feature: Implement display rotation

We don't really need to run at twice the speed of the display's refresh
rate as Raylib manages the target time between frames well.

app/config/config.go

@@ -6,10 +6,12 @@ import _ "embed"
 var InitialConfig []byte
 
 type DisplayConfig struct {
-	Angle   *int     `yaml:"angle"`
+	Angle              *int     `yaml:"angle"`
-	FOV     *int     `yaml:"fov"`
+	FOV                *int     `yaml:"fov"`
-	Spacing *float32 `yaml:"spacing"`
+	Spacing            *float32 `yaml:"spacing"`
-	Count   *int     `yaml:"count"`
+	RadiusMultiplier   *float32 `yaml:"circle_radius_multiplier"`
+	UseCircularSpacing *bool    `yaml:"use_circular_spacing"`
+	Count              *int     `yaml:"count"`
 }
 
 type AppOverrides struct {
@@ -38,10 +40,12 @@ func getPtrToBool(bool bool) *bool {
 
 var DefaultConfig = &Config{
 	DisplayConfig: DisplayConfig{
-		Angle:   getPtrToInt(45),
+		Angle:              getPtrToInt(45),
-		FOV:     getPtrToInt(45),
+		FOV:                getPtrToInt(45),
-		Spacing: getPtrToFloat32(0.5),
+		Spacing:            getPtrToFloat32(0.5),
-		Count:   getPtrToInt(3),
+		RadiusMultiplier:   getPtrToFloat32(2),
+		UseCircularSpacing: getPtrToBool(true),
+		Count:              getPtrToInt(3),
 	},
 	Overrides: AppOverrides{
 		AllowUnsupportedDevices: getPtrToBool(false),

app/config/default_config.yml

@@ -9,7 +9,9 @@
 display:
   angle: 45 # Angle of the virtual displays
   fov: 45 # FOV of the 3D camera
-  spacing: 0.5 # Spacing between virtual displays
+  spacing: 0.5 # Raw spacing between virtual displays. Does not use circles in the layout. Purely flat plane.
+  circle_radius_multiplier: 2 # Multiplier for the radius of the circle used to calculate the spacing between virtual displays. "Rounded" plane of sorts.
+  use_circular_spacing: true # If true, uses a circular layout for the virtual displays.
   count: 3 # Count of virtual displays
 overrides:
   allow_unsupported_devices: false # If true, allows unsupported devices to be used as long as they're a compatible vendor (Xreal)

app/main.go

@@ -118,7 +118,7 @@ func mainEntrypoint(context.Context, *cli.Command) error {
 	bufio.NewReader(os.Stdin).ReadBytes('\n') // Wait for Enter key press before continuing
 
 	log.Info("Initializing XR headset")
-	rl.SetTargetFPS(int32(displayMetadata.MaxRefreshRate * 2))
+	rl.SetTargetFPS(int32(displayMetadata.MaxRefreshRate))
 	rl.InitWindow(int32(displayMetadata.MaxWidth), int32(displayMetadata.MaxHeight), "UnrealXR")
 
 	atexit.Register(func() {

app/renderer/renderer.go

@@ -35,6 +35,15 @@ func findOptimalHorizontalRes(verticalDisplayRes float32, horizontalDisplayRes f
 	return horizontalSize
 }
 
+func findHfovFromVfov(vfovDeg, w, h float64) float64 {
+	vfovRad := vfovDeg * math.Pi / 180
+
+	ar := w / h
+	hfovRad := 2 * math.Atan(math.Tan(vfovRad/2)*ar)
+
+	return hfovRad * 180 / math.Pi
+}
+
 func EnterRenderLoop(config *libconfig.Config, displayMetadata *edidtools.DisplayMetadata, evdiCards []*EvdiDisplayMetadata) {
 	log.Info("Initializing AR driver")
 	headset, err := ardriver.GetDevice()
@@ -99,7 +108,9 @@ func EnterRenderLoop(config *libconfig.Config, displayMetadata *edidtools.Displa
 
 	headset.RegisterEventListeners(arEventListner)
 
