refactor ImGUI code files

internal/igwrap/backend/glfw.go

@@ -0,0 +1,126 @@
+package backend
+
+import (
+	"time"
+
+	"github.com/go-gl/glfw/v3.3/glfw"
+	"github.com/inkyblackness/imgui-go/v4"
+)
+
+const (
+	mouseButtonPrimary = iota
+	mouseButtonSecondary
+	mouseButtonTertiary
+	mouseButtonCount
+)
+
+var (
+	win *glfw.Window
+	io  imgui.IO
+
+	lastframe        time.Time
+	mouseJustPressed [mouseButtonCount]bool
+)
+
+func Init(window *glfw.Window) {
+	win = window
+	io = imgui.CurrentIO()
+
+	setKeymap()
+	lastframe = time.Now()
+
+	renderInit()
+}
+
+// NewFrame marks the begin of a render pass.
+func NewFrame() {
+	dsx, dsy := win.GetSize()
+	io.SetDisplaySize(imgui.Vec2{X: float32(dsx), Y: float32(dsy)})
+
+	now := time.Now()
+	deltaTime := float32(time.Since(lastframe).Seconds())
+	if deltaTime <= 0.0 {
+		deltaTime = 1e-6
+	}
+	io.SetDeltaTime(deltaTime)
+	lastframe = now
+
+	if win.GetAttrib(glfw.Focused) != 0 {
+		x, y := win.GetCursorPos()
+		io.SetMousePosition(imgui.Vec2{X: float32(x), Y: float32(y)})
+	}
+
+	for i := 0; i < mouseButtonCount; i++ {
+		down := mouseJustPressed[i] || (win.GetMouseButton(glfwButtonIDByIndex[i]) == glfw.Press)
+		io.SetMouseButtonDown(i, down)
+		mouseJustPressed[i] = false
+	}
+	imgui.NewFrame()
+}
+
+func setKeymap() {
+	io.KeyMap(imgui.KeyTab, int(glfw.KeyTab))
+	io.KeyMap(imgui.KeyLeftArrow, int(glfw.KeyLeft))
+	io.KeyMap(imgui.KeyRightArrow, int(glfw.KeyRight))
+	io.KeyMap(imgui.KeyUpArrow, int(glfw.KeyUp))
+	io.KeyMap(imgui.KeyDownArrow, int(glfw.KeyDown))
+	io.KeyMap(imgui.KeyPageUp, int(glfw.KeyPageUp))
+	io.KeyMap(imgui.KeyPageDown, int(glfw.KeyPageDown))
+	io.KeyMap(imgui.KeyHome, int(glfw.KeyHome))
+	io.KeyMap(imgui.KeyEnd, int(glfw.KeyEnd))
+	io.KeyMap(imgui.KeyInsert, int(glfw.KeyInsert))
+	io.KeyMap(imgui.KeyDelete, int(glfw.KeyDelete))
+	io.KeyMap(imgui.KeyBackspace, int(glfw.KeyBackspace))
+	io.KeyMap(imgui.KeySpace, int(glfw.KeySpace))
+	io.KeyMap(imgui.KeyEnter, int(glfw.KeyEnter))
+	io.KeyMap(imgui.KeyEscape, int(glfw.KeyEscape))
+	io.KeyMap(imgui.KeyA, int(glfw.KeyA))
+	io.KeyMap(imgui.KeyC, int(glfw.KeyC))
+	io.KeyMap(imgui.KeyV, int(glfw.KeyV))
+	io.KeyMap(imgui.KeyX, int(glfw.KeyX))
+	io.KeyMap(imgui.KeyY, int(glfw.KeyY))
+	io.KeyMap(imgui.KeyZ, int(glfw.KeyZ))
+}
+
+var glfwButtonIndexByID = map[glfw.MouseButton]int{
+	glfw.MouseButton1: mouseButtonPrimary,
+	glfw.MouseButton2: mouseButtonSecondary,
+	glfw.MouseButton3: mouseButtonTertiary,
+}
+
+var glfwButtonIDByIndex = map[int]glfw.MouseButton{
+	mouseButtonPrimary:   glfw.MouseButton1,
+	mouseButtonSecondary: glfw.MouseButton2,
+	mouseButtonTertiary:  glfw.MouseButton3,
+}
+
+// MouseButtonCallback is the callback called when the mouse button changes.
+func MouseButtonCallback(button glfw.MouseButton, action glfw.Action) {
+	if index, known := glfwButtonIndexByID[button]; known && (action == glfw.Press) {
+		mouseJustPressed[index] = true
+	}
+}
+
+// MouseScrollCallback is called when scroll status changes.
+func MouseScrollCallback(x, y float64) {
+	io.AddMouseWheelDelta(float32(x), float32(y))
+}
+
+// KeyCallback is called when a key is pressed or released.
+func KeyCallback(key glfw.Key, action glfw.Action) {
+	if action == glfw.Press {
+		io.KeyPress(int(key))
+	}
+	if action == glfw.Release {
+		io.KeyRelease(int(key))
+	}
+	io.KeyCtrl(int(glfw.KeyLeftControl), int(glfw.KeyRightControl))
+	io.KeyShift(int(glfw.KeyLeftShift), int(glfw.KeyRightShift))
+	io.KeyAlt(int(glfw.KeyLeftAlt), int(glfw.KeyRightAlt))
+	io.KeySuper(int(glfw.KeyLeftSuper), int(glfw.KeyRightSuper))
+}
+
+// InputCallback is called when a char is inputed (CharChange)
+func InputCallback(input rune) {
+	io.AddInputCharacters(string(input))
+}