laya-coreui-es
Version:
laya核心库、ui库es版本，剔除了媒体、TTF等功能。基于 LayaAir-release_2.12.0 修改
91 lines (90 loc) • 3.96 kB
JavaScript
export class HalfFloatUtils {
static __init__() {
for (var i = 0; i < 256; ++i) {
var e = i - 127;
if (e < -27) {
HalfFloatUtils._baseTable[i | 0x000] = 0x0000;
HalfFloatUtils._baseTable[i | 0x100] = 0x8000;
HalfFloatUtils._shiftTable[i | 0x000] = 24;
HalfFloatUtils._shiftTable[i | 0x100] = 24;
}
else if (e < -14) {
HalfFloatUtils._baseTable[i | 0x000] = 0x0400 >> (-e - 14);
HalfFloatUtils._baseTable[i | 0x100] = (0x0400 >> (-e - 14)) | 0x8000;
HalfFloatUtils._shiftTable[i | 0x000] = -e - 1;
HalfFloatUtils._shiftTable[i | 0x100] = -e - 1;
}
else if (e <= 15) {
HalfFloatUtils._baseTable[i | 0x000] = (e + 15) << 10;
HalfFloatUtils._baseTable[i | 0x100] = ((e + 15) << 10) | 0x8000;
HalfFloatUtils._shiftTable[i | 0x000] = 13;
HalfFloatUtils._shiftTable[i | 0x100] = 13;
}
else if (e < 128) {
HalfFloatUtils._baseTable[i | 0x000] = 0x7c00;
HalfFloatUtils._baseTable[i | 0x100] = 0xfc00;
HalfFloatUtils._shiftTable[i | 0x000] = 24;
HalfFloatUtils._shiftTable[i | 0x100] = 24;
}
else {
HalfFloatUtils._baseTable[i | 0x000] = 0x7c00;
HalfFloatUtils._baseTable[i | 0x100] = 0xfc00;
HalfFloatUtils._shiftTable[i | 0x000] = 13;
HalfFloatUtils._shiftTable[i | 0x100] = 13;
}
}
HalfFloatUtils._mantissaTable[0] = 0;
for (i = 1; i < 1024; ++i) {
var m = i << 13;
e = 0;
while ((m & 0x00800000) === 0) {
e -= 0x00800000;
m <<= 1;
}
m &= ~0x00800000;
e += 0x38800000;
HalfFloatUtils._mantissaTable[i] = m | e;
}
for (i = 1024; i < 2048; ++i) {
HalfFloatUtils._mantissaTable[i] = 0x38000000 + ((i - 1024) << 13);
}
HalfFloatUtils._exponentTable[0] = 0;
for (i = 1; i < 31; ++i) {
HalfFloatUtils._exponentTable[i] = i << 23;
}
HalfFloatUtils._exponentTable[31] = 0x47800000;
HalfFloatUtils._exponentTable[32] = 0x80000000;
for (i = 33; i < 63; ++i) {
HalfFloatUtils._exponentTable[i] = 0x80000000 + ((i - 32) << 23);
}
HalfFloatUtils._exponentTable[63] = 0xc7800000;
HalfFloatUtils._offsetTable[0] = 0;
for (i = 1; i < 64; ++i) {
if (i === 32) {
HalfFloatUtils._offsetTable[i] = 0;
}
else {
HalfFloatUtils._offsetTable[i] = 1024;
}
}
}
static roundToFloat16Bits(num) {
HalfFloatUtils._floatView[0] = num;
var f = HalfFloatUtils._uint32View[0];
var e = (f >> 23) & 0x1ff;
return HalfFloatUtils._baseTable[e] + ((f & 0x007fffff) >> HalfFloatUtils._shiftTable[e]);
}
static convertToNumber(float16bits) {
var m = float16bits >> 10;
HalfFloatUtils._uint32View[0] = HalfFloatUtils._mantissaTable[HalfFloatUtils._offsetTable[m] + (float16bits & 0x3ff)] + HalfFloatUtils._exponentTable[m];
return HalfFloatUtils._floatView[0];
}
}
HalfFloatUtils._buffer = new ArrayBuffer(4);
HalfFloatUtils._floatView = new Float32Array(HalfFloatUtils._buffer);
HalfFloatUtils._uint32View = new Uint32Array(HalfFloatUtils._buffer);
HalfFloatUtils._baseTable = new Uint32Array(512);
HalfFloatUtils._shiftTable = new Uint32Array(512);
HalfFloatUtils._mantissaTable = new Uint32Array(2048);
HalfFloatUtils._exponentTable = new Uint32Array(64);
HalfFloatUtils._offsetTable = new Uint32Array(64);