func init() {
ui.Init()
ui.ExecOnUIThread(func() {
glContext = opengl.NewContext()
})
audio.Init()
}
// Run runs the game.
// f is a function which is called at every frame.
// The argument (*Image) is the render target that represents the screen.
//
// This function must be called from the main thread.
//
// The given function f is guaranteed to be called 60 times a second
// even if a rendering frame is skipped.
// f is not called when the screen is not shown.
func Run(f func(*Image) error, width, height, scale int, title string) error {
runContext.running = true
defer func() {
runContext.running = false
}()
actualScale, err := ui.Start(width, height, scale, title)
if err != nil {
return err
}
defer ui.Terminate()
ui.ExecOnUIThread(func() {
glContext.Check()
})
graphicsContext, err := newGraphicsContext(width, height, actualScale)
if err != nil {
return err
}
frames := 0
gameTime := ui.Now()
before := ui.Now()
for {
if 0 < runContext.newScreenWidth || 0 < runContext.newScreenHeight || 0 < runContext.newScreenScale {
changed := false
actualScale := 0
if 0 < runContext.newScreenWidth || 0 < runContext.newScreenHeight {
c, a := ui.SetScreenSize(runContext.newScreenWidth, runContext.newScreenHeight)
changed = changed || c
actualScale = a
}
if 0 < runContext.newScreenScale {
c, a := ui.SetScreenScale(runContext.newScreenScale)
changed = changed || c
// actualScale of SetScreenState is more reliable than one of SetScreenSize
actualScale = a
}
if changed {
w, h := runContext.newScreenWidth, runContext.newScreenHeight
if err := graphicsContext.setSize(w, h, actualScale); err != nil {
return err
}
}
}
runContext.newScreenWidth = 0
runContext.newScreenHeight = 0
runContext.newScreenScale = 0
if err := ui.DoEvents(); err != nil {
return err
}
if ui.IsClosed() {
return nil
}
now := ui.Now()
// If gameTime is too old, we assume that screen is not shown.
if int64(5*time.Second/60) < now-gameTime {
gameTime = now
}
for gameTime < now {
gameTime += int64(time.Second / 60)
if err := graphicsContext.preUpdate(); err != nil {
return err
}
if err := f(graphicsContext.screen); err != nil {
return err
}
audio.Tick()
}
if err := graphicsContext.postUpdate(); err != nil {
return err
}
ui.SwapBuffers()
// Calc the current FPS.
now = ui.Now()
frames++
if time.Second <= time.Duration(now-before) {
runContext.fps = float64(frames) * float64(time.Second) / float64(now-before)
before = now
frames = 0
}
}
}
func useGLContext(f func(*opengl.Context)) {
ui.ExecOnUIThread(func() {
f(glContext)
})
}