qol

NResUI/ImGuiUI/ViewportPanel.cs

@@ -33,7 +33,8 @@ public sealed class ViewportPanel : IImGuiPanel
         }
 
         DrawSelectionStatus();
-        DrawGridToggle();
+        DrawViewportToolbar();
+        DrawDebugControls();
 
         var imageSize = ImGui.GetContentRegionAvail();
         if (imageSize.X < 32 || imageSize.Y < 32)
@@ -56,6 +57,7 @@ public sealed class ViewportPanel : IImGuiPanel
             new Vector2(1, 0));
 
         var viewportHovered = ImGui.IsItemHovered();
+        var viewportFocused = ImGui.IsWindowFocused(ImGuiFocusedFlags.RootAndChildWindows);
         var imageMin = ImGui.GetItemRectMin();
 
         DrawViewportHelpOverlay();
@@ -64,6 +66,7 @@ public sealed class ViewportPanel : IImGuiPanel
             _scene,
             _camera,
             viewportHovered,
+            viewportFocused,
             imageMin,
             imageSize);
 
@@ -79,17 +82,71 @@ public sealed class ViewportPanel : IImGuiPanel
             ImGui.TextDisabled("Selected: none");
     }
 
-    private void DrawGridToggle()
+    private void DrawViewportToolbar()
+    {
+        if (ImGui.Button("Reset view"))
+            _camera.Reset();
+
+        ImGui.SameLine();
+
+        if (ImGui.Button("Frame selected"))
+        {
+            if (_scene.TryGetSelectedPieceWorldBounds(out var selectedBounds))
+                _camera.FrameBounds(selectedBounds.Min, selectedBounds.Max);
+        }
+
+        ImGui.SameLine();
+
+        if (ImGui.Button("Frame all"))
+        {
+            if (_scene.TryGetSceneWorldBounds(out var sceneBounds))
+                _camera.FrameBounds(sceneBounds.Min, sceneBounds.Max);
+            else
+                _camera.Reset();
+        }
+    }
+
+    private void DrawDebugControls()
     {
         var grid = _scene.Grid;
-        if (grid == null)
-            return;
-
+        if (grid != null)
+        {
             var isVisible = grid.IsVisible;
-        if (ImGui.Checkbox("Show grid", ref isVisible))
+            if (ImGui.Checkbox("Grid", ref isVisible))
                 grid.IsVisible = isVisible;
         }
 
+        ImGui.SameLine();
+
+        var showOriginAxes = _scene.Debug.ShowOriginAxes;
+        if (ImGui.Checkbox("Origin axes", ref showOriginAxes))
+            _scene.Debug.ShowOriginAxes = showOriginAxes;
+
+        ImGui.SameLine();
+
+        var showPieceOrigins = _scene.Debug.ShowPieceOrigins;
+        if (ImGui.Checkbox("Piece axes", ref showPieceOrigins))
+            _scene.Debug.ShowPieceOrigins = showPieceOrigins;
+
+        ImGui.SameLine();
+
+        var showSelectedBounds = _scene.Debug.ShowSelectedBounds;
+        if (ImGui.Checkbox("Selected bounds", ref showSelectedBounds))
+            _scene.Debug.ShowSelectedBounds = showSelectedBounds;
+
+        ImGui.SameLine();
+
+        var showSceneBounds = _scene.Debug.ShowSceneBounds;
+        if (ImGui.Checkbox("Scene bounds", ref showSceneBounds))
+            _scene.Debug.ShowSceneBounds = showSceneBounds;
+
+        ImGui.SameLine();
+
+        var wireframe = _scene.Debug.Wireframe;
+        if (ImGui.Checkbox("Wireframe", ref wireframe))
+            _scene.Debug.Wireframe = wireframe;
+    }
+
     private static void DrawViewportHelpOverlay()
     {
         var drawList = ImGui.GetWindowDrawList();
@@ -97,7 +154,12 @@ public sealed class ViewportPanel : IImGuiPanel
         var imageMin = ImGui.GetItemRectMin();
         var imageMax = ImGui.GetItemRectMax();
 
