result) {
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//>>includeStart('debug', pragmas.debug);
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Check.Check.typeOf.object('encoded', encoded);
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Check.Check.typeOf.object('result', result);
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//>>includeEnd('debug');
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var x = encoded.x;
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var y = encoded.y;
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var z = encoded.z;
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var w = encoded.w;
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//>>includeStart('debug', pragmas.debug);
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if (x < 0 || x > 255 || y < 0 || y > 255 || z < 0 || z > 255 || w < 0 || w > 255) {
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throw new Check.DeveloperError('x, y, z, and w must be unsigned normalized integers between 0 and 255');
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}
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//>>includeEnd('debug');
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var xOct16 = x * LEFT_SHIFT + y;
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var yOct16 = z * LEFT_SHIFT + w;
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return AttributeCompression.octDecodeInRange(xOct16, yOct16, 65535, result);
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};
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/**
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* Packs an oct encoded vector into a single floating-point number.
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*
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* @param {Cartesian2} encoded The oct encoded vector.
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* @returns {Number} The oct encoded vector packed into a single float.
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*
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*/
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AttributeCompression.octPackFloat = function(encoded) {
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//>>includeStart('debug', pragmas.debug);
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Check.Check.defined('encoded', encoded);
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//>>includeEnd('debug');
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return 256.0 * encoded.x + encoded.y;
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};
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var scratchEncodeCart2 = new Cartesian2.Cartesian2();
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/**
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* Encodes a normalized vector into 2 SNORM values in the range of [0-255] following the 'oct' encoding and
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* stores those values in a single float-point number.
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*
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* @param {Cartesian3} vector The normalized vector to be compressed into 2 byte 'oct' encoding.
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* @returns {Number} The 2 byte oct-encoded unit length vector.
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*
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* @exception {DeveloperError} vector must be normalized.
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*/
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AttributeCompression.octEncodeFloat = function(vector) {
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AttributeCompression.octEncode(vector, scratchEncodeCart2);
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return AttributeCompression.octPackFloat(scratchEncodeCart2);
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};
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/**
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* Decodes a unit-length vector in 'oct' encoding packed in a floating-point number to a normalized 3-component vector.
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*
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* @param {Number} value The oct-encoded unit length vector stored as a single floating-point number.
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* @param {Cartesian3} result The decoded and normalized vector
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* @returns {Cartesian3} The decoded and normalized vector.
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*
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*/
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AttributeCompression.octDecodeFloat = function(value, result) {
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//>>includeStart('debug', pragmas.debug);
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Check.Check.defined('value', value);
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//>>includeEnd('debug');
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var temp = value / 256.0;
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var x = Math.floor(temp);
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var y = (temp - x) * 256.0;
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return AttributeCompression.octDecode(x, y, result);
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};
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/**
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* Encodes three normalized vectors into 6 SNORM values in the range of [0-255] following the 'oct' encoding and
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* packs those into two floating-point numbers.
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*
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* @param {Cartesian3} v1 A normalized vector to be compressed.
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* @param {Cartesian3} v2 A normalized vector to be compressed.
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* @param {Cartesian3} v3 A normalized vector to be compressed.
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* @param {Cartesian2} result The 'oct' encoded vectors packed into two floating-point numbers.
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* @returns {Cartesian2} The 'oct' encoded vectors packed into two floating-point numbers.
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*
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*/
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AttributeCompression.octPack = function(v1, v2, v3, result) {
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//>>includeStart('debug', pragmas.debug);
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Check.Check.defined('v1', v1);
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Check.Check.defined('v2', v2);
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Check.Check.defined('v3', v3);
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Check.Check.defined('result', result);
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//>>includeEnd('debug');
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var encoded1 = AttributeCompression.octEncodeFloat(v1);
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var encoded2 = AttributeCompression.octEncodeFloat(v2);
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var encoded3 = AttributeCompression.octEncode(v3, scratchEncodeCart2);
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result.x = 65536.0 * encoded3.x + encoded1;
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result.y = 65536.0 * encoded3.y + encoded2;
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return result;
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};
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/**
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* Decodes three unit-length vectors in 'oct' encoding packed into a floating-point number to a normalized 3-component vector.
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*
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* @param {Cartesian2} packed The three oct-encoded unit length vectors stored as two floating-point number.
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* @param {Cartesian3} v1 One decoded and normalized vector.
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* @param {Cartesian3} v2 One decoded and normalized vector.
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* @param {Cartesian3} v3 One decoded and normalized vector.
