func main(f func(screen.Screen)) error {
if tid := C.threadID(); tid != initThreadID {
log.Fatalf("gldriver.Main called on thread %d, but gldriver.init ran on %d", tid, initThreadID)
}
mainCallback = f
C.startDriver()
return nil
}
func main(f func(screen.Screen)) error {
if gl.Version() == "GL_ES_2_0" {
return errors.New("gldriver: ES 3 required on X11")
}
C.startDriver()
glctx, worker = gl.NewContext()
closec := make(chan struct{})
go func() {
f(theScreen)
close(closec)
}()
// heartbeat is a channel that, at regular intervals, directs the select
// below to also consider X11 events, not just Go events (channel
// communications).
//
// TODO: select instead of poll. Note that knowing whether to call
// C.processEvents needs to select on a file descriptor, and the other
// cases below select on Go channels.
heartbeat := time.NewTicker(time.Second / 60)
workAvailable := worker.WorkAvailable()
for {
select {
case <-closec:
return nil
case ctx := <-glcontextc:
// TODO: do we need to synchronize with seeing a size event for
// this window's context before or after calling makeCurrent?
// Otherwise, are we racing with the gl.Viewport call? I've
// occasionally seen a stale viewport, if the window manager sets
// the window width and height to something other than that
// requested by XCreateWindow, but it's not easily reproducible.
C.makeCurrent(C.uintptr_t(ctx))
case w := <-publishc:
C.swapBuffers(C.uintptr_t(w.ctx.(uintptr)))
w.publishDone <- screen.PublishResult{}
case req := <-uic:
ret := req.f()
if req.retc != nil {
req.retc <- ret
}
case <-heartbeat.C:
C.processEvents()
case <-workAvailable:
worker.DoWork()
}
}
}