-        const string helpText = "LMB click: select / deselect\nMMB drag: rotate\nMouse wheel: zoom";
+        const string helpText =
+            "LMB click: select / deselect\n" +
+            "MMB drag: rotate\n" +
+            "RMB drag or Alt+MMB: pan\n" +
+            "Mouse wheel: zoom\n" +
+            "F: frame selected   Home: frame all";
 
         var textSize = ImGui.CalcTextSize(helpText);
         var padding = new Vector2(8.0f, 6.0f);

NResUI/Rendering/Viewport/Meshes/GpuMesh.cs

@@ -28,7 +28,7 @@ public sealed class GpuMesh
         PrimitiveType = primitiveType;
     }
 
-    public void Draw()
+    public unsafe void Draw()
     {
         _gl.BindVertexArray(VertexArrayObject);
         _gl.DrawElements(PrimitiveType, IndexCount, DrawElementsType.UnsignedInt, null);

NResUI/Rendering/Viewport/Meshes/PrimitiveMeshes.cs

@@ -132,6 +132,59 @@ public static unsafe class PrimitiveMeshes
         return CreateIndexedMesh(gl, vertices.ToArray(), indices.ToArray(), PrimitiveType.Lines);
     }
 
+
+
+    public static GpuMesh CreateUnitWireBox(GL gl)
+    {
+        float[] vertices =
+        {
+            -1, -1, -1,  1.0f, 0.82f, 0.15f,
+             1, -1, -1,  1.0f, 0.82f, 0.15f,
+             1,  1, -1,  1.0f, 0.82f, 0.15f,
+            -1,  1, -1,  1.0f, 0.82f, 0.15f,
+            -1, -1,  1,  1.0f, 0.82f, 0.15f,
+             1, -1,  1,  1.0f, 0.82f, 0.15f,
+             1,  1,  1,  1.0f, 0.82f, 0.15f,
+            -1,  1,  1,  1.0f, 0.82f, 0.15f,
+        };
+
+        uint[] indices =
+        {
+            0, 1, 1, 2, 2, 3, 3, 0,
+            4, 5, 5, 6, 6, 7, 7, 4,
+            0, 4, 1, 5, 2, 6, 3, 7,
+        };
+
+        return CreateIndexedMesh(gl, vertices, indices, PrimitiveType.Lines);
+    }
+
+    public static GpuMesh CreateAxes(GL gl, float length = 1.0f)
+    {
+        if (length <= 0.0f)
+            throw new ArgumentOutOfRangeException(nameof(length));
+
+        float[] vertices =
+        {
+            0, 0, 0,       1.0f, 0.25f, 0.25f,
+            length, 0, 0,  1.0f, 0.25f, 0.25f,
+
+            0, 0, 0,       0.25f, 1.0f, 0.25f,
+            0, length, 0,  0.25f, 1.0f, 0.25f,
+
+            0, 0, 0,       0.25f, 0.45f, 1.0f,
+            0, 0, length,  0.25f, 0.45f, 1.0f,
+        };
+
+        uint[] indices =
+        {
+            0, 1,
+            2, 3,
+            4, 5,
+        };
+
+        return CreateIndexedMesh(gl, vertices, indices, PrimitiveType.Lines);
+    }
+
     private static GpuMesh CreateIndexedMesh(
         GL gl,
         float[] vertices,

NResUI/Rendering/Viewport/OpenGL/MsaaFramebuffer.cs

@@ -25,7 +25,7 @@ public sealed class MsaaFramebuffer
         _samples = samples;
     }
 
-    public void EnsureSize(int width, int height)
+    public unsafe void EnsureSize(int width, int height)
     {
         width = Math.Max(1, width);
         height = Math.Max(1, height);

NResUI/Rendering/Viewport/ViewportBounds.cs

@@ -0,0 +1,18 @@
+using System.Numerics;
+
+namespace NResUI.Rendering.Viewport;
+
+public readonly struct ViewportBounds
+{
+    public Vector3 Min { get; }
+    public Vector3 Max { get; }
+
+    public ViewportBounds(Vector3 min, Vector3 max)
+    {
+        Min = min;
+        Max = max;
+    }
+
+    public Vector3 Center => (Min + Max) * 0.5f;
+    public Vector3 Size => Max - Min;
+}

