shiny/driver/gldriver/x11.go - exp - Git at Google

 // Copyright 2015 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.

 // +build linux,!android

 package gldriver

 /*
 #cgo LDFLAGS: -lEGL -lGLESv2 -lX11

 #include <stdbool.h>
 #include <stdint.h>
 #include <stdlib.h>

 char *eglGetErrorStr();
 void startDriver();
 void processEvents();
 void makeCurrent(uintptr_t ctx);
 void swapBuffers(uintptr_t ctx);
 void doCloseWindow(uintptr_t id);
 uintptr_t doNewWindow(int width, int height, char* title, int title_len);
 uintptr_t doShowWindow(uintptr_t id);
 uintptr_t surfaceCreate();
 */
 import "C"
 import (
 	"errors"
 	"runtime"
 	"time"
 	"unsafe"

 	"golang.org/x/exp/shiny/driver/internal/x11key"
 	"golang.org/x/exp/shiny/screen"
 	"golang.org/x/mobile/event/key"
 	"golang.org/x/mobile/event/mouse"
 	"golang.org/x/mobile/event/paint"
 	"golang.org/x/mobile/event/size"
 	"golang.org/x/mobile/geom"
 	"golang.org/x/mobile/gl"
 )

 const useLifecycler = true

 var theKeysyms x11key.KeysymTable

 func init() {
 	// It might not be necessary, but it probably doesn't hurt to try to make
 	// 'the main thread' be 'the X11 / OpenGL thread'.
 	runtime.LockOSThread()
 }

 func newWindow(opts *screen.NewWindowOptions) (uintptr, error) {
 	width, height := optsSize(opts)

 	title := opts.GetTitle()
 	ctitle := C.CString(title)
 	defer C.free(unsafe.Pointer(ctitle))

 	retc := make(chan uintptr)
 	uic <- uiClosure{
 		f: func() uintptr {
 			return uintptr(C.doNewWindow(C.int(width), C.int(height), ctitle, C.int(len(title))))
 		},
 		retc: retc,
 	}
 	return <-retc, nil
 }

 func initWindow(w *windowImpl) {
 	w.glctx, w.worker = glctx, worker
 }

 func showWindow(w *windowImpl) {
 	retc := make(chan uintptr)
 	uic <- uiClosure{
 		f: func() uintptr {
 			return uintptr(C.doShowWindow(C.uintptr_t(w.id)))
 		},
 		retc: retc,
 	}
 	w.ctx = <-retc
 	go drawLoop(w)
 }

 func closeWindow(id uintptr) {
 	uic <- uiClosure{
 		f: func() uintptr {
 			C.doCloseWindow(C.uintptr_t(id))
 			return 0
 		},
 	}
 }

 func drawLoop(w *windowImpl) {
 	glcontextc <- w.ctx.(uintptr)
 	go func() {
 		for range w.publish {
 			publishc <- w
 		}
 	}()
 }

 var (
 	glcontextc = make(chan uintptr)
 	publishc   = make(chan *windowImpl)
 	uic        = make(chan uiClosure)

 	// TODO: don't assume that there is only one window, and hence only
 	// one (global) GL context.
 	//
 	// TODO: should we be able to make a shiny.Texture before having a
 	// shiny.Window's GL context? Should something like gl.IsProgram be a
 	// method instead of a function, and have each shiny.Window have its own
 	// gl.Context?
 	glctx  gl.Context
 	worker gl.Worker
 )

 // uiClosure is a closure to be run on C's UI thread.
 type uiClosure struct {
 	f    func() uintptr
 	retc chan uintptr
 }

 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()
 		}
 	}
 }

 //export onExpose
 func onExpose(id uintptr) {
 	theScreen.mu.Lock()
 	w := theScreen.windows[id]
 	theScreen.mu.Unlock()

 	if w == nil {
 		return
 	}

 	w.Send(paint.Event{External: true})
 }

 //export onKeysym
 func onKeysym(k, unshifted, shifted uint32) {
 	theKeysyms[k][0] = unshifted
 	theKeysyms[k][1] = shifted
 }

