mirror of
https://github.com/hajimehoshi/ebiten.git
synced 2024-11-10 04:57:26 +01:00
87 lines
2.2 KiB
Go
87 lines
2.2 KiB
Go
// Copyright 2014 Hajime Hoshi
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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 ebiten
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import (
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"github.com/hajimehoshi/ebiten/internal/opengl"
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"github.com/hajimehoshi/ebiten/internal/ui"
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"time"
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)
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var fps = 0.0
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// CurrentFPS returns the current number of frames per second.
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func CurrentFPS() float64 {
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return fps
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}
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// Run runs the game.
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// f is a function which is called at every frame.
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// The argument (*Image) is the render target that represents the screen.
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//
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// This function must be called from the main thread.
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//
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// The given function f is expected to be called 60 times a second,
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// but this is not strictly guaranteed.
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// If you need to care about time, you need to check current time every time f is called.
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func Run(f func(*Image) error, width, height, scale int, title string) error {
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actualScale, err := ui.Start(width, height, scale, title)
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if err != nil {
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return err
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}
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defer ui.Terminate()
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var graphicsContext *graphicsContext
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ui.Use(func(c *opengl.Context) {
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graphicsContext, err = newGraphicsContext(c, width, height, actualScale)
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})
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if err != nil {
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return err
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}
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frames := 0
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t := time.Now().UnixNano()
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for {
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if err := ui.DoEvents(); err != nil {
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return err
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}
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if ui.IsClosed() {
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return nil
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}
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if err := graphicsContext.preUpdate(); err != nil {
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return err
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}
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if err := f(graphicsContext.screen); err != nil {
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return err
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}
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if err := graphicsContext.postUpdate(); err != nil {
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return err
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}
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ui.SwapBuffers()
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if err != nil {
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return err
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}
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// Calc the current FPS.
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now := time.Now().UnixNano()
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frames++
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if time.Second <= time.Duration(now-t) {
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fps = float64(frames) * float64(time.Second) / float64(now-t)
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t = now
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frames = 0
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}
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}
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}
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