mirror of
https://github.com/hajimehoshi/ebiten.git
synced 2024-09-20 05:12:18 +02:00
78 lines
1.7 KiB
Go
78 lines
1.7 KiB
Go
// Copyright 2017 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 clock
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import (
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"time"
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"github.com/hajimehoshi/ebiten/internal/sync"
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)
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var (
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m sync.Mutex
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valid bool
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tick int64
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lastTick int64
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frames int64
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)
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func Inc() {
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m.Lock()
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valid = true
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tick++
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m.Unlock()
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}
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func Frames(timeDuration time.Duration, fps int) (int, bool) {
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m.Lock()
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defer m.Unlock()
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count := 0
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sync := false
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if valid && lastTick != tick {
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if frames < tick {
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count = int(tick - frames)
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}
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lastTick = tick
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sync = true
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} else {
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// Use system clock when
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// 1) Inc() is not called, or
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// 2) tick is not updated yet.
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// As tick can be updated discountinuously, use system clock supplementarily.
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if int64(timeDuration) > 5*int64(time.Second)/int64(fps) {
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// The previous time is too old. Let's assume that the window was unfocused.
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return 0, true
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}
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count = int(int64(timeDuration) * int64(fps) / int64(time.Second))
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}
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// Stabilize FPS.
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if count == 0 && (int64(time.Second)/int64(fps)/2) < int64(timeDuration) {
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count = 1
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}
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if count == 2 && (int64(time.Second)/int64(fps)*3/2) > int64(timeDuration) {
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count = 1
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}
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if count > 3 {
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count = 3
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}
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frames += int64(count)
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return count, sync
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}
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