NResUI/Rendering/Viewport/ViewportCamera.cs

@@ -4,31 +4,104 @@ namespace NResUI.Rendering.Viewport;
 
 public sealed class ViewportCamera
 {
+    public const float FieldOfViewDegrees = 60.0f;
+
     public float YawDegrees { get; set; } = 35.0f;
     public float PitchDegrees { get; set; } = 25.0f;
     public float Distance { get; set; } = 4.0f;
+    public Vector3 Target { get; set; } = Vector3.Zero;
 
     public Matrix4x4 GetSceneRotationMatrix()
     {
-        return Matrix4x4.CreateRotationY(ToRadians(YawDegrees)) *
-               Matrix4x4.CreateRotationX(ToRadians(PitchDegrees));
+        // Kept as an explicit hook for future scene-wide transforms.
+        // Camera orbit is handled by GetViewMatrix().
+        return Matrix4x4.Identity;
     }
 
     public Matrix4x4 GetViewMatrix()
     {
-        return Matrix4x4.CreateLookAt(
-            new Vector3(0.0f, 0.0f, Distance),
-            Vector3.Zero,
-            Vector3.UnitY);
+        return Matrix4x4.CreateLookAt(GetEyePosition(), Target, Vector3.UnitY);
     }
 
     public Matrix4x4 GetProjectionMatrix(float aspectRatio)
     {
         return Matrix4x4.CreatePerspectiveFieldOfView(
-            ToRadians(60.0f),
+            ToRadians(FieldOfViewDegrees),
             aspectRatio,
             0.01f,
-            100.0f);
+            1000.0f);
+    }
+
+    public Vector3 GetEyePosition()
+    {
+        return Target + GetOrbitDirection() * Distance;
+    }
+
+    public Vector3 GetForwardDirection()
+    {
+        return Vector3.Normalize(Target - GetEyePosition());
+    }
+
+    public Vector3 GetRightDirection()
+    {
+        var forward = GetForwardDirection();
+        var right = Vector3.Cross(forward, Vector3.UnitY);
+
+        if (right.LengthSquared() < 1e-8f)
+            return Vector3.UnitX;
+
+        return Vector3.Normalize(right);
+    }
+
+    public Vector3 GetUpDirection()
+    {
+        var right = GetRightDirection();
+        var forward = GetForwardDirection();
+        return Vector3.Normalize(Vector3.Cross(right, forward));
+    }
+
+    public void Pan(Vector2 mouseDelta, Vector2 viewportSize)
+    {
+        if (viewportSize.Y <= 1.0f)
+            return;
+
+        var worldUnitsPerPixel = 2.0f * Distance * MathF.Tan(ToRadians(FieldOfViewDegrees) * 0.5f) / viewportSize.Y;
+        var right = GetRightDirection();
+        var up = GetUpDirection();
+
+        Target -= right * (mouseDelta.X * worldUnitsPerPixel);
+        Target += up * (mouseDelta.Y * worldUnitsPerPixel);
+    }
+
+    public void Reset()
+    {
+        YawDegrees = 35.0f;
+        PitchDegrees = 25.0f;
+        Distance = 4.0f;
+        Target = Vector3.Zero;
+    }
+
+    public void FrameBounds(Vector3 boundsMin, Vector3 boundsMax)
+    {
+        var center = (boundsMin + boundsMax) * 0.5f;
+        var extents = (boundsMax - boundsMin) * 0.5f;
+        var radius = MathF.Max(extents.Length(), 0.25f);
+
+        Target = center;
+        Distance = Math.Clamp(radius * 2.8f, 1.5f, 200.0f);
+    }
+
+    private Vector3 GetOrbitDirection()
+    {
+        var yaw = ToRadians(YawDegrees);
+        var pitch = ToRadians(PitchDegrees);
+
+        var cosPitch = MathF.Cos(pitch);
+
+        return Vector3.Normalize(new Vector3(
+            MathF.Sin(yaw) * cosPitch,
+            MathF.Sin(pitch),
+            MathF.Cos(yaw) * cosPitch));
     }
 
     public static float ToRadians(float degrees)

