imgui wrapper

internal/imgui/input_sdl3.go

@@ -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))
+}

internal/imgui/shaders.go

@@ -0,0 +1,9 @@
+package imgui
+
+import _ "embed"
+
+//go:embed shaders/imgui.vert.spv
+var vertSPV []byte
+
+//go:embed shaders/imgui.frag.spv
+var fragSPV []byte

internal/imgui/shaders/imgui.frag

@@ -0,0 +1,14 @@
+#version 450 core
+layout(location = 0) out vec4 fColor;
+
+layout(set=0, binding=0) uniform sampler2D sTexture;
+
+layout(location = 0) in struct {
+    vec4 Color;
+    vec2 UV;
+} In;
+
+void main()
+{
+    fColor = In.Color * texture(sTexture, In.UV.st);
+}

internal/imgui/shaders/imgui.vert

@@ -0,0 +1,25 @@
+#version 450 core
+layout(location = 0) in vec2 aPos;
+layout(location = 1) in vec2 aUV;
+layout(location = 2) in vec4 aColor;
+
+layout(push_constant) uniform uPushConstant {
+    vec2 uScale;
+    vec2 uTranslate;
+} pc;
+
+out gl_PerVertex {
+    vec4 gl_Position;
+};
+
+layout(location = 0) out struct {
+    vec4 Color;
+    vec2 UV;
+} Out;
+
+void main()
+{
+    Out.Color = aColor;
+    Out.UV = aUV;
+    gl_Position = vec4(aPos * pc.uScale + pc.uTranslate, 0, 1);
+}

internal/sdl/sdl.go

@@ -16,7 +16,16 @@ const (
 	EventQuit             uint32 = 0x100
 	EventWindowResized    uint32 = 0x206
 	EventPixelSizeChanged uint32 = 0x207
-	EventKeyDown          uint32 = 0x300
+
+	EventKeyDown uint32 = 0x300
+	EventKeyUp   uint32 = 0x301
+
+	EventMouseMotion     uint32 = 0x400
+	EventMouseButtonDown uint32 = 0x401
+	EventMouseButtonUp   uint32 = 0x402
+	EventMouseWheel      uint32 = 0x403
+
+	EventTextInput uint32 = 0x303
 
 	KeyEscape uint32 = 0x1B
 	KeyF      uint32 = 0x66
@@ -49,6 +58,9 @@ var (
 	sdlDestroyAudioStream      func(stream uintptr)
 	sdlGetAudioPlaybackDevices func(count *int32) uintptr
 	sdlGetAudioDeviceName      func(devid uint32) uintptr
+
+	sdlStartTextInput func(window uintptr)
+	sdlStopTextInput  func(window uintptr)
 )
 
 var loaded = false
@@ -79,6 +91,9 @@ func Load() error {
 	purego.RegisterLibFunc(&sdlDestroyAudioStream, h, "SDL_DestroyAudioStream")
 	purego.RegisterLibFunc(&sdlGetAudioPlaybackDevices, h, "SDL_GetAudioPlaybackDevices")
 	purego.RegisterLibFunc(&sdlGetAudioDeviceName, h, "SDL_GetAudioDeviceName")
+	// input
+	purego.RegisterLibFunc(&sdlStartTextInput, h, "SDL_StartTextInput")
+	purego.RegisterLibFunc(&sdlStopTextInput, h, "SDL_StopTextInput")
 	loaded = true
 	return nil
 }
@@ -174,3 +189,7 @@ func GetAudioPlaybackDevices() []AudioDevice {
 	}
 	return devs
 }
+
+// Input wrappers
+func StartTextInput(window uintptr) { sdlStartTextInput(window) }
+func StopTextInput(window uintptr)  { sdlStopTextInput(window) }