internal/ui: refactoring: add monitor_glfw.go

internal/ui/monitor_glfw.go

@@ -0,0 +1,126 @@
+// Copyright 2023 The Ebitengine Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//go:build !android && !ios && !js && !nintendosdk
+
+package ui
+
+import (
+	"image"
+	"sync"
+	"sync/atomic"
+
+	"github.com/hajimehoshi/ebiten/v2/internal/devicescale"
+	"github.com/hajimehoshi/ebiten/v2/internal/glfw"
+)
+
+// Monitor is a wrapper around glfw.Monitor.
+type Monitor struct {
+	m  *glfw.Monitor
+	vm *glfw.VidMode
+	// Pos of monitor in virtual coords
+	x      int
+	y      int
+	width  int
+	height int
+	id     int
+	name   string
+}
+
+// Bounds returns the monitor's bounds.
+func (m *Monitor) Bounds() image.Rectangle {
+	ui := Get()
+	return image.Rect(
+		int(ui.dipFromGLFWMonitorPixel(float64(m.x), m.m)),
+		int(ui.dipFromGLFWMonitorPixel(float64(m.y), m.m)),
+		int(ui.dipFromGLFWMonitorPixel(float64(m.x+m.width), m.m)),
+		int(ui.dipFromGLFWMonitorPixel(float64(m.x+m.height), m.m)),
+	)
+}
+
+// Name returns the monitor's name.
+func (m *Monitor) Name() string {
+	return m.name
+}
+
+type monitors struct {
+	// monitors is the monitor list cache for desktop glfw compile targets.
+	// populated by 'updateMonitors' which is called on init and every
+	// monitor config change event.
+	monitors []*Monitor
+
+	m sync.Mutex
+
+	updateCalled int32
+}
+
+var theMonitors monitors
+
+func (m *monitors) append(ms []*Monitor) []*Monitor {
+	if atomic.LoadInt32(&m.updateCalled) == 0 {
+		m.update()
+	}
+
+	m.m.Lock()
+	defer m.m.Unlock()
+
+	return append(ms, m.monitors...)
+}
+
+func (m *monitors) monitorFromGLFWMonitor(glfwMonitor *glfw.Monitor) *Monitor {
+	m.m.Lock()
+	defer m.m.Unlock()
+
+	for _, m := range m.monitors {
+		if m.m == glfwMonitor {
+			return m
+		}
+	}
+	return nil
+}
+
+func (m *monitors) monitorFromID(id int) *Monitor {
+	m.m.Lock()
+	defer m.m.Unlock()
+
+	return m.monitors[id]
+}
+
+func (m *monitors) update() {
+	glfwMonitors := glfw.GetMonitors()
+	newMonitors := make([]*Monitor, 0, len(glfwMonitors))
+	for i, m := range glfwMonitors {
+		x, y := m.GetPos()
+		vm := m.GetVideoMode()
+		newMonitors = append(newMonitors, &Monitor{
+			m:      m,
+			vm:     m.GetVideoMode(),
+			x:      x,
+			y:      y,
+			width:  vm.Width,
+			height: vm.Height,
+			name:   m.GetName(),
+			id:     i,
+		})
+	}
+
+	m.m.Lock()
+	m.monitors = newMonitors
+	m.m.Unlock()
+
+	clearVideoModeScaleCache()
+	devicescale.ClearCache()
+
+	atomic.StoreInt32(&m.updateCalled, 1)
+}

internal/ui/ui_glfw.go

@@ -155,9 +155,9 @@ func init() {
 		panic(err)
 	}
 	glfw.SetMonitorCallback(glfw.ToMonitorCallback(func(monitor *glfw.Monitor, event glfw.PeripheralEvent) {
-		updateMonitors()
+		theMonitors.update()
 	}))
-	updateMonitors()
+	theMonitors.update()
 }
 
 var glfwSystemCursors = map[CursorShape]*glfw.Cursor{}
@@ -210,81 +210,9 @@ func (u *userInterfaceImpl) setInitMonitor(m *glfw.Monitor) {
 	u.initFullscreenHeightInDIP = int(u.dipFromGLFWMonitorPixel(float64(v.Height), m))
 }
 
