input: Make functions goroutine-safe (#192)

input.go

@@ -19,48 +19,62 @@ import (
 )
 
 // IsKeyPressed returns a boolean indicating whether key is pressed.
+//
+// This function is goroutine-safe.
 func IsKeyPressed(key Key) bool {
-	return ui.IsKeyPressed(ui.Key(key))
+	return ui.CurrentInput().IsKeyPressed(ui.Key(key))
 }
 
 // CursorPosition returns a position of a mouse cursor.
+//
+// This function is goroutine-safe.
 func CursorPosition() (x, y int) {
-	return ui.CursorPosition()
+	return ui.CurrentInput().CursorPosition()
 }
 
 // IsMouseButtonPressed returns a boolean indicating whether mouseButton is pressed.
+//
+// This function is goroutine-safe.
 func IsMouseButtonPressed(mouseButton MouseButton) bool {
-	return ui.IsMouseButtonPressed(ui.MouseButton(mouseButton))
+	return ui.CurrentInput().IsMouseButtonPressed(ui.MouseButton(mouseButton))
 }
 
 // GamepadAxisNum returns the number of axes of the gamepad.
 //
+// This function is goroutine-safe.
+//
 // NOTE: Gamepad API is available only on desktops, Chrome and Firefox.
 // To use this API, browsers might require rebooting the browser.
 func GamepadAxisNum(id int) int {
-	return ui.GamepadAxisNum(id)
+	return ui.CurrentInput().GamepadAxisNum(id)
 }
 
 // GamepadAxis returns the float value [-1.0 - 1.0] of the axis.
 //
+// This function is goroutine-safe.
+//
 // NOTE: Gamepad API is available only on desktops, Chrome and Firefox.
 // To use this API, browsers might require rebooting the browser.
 func GamepadAxis(id int, axis int) float64 {
-	return ui.GamepadAxis(id, axis)
+	return ui.CurrentInput().GamepadAxis(id, axis)
 }
 
 // GamepadButtonNum returns the number of the buttons of the gamepad.
 //
+// This function is goroutine-safe.
+//
 // NOTE: Gamepad API is available only on desktops, Chrome and Firefox.
 // To use this API, browsers might require rebooting the browser.
 func GamepadButtonNum(id int) int {
-	return ui.GamepadButtonNum(id)
+	return ui.CurrentInput().GamepadButtonNum(id)
 }
 
 // IsGamepadButtonPressed returns the boolean indicating the buttons is pressed or not.
 //
+// This function is goroutine-safe.
+//
 // NOTE: Gamepad API is available only on desktops, Chrome and Firefox.
 // To use this API, browsers might require rebooting the browser.
 func IsGamepadButtonPressed(id int, button GamepadButton) bool {
-	return ui.IsGamepadButtonPressed(id, ui.GamepadButton(button))
+	return ui.CurrentInput().IsGamepadButtonPressed(id, ui.GamepadButton(button))
 }

internal/ui/input.go

@@ -14,54 +14,19 @@
 
 package ui
 
-func IsKeyPressed(key Key) bool {
+import (
-	return currentInput.keyPressed[key]
+	"sync"
-}
+)
 
-func CursorPosition() (x, y int) {
+var currentInput = &Input{}
-	return currentInput.cursorX, currentInput.cursorY
-}
 
-func IsMouseButtonPressed(button MouseButton) bool {
+type Input struct {
-	return currentInput.mouseButtonPressed[button]
-}
-
-func GamepadAxisNum(id int) int {
-	if len(currentInput.gamepads) <= id {
-		return 0
-	}
-	return currentInput.gamepads[id].axisNum
-}
-
-func GamepadAxis(id int, axis int) float64 {
-	if len(currentInput.gamepads) <= id {
-		return 0
-	}
-	return currentInput.gamepads[id].axes[axis]
-}
-
-func GamepadButtonNum(id int) int {
-	if len(currentInput.gamepads) <= id {
-		return 0
-	}
-	return currentInput.gamepads[id].buttonNum
-}
-
-func IsGamepadButtonPressed(id int, button GamepadButton) bool {
-	if len(currentInput.gamepads) <= id {
-		return false
-	}
-	return currentInput.gamepads[id].buttonPressed[button]
-}
-
-var currentInput input
-
-type input struct {
 	keyPressed         [256]bool
 	mouseButtonPressed [256]bool
 	cursorX            int
 	cursorY            int
 	gamepads           [16]gamePad
+	m                  sync.RWMutex
 }
 
