ebiten/internal/jsutil/buf_js.go

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// Copyright 2019 The Ebiten Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package jsutil
import (
"syscall/js"
)
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var (
object = js.Global().Get("Object")
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arrayBuffer = js.Global().Get("ArrayBuffer")
uint8Array = js.Global().Get("Uint8Array")
float32Array = js.Global().Get("Float32Array")
int32Array = js.Global().Get("Int32Array")
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)
var (
temporaryArrayBufferByteLength = 16
// temporaryArrayBuffer is a temporary buffer used at gl.readPixels or gl.texSubImage2D.
// The read data is converted to Go's byte slice as soon as possible.
// To avoid often allocating ArrayBuffer, reuse the buffer whenever possible.
temporaryArrayBuffer = arrayBuffer.New(temporaryArrayBufferByteLength)
// temporaryUint8Array is a Uint8ArrayBuffer whose underlying buffer is always temporaryArrayBuffer.
temporaryUint8Array = uint8Array.New(temporaryArrayBuffer)
// temporaryFloat32Array is a Float32ArrayBuffer whose underlying buffer is always temporaryArrayBuffer.
temporaryFloat32Array = float32Array.New(temporaryArrayBuffer)
// temporaryInt32Array is a Float32ArrayBuffer whose underlying buffer is always temporaryArrayBuffer.
temporaryInt32Array = int32Array.New(temporaryArrayBuffer)
)
func ensureTemporaryArrayBufferSize(byteLength int) {
if bufl := temporaryArrayBufferByteLength; bufl < byteLength {
for bufl < byteLength {
bufl *= 2
}
temporaryArrayBufferByteLength = bufl
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temporaryArrayBuffer = arrayBuffer.New(bufl)
temporaryUint8Array = uint8Array.New(temporaryArrayBuffer)
temporaryFloat32Array = float32Array.New(temporaryArrayBuffer)
temporaryInt32Array = int32Array.New(temporaryArrayBuffer)
}
}
// TemporaryUint8ArrayFromUint8Slice returns a Uint8Array whose length is at least minLength from an uint8 slice.
// Be careful that the length can exceed the given minLength.
// data must be a slice of a numeric type for initialization, or nil if you don't need initialization.
func TemporaryUint8ArrayFromUint8Slice(minLength int, data []uint8) js.Value {
ensureTemporaryArrayBufferSize(minLength)
copyUint8SliceToTemporaryArrayBuffer(data)
return temporaryUint8Array
}
// TemporaryUint8ArrayFromUint16Slice returns a Uint8Array whose length is at least minLength from an uint16 slice.
// Be careful that the length can exceed the given minLength.
// data must be a slice of a numeric type for initialization, or nil if you don't need initialization.
func TemporaryUint8ArrayFromUint16Slice(minLength int, data []uint16) js.Value {
ensureTemporaryArrayBufferSize(minLength * 2)
copySliceToTemporaryArrayBuffer(data)
return temporaryUint8Array
}
// TemporaryUint8ArrayFromFloat32Slice returns a Uint8Array whose length is at least minLength from a float32 slice.
// Be careful that the length can exceed the given minLength.
// data must be a slice of a numeric type for initialization, or nil if you don't need initialization.
func TemporaryUint8ArrayFromFloat32Slice(minLength int, data []float32) js.Value {
ensureTemporaryArrayBufferSize(minLength * 4)
copySliceToTemporaryArrayBuffer(data)
return temporaryUint8Array
}
// TemporaryFloat32Array returns a Float32Array whose length is at least minLength.
// Be careful that the length can exceed the given minLength.
// data must be a slice of a numeric type for initialization, or nil if you don't need initialization.
func TemporaryFloat32Array(minLength int, data []float32) js.Value {
ensureTemporaryArrayBufferSize(minLength * 4)
copySliceToTemporaryArrayBuffer(data)
return temporaryFloat32Array
}
// TemporaryInt32Array returns a Int32Array whose length is at least minLength.
// Be careful that the length can exceed the given minLength.
// data must be a slice of a numeric type for initialization, or nil if you don't need initialization.
func TemporaryInt32Array(minLength int, data []int32) js.Value {
ensureTemporaryArrayBufferSize(minLength * 4)
copySliceToTemporaryArrayBuffer(data)
return temporaryInt32Array
}