Use atomic mouse states

pkg/worker/caged/libretro/nanoarch/input.go

@@ -18,8 +18,9 @@ const (
 // It consists of:
 //   - uint16 button values
 //   - int16 analog stick values
+type InputState [maxPort]RetroPadState
+
 type (
-	InputState    [maxPort]RetroPadState
 	RetroPadState struct {
 		keys uint32
 		axes [dpadAxes]int32
@@ -30,15 +31,13 @@ type (
 		mu   sync.Mutex
 	}
 	MouseState struct {
-		x, y int16
-		mp   sync.Mutex
-		l    bool
-		r    bool
-		m    bool
-		mb   sync.Mutex
+		dx, dy  atomic.Int32
+		buttons atomic.Int32
 	}
 )
 
+type MouseBtnState int32
+
 type Device byte
 
 const (
@@ -52,6 +51,12 @@ const (
 	MouseButton
 )
 
+const (
+	MouseLeft MouseBtnState = 1 << iota
+	MouseRight
+	MouseMiddle
+)
+
 const (
 	maxPort  = 8
 	dpadAxes = 4
@@ -87,8 +92,6 @@ func NewKeyboardState() KeyboardState {
 
 // SetKey sets keyboard state.
 //
-//	data format
-//
 //	0 1 2 3 4 5 6
 //	[ KEY ] P MOD
 //
@@ -128,67 +131,30 @@ func (ks *KeyboardState) Pressed(key uint) C.int16_t {
 
 // ShiftPos sets mouse relative position state.
 //
-//	data format
+//	0  1 2  3
+//	[dx] [dy]
 //
-//	0 1 2 3
-//	[x] [y]
-//
-//	x and y contain relative (to the previous values)
-//	X, Y positions as signed int.
+//	dx and dy are relative mouse coordinates
 func (ms *MouseState) ShiftPos(data []byte) {
 	if len(data) != 4 {
 		return
 	}
 	dx := int16(data[0])<<8 + int16(data[1])
 	dy := int16(data[2])<<8 + int16(data[3])
-	ms.mp.Lock()
-	ms.x += dx
-	ms.y += dy
-	ms.mp.Unlock()
-}
-
-func (ms *MouseState) PopX() C.int16_t {
-	var x int16
-	ms.mp.Lock()
-	x = ms.x
-	ms.x = 0
-	ms.mp.Unlock()
-	return C.int16_t(x)
+	ms.dx.Add(int32(dx))
+	ms.dy.Add(int32(dy))
 }
 
-func (ms *MouseState) PopY() C.int16_t {
-	var y int16
-	ms.mp.Lock()
-	y = ms.y
-	ms.y = 0
-	ms.mp.Unlock()
-	return C.int16_t(y)
-}
+func (ms *MouseState) PopX() C.int16_t { return C.int16_t(ms.dx.Swap(0)) }
+func (ms *MouseState) PopY() C.int16_t { return C.int16_t(ms.dy.Swap(0)) }
 
-// SetButtons sets the state of mouse buttons.
-//
-//	data format
-//
-//	0 1 2
-//	L R M
-//
-//	L is the left button, R is right, and M is the middle button.
-func (ms *MouseState) SetButtons(data []byte) {
-	if len(data) != 3 {
-		return
-	}
-	ms.mb.Lock()
-	ms.l = data[0] == 1
-	ms.r = data[1] == 1
-	ms.m = data[2] == 1
-	ms.mb.Unlock()
-}
+// SetButtons sets the state MouseBtnState of mouse buttons.
+func (ms *MouseState) SetButtons(data byte) { ms.buttons.Store(int32(data)) }
 
 func (ms *MouseState) Buttons() (l, r, m bool) {
-	ms.mb.Lock()
-	l = ms.l
-	r = ms.r
-	m = ms.m
-	ms.mb.Unlock()
+	mbs := MouseBtnState(ms.buttons.Load())
+	l = mbs&MouseLeft != 0
+	r = mbs&MouseRight != 0
+	m = mbs&MouseMiddle != 0
 	return
 }