 //export onKey
 func onKey(id uintptr, state uint16, detail, dir uint8) {
 	theScreen.mu.Lock()
 	w := theScreen.windows[id]
 	theScreen.mu.Unlock()

 	if w == nil {
 		return
 	}

 	r, c := theKeysyms.Lookup(detail, state)
 	w.Send(key.Event{
 		Rune:      r,
 		Code:      c,
 		Modifiers: x11key.KeyModifiers(state),
 		Direction: key.Direction(dir),
 	})
 }

 //export onMouse
 func onMouse(id uintptr, x, y int32, state uint16, button, dir uint8) {
 	theScreen.mu.Lock()
 	w := theScreen.windows[id]
 	theScreen.mu.Unlock()

 	if w == nil {
 		return
 	}

 	// TODO: should a mouse.Event have a separate MouseModifiers field, for
 	// which buttons are pressed during a mouse move?
 	btn := mouse.Button(button)
 	switch btn {
 	case 4:
 		btn = mouse.ButtonWheelUp
 	case 5:
 		btn = mouse.ButtonWheelDown
 	case 6:
 		btn = mouse.ButtonWheelLeft
 	case 7:
 		btn = mouse.ButtonWheelRight
 	}
 	if btn.IsWheel() {
 		if dir != uint8(mouse.DirPress) {
 			return
 		}
 		dir = uint8(mouse.DirStep)
 	}
 	w.Send(mouse.Event{
 		X:         float32(x),
 		Y:         float32(y),
 		Button:    btn,
 		Modifiers: x11key.KeyModifiers(state),
 		Direction: mouse.Direction(dir),
 	})
 }

 //export onFocus
 func onFocus(id uintptr, focused bool) {
 	theScreen.mu.Lock()
 	w := theScreen.windows[id]
 	theScreen.mu.Unlock()

 	if w == nil {
 		return
 	}

 	w.lifecycler.SetFocused(focused)
 	w.lifecycler.SendEvent(w, w.glctx)
 }

 //export onConfigure
 func onConfigure(id uintptr, x, y, width, height, displayWidth, displayWidthMM int32) {
 	theScreen.mu.Lock()
 	w := theScreen.windows[id]
 	theScreen.mu.Unlock()

 	if w == nil {
 		return
 	}

 	// TODO: should this really be done on the receiving end of the w.Events()
 	// channel, in the same goroutine as other GL calls in the app's 'business
 	// logic'?
 	go func() {
 		w.glctxMu.Lock()
 		// Force a w.glctx.Viewport call.
 		//
 		// TODO: is this racy? See also the TODO immediately above.
 		w.backBufferBound = false
 		w.glctxMu.Unlock()
 	}()

 	w.lifecycler.SetVisible(x+width > 0 && y+height > 0)
 	w.lifecycler.SendEvent(w, w.glctx)

 	const (
 		mmPerInch = 25.4
 		ptPerInch = 72
 	)
 	pixelsPerMM := float32(displayWidth) / float32(displayWidthMM)
 	sz := size.Event{
 		WidthPx:     int(width),
 		HeightPx:    int(height),
 		WidthPt:     geom.Pt(width),
 		HeightPt:    geom.Pt(height),
 		PixelsPerPt: pixelsPerMM * mmPerInch / ptPerInch,
 	}

 	w.szMu.Lock()
 	w.sz = sz
 	w.szMu.Unlock()

 	w.Send(sz)
 }

 //export onDeleteWindow
 func onDeleteWindow(id uintptr) {
 	theScreen.mu.Lock()
 	w := theScreen.windows[id]
 	theScreen.mu.Unlock()

 	if w == nil {
 		return
 	}

 	w.lifecycler.SetDead(true)
 	w.lifecycler.SendEvent(w, w.glctx)
 }

 func surfaceCreate() error {
 	if C.surfaceCreate() == 0 {
 		return errors.New("gldriver: surface creation failed")
 	}
 	return nil
 }
	// Copyright 2015 The Go Authors. All rights reserved.
	// Use of this source code is governed by a BSD-style
	// license that can be found in the LICENSE file.