-// Monitor is a wrapper around glfw.Monitor.
-type Monitor struct {
-	m  *glfw.Monitor
-	vm *glfw.VidMode
-	// Pos of monitor in virtual coords
-	x      int
-	y      int
-	width  int
-	height int
-	id     int
-	name   string
-}
-
-// Bounds returns the monitor's bounds.
-func (m *Monitor) Bounds() image.Rectangle {
-	ui := Get()
-	return image.Rect(
-		int(ui.dipFromGLFWMonitorPixel(float64(m.x), m.m)),
-		int(ui.dipFromGLFWMonitorPixel(float64(m.y), m.m)),
-		int(ui.dipFromGLFWMonitorPixel(float64(m.x+m.width), m.m)),
-		int(ui.dipFromGLFWMonitorPixel(float64(m.x+m.height), m.m)),
-	)
-}
-
-// Name returns the monitor's name.
-func (m *Monitor) Name() string {
-	return m.name
-}
-
-var (
-	// monitors is the monitor list cache for desktop glfw compile targets.
-	// populated by 'updateMonitors' which is called on init and every
-	// monitor config change event.
-	//
-	// monitors must be manipulated on the main thread.
-	monitors []*Monitor
-
-	monitorsM sync.Mutex
-
-	updateMonitorsCalled int32
-)
-
-func appendMonitors(ms []*Monitor) []*Monitor {
-	if atomic.LoadInt32(&updateMonitorsCalled) == 0 {
-		updateMonitors()
-	}
-
-	monitorsM.Lock()
-	defer monitorsM.Unlock()
-
-	return append(ms, monitors...)
-}
-
-func monitorFromGLFWMonitor(glfwMonitor *glfw.Monitor) *Monitor {
-	monitorsM.Lock()
-	defer monitorsM.Unlock()
-
-	for _, m := range monitors {
-		if m.m == glfwMonitor {
-			return m
-		}
-	}
-	return nil
-}
-
-func monitorFromID(id int) *Monitor {
-	monitorsM.Lock()
-	defer monitorsM.Unlock()
-
-	return monitors[id]
-}
-
 // AppendMonitors appends the current monitors to the passed in mons slice and returns it.
 func (u *userInterfaceImpl) AppendMonitors(monitors []*Monitor) []*Monitor {
-	return appendMonitors(monitors)
+	return theMonitors.append(monitors)
 }
 
 // Monitor returns the window's current monitor. Returns nil if there is no current monitor yet.
@@ -301,50 +229,17 @@ func (u *userInterfaceImpl) Monitor() *Monitor {
 		if glfwMonitor == nil {
 			return
 		}
-		monitor = monitorFromGLFWMonitor(glfwMonitor)
+		monitor = theMonitors.monitorFromGLFWMonitor(glfwMonitor)
 	})
 	return monitor
 }
 
-func updateMonitors() {
-	glfwMonitors := glfw.GetMonitors()
-	newMonitors := make([]*Monitor, 0, len(glfwMonitors))
-	for i, m := range glfwMonitors {
-		monitor := glfwMonitorToMonitor(m)
-		monitor.id = i
-		newMonitors = append(newMonitors, &monitor)
-	}
-
-	monitorsM.Lock()
-	monitors = newMonitors
-	monitorsM.Unlock()
-
-	clearVideoModeScaleCache()
-	devicescale.ClearCache()
-
-	atomic.StoreInt32(&updateMonitorsCalled, 1)
-}
-
-func glfwMonitorToMonitor(m *glfw.Monitor) Monitor {
-	x, y := m.GetPos()
-	vm := m.GetVideoMode()
-	return Monitor{
-		m:      m,
-		vm:     m.GetVideoMode(),
-		x:      x,
-		y:      y,
-		width:  vm.Width,
-		height: vm.Height,
-		name:   m.GetName(),
-	}
-}
-
 // getMonitorFromPosition returns a monitor for the given window x/y,
 // or returns nil if monitor is not found.
 //
 // getMonitorFromPosition must be called on the main thread.
 func getMonitorFromPosition(wx, wy int) *Monitor {
-	for _, m := range appendMonitors(nil) {
+	for _, m := range theMonitors.append(nil) {
 		// TODO: Fix incorrectness in the cases of https://github.com/glfw/glfw/issues/1961.
 		// See also internal/devicescale/impl_desktop.go for a maybe better way of doing this.
 		if m.x <= wx && wx < m.x+m.vm.Width && m.y <= wy && wy < m.y+m.vm.Height {
@@ -380,7 +275,7 @@ func (u *userInterfaceImpl) setWindowMonitor(monitor int) {
 		return
 	}
 