-	fovY := float32(45.0)
+	fovY := float32(*config.DisplayConfig.FOV)
+	fovX := findHfovFromVfov(float64(fovY), float64(displayMetadata.MaxWidth), float64(displayMetadata.MaxHeight))
+
 	verticalSize := findMaxVerticalSize(fovY, 5.0)
 
 	camera := rl.NewCamera3D(
@@ -125,6 +136,21 @@ func EnterRenderLoop(config *libconfig.Config, displayMetadata *edidtools.Displa
 	horizontalSize := findOptimalHorizontalRes(float32(displayMetadata.MaxHeight), float32(displayMetadata.MaxWidth), verticalSize)
 	coreMesh := rl.GenMeshPlane(horizontalSize, verticalSize, 1, 1)
 
+	var radius float32
+
+	if *config.DisplayConfig.UseCircularSpacing == true {
+		radiusX := (horizontalSize / 2) / float32(math.Tan((float64(fovX)*math.Pi/180.0)/2))
+		radiusY := (verticalSize / 2) / float32(math.Tan((float64(fovY)*math.Pi/180.0)/2))
+
+		if radiusY > radiusX {
+			radius = radiusY
+		} else {
+			radius = radiusX
+		}
+
+		radius *= *config.DisplayConfig.RadiusMultiplier
+	}
+
 	movementVector := rl.Vector3{
 		X: 0.0,
 		Y: 0.0,
@@ -171,6 +197,17 @@ func EnterRenderLoop(config *libconfig.Config, displayMetadata *edidtools.Displa
 		texture := rl.LoadTextureFromImage(image)
 		model := rl.LoadModelFromMesh(coreMesh)
 
+		// spin up/down
+		pitchRad := float32(-90 * rl.Deg2rad)
+		// spin left/right
+		yawRad := currentAngle * rl.Deg2rad
+
+		rotX := rl.MatrixRotateX(pitchRad)
+		rotY := rl.MatrixRotateY(yawRad)
+
+		transform := rl.MatrixMultiply(rotX, rotY)
+		model.Transform = transform
+
 		rl.SetMaterialTexture(model.Materials, rl.MapAlbedo, texture)
 
 		rects[i] = &TextureModelPair{
@@ -235,20 +272,35 @@ func EnterRenderLoop(config *libconfig.Config, displayMetadata *edidtools.Displa
 				card.EvdiNode.RequestUpdate(card.Buffer)
 			}
 
+			worldPos := rl.Vector3{
+				X: 0,
+				Y: verticalSize / 2,
+				Z: 0,
+			}
+
+			if *config.DisplayConfig.UseCircularSpacing == true {
+				yawRad := float32(rl.Deg2rad * rect.CurrentAngle)
+
+				// WTF?
+				posX := float32(math.Sin(float64(yawRad))) * radius
+				posZ := -float32(math.Cos(float64(yawRad))) * radius
+
+				worldPos.X = posX
+				worldPos.Z = posZ + radius
+			} else {
+				worldPos.X = rect.CurrentDisplaySpacing
+			}
+
 			rl.DrawModelEx(
 				rect.Model,
-				rl.Vector3{
+				worldPos,
-					X: rect.CurrentDisplaySpacing,
-					Y: verticalSize / 2,
-					Z: 0,
-				},
 				// rotate around X to make it vertical
 				rl.Vector3{
-					X: 1,
+					X: 0,
 					Y: 0,
 					Z: 0,
 				},
-				90,
+				0,
 				rl.Vector3{
 					X: 1,
 					Y: 1,

unrealxr

@@ -1 +1,2 @@
+#!/usr/bin/env bash
 sudo UNREALXR_LOG_LEVEL="$UNREALXR_LOG_LEVEL" LD_LIBRARY_PATH="$LD_LIBRARY_PATH" UNREALXR_CONFIG_PATH="$UNREALXR_CONFIG_PATH" UNREALXR_DATA_PATH="$UNREALXR_DATA_PATH" WAYLAND_DISPLAY="$XDG_RUNTIME_DIR/$WAYLAND_DISPLAY" XDG_RUNTIME_DIR="/user/run/0" ./uxr