 type gamePad struct {
@@ -70,3 +35,61 @@ type gamePad struct {
 	buttonNum     int
 	buttonPressed [256]bool
 }
+
+func CurrentInput() *Input {
+	return currentInput
+}
+
+func (i *Input) IsKeyPressed(key Key) bool {
+	i.m.RLock()
+	defer i.m.RUnlock()
+	return i.keyPressed[key]
+}
+
+func (i *Input) CursorPosition() (x, y int) {
+	i.m.RLock()
+	defer i.m.RUnlock()
+	return i.cursorX, currentInput.cursorY
+}
+
+func (i *Input) IsMouseButtonPressed(button MouseButton) bool {
+	i.m.RLock()
+	defer i.m.RUnlock()
+	return i.mouseButtonPressed[button]
+}
+
+func (i *Input) GamepadAxisNum(id int) int {
+	i.m.RLock()
+	defer i.m.RUnlock()
+	if len(i.gamepads) <= id {
+		return 0
+	}
+	return i.gamepads[id].axisNum
+}
+
+func (i *Input) GamepadAxis(id int, axis int) float64 {
+	i.m.RLock()
+	defer i.m.RUnlock()
+	if len(i.gamepads) <= id {
+		return 0
+	}
+	return i.gamepads[id].axes[axis]
+}
+
+func (i *Input) GamepadButtonNum(id int) int {
+	i.m.RLock()
+	defer i.m.RUnlock()
+	if len(i.gamepads) <= id {
+		return 0
+	}
+	return i.gamepads[id].buttonNum
+}
+
+func (i *Input) IsGamepadButtonPressed(id int, button GamepadButton) bool {
+	i.m.RLock()
+	defer i.m.RUnlock()
+	if len(i.gamepads) <= id {
+		return false
+	}
+	return i.gamepads[id].buttonPressed[button]
+}

internal/ui/input_glfw.go

@@ -21,17 +21,16 @@ import (
 	"math"
 )
 
-func updateInput(window *glfw.Window, scale int) error {
-	return currentInput.update(window, scale)
-}
-
 var glfwMouseButtonToMouseButton = map[glfw.MouseButton]MouseButton{
 	glfw.MouseButtonLeft:   MouseButtonLeft,
 	glfw.MouseButtonRight:  MouseButtonRight,
 	glfw.MouseButtonMiddle: MouseButtonMiddle,
 }
 
-func (i *input) update(window *glfw.Window, scale int) error {
+func (i *Input) update(window *glfw.Window, scale int) error {
+	i.m.Lock()
+	defer i.m.Unlock()
+
 	for g, e := range glfwKeyCodeToKey {
 		i.keyPressed[e] = window.GetKey(g) == glfw.Press
 	}

internal/ui/input_js.go

@@ -20,11 +20,9 @@ import (
 	"github.com/gopherjs/gopherjs/js"
 )
 
-func CurrentInput() *input {
+func (i *Input) KeyDown(key int) {
-	return &currentInput
+	i.m.Lock()
-}
+	defer i.m.Unlock()
-
-func (i *input) KeyDown(key int) {
 	k, ok := keyCodeToKey[key]
 	if !ok {
 		return
@@ -32,7 +30,9 @@ func (i *input) KeyDown(key int) {
 	i.keyPressed[k] = true
 }
 
-func (i *input) KeyUp(key int) {
+func (i *Input) KeyUp(key int) {
+	i.m.Lock()
+	defer i.m.Unlock()
 	k, ok := keyCodeToKey[key]
 	if !ok {
 		return
@@ -40,7 +40,9 @@ func (i *input) KeyUp(key int) {
 	i.keyPressed[k] = false
 }
 
-func (i *input) MouseDown(button int) {
+func (i *Input) MouseDown(button int) {
+	i.m.Lock()
+	defer i.m.Unlock()
 	p := &i.mouseButtonPressed
 	switch button {
 	case 0:
@@ -52,7 +54,9 @@ func (i *input) MouseDown(button int) {
 	}
 }
 
-func (i *input) MouseUp(button int) {
+func (i *Input) MouseUp(button int) {
+	i.m.Lock()
+	defer i.m.Unlock()
 	p := &i.mouseButtonPressed
 	switch button {
 	case 0:
@@ -64,11 +68,15 @@ func (i *input) MouseUp(button int) {
 	}
 }
 
-func (i *input) SetMouseCursor(x, y int) {
+func (i *Input) SetMouseCursor(x, y int) {
+	i.m.Lock()
+	defer i.m.Unlock()
 	i.cursorX, i.cursorY = x, y
 }
 
-func (i *input) UpdateGamepads() {
+func (i *Input) UpdateGamepads() {
+	i.m.Lock()
+	defer i.m.Unlock()
 	nav := js.Global.Get("navigator")
 	if nav.Get("getGamepads") == js.Undefined {
 		return

internal/ui/ui_glfw.go

@@ -153,7 +153,7 @@ func (u *userInterface) actualScreenScale() int {
 
 func (u *userInterface) pollEvents() error {
 	glfw.PollEvents()
-	return updateInput(u.window, u.windowScale())
+	return currentInput.update(u.window, u.windowScale())
 }
 
 func (u *userInterface) doEvents() error {