From 676509d8560dec370aed306dd63657337c5492a0 Mon Sep 17 00:00:00 2001
From: Humphrey Shotton <humpheh@gmail.com>
Date: Sun, 30 Dec 2018 18:42:02 +0000
Subject: [PATCH] Added joystick input

---
 pixelgl/input.go    |   2 +
 pixelgl/joystick.go | 132 ++++++++++++++++++++++++++++++++++++++++++++
 pixelgl/window.go   |   2 +
 3 files changed, 136 insertions(+)
 create mode 100644 pixelgl/joystick.go

diff --git a/pixelgl/input.go b/pixelgl/input.go
index 2eedb0d..a2ef808 100644
--- a/pixelgl/input.go
+++ b/pixelgl/input.go
@@ -385,4 +385,6 @@ func (w *Window) UpdateInput() {
 	w.tempInp.repeat = [KeyLast + 1]bool{}
 	w.tempInp.scroll = pixel.ZV
 	w.tempInp.typed = ""
+
+	w.updateJoystickInput()
 }
diff --git a/pixelgl/joystick.go b/pixelgl/joystick.go
new file mode 100644
index 0000000..a1eb8d9
--- /dev/null
+++ b/pixelgl/joystick.go
@@ -0,0 +1,132 @@
+package pixelgl
+
+import (
+	"github.com/go-gl/glfw/v3.2/glfw"
+)
+
+// Joystick is a joystick or controller.
+type Joystick int
+
+// List all of the joysticks.
+const (
+	Joystick1  = Joystick(glfw.Joystick1)
+	Joystick2  = Joystick(glfw.Joystick2)
+	Joystick3  = Joystick(glfw.Joystick3)
+	Joystick4  = Joystick(glfw.Joystick4)
+	Joystick5  = Joystick(glfw.Joystick5)
+	Joystick6  = Joystick(glfw.Joystick6)
+	Joystick7  = Joystick(glfw.Joystick7)
+	Joystick8  = Joystick(glfw.Joystick8)
+	Joystick9  = Joystick(glfw.Joystick9)
+	Joystick10 = Joystick(glfw.Joystick10)
+	Joystick11 = Joystick(glfw.Joystick11)
+	Joystick12 = Joystick(glfw.Joystick12)
+	Joystick13 = Joystick(glfw.Joystick13)
+	Joystick14 = Joystick(glfw.Joystick14)
+	Joystick15 = Joystick(glfw.Joystick15)
+	Joystick16 = Joystick(glfw.Joystick16)
+	//JoystickLast = Joystick(glfw.JoystickLast)
+)
+
+// JoystickPresent returns if the joystick is currently connected.
+func (w *Window) JoystickPresent(js Joystick) bool {
+	return w.currJoy.connected[js]
+}
+
+// JoystickName returns the name of the joystick. A disconnected joystick will return an
+// empty string.
+func (w *Window) JoystickName(js Joystick) string {
+	return w.currJoy.name[js]
+}
+
+// JoystickButtonCount returns the number of buttons a connected joystick has.
+func (w *Window) JoystickButtonCount(js Joystick) int {
+	return len(w.currJoy.buttons[js])
+}
+
+// JoystickAxisCount returns the number of axes a connected joystick has.
+func (w *Window) JoystickAxisCount(js Joystick) int {
+	return len(w.currJoy.axis[js])
+}
+
+// JoystickPressed returns whether the joystick Button is currently pressed down.
+//
+// If the button index is out of range, this will return false.
+func (w *Window) JoystickPressed(js Joystick, button int) bool {
+	return w.currJoy.getButton(js, button)
+}
+
+// JoystickJustPressed returns whether the joystick Button has just been pressed down.
+//
+// If the button index is out of range, this will return false.
+func (w *Window) JoystickJustPressed(js Joystick, button int) bool {
+	return w.currJoy.getButton(js, button) && !w.prevJoy.getButton(js, button)
+}
+
+// JoystickJustReleased returns whether the joystick Button has just been released up.
+//
+// If the button index is out of range, this will return false.
+func (w *Window) JoystickJustReleased(js Joystick, button int) bool {
+	return !w.currJoy.getButton(js, button) && w.prevJoy.getButton(js, button)
+}
+
+// JoystickAxis returns the value of a joystick axis at the last call to Window.Update.
+//
+// If the axis index is out of range, this will return 0.
+func (w *Window) JoystickAxis(js Joystick, axis int) float64 {
+	return w.currJoy.getAxis(js, axis)
+}
+
+// Used internally during Window.UpdateInput to update the state of the joysticks.
+func (w *Window) updateJoystickInput() {
+	for js := Joystick1; js < Joystick16; js++ {
+		// Determine and store if the joystick was connected
+		joystickPresent := glfw.JoystickPresent(glfw.Joystick(js))
+		w.tempJoy.connected[js] = joystickPresent
+
+		if joystickPresent {
+			w.tempJoy.buttons[js] = glfw.GetJoystickButtons(glfw.Joystick(js))
+			w.tempJoy.axis[js] = glfw.GetJoystickAxes(glfw.Joystick(js))
+
+			if !w.currJoy.connected[js] {
+				// The joystick was recently connected, we get the name
+				w.tempJoy.name[js] = glfw.GetJoystickName(glfw.Joystick(js))
+			} else {
+				// Use the name from the previous one
+				w.tempJoy.name[js] = w.currJoy.name[js]
+			}
+		} else {
+			w.tempJoy.buttons[js] = []byte{}
+			w.tempJoy.axis[js] = []float32{}
+			w.tempJoy.name[js] = ""
+		}
+	}
+
+	w.prevJoy = w.currJoy
+	w.currJoy = w.tempJoy
+}
+
+type joystickState struct {
+	connected [Joystick16]bool
+	name      [Joystick16]string
+	buttons   [Joystick16][]byte
+	axis      [Joystick16][]float32
+}
+
+// Returns if a button on a joystick is down, returning false if the button or joystick is invalid.
+func (js *joystickState) getButton(joystick Joystick, button int) bool {
+	// Check that the joystick and button is valid, return false by default
+	if js.buttons[joystick] == nil || button >= len(js.buttons[joystick]) || button < 0 {
+		return false
+	}
+	return js.buttons[joystick][byte(button)] == 1
+}
+
+// Returns the value of a joystick axis, returning 0 if the button or joystick is invalid.
+func (js *joystickState) getAxis(joystick Joystick, axis int) float64 {
+	// Check that the joystick and axis is valid, return 0 by default.
+	if js.axis[joystick] == nil || axis >= len(js.axis[joystick]) || axis < 0 {
+		return 0
+	}
+	return float64(js.axis[joystick][axis])
+}
diff --git a/pixelgl/window.go b/pixelgl/window.go
index 2d646c5..c124152 100644
--- a/pixelgl/window.go
+++ b/pixelgl/window.go
@@ -72,6 +72,8 @@ type Window struct {
 		scroll  pixel.Vec
 		typed   string
 	}
+
+	prevJoy, currJoy, tempJoy joystickState
 }
 
 var currWin *Window