mirror of
https://github.com/hajimehoshi/ebiten.git
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76 lines
2.1 KiB
Go
76 lines
2.1 KiB
Go
// Copyright 2023 The Ebitengine 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 graphicscommand
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type temporaryBytes struct {
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pixels []byte
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pos int
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notFullyUsedTime int
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}
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func temporaryBytesSize(size int) int {
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l := 16
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for l < size {
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l *= 2
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}
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return l
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}
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// alloc allocates the pixels and returns it.
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//
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// Be careful that the returned pixels might not be zero-cleared.
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func (t *temporaryBytes) alloc(size int) []byte {
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if len(t.pixels) < t.pos+size {
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t.pixels = make([]byte, max(len(t.pixels)*2, temporaryBytesSize(size)))
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t.pos = 0
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}
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pix := t.pixels[t.pos : t.pos+size]
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t.pos += size
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return pix
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}
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func (t *temporaryBytes) reset() {
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// reset is called in a render thread.
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// When reset is called, a queue is being flushed in a render thread, and the queue is never used in the game thread.
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// Thus, a mutex lock is not needed in alloc and reset.
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const maxNotFullyUsedTime = 60
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if temporaryBytesSize(t.pos) < len(t.pixels) {
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if t.notFullyUsedTime < maxNotFullyUsedTime {
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t.notFullyUsedTime++
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}
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} else {
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t.notFullyUsedTime = 0
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}
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// Let the pixels GCed if this is not used for a while.
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if t.notFullyUsedTime == maxNotFullyUsedTime && len(t.pixels) > 0 {
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t.pixels = nil
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t.notFullyUsedTime = 0
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}
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// Reset the position and reuse the allocated bytes.
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// t.pixels should already be sent to GPU, then this can be reused.
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t.pos = 0
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}
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// AllocBytes allocates bytes from the cache.
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//
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// Be careful that the returned pixels might not be zero-cleared.
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func AllocBytes(size int) []byte {
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return currentCommandQueue().temporaryBytes.alloc(size)
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}
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