ebiten: add IsStandardGamepadAxisAvailable and IsStandardGamepadButtonAvailable (#2241)

Closes #2040

examples/gamepad/main.go

@@ -154,13 +154,17 @@ func standardMap(id ebiten.GamepadID) string {
 	for b, str := range standardButtonToString {
 		placeholder := "[" + str + strings.Repeat(" ", 4-len(str)) + "]"
 		v := ebiten.StandardGamepadButtonValue(id, b)
-		if ebiten.IsStandardGamepadButtonPressed(id, b) {
+		switch {
+		case !ebiten.IsStandardGamepadButtonAvailable(id, b):
+			m = strings.Replace(m, placeholder, "  --  ", 1)
+		case ebiten.IsStandardGamepadButtonPressed(id, b):
 			m = strings.Replace(m, placeholder, fmt.Sprintf("[%0.2f]", v), 1)
-		} else {
+		default:
 			m = strings.Replace(m, placeholder, fmt.Sprintf(" %0.2f ", v), 1)
 		}
 	}
 
+	// TODO: Use ebiten.IsStandardGamepadAxisAvailable
 	m += fmt.Sprintf("    Left Stick:  X: %+0.2f, Y: %+0.2f\n    Right Stick: X: %+0.2f, Y: %+0.2f",
 		ebiten.StandardGamepadAxisValue(id, ebiten.StandardGamepadAxisLeftStickHorizontal),
 		ebiten.StandardGamepadAxisValue(id, ebiten.StandardGamepadAxisLeftStickVertical),

input.go

@@ -303,6 +303,28 @@ func IsStandardGamepadLayoutAvailable(id GamepadID) bool {
 	return g.IsStandardLayoutAvailable()
 }
 
+// IsStandardGamepadAxisAvailable reports whether the standard gamepad axis is available on the gamepad (id).
+//
+// IsStandardGamepadAxisAvailable is concurrent-safe.
+func IsStandardGamepadAxisAvailable(id GamepadID, axis StandardGamepadAxis) bool {
+	g := gamepad.Get(id)
+	if g == nil {
+		return false
+	}
+	return g.IsStandardAxisAvailable(axis)
+}
+
+// IsStandardGamepadButtonAvailable reports whether the standard gamepad button is available on the gamepad (id).
+//
+// IsStandardGamepadButtonAvailable is concurrent-safe.
+func IsStandardGamepadButtonAvailable(id GamepadID, button StandardGamepadButton) bool {
+	g := gamepad.Get(id)
+	if g == nil {
+		return false
+	}
+	return g.IsStandardButtonAvailable(button)
+}
+
 // UpdateStandardGamepadLayoutMappings parses the specified string mappings in SDL_GameControllerDB format and
 // updates the gamepad layout definitions.
 //

internal/gamepad/gamepad.go

@@ -190,6 +190,8 @@ type Gamepad struct {
 type nativeGamepad interface {
 	update(gamepads *gamepads) error
 	hasOwnStandardLayoutMapping() bool
+	isStandardAxisAvailableInOwnMapping(axis gamepaddb.StandardAxis) bool
+	isStandardButtonAvailableInOwnMapping(button gamepaddb.StandardButton) bool
 	axisCount() int
 	buttonCount() int
 	hatCount() int
@@ -281,6 +283,28 @@ func (g *Gamepad) IsStandardLayoutAvailable() bool {
 	return g.native.hasOwnStandardLayoutMapping()
 }
 
+// IsStandardAxisAvailable is concurrent safe.
+func (g *Gamepad) IsStandardAxisAvailable(button gamepaddb.StandardAxis) bool {
+	g.m.Lock()
+	defer g.m.Unlock()
+
+	if gamepaddb.HasStandardLayoutMapping(g.sdlID) {
+		return gamepaddb.HasStandardAxis(g.sdlID, button)
+	}
+	return g.native.isStandardAxisAvailableInOwnMapping(button)
+}
+
+// IsStandardButtonAvailable is concurrent safe.
+func (g *Gamepad) IsStandardButtonAvailable(button gamepaddb.StandardButton) bool {
+	g.m.Lock()
+	defer g.m.Unlock()
+
+	if gamepaddb.HasStandardLayoutMapping(g.sdlID) {
+		return gamepaddb.HasStandardButton(g.sdlID, button)
+	}
+	return g.native.isStandardButtonAvailableInOwnMapping(button)
+}
+
 // StandardAxisValue is concurrent-safe.
 func (g *Gamepad) StandardAxisValue(axis gamepaddb.StandardAxis) float64 {
 	if gamepaddb.HasStandardLayoutMapping(g.sdlID) {

internal/gamepad/gamepad_android.go

@@ -19,6 +19,8 @@ package gamepad
 
 import (
 	"time"
+
+	"github.com/hajimehoshi/ebiten/v2/internal/gamepaddb"
 )
 
 type nativeGamepadsImpl struct{}
@@ -52,6 +54,14 @@ func (*nativeGamepadImpl) hasOwnStandardLayoutMapping() bool {
 	return false
 }
 
