45 lines
1.1 KiB
JavaScript
45 lines
1.1 KiB
JavaScript
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var pool = require('./pool')
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var FLOAT = new Float32Array(1)
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var INT = new Uint32Array(FLOAT.buffer)
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var GL_UNSIGNED_SHORT = 5123
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module.exports = function convertToHalfFloat (array) {
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var ushorts = pool.allocType(GL_UNSIGNED_SHORT, array.length)
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for (var i = 0; i < array.length; ++i) {
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if (isNaN(array[i])) {
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ushorts[i] = 0xffff
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} else if (array[i] === Infinity) {
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ushorts[i] = 0x7c00
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} else if (array[i] === -Infinity) {
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ushorts[i] = 0xfc00
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} else {
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FLOAT[0] = array[i]
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var x = INT[0]
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var sgn = (x >>> 31) << 15
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var exp = ((x << 1) >>> 24) - 127
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var frac = (x >> 13) & ((1 << 10) - 1)
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if (exp < -24) {
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// round non-representable denormals to 0
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ushorts[i] = sgn
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} else if (exp < -14) {
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// handle denormals
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var s = -14 - exp
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ushorts[i] = sgn + ((frac + (1 << 10)) >> s)
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} else if (exp > 15) {
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// round overflow to +/- Infinity
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ushorts[i] = sgn + 0x7c00
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} else {
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// otherwise convert directly
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ushorts[i] = sgn + ((exp + 15) << 10) + frac
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}
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}
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}
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return ushorts
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}
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