imgui wrapper

2026-08-25 12:09:40 +03:00
parent 16692b693a
commit 3398cdf3f1
10 changed files with 186 additions and 2 deletions
@@ -0,0 +1,108 @@
+package imgui
+
+import (
+	"mxl-player/internal/sdl"
+	"unsafe"
+
+	cimgui "github.com/AllenDang/cimgui-go/imgui"
+)
+
+// SDL3 event (128 byte raw buffer) -> imgui
+func (c *Context) ProcessEvent(event *[128]byte) {
+	eventType := *(*uint32)(unsafe.Pointer(&event[0]))
+
+	// CommonEvent (16 bytes: type uint32 + reserved uint32 + timestamp uint64)
+	switch eventType {
+	case sdl.EventKeyDown, sdl.EventKeyUp:
+		scancode := *(*uint32)(unsafe.Pointer(&event[24]))
+		down := eventType == sdl.EventKeyDown
+		key := sdlScancodeToImGuiKey(scancode)
+		if key >= 0 {
+			c.io.AddKeyEvent(key, down)
+		}
+	// MouseMotionEvent: +16 windowID(4), +20 which(4), +24 state(4), +28 x(float32), +32 y(float32)
+	case sdl.EventMouseMotion:
+		x := *(*float32)(unsafe.Pointer(&event[28]))
+		y := *(*float32)(unsafe.Pointer(&event[32]))
+		c.io.AddMousePosEvent(x, y)
+	// MouseButtonEvent: +16 windowID(4), +20 which(4), +24 button(1), +25 down(bool)
+	case sdl.EventMouseButtonDown, sdl.EventMouseButtonUp:
+		button := *(*uint8)(unsafe.Pointer(&event[24]))
+		down := eventType == sdl.EventMouseButtonDown
+		c.io.AddMouseButtonEvent(int32(button-1), down)
+	// MouseWheelEvent: +16 windowID(4), +20 which(4), +24 x(float32), +28 y(float32)
+	case sdl.EventMouseWheel:
+		x := *(*float32)(unsafe.Pointer(&event[24]))
+		y := *(*float32)(unsafe.Pointer(&event[28]))
+		c.io.AddMouseWheelEvent(x, y)
+	// TextInputEvent: +16 windowID(4), +20 text(*char pointer, 8 bytes on 64-bit)
+	case sdl.EventTextInput:
+		// text pointer is at offset 24, 8 bytes (pointer)
+		ptr := *(*uintptr)(unsafe.Pointer(&event[24]))
+		if ptr != 0 {
+			text := cstr(ptr)
+			c.io.AddInputCharactersUTF8(text)
+		}
+
+	}
+}
+
+func sdlScancodeToImGuiKey(scancode uint32) cimgui.Key {
+	switch scancode {
+	case 40: // SDL_SCANCODE_RETURN
+		return cimgui.KeyEnter
+	case 42: // SDL_SCANCODE_BACKSPACE
+		return cimgui.KeyBackspace
+	case 41: // SDL_SCANCODE_ESCAPE
+		return cimgui.KeyEscape
+	case 43: // SDL_SCANCODE_TAB
+		return cimgui.KeyTab
+	case 44: // SDL_SCANCODE_SPACE
+		return cimgui.KeySpace
+	case 80: // SDL_SCANCODE_LEFT
+		return cimgui.KeyLeftArrow
+	case 79: // SDL_SCANCODE_RIGHT
+		return cimgui.KeyRightArrow
+	case 82: // SDL_SCANCODE_UP
+		return cimgui.KeyUpArrow
+	case 81: // SDL_SCANCODE_DOWN
+		return cimgui.KeyDownArrow
+	case 225: // SDL_SCANCODE_LSHIFT
+		return cimgui.KeyLeftShift
+	case 229: // SDL_SCANCODE_RSHIFT
+		return cimgui.KeyRightShift
+	case 224: // SDL_SCANCODE_LCTRL
+		return cimgui.KeyLeftCtrl
+	case 228: // SDL_SCANCODE_RCTRL
+		return cimgui.KeyRightCtrl
+	case 226: // SDL_SCANCODE_LALT
+		return cimgui.KeyLeftAlt
+	case 230: // SDL_SCANCODE_RALT
+		return cimgui.KeyRightAlt
+	default:
+		// Letters A-Z: scancodes 4-29 map to ImGui KeyA-KeyZ
+		if scancode >= 4 && scancode <= 29 {
+			return cimgui.Key(int(cimgui.KeyA) + int(scancode-4))
+		}
+		// Numbers 0-9: scancodes 30-39
+		if scancode >= 30 && scancode <= 39 {
+			return cimgui.Key(int(cimgui.Key0) + int(scancode-30))
+		}
+		return -1
+	}
+}
+
+// cstr reads a NUL-terminated C string at p.
+// TODO: same func used in Vulkan
+// Maybe i should create something like "package common"
+// for funcs like this
+func cstr(p uintptr) string {
+	if p == 0 {
+		return ""
+	}
+	var n int
+	for *(*byte)(unsafe.Pointer(p + uintptr(n))) != 0 {
+		n++
+	}
+	return string(unsafe.Slice((*byte)(unsafe.Pointer(p)), n))
+}