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*/
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AttributeCompression.octUnpack = function(packed, v1, v2, v3) {
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//>>includeStart('debug', pragmas.debug);
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Check.Check.defined('packed', packed);
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Check.Check.defined('v1', v1);
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Check.Check.defined('v2', v2);
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Check.Check.defined('v3', v3);
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//>>includeEnd('debug');
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var temp = packed.x / 65536.0;
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var x = Math.floor(temp);
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var encodedFloat1 = (temp - x) * 65536.0;
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temp = packed.y / 65536.0;
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var y = Math.floor(temp);
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var encodedFloat2 = (temp - y) * 65536.0;
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AttributeCompression.octDecodeFloat(encodedFloat1, v1);
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AttributeCompression.octDecodeFloat(encodedFloat2, v2);
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AttributeCompression.octDecode(x, y, v3);
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};
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/**
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* Pack texture coordinates into a single float. The texture coordinates will only preserve 12 bits of precision.
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*
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* @param {Cartesian2} textureCoordinates The texture coordinates to compress. Both coordinates must be in the range 0.0-1.0.
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* @returns {Number} The packed texture coordinates.
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*
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*/
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AttributeCompression.compressTextureCoordinates = function(textureCoordinates) {
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//>>includeStart('debug', pragmas.debug);
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Check.Check.defined('textureCoordinates', textureCoordinates);
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//>>includeEnd('debug');
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// Move x and y to the range 0-4095;
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var x = (textureCoordinates.x * 4095.0) | 0;
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var y = (textureCoordinates.y * 4095.0) | 0;
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return 4096.0 * x + y;
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};
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/**
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* Decompresses texture coordinates that were packed into a single float.
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*
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* @param {Number} compressed The compressed texture coordinates.
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* @param {Cartesian2} result The decompressed texture coordinates.
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* @returns {Cartesian2} The modified result parameter.
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*
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*/
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AttributeCompression.decompressTextureCoordinates = function(compressed, result) {
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//>>includeStart('debug', pragmas.debug);
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Check.Check.defined('compressed', compressed);
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Check.Check.defined('result', result);
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//>>includeEnd('debug');
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var temp = compressed / 4096.0;
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var xZeroTo4095 = Math.floor(temp);
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result.x = xZeroTo4095 / 4095.0;
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result.y = (compressed - xZeroTo4095 * 4096) / 4095;
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return result;
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};
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function zigZagDecode(value) {
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return (value >> 1) ^ (-(value & 1));
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}
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/**
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* Decodes delta and ZigZag encoded vertices. This modifies the buffers in place.
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*
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* @param {Uint16Array} uBuffer The buffer view of u values.
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* @param {Uint16Array} vBuffer The buffer view of v values.
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* @param {Uint16Array} [heightBuffer] The buffer view of height values.
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*
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* @see {@link https://github.com/AnalyticalGraphicsInc/quantized-mesh|quantized-mesh-1.0 terrain format}
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*/
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AttributeCompression.zigZagDeltaDecode = function(uBuffer, vBuffer, heightBuffer) {
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//>>includeStart('debug', pragmas.debug);
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Check.Check.defined('uBuffer', uBuffer);
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Check.Check.defined('vBuffer', vBuffer);
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Check.Check.typeOf.number.equals('uBuffer.length', 'vBuffer.length', uBuffer.length, vBuffer.length);
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if (when.defined(heightBuffer)) {
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Check.Check.typeOf.number.equals('uBuffer.length', 'heightBuffer.length', uBuffer.length, heightBuffer.length);
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}
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//>>includeEnd('debug');
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var count = uBuffer.length;
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var u = 0;
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var v = 0;
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var height = 0;
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for (var i = 0; i < count; ++i) {
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u += zigZagDecode(uBuffer[i]);
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v += zigZagDecode(vBuffer[i]);
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uBuffer[i] = u;
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vBuffer[i] = v;
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if (when.defined(heightBuffer)) {
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height += zigZagDecode(heightBuffer[i]);
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heightBuffer[i] = height;
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}
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}
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};
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// 将oct压缩的short转化为float
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AttributeCompression.octShortToFloat = function(s){
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//var tempF = s * 1.0 / ((1 << 15) - 1);
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return _Math.CesiumMath.clamp(s * 0.00003051850947599719, -1.0, 1.0);
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};
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// 将oct压缩的两个short解压为三个float
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AttributeCompression.octShortDecode = function(x, y, result) {
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Check.Check.defined('result', result);
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result.x = AttributeCompression.octShortToFloat(x);
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result.y = AttributeCompression.octShortToFloat(y);
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result.z = 1.0 - (Math.abs(result.x) + Math.abs(result.y));
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if (result.z < 0.0)
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{
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var oldVX = result.x;
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result.x = (1.0 - Math.abs(result.y)) * _Math.CesiumMath.signNotZero(oldVX);
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result.y = (1.0 - Math.abs(oldVX)) * _Math.CesiumMath.signNotZero(result.y);
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}
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return Cartographic.Cartesian3.normalize(result, result);
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};
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exports.AttributeCompression = AttributeCompression;
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});
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