From b03a017a7ff87083d74938a4d554ac340b1cfe2b Mon Sep 17 00:00:00 2001
From: bloeys <bloeys@outlook.com>
Date: Sat, 9 Oct 2021 05:32:17 +0400
Subject: [PATCH] Keyboard and mouse input system

---
 input/input.go    | 47 ++++++++++++++++++++++++++++
 input/keyboard.go | 67 ++++++++++++++++++++++++++++++++++++++++
 input/mouse.go    | 79 +++++++++++++++++++++++++++++++++++++++++++++++
 main.go           | 14 +++++++++
 4 files changed, 207 insertions(+)
 create mode 100755 input/input.go
 create mode 100755 input/keyboard.go
 create mode 100755 input/mouse.go

diff --git a/input/input.go b/input/input.go
new file mode 100755
index 0000000..55bcf90
--- /dev/null
+++ b/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
+}
diff --git a/input/keyboard.go b/input/keyboard.go
new file mode 100755
index 0000000..62e0c90
--- /dev/null
+++ b/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
+}
diff --git a/input/mouse.go b/input/mouse.go
new file mode 100755
index 0000000..3756eef
--- /dev/null
+++ b/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
+}
diff --git a/main.go b/main.go
index ac3d90e..2405392 100755
--- a/main.go
+++ b/main.go
@@ -3,6 +3,7 @@ package main
 import (
 	"fmt"
 
+	"github.com/bloeys/go-sdl-engine/input"
 	"github.com/bloeys/go-sdl-engine/timing"
 	"github.com/go-gl/gl/v4.6-compatibility/gl"
 	"github.com/veandco/go-sdl2/sdl"
@@ -105,6 +106,7 @@ func gameLoop() {
 		timing.FrameStarted()
 
 		handleEvents()
+		update()
 		draw()
 
 		window.GLSwap()
@@ -116,10 +118,18 @@ func gameLoop() {
 
 func handleEvents() {
 
+	input.EventLoopStarted()
+
 	for event := sdl.PollEvent(); event != nil; event = sdl.PollEvent() {
 
 		switch e := event.(type) {
 
+		case *sdl.KeyboardEvent:
+			input.HandleKeyboardEvent(e)
+
+		case *sdl.MouseButtonEvent:
+			input.HandleMouseBtnEvent(e)
+
 		case *sdl.QuitEvent:
 			println("Quit at ", e.Timestamp)
 			isRunning = false
@@ -127,6 +137,10 @@ func handleEvents() {
 	}
 }
 
+func update() {
+	println(input.AnyKeyDown(), ";", input.AnyMouseBtnDown())
+}
+
 func draw() {
 	//Clear screen and depth buffers
 	gl.Clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT)