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Return split values in a single interleaved Float32Array

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This commit is contained in:
Tom Payne
2013-05-30 20:05:02 +02:00
parent 42f15f000b
commit db2f805ed9
2 changed files with 25 additions and 35 deletions
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32
src/ol/structs/buffer.js
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@@ -22,12 +22,6 @@ ol.structs.BufferUsage = {
ol.BUFFER_REPLACE_UNUSED_ENTRIES_WITH_NANS = goog.DEBUG;
/**
* @typedef {{high: Float32Array, low: Float32Array}}
*/
ol.structs.BufferSplit32;
/**
* @constructor
@@ -70,7 +64,7 @@ ol.structs.Buffer = function(opt_arr, opt_used, opt_usage) {
/**
* @private
* @type {?ol.structs.BufferSplit32}
* @type {?Float32Array}
*/
this.split32_ = null;
@@ -165,9 +159,12 @@ ol.structs.Buffer.prototype.getFreeSet = function() {
/**
* Splits this buffer into two Float32Arrays.
* Returns a Float32Array twice the length of the buffer containing each value
* split into two 32-bit floating point values that, when added together,
* approximate the original value. Even indicies contain the high bits, odd
* indicies contain the low bits.
* @see http://blogs.agi.com/insight3d/index.php/2008/09/03/precisions-precisions/
* @return {ol.structs.BufferSplit32} Split.
* @return {Float32Array} Split.
*/
ol.structs.Buffer.prototype.getSplit32 = function() {
var arr = this.arr_;
@@ -177,24 +174,21 @@ ol.structs.Buffer.prototype.getSplit32 = function() {
this.addDirtySet(this.split32DirtySet_);
}
if (goog.isNull(this.split32_)) {
this.split32_ = {
high: new Float32Array(n),
low: new Float32Array(n)
};
this.split32_ = new Float32Array(2 * n);
}
var split32 = this.split32_;
this.split32DirtySet_.forEachRange(function(start, stop) {
var doubleHigh, i, value;
for (i = start; i < stop; ++i) {
var doubleHigh, i, j, value;
for (i = start, j = 2 * start; i < stop; ++i, j += 2) {
value = arr[i];
if (value < 0) {
doubleHigh = 65536 * Math.floor(-value / 65536);
split32.high[i] = -doubleHigh;
split32.low[i] = value + doubleHigh;
split32[j] = -doubleHigh;
split32[j + 1] = value + doubleHigh;
} else {
doubleHigh = 65536 * Math.floor(value / 65536);
split32.high[i] = doubleHigh;
split32.low[i] = value - doubleHigh;
split32[j] = doubleHigh;
split32[j + 1] = value - doubleHigh;
}
}
});