-	m := monitorFromID(monitor).m
+	m := theMonitors.monitorFromID(monitor).m
 
 	// Ignore if it is the same monitor.
 	if m == u.currentMonitor() {
@@ -897,7 +792,7 @@ func (u *userInterfaceImpl) createWindow(width, height int, monitor int) error {
 
 	// Set our target monitor if provided. This is required to prevent an initial window flash on the default monitor.
 	if monitor != glfw.DontCare {
-		m := monitorFromID(monitor)
+		m := theMonitors.monitorFromID(monitor)
 		x, y := m.m.GetPos()
 		px, py := InitialWindowPosition(m.m.GetVideoMode().Width, m.m.GetVideoMode().Height, width, height)
 		window.SetPos(x+px, y+py)
@@ -1093,7 +988,7 @@ func (u *userInterfaceImpl) initOnMainThread(options *RunOptions) error {
 	monitor := u.getInitWindowMonitor()
 
 	if monitor != glfw.DontCare {
-		u.setInitMonitor(monitorFromID(monitor).m)
+		u.setInitMonitor(theMonitors.monitorFromID(monitor).m)
 	}
 
 	ww, wh := u.getInitWindowSizeInDIP()

internal/ui/ui_glfw_darwin.go

@@ -256,7 +256,7 @@ func initialMonitorByOS() (*glfw.Monitor, error) {
 	x, y := currentMouseLocation()
 
 	// Find the monitor including the cursor.
-	for _, m := range appendMonitors(nil) {
+	for _, m := range theMonitors.append(nil) {
 		w, h := m.vm.Width, m.vm.Height
 		if x >= m.x && x < m.x+w && y >= m.y && y < m.y+h {
 			return m.m, nil
@@ -279,7 +279,7 @@ func monitorFromWindowByOS(w *glfw.Window) *glfw.Monitor {
 	screenID := cocoa.NSNumber{ID: screenDictionary.ObjectForKey(cocoa.NSString_alloc().InitWithUTF8String("NSScreenNumber").ID)}
 	aID := uintptr(screenID.UnsignedIntValue()) // CGDirectDisplayID
 	pool.Release()
-	for _, m := range appendMonitors(nil) {
+	for _, m := range theMonitors.append(nil) {
 		if m.m.GetCocoaMonitor() == aID {
 			return m.m
 		}

internal/ui/ui_glfw_linbsd.go

@@ -176,7 +176,7 @@ func initialMonitorByOS() (*glfw.Monitor, error) {
 	x, y := int(rep.RootX), int(rep.RootY)
 
 	// Find the monitor including the cursor.
-	for _, m := range appendMonitors(nil) {
+	for _, m := range theMonitors.append(nil) {
 		w, h := m.vm.Width, m.vm.Height
 		if x >= m.x && x < m.x+w && y >= m.y && y < m.y+h {
 			return m.m, nil

internal/ui/ui_glfw_windows.go

@@ -140,7 +140,7 @@ func initialMonitorByOS() (*glfw.Monitor, error) {
 	x, y := int(px), int(py)
 
 	// Find the monitor including the cursor.
-	for _, m := range appendMonitors(nil) {
+	for _, m := range theMonitors.append(nil) {
 		w, h := m.vm.Width, m.vm.Height
 		if x >= m.x && x < m.x+w && y >= m.y && y < m.y+h {
 			return m.m, nil
@@ -173,7 +173,7 @@ func monitorFromWin32Window(w windows.HWND) *glfw.Monitor {
 	}
 
 	x, y := int(mi.rcMonitor.left), int(mi.rcMonitor.top)
-	for _, m := range appendMonitors(nil) {
+	for _, m := range theMonitors.append(nil) {
 		if m.x == x && m.y == y {
 			return m.m
 		}