NResUI/Rendering/Viewport/ViewportDebugSettings.cs

@@ -0,0 +1,10 @@
+namespace NResUI.Rendering.Viewport;
+
+public sealed class ViewportDebugSettings
+{
+    public bool ShowOriginAxes { get; set; } = true;
+    public bool ShowPieceOrigins { get; set; } = true;
+    public bool ShowSelectedBounds { get; set; } = true;
+    public bool ShowSceneBounds { get; set; }
+    public bool Wireframe { get; set; }
+}

NResUI/Rendering/Viewport/ViewportInputController.cs

@@ -9,33 +9,49 @@ public sealed class ViewportInputController
     private const float MouseZoomSpeed = 0.35f;
 
     private bool _isRotatingViewport;
+    private bool _isPanningViewport;
 
     public void Handle(
         ViewportScene scene,
         ViewportCamera camera,
         bool viewportHovered,
+        bool viewportFocused,
         Vector2 imageMin,
         Vector2 imageSize)
     {
         var io = ImGui.GetIO();
 
-        if (viewportHovered && ImGui.IsMouseClicked(ImGuiMouseButton.Middle))
+        var wantsPanWithMiddle = io.KeyAlt && ImGui.IsMouseClicked(ImGuiMouseButton.Middle);
+        var wantsPanWithRight = ImGui.IsMouseClicked(ImGuiMouseButton.Right);
+
+        if (viewportHovered && wantsPanWithMiddle)
+            _isPanningViewport = true;
+        else if (viewportHovered && ImGui.IsMouseClicked(ImGuiMouseButton.Middle))
             _isRotatingViewport = true;
 
+        if (viewportHovered && wantsPanWithRight)
+            _isPanningViewport = true;
+
         if (!ImGui.IsMouseDown(ImGuiMouseButton.Middle))
             _isRotatingViewport = false;
 
+        if (!ImGui.IsMouseDown(ImGuiMouseButton.Right) && !(io.KeyAlt && ImGui.IsMouseDown(ImGuiMouseButton.Middle)))
+            _isPanningViewport = false;
+
         if (_isRotatingViewport)
         {
-            camera.YawDegrees += io.MouseDelta.X * MouseRotationSpeed;
+            camera.YawDegrees += -io.MouseDelta.X * MouseRotationSpeed;
             camera.PitchDegrees += io.MouseDelta.Y * MouseRotationSpeed;
             camera.PitchDegrees = Math.Clamp(camera.PitchDegrees, -89.0f, 89.0f);
         }
 
+        if (_isPanningViewport)
+            camera.Pan(io.MouseDelta, imageSize);
+
         if (viewportHovered && Math.Abs(io.MouseWheel) > float.Epsilon)
         {
-            camera.Distance -= io.MouseWheel * MouseZoomSpeed;
-            camera.Distance = Math.Clamp(camera.Distance, 1.5f, 40.0f);
+            camera.Distance -= io.MouseWheel * MouseZoomSpeed * MathF.Max(1.0f, camera.Distance * 0.15f);
+            camera.Distance = Math.Clamp(camera.Distance, 0.25f, 400.0f);
         }
 
         if (viewportHovered && ImGui.IsMouseClicked(ImGuiMouseButton.Left))
@@ -49,5 +65,27 @@ public sealed class ViewportInputController
                 localMouse,
                 imageSize);
         }
+
+        if (viewportFocused || viewportHovered)
+            HandleKeyboardShortcuts(scene, camera);
+    }
+
+    private static void HandleKeyboardShortcuts(ViewportScene scene, ViewportCamera camera)
+    {
+        if (ImGui.IsKeyPressed(ImGuiKey.F))
+        {
+            if (scene.TryGetSelectedPieceWorldBounds(out var selectedBounds))
+                camera.FrameBounds(selectedBounds.Min, selectedBounds.Max);
+            else if (scene.TryGetSceneWorldBounds(out var sceneBounds))
+                camera.FrameBounds(sceneBounds.Min, sceneBounds.Max);
+        }
+
+        if (ImGui.IsKeyPressed(ImGuiKey.Home))
+        {
+            if (scene.TryGetSceneWorldBounds(out var sceneBounds))
+                camera.FrameBounds(sceneBounds.Min, sceneBounds.Max);
+            else
+                camera.Reset();
+        }
     }
 }

