molstar
Version:
A comprehensive macromolecular library.
37 lines • 1.79 kB
JavaScript
/**
* Copyright (c) 2019-2020 mol* contributors, licensed under MIT, See LICENSE file for more info.
*
* @author Alexander Rose <alexander.rose@weirdbyte.de>
*/
import { clamp } from '../mol-math/interpolate';
import { fasterExp, fasterLog } from '../mol-math/approx';
import { Vec3, Vec4 } from '../mol-math/linear-algebra';
var maxFloat = 10000.0; // NOTE same constant is set in shaders
var floatLogFactor = fasterLog(maxFloat + 1);
/** encode float logarithmically */
export function encodeFloatLog(value) { return fasterLog(value + 1) / floatLogFactor; }
/** decode logarithmically encoded float */
export function decodeFloatLog(value) { return fasterExp(value * floatLogFactor) - 1; }
/** encode float as rgb triplet into array at offset */
export function encodeFloatRGBtoArray(value, array, offset) {
value = clamp(value, 0, 16777216 - 1) + 1;
array[offset + 2] = value % 256;
value = Math.floor(value / 256);
array[offset + 1] = value % 256;
value = Math.floor(value / 256);
array[offset] = value % 256;
return array;
}
/** decode float encoded as rgb triplet */
export function decodeFloatRGB(r, g, b) {
return (Math.floor(r) * 256 * 256 + Math.floor(g) * 256 + Math.floor(b)) - 1;
}
var UnpackDownscale = 255 / 256; // 0..1 -> fraction (excluding 1)
var PackFactors = Vec3.create(256 * 256 * 256, 256 * 256, 256);
var UnpackFactors = Vec4.create(UnpackDownscale / PackFactors[0], UnpackDownscale / PackFactors[1], UnpackDownscale / PackFactors[2], UnpackDownscale / 1);
var tmpDepthRGBA = Vec4();
export function unpackRGBAToDepth(r, g, b, a) {
Vec4.set(tmpDepthRGBA, r / 255, g / 255, b / 255, a / 255);
return Vec4.dot(tmpDepthRGBA, UnpackFactors);
}
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