	// +build linux,!android

	package gldriver

	/*
	#cgo LDFLAGS: -lEGL -lGLESv2 -lX11

	#include <stdbool.h>
	#include <stdint.h>
	#include <stdlib.h>

	char *eglGetErrorStr();
	void startDriver();
	void processEvents();
	void makeCurrent(uintptr_t ctx);
	void swapBuffers(uintptr_t ctx);
	void doCloseWindow(uintptr_t id);
	uintptr_t doNewWindow(int width, int height, char* title, int title_len);
	uintptr_t doShowWindow(uintptr_t id);
	uintptr_t surfaceCreate();
	*/
	import "C"
	import (
	"errors"
	"runtime"
	"time"
	"unsafe"

	"golang.org/x/exp/shiny/driver/internal/x11key"
	"golang.org/x/exp/shiny/screen"
	"golang.org/x/mobile/event/key"
	"golang.org/x/mobile/event/mouse"
	"golang.org/x/mobile/event/paint"
	"golang.org/x/mobile/event/size"
	"golang.org/x/mobile/geom"
	"golang.org/x/mobile/gl"
	)

	const useLifecycler = true

	var theKeysyms x11key.KeysymTable

	func init() {
	// It might not be necessary, but it probably doesn't hurt to try to make
	// 'the main thread' be 'the X11 / OpenGL thread'.
	runtime.LockOSThread()
	}

	func newWindow(opts *screen.NewWindowOptions) (uintptr, error) {
	width, height := optsSize(opts)

	title := opts.GetTitle()
	ctitle := C.CString(title)
	defer C.free(unsafe.Pointer(ctitle))

	retc := make(chan uintptr)
	uic <- uiClosure{
	f: func() uintptr {
	return uintptr(C.doNewWindow(C.int(width), C.int(height), ctitle, C.int(len(title))))
	},
	retc: retc,
	}
	return <-retc, nil
	}

	func initWindow(w *windowImpl) {
	w.glctx, w.worker = glctx, worker
	}

	func showWindow(w *windowImpl) {
	retc := make(chan uintptr)
	uic <- uiClosure{
	f: func() uintptr {
	return uintptr(C.doShowWindow(C.uintptr_t(w.id)))
	},
	retc: retc,
	}
	w.ctx = <-retc
	go drawLoop(w)
	}

	func closeWindow(id uintptr) {
	uic <- uiClosure{
	f: func() uintptr {
	C.doCloseWindow(C.uintptr_t(id))
	return 0
	},
	}
	}

	func drawLoop(w *windowImpl) {
	glcontextc <- w.ctx.(uintptr)
	go func() {
	for range w.publish {
	publishc <- w
	}
	}()
	}

	var (
	glcontextc = make(chan uintptr)
	publishc = make(chan *windowImpl)
	uic = make(chan uiClosure)

	// TODO: don't assume that there is only one window, and hence only
	// one (global) GL context.
	//
	// TODO: should we be able to make a shiny.Texture before having a
	// shiny.Window's GL context? Should something like gl.IsProgram be a
	// method instead of a function, and have each shiny.Window have its own
	// gl.Context?
	glctx gl.Context
	worker gl.Worker
	)

	// uiClosure is a closure to be run on C's UI thread.
	type uiClosure struct {
	f func() uintptr
	retc chan uintptr
	}