NResUI/Rendering/Viewport/ViewportRenderer.cs

@@ -1,4 +1,5 @@
 using System.Numerics;
+using NResUI.Rendering.Viewport.Meshes;
 using NResUI.Rendering.Viewport.OpenGL;
 using Silk.NET.OpenGL;
 using Silk.NET.Windowing;
@@ -14,6 +15,9 @@ public sealed class ViewportRenderer
     private ShaderProgram? _meshShader;
     private ShaderProgram? _outlineShader;
 
+    private GpuMesh? _unitWireBoxMesh;
+    private GpuMesh? _axesMesh;
+
     private int _meshMvpLocation;
     private int _outlineMvpLocation;
     private int _outlineColorLocation;
@@ -55,7 +59,9 @@ public sealed class ViewportRenderer
 
         DrawGrid(scene, sceneRotation, view, projection);
         DrawScene(scene, sceneRotation, view, projection);
+        DrawDebugOverlays(scene, sceneRotation, view, projection);
 
+        _gl.PolygonMode(TriangleFace.FrontAndBack, PolygonMode.Fill);
         _framebuffer.Resolve();
 
         _gl.Disable(EnableCap.CullFace);
@@ -71,7 +77,6 @@ public sealed class ViewportRenderer
         return _framebuffer.ColorTexture;
     }
 
-
     private void DrawGrid(
         ViewportScene scene,
         Matrix4x4 sceneRotation,
@@ -90,6 +95,7 @@ public sealed class ViewportRenderer
 
         _gl.Disable(EnableCap.StencilTest);
         _gl.Disable(EnableCap.CullFace);
+        _gl.PolygonMode(TriangleFace.FrontAndBack, PolygonMode.Fill);
 
         _meshShader.Use();
         _meshShader.SetMatrix4(_meshMvpLocation, mvp);
@@ -109,6 +115,9 @@ public sealed class ViewportRenderer
 
         _gl.Disable(EnableCap.StencilTest);
         _meshShader.Use();
+        _gl.PolygonMode(
+            TriangleFace.FrontAndBack,
+            scene.Debug.Wireframe ? PolygonMode.Line : PolygonMode.Fill);
 
         foreach (var piece in scene.Pieces)
         {
@@ -120,7 +129,10 @@ public sealed class ViewportRenderer
 
         var selectedPiece = scene.SelectedPiece;
         if (selectedPiece == null)
+        {
+            _gl.PolygonMode(TriangleFace.FrontAndBack, PolygonMode.Fill);
             return;
+        }
 
         _gl.Enable(EnableCap.StencilTest);
         _gl.StencilMask(0xFF);
@@ -130,6 +142,7 @@ public sealed class ViewportRenderer
         _meshShader.Use();
         DrawPiece(selectedPiece, sceneRotation, view, projection);
 
+        _gl.PolygonMode(TriangleFace.FrontAndBack, PolygonMode.Fill);
         _gl.StencilFunc(StencilFunction.Notequal, 1, 0xFF);
         _gl.StencilMask(0x00);
         _gl.Disable(EnableCap.DepthTest);
@@ -141,21 +154,64 @@ public sealed class ViewportRenderer
         _gl.Disable(EnableCap.StencilTest);
     }
 