+func (*nativeGamepadImpl) isStandardAxisAvailableInOwnMapping(axis gamepaddb.StandardAxis) bool {
+	return false
+}
+
+func (*nativeGamepadImpl) isStandardButtonAvailableInOwnMapping(button gamepaddb.StandardButton) bool {
+	return false
+}
+
 func (g *nativeGamepadImpl) axisCount() int {
 	return len(g.axes)
 }

internal/gamepad/gamepad_cbackend.go

@@ -21,6 +21,7 @@ import (
 	"time"
 
 	"github.com/hajimehoshi/ebiten/v2/internal/cbackend"
+	"github.com/hajimehoshi/ebiten/v2/internal/gamepaddb"
 )
 
 type nativeGamepadsImpl struct {
@@ -98,6 +99,16 @@ func (g *nativeGamepadImpl) hasOwnStandardLayoutMapping() bool {
 	return g.standard
 }
 
+func (g *nativeGamepadImpl) isStandardAxisAvailableInOwnMapping(axis gamepaddb.StandardAxis) bool {
+	// TODO: Implement this on the C side.
+	return axis >= 0 && int(axis) < len(g.axisValues)
+}
+
+func (g *nativeGamepadImpl) isStandardButtonAvailableInOwnMapping(button gamepaddb.StandardButton) bool {
+	// TODO: Implement this on the C side.
+	return button >= 0 && int(button) < len(g.buttonValues)
+}
+
 func (g *nativeGamepadImpl) axisCount() int {
 	return len(g.axisValues)
 }

internal/gamepad/gamepad_darwin.go

@@ -24,6 +24,8 @@ import (
 	"sync"
 	"time"
 	"unsafe"
+
+	"github.com/hajimehoshi/ebiten/v2/internal/gamepaddb"
 )
 
 // #cgo LDFLAGS: -framework CoreFoundation -framework IOKit
@@ -406,6 +408,14 @@ func (g *nativeGamepadImpl) hasOwnStandardLayoutMapping() bool {
 	return false
 }
 
+func (g *nativeGamepadImpl) isStandardAxisAvailableInOwnMapping(axis gamepaddb.StandardAxis) bool {
+	return false
+}
+
+func (g *nativeGamepadImpl) isStandardButtonAvailableInOwnMapping(button gamepaddb.StandardButton) bool {
+	return false
+}
+
 func (g *nativeGamepadImpl) axisCount() int {
 	return len(g.axisValues)
 }

internal/gamepad/gamepad_desktop_windows.go

@@ -28,6 +28,8 @@ import (
 	"unsafe"
 
 	"golang.org/x/sys/windows"
+
+	"github.com/hajimehoshi/ebiten/v2/internal/gamepaddb"
 )
 
 type dinputObjectType int
@@ -571,6 +573,14 @@ func (*nativeGamepadDesktop) hasOwnStandardLayoutMapping() bool {
 	return false
 }
 
+func (*nativeGamepadDesktop) isStandardAxisAvailableInOwnMapping(axis gamepaddb.StandardAxis) bool {
+	return false
+}
+
+func (*nativeGamepadDesktop) isStandardButtonAvailableInOwnMapping(button gamepaddb.StandardButton) bool {
+	return false
+}
+
 func (g *nativeGamepadDesktop) usesDInput() bool {
 	return g.dinputDevice != nil
 }

internal/gamepad/gamepad_ios.go

@@ -19,6 +19,8 @@ package gamepad
 
 import (
 	"time"
+
+	"github.com/hajimehoshi/ebiten/v2/internal/gamepaddb"
 )
 
 type nativeGamepadsImpl struct{}
@@ -57,6 +59,14 @@ func (*nativeGamepadImpl) hasOwnStandardLayoutMapping() bool {
 	return false
 }
 
+func (*nativeGamepadImpl) isStandardAxisAvailableInOwnMapping(axis gamepaddb.StandardAxis) bool {
+	return false
+}
+
+func (*nativeGamepadImpl) isStandardButtonAvailableInOwnMapping(button gamepaddb.StandardButton) bool {
+	return false
+}
+
 func (g *nativeGamepadImpl) axisCount() int {
 	return len(g.axes)
 }

internal/gamepad/gamepad_js.go

@@ -18,6 +18,8 @@ import (
 	"encoding/hex"
 	"syscall/js"
 	"time"
+
+	"github.com/hajimehoshi/ebiten/v2/internal/gamepaddb"
 )
 
 var (
@@ -114,6 +116,20 @@ func (g *nativeGamepadImpl) hasOwnStandardLayoutMapping() bool {
 	return g.mapping == "standard"
 }
 
