mirror of
https://github.com/hajimehoshi/ebiten.git
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76 lines
2.8 KiB
Go
76 lines
2.8 KiB
Go
// Copyright 2019 The Ebiten Authors
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package jsutil
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import (
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"syscall/js"
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)
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var (
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arrayBuffer = js.Global().Get("ArrayBuffer")
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uint8Array = js.Global().Get("Uint8Array")
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float32Array = js.Global().Get("Float32Array")
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)
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var (
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// temporaryArrayBuffer is a temporary buffer used at gl.readPixels or gl.texSubImage2D.
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// The read data is converted to Go's byte slice as soon as possible.
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// To avoid often allocating ArrayBuffer, reuse the buffer whenever possible.
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temporaryArrayBuffer = arrayBuffer.New(16)
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// temporaryUint8Array is a Uint8ArrayBuffer whose underlying buffer is always temporaryArrayBuffer.
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temporaryUint8Array = uint8Array.New(temporaryArrayBuffer)
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// temporaryFloat32Array is a Float32ArrayBuffer whose underlying buffer is always temporaryArrayBuffer.
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temporaryFloat32Array = float32Array.New(temporaryArrayBuffer)
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)
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func ensureTemporaryArrayBufferSize(byteLength int) {
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if bufl := temporaryArrayBuffer.Get("byteLength").Int(); bufl < byteLength {
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for bufl < byteLength {
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bufl *= 2
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}
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temporaryArrayBuffer = arrayBuffer.New(bufl)
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}
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if temporaryUint8Array.Get("byteLength").Int() < temporaryArrayBuffer.Get("byteLength").Int() {
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temporaryUint8Array = uint8Array.New(temporaryArrayBuffer)
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}
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if temporaryFloat32Array.Get("byteLength").Int() < temporaryArrayBuffer.Get("byteLength").Int() {
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temporaryFloat32Array = float32Array.New(temporaryArrayBuffer)
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}
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}
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// TemporaryUint8Array returns a Uint8Array whose length is at least minLength.
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// Be careful that the length can exceed the given minLength.
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// data must be a slice of a numeric type for initialization, or nil if you don't need initialization.
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func TemporaryUint8Array(minLength int, data interface{}) js.Value {
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ensureTemporaryArrayBufferSize(minLength)
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if data != nil {
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copySliceToTemporaryArrayBuffer(data)
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}
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return temporaryUint8Array
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}
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// TemporaryFloat32Array returns a Float32Array whose length is at least minLength.
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// Be careful that the length can exceed the given minLength.
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// data must be a slice of a numeric type for initialization, or nil if you don't need initialization.
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func TemporaryFloat32Array(minLength int, data interface{}) js.Value {
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ensureTemporaryArrayBufferSize(minLength * 4)
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if data != nil {
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copySliceToTemporaryArrayBuffer(data)
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}
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return temporaryFloat32Array
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}
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