	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()
	}
	}
	}

	//export onExpose
	func onExpose(id uintptr) {
	theScreen.mu.Lock()
	w := theScreen.windows[id]
	theScreen.mu.Unlock()

	if w == nil {
	return
	}

	w.Send(paint.Event{External: true})
	}

	//export onKeysym
	func onKeysym(k, unshifted, shifted uint32) {
	theKeysyms[k][0] = unshifted
	theKeysyms[k][1] = shifted
	}

	//export onKey
	func onKey(id uintptr, state uint16, detail, dir uint8) {
	theScreen.mu.Lock()
	w := theScreen.windows[id]
	theScreen.mu.Unlock()

	if w == nil {
	return
	}

	r, c := theKeysyms.Lookup(detail, state)
	w.Send(key.Event{
	Rune: r,
	Code: c,
	Modifiers: x11key.KeyModifiers(state),
	Direction: key.Direction(dir),
	})
	}

	//export onMouse
	func onMouse(id uintptr, x, y int32, state uint16, button, dir uint8) {
	theScreen.mu.Lock()
	w := theScreen.windows[id]
	theScreen.mu.Unlock()

	if w == nil {
	return
	}

	// TODO: should a mouse.Event have a separate MouseModifiers field, for
	// which buttons are pressed during a mouse move?
	btn := mouse.Button(button)
	switch btn {
	case 4:
	btn = mouse.ButtonWheelUp
	case 5:
	btn = mouse.ButtonWheelDown
	case 6:
	btn = mouse.ButtonWheelLeft
	case 7:
	btn = mouse.ButtonWheelRight
	}
	if btn.IsWheel() {
	if dir != uint8(mouse.DirPress) {
	return
	}
	dir = uint8(mouse.DirStep)
	}
	w.Send(mouse.Event{
	X: float32(x),
	Y: float32(y),
	Button: btn,
	Modifiers: x11key.KeyModifiers(state),
	Direction: mouse.Direction(dir),
	})
	}

	//export onFocus
	func onFocus(id uintptr, focused bool) {
	theScreen.mu.Lock()
	w := theScreen.windows[id]
	theScreen.mu.Unlock()

	if w == nil {
	return
	}

	w.lifecycler.SetFocused(focused)
	w.lifecycler.SendEvent(w, w.glctx)
	}

	//export onConfigure
	func onConfigure(id uintptr, x, y, width, height, displayWidth, displayWidthMM int32) {
	theScreen.mu.Lock()
	w := theScreen.windows[id]
	theScreen.mu.Unlock()

	if w == nil {
	return
	}

	// TODO: should this really be done on the receiving end of the w.Events()
	// channel, in the same goroutine as other GL calls in the app's 'business
	// logic'?
	go func() {
	w.glctxMu.Lock()
	// Force a w.glctx.Viewport call.
	//
	// TODO: is this racy? See also the TODO immediately above.
	w.backBufferBound = false
	w.glctxMu.Unlock()
	}()

	w.lifecycler.SetVisible(x+width > 0 && y+height > 0)
	w.lifecycler.SendEvent(w, w.glctx)

	const (
	mmPerInch = 25.4
	ptPerInch = 72
	)
	pixelsPerMM := float32(displayWidth) / float32(displayWidthMM)
	sz := size.Event{
	WidthPx: int(width),
	HeightPx: int(height),
	WidthPt: geom.Pt(width),
	HeightPt: geom.Pt(height),
	PixelsPerPt: pixelsPerMM * mmPerInch / ptPerInch,
	}

	w.szMu.Lock()
	w.sz = sz
	w.szMu.Unlock()

	w.Send(sz)
	}

	//export onDeleteWindow
	func onDeleteWindow(id uintptr) {
	theScreen.mu.Lock()
	w := theScreen.windows[id]
	theScreen.mu.Unlock()

	if w == nil {
	return
	}

	w.lifecycler.SetDead(true)
	w.lifecycler.SendEvent(w, w.glctx)
	}

	func surfaceCreate() error {
	if C.surfaceCreate() == 0 {
	return errors.New("gldriver: surface creation failed")
	}
	return nil
	}