pkg/worker/caged/libretro/nanoarch/input_test.go

@@ -1,6 +1,7 @@
 package nanoarch
 
 import (
+	"encoding/binary"
 	"math/rand"
 	"sync"
 	"testing"
@@ -19,3 +20,54 @@ func TestConcurrentInput(t *testing.T) {
 	}
 	wg.Wait()
 }
+
+func TestMousePos(t *testing.T) {
+	data := []byte{0, 0, 0, 0}
+
+	dx := 1111
+	dy := 2222
+
+	binary.BigEndian.PutUint16(data, uint16(dx))
+	binary.BigEndian.PutUint16(data[2:], uint16(dy))
+
+	ms := MouseState{}
+	ms.ShiftPos(data)
+
+	x := int(ms.PopX())
+	y := int(ms.PopY())
+
+	if x != dx || y != dy {
+		t.Errorf("invalid state, %v = %v, %v = %v", dx, x, dy, y)
+	}
+
+	if ms.dx.Load() != 0 || ms.dy.Load() != 0 {
+		t.Errorf("coordinates weren't cleared")
+	}
+}
+
+func TestMouseButtons(t *testing.T) {
+	tests := []struct {
+		name string
+		data byte
+		l    bool
+		r    bool
+		m    bool
+	}{
+		{name: "l+r+m+", data: 1 + 2 + 4, l: true, r: true, m: true},
+		{name: "l-r-m-", data: 0},
+		{name: "l-r+m-", data: 2, r: true},
+		{name: "l+r-m+", data: 1 + 4, l: true, m: true},
+	}
+
+	ms := MouseState{}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			ms.SetButtons(test.data)
+			l, r, m := ms.Buttons()
+			if l != test.l || r != test.r || m != test.m {
+				t.Errorf("wrong button state: %v -> %v, %v, %v", test.data, l, r, m)
+			}
+		})
+	}
+}

pkg/worker/caged/libretro/nanoarch/nanoarch.go

@@ -402,7 +402,7 @@ func (n *Nanoarch) InputMouse(_ int, data []byte) {
 	case MouseMove:
 		n.mouse.ShiftPos(state)
 	case MouseButton:
-		n.mouse.SetButtons(state)
+		n.mouse.SetButtons(state[0])
 	}
 }
 

web/js/api/api.js

@@ -80,36 +80,23 @@ const api = (() => {
     })();
 
     const mousePress = (() => {
-        // 0 1 2 3
-        // T L R M
-        const buffer = new ArrayBuffer(4);
+        // 0 1
+        // T B
+        const buffer = new ArrayBuffer(2);
         const dv = new DataView(buffer);
 
-        // #define RETRO_DEVICE_ID_MOUSE_LEFT             2
-        // #define RETRO_DEVICE_ID_MOUSE_RIGHT            3
-        // #define RETRO_DEVICE_ID_MOUSE_WHEELUP          4
-        // #define RETRO_DEVICE_ID_MOUSE_WHEELDOWN        5
-        // #define RETRO_DEVICE_ID_MOUSE_MIDDLE           6
-        // #define RETRO_DEVICE_ID_MOUSE_HORIZ_WHEELUP    7
-        // #define RETRO_DEVICE_ID_MOUSE_HORIZ_WHEELDOWN  8
-        // #define RETRO_DEVICE_ID_MOUSE_BUTTON_4         9
-        // #define RETRO_DEVICE_ID_MOUSE_BUTTON_5         10
-
         // 0: Main button pressed, usually the left button or the un-initialized state
         // 1: Auxiliary button pressed, usually the wheel button or the middle button (if present)
         // 2: Secondary button pressed, usually the right button
         // 3: Fourth button, typically the Browser Back button
         // 4: Fifth button, typically the Browser Forward button
 
-        const b2r = [1, 3, 2, 9, 10] // browser mouse button to retro button
+        const b2r = [1, 4, 2, 0, 0] // browser mouse button to retro button
+        // assumed that only one button pressed / released
 
-        /* @param buttons contains pressed state of mouse buttons according to
-         * https://developer.mozilla.org/en-US/docs/Web/API/MouseEvent/button
-         */
         return (button = 0, pressed = false) => {
-            dv.setUint32(0, 0);
             dv.setUint8(0, mouse.BUTTONS);
-            dv.setUint8(b2r[button], +pressed);
+            dv.setUint8(1, pressed ? b2r[button] : 0);
             webrtc.mouse(buffer);
         }
     })();