+func (g *nativeGamepadImpl) isStandardAxisAvailableInOwnMapping(axis gamepaddb.StandardAxis) bool {
+	if !g.hasOwnStandardLayoutMapping() {
+		return false
+	}
+	return axis >= 0 && int(axis) < g.axisCount()
+}
+
+func (g *nativeGamepadImpl) isStandardButtonAvailableInOwnMapping(button gamepaddb.StandardButton) bool {
+	if !g.hasOwnStandardLayoutMapping() {
+		return false
+	}
+	return button >= 0 && int(button) < g.buttonCount()
+}
+
 func (g *nativeGamepadImpl) update(gamepads *gamepads) error {
 	return nil
 }

internal/gamepad/gamepad_linux.go

@@ -27,6 +27,8 @@ import (
 	"unsafe"
 
 	"golang.org/x/sys/unix"
+
+	"github.com/hajimehoshi/ebiten/v2/internal/gamepaddb"
 )
 
 const dirName = "/dev/input"
@@ -410,6 +412,14 @@ func (*nativeGamepadImpl) hasOwnStandardLayoutMapping() bool {
 	return false
 }
 
+func (*nativeGamepadImpl) isStandardAxisAvailableInOwnMapping(axis gamepaddb.StandardAxis) bool {
+	return false
+}
+
+func (*nativeGamepadImpl) isStandardButtonAvailableInOwnMapping(button gamepaddb.StandardButton) bool {
+	return false
+}
+
 func (g *nativeGamepadImpl) axisCount() int {
 	return g.axisCount_
 }

internal/gamepad/gamepad_null.go

@@ -19,6 +19,8 @@ package gamepad
 
 import (
 	"time"
+
+	"github.com/hajimehoshi/ebiten/v2/internal/gamepaddb"
 )
 
 type nativeGamepadsImpl struct{}
@@ -45,6 +47,14 @@ func (*nativeGamepadImpl) hasOwnStandardLayoutMapping() bool {
 	return false
 }
 
+func (*nativeGamepadImpl) isStandardAxisAvailableInOwnMapping(axis gamepaddb.StandardAxis) bool {
+	return false
+}
+
+func (*nativeGamepadImpl) isStandardButtonAvailableInOwnMapping(button gamepaddb.StandardButton) bool {
+	return false
+}
+
 func (*nativeGamepadImpl) axisCount() int {
 	return 0
 }

internal/gamepad/gamepad_xbox_windows.go

@@ -158,6 +158,27 @@ func (n *nativeGamepadXbox) hasOwnStandardLayoutMapping() bool {
 	return true
 }
 
+func (n *nativeGamepadXbox) isStandardAxisAvailableInOwnMapping(axis gamepaddb.StandardAxis) bool {
+	switch gamepaddb.StandardAxis(axis) {
+	case gamepaddb.StandardAxisLeftStickHorizontal,
+		gamepaddb.StandardAxisLeftStickVertical,
+		gamepaddb.StandardAxisRightStickHorizontal,
+		gamepaddb.StandardAxisRightStickVertical:
+		return true
+	}
+	return false
+}
+
+func (n *nativeGamepadXbox) isStandardButtonAvailableInOwnMapping(button gamepaddb.StandardButton) bool {
+	switch gamepaddb.StandardButton(button) {
+	case gamepaddb.StandardButtonFrontBottomLeft,
+		gamepaddb.StandardButtonFrontBottomRight:
+		return true
+	}
+	_, ok := standardButtonToGamepadInputGamepadButton(button)
+	return ok
+}
+
 func (n *nativeGamepadXbox) axisCount() int {
 	return int(gamepaddb.StandardAxisMax) + 1
 }

internal/gamepaddb/gamepaddb.go

@@ -389,6 +389,23 @@ func Name(id string) string {
 	return gamepadNames[id]
 }
 
+func HasStandardAxis(id string, axis StandardAxis) bool {
+	mappingsM.RLock()
+	defer mappingsM.RUnlock()
+
+	mappings := axisMappings(id)
+	if mappings == nil {
+		return false
+	}
+
+	mapping := mappings[axis]
+	if mapping == nil {
+		return false
+	}
+
+	return true
+}
+
 func AxisValue(id string, axis StandardAxis, state GamepadState) float64 {
 	mappingsM.RLock()
 	defer mappingsM.RUnlock()
@@ -429,6 +446,23 @@ func AxisValue(id string, axis StandardAxis, state GamepadState) float64 {
 	return 0
 }
 
+func HasStandardButton(id string, button StandardButton) bool {
+	mappingsM.RLock()
+	defer mappingsM.RUnlock()
+
+	mappings := buttonMappings(id)
+	if mappings == nil {
+		return false
+	}
+
+	mapping := mappings[button]
+	if mapping == nil {
+		return false
+	}
+
+	return true
+}
+
 func ButtonValue(id string, button StandardButton, state GamepadState) float64 {
 	mappingsM.RLock()
 	defer mappingsM.RUnlock()