Keyboard and mouse input system

input/input.go

@@ -0,0 +1,47 @@
+package input
+
+import "github.com/veandco/go-sdl2/sdl"
+
+type InputKey int
+
+var (
+	anyKeyDown      bool
+	anyMouseBtnDown bool
+)
+
+//EventLoopStarted should be called just before processing SDL events
+func EventLoopStarted() {
+
+	anyKeyDown = false
+	anyMouseBtnDown = false
+
+	//Clear XThisFrame which is needed because a repeat event needs multiple frames to happen
+	for _, v := range mouseBtns {
+
+		v.isDoubleClick = false
+		v.pressedThisFrame = false
+		v.releasedThisFrame = false
+
+		if v.state == sdl.PRESSED {
+			anyMouseBtnDown = true
+		}
+	}
+
+	for _, v := range keyboardKeys {
+
+		v.pressedThisFrame = false
+		v.releasedThisFrame = false
+
+		if v.state == sdl.PRESSED {
+			anyKeyDown = true
+		}
+	}
+}
+
+func AnyKeyDown() bool {
+	return anyKeyDown
+}
+
+func AnyMouseBtnDown() bool {
+	return anyMouseBtnDown
+}

input/keyboard.go

@@ -0,0 +1,67 @@
+package input
+
+import "github.com/veandco/go-sdl2/sdl"
+
+type keyState struct {
+	key               sdl.Keycode
+	state             byte
+	pressedThisFrame  bool
+	releasedThisFrame bool
+}
+
+var (
+	keyboardKeys = make(map[sdl.Keycode]*keyState)
+)
+
+func HandleKeyboardEvent(e *sdl.KeyboardEvent) {
+
+	ks := keyboardKeys[e.Keysym.Sym]
+	if ks == nil {
+		ks = &keyState{key: e.Keysym.Sym}
+		keyboardKeys[e.Keysym.Sym] = ks
+	}
+
+	ks.state = e.State
+	ks.pressedThisFrame = e.Repeat == 0 && e.State == sdl.PRESSED
+	ks.releasedThisFrame = e.Repeat == 0 && e.State == sdl.RELEASED
+}
+
+func KeyClicked(kc sdl.Keycode) bool {
+
+	key := keyboardKeys[kc]
+	if key == nil {
+		return false
+	}
+
+	return key.pressedThisFrame
+}
+
+func KeyReleased(kc sdl.Keycode) bool {
+
+	key := keyboardKeys[kc]
+	if key == nil {
+		return false
+	}
+
+	return key.releasedThisFrame
+}
+
+func KeyDown(kc sdl.Keycode) bool {
+
+	key := keyboardKeys[kc]
+	if key == nil {
+		return false
+	}
+
+	return key.state == sdl.PRESSED
+}
+
+func KeyUp(kc sdl.Keycode) bool {
+
+	key := keyboardKeys[kc]
+	if key == nil {
+		return true
+	}
+
+	return key.state == sdl.RELEASED
+}

input/mouse.go

@@ -0,0 +1,79 @@
+package input
+
+import "github.com/veandco/go-sdl2/sdl"
+
+type mouseBtnState struct {
+	button            byte
+	state             byte
+	isDoubleClick     bool
+	pressedThisFrame  bool
+	releasedThisFrame bool
+}
+
+var (
+	mouseBtns = make(map[byte]*mouseBtnState)
+)
+
+func HandleMouseBtnEvent(e *sdl.MouseButtonEvent) {
+
+	mb := mouseBtns[e.Button]
+	if mb == nil {
+		mb = &mouseBtnState{button: e.Button}
+		mouseBtns[e.Button] = mb
+	}
+
+	mb.state = e.State
+	mb.isDoubleClick = e.Clicks > 1 && e.State == sdl.PRESSED
+	mb.pressedThisFrame = e.State == sdl.PRESSED
+	mb.releasedThisFrame = e.State == sdl.RELEASED
+}
+
+func MouseClicked(mouseBtn byte) bool {
+
+	mb := mouseBtns[mouseBtn]
+	if mb == nil {
+		return false
+	}
+
+	return mb.pressedThisFrame
+}
+
+func MouseDoubleClicked(mouseBtn byte) bool {
+
+	mb := mouseBtns[mouseBtn]
+	if mb == nil {
+		return false
+	}
+
+	return mb.isDoubleClick
+}
+
+func MouseReleased(mouseBtn byte) bool {
+
+	mb := mouseBtns[mouseBtn]
+	if mb == nil {
+		return false
+	}
+
+	return mb.releasedThisFrame
+}
+
+func MouseDown(mouseBtn byte) bool {
+
+	mb := mouseBtns[mouseBtn]
+	if mb == nil {
+		return false
+	}
+
+	return mb.state == sdl.PRESSED
+}
+
+func MouseUp(mouseBtn byte) bool {
+
+	mb := mouseBtns[mouseBtn]
+	if mb == nil {
+		return true
+	}
+
+	return mb.state == sdl.RELEASED
+}