onnxruntime-web
Version:
A Javascript library for running ONNX models on browsers
103 lines (102 loc) • 3.5 kB
JavaScript
;
// Copyright (c) Microsoft Corporation. All rights reserved.
// Licensed under the MIT License.
Object.defineProperty(exports, '__esModule', { value: true });
exports.EncodingGlslLib = void 0;
const glsl_definitions_1 = require('./glsl-definitions');
/**
* This GLSL library handles routines converting
* float32 to/from Unsigned byte or float 16
*/
class EncodingGlslLib extends glsl_definitions_1.GlslLib {
constructor(context) {
super(context);
}
getFunctions() {
return { ...this.encodeFloat32(), ...this.decodeFloat32() };
}
getCustomTypes() {
return {};
}
encodeFloat32() {
return {
encode: new glsl_definitions_1.GlslLibRoutine(`highp vec4 encode(highp float f) {
return vec4(f, 0.0, 0.0, 0.0);
}
`),
};
}
decodeFloat32() {
return {
decode: new glsl_definitions_1.GlslLibRoutine(`highp float decode(highp vec4 rgba) {
return rgba.r;
}
`),
};
}
/**
* returns the routine to encode encode a 32bit float to a vec4 (of unsigned bytes)
* @credit: https://stackoverflow.com/questions/7059962/how-do-i-convert-a-vec4-rgba-value-to-a-float
*/
encodeUint8() {
const endianness = EncodingGlslLib.isLittleEndian() ? 'rgba.rgba=rgba.abgr;' : '';
return {
encode: new glsl_definitions_1.GlslLibRoutine(`
highp vec4 encode(highp float f) {
highp float F = abs(f);
highp float Sign = step(0.0,-f);
highp float Exponent = floor(log2(F));
highp float Mantissa = (exp2(- Exponent) * F);
Exponent = floor(log2(F) + 127.0) + floor(log2(Mantissa));
highp vec4 rgba;
rgba[0] = 128.0 * Sign + floor(Exponent*exp2(-1.0));
rgba[1] = 128.0 * mod(Exponent,2.0) + mod(floor(Mantissa*128.0),128.0);
rgba[2] = floor(mod(floor(Mantissa*exp2(23.0 -8.0)),exp2(8.0)));
rgba[3] = floor(exp2(23.0)*mod(Mantissa,exp2(-15.0)));
${endianness}
rgba = rgba / 255.0; // values need to be normalized to [0,1]
return rgba;
}
`),
};
}
/**
* returns the routine to encode a vec4 of unsigned bytes to float32
* @credit: https://stackoverflow.com/questions/7059962/how-do-i-convert-a-vec4-rgba-value-to-a-float
*/
decodeUint8() {
const endianness = EncodingGlslLib.isLittleEndian() ? 'rgba.rgba=rgba.abgr;' : '';
return {
decode: new glsl_definitions_1.GlslLibRoutine(`
highp float decode(highp vec4 rgba) {
rgba = rgba * 255.0; // values need to be de-normalized from [0,1] to [0,255]
${endianness}
highp float Sign = 1.0 - step(128.0,rgba[0])*2.0;
highp float Exponent = 2.0 * mod(rgba[0],128.0) + step(128.0,rgba[1]) - 127.0;
highp float Mantissa = mod(rgba[1],128.0)*65536.0 + rgba[2]*256.0 +rgba[3] + float(0x800000);
highp float Result = Sign * exp2(Exponent) * (Mantissa * exp2(-23.0 ));
return Result;
}
`),
};
}
/**
* Determines if the machine is little endian or not
* @credit: https://gist.github.com/TooTallNate/4750953
*/
static isLittleEndian() {
const b = new ArrayBuffer(4);
const a = new Uint32Array(b);
const c = new Uint8Array(b);
a[0] = 0xdeadbeef;
if (c[0] === 0xef) {
return true;
}
if (c[0] === 0xde) {
return false;
}
throw new Error('unknown endianness');
}
}
exports.EncodingGlslLib = EncodingGlslLib;
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