+    private void DrawDebugOverlays(
+        ViewportScene scene,
+        Matrix4x4 sceneRotation,
+        Matrix4x4 view,
+        Matrix4x4 projection)
+    {
+        if (_meshShader == null || _unitWireBoxMesh == null || _axesMesh == null)
+            throw new InvalidOperationException("Viewport debug resources are not initialized.");
+
+        _gl.Disable(EnableCap.StencilTest);
+        _gl.Disable(EnableCap.CullFace);
+        _gl.Disable(EnableCap.DepthTest);
+        _gl.PolygonMode(TriangleFace.FrontAndBack, PolygonMode.Fill);
+        _gl.LineWidth(2.0f);
+
+        _meshShader.Use();
+
+        if (scene.Debug.ShowOriginAxes)
+            DrawMesh(_axesMesh, Matrix4x4.CreateScale(1.25f) * sceneRotation, view, projection);
+
+        if (scene.Debug.ShowPieceOrigins)
+        {
+            foreach (var piece in scene.Pieces)
+            {
+                var axesModel = Matrix4x4.CreateScale(0.45f) * piece.LocalTransform * sceneRotation;
+                DrawMesh(_axesMesh, axesModel, view, projection);
+            }
+        }
+
+        if (scene.Debug.ShowSelectedBounds && scene.SelectedPiece != null)
+        {
+            var selectedPiece = scene.SelectedPiece;
+            var boundsModel = BuildLocalBoundsModel(selectedPiece.BoundsMin, selectedPiece.BoundsMax) *
+                              selectedPiece.LocalTransform *
+                              sceneRotation;
+
+            DrawMesh(_unitWireBoxMesh, boundsModel, view, projection);
+        }
+
+        if (scene.Debug.ShowSceneBounds && scene.TryGetSceneWorldBounds(out var sceneBounds))
+        {
+            var sceneBoundsModel = BuildLocalBoundsModel(sceneBounds.Min, sceneBounds.Max) * sceneRotation;
+            DrawMesh(_unitWireBoxMesh, sceneBoundsModel, view, projection);
+        }
+
+        _gl.LineWidth(1.0f);
+        _gl.Enable(EnableCap.DepthTest);
+        _gl.Enable(EnableCap.CullFace);
+    }
+
     private void DrawPiece(
         ViewportPiece piece,
         Matrix4x4 sceneRotation,
         Matrix4x4 view,
         Matrix4x4 projection)
     {
-        if (_meshShader == null)
-            throw new InvalidOperationException("Viewport mesh shader is not initialized.");
-
         var model = piece.LocalTransform * sceneRotation;
-        var mvp = model * view * projection;
-
-        _meshShader.Use();
-        _meshShader.SetMatrix4(_meshMvpLocation, mvp);
-        piece.Mesh.Draw();
+        DrawMesh(piece.Mesh, model, view, projection);
     }
 
     private void DrawPieceOutline(
@@ -179,12 +235,38 @@ public sealed class ViewportRenderer
         piece.Mesh.Draw();
     }
 
+    private void DrawMesh(
+        GpuMesh mesh,
+        Matrix4x4 model,
+        Matrix4x4 view,
+        Matrix4x4 projection)
+    {
+        if (_meshShader == null)
+            throw new InvalidOperationException("Viewport mesh shader is not initialized.");
+
+        var mvp = model * view * projection;
+
+        _meshShader.Use();
+        _meshShader.SetMatrix4(_meshMvpLocation, mvp);
+        mesh.Draw();
+    }
+
+    private static Matrix4x4 BuildLocalBoundsModel(Vector3 boundsMin, Vector3 boundsMax)
+    {
+        var center = (boundsMin + boundsMax) * 0.5f;
+        var size = boundsMax - boundsMin;
+
+        return Matrix4x4.CreateScale(size * 0.5f) * Matrix4x4.CreateTranslation(center);
+    }
+
     private void EnsureInitialized()
     {
         if (_initialized)
             return;
 
         CreateShaders();
+        _unitWireBoxMesh = PrimitiveMeshes.CreateUnitWireBox(_gl);
+        _axesMesh = PrimitiveMeshes.CreateAxes(_gl);
         _initialized = true;
     }
 

NResUI/Rendering/Viewport/ViewportScene.cs

@@ -1,3 +1,4 @@
+using System.Numerics;
 using NResUI.Rendering.Viewport.Meshes;
 
 namespace NResUI.Rendering.Viewport;
@@ -10,6 +11,8 @@ public sealed class ViewportScene
 
     public ViewportGrid? Grid { get; set; }
 
+    public ViewportDebugSettings Debug { get; } = new();
+
     public int SelectedPieceId { get; set; } = -1;
 
     public ViewportPiece? SelectedPiece
@@ -39,6 +42,43 @@ public sealed class ViewportScene
         SelectedPieceId = -1;
     }
 
+    public bool TryGetPieceWorldBounds(ViewportPiece piece, out ViewportBounds bounds)
+    {
+        return TryTransformBounds(piece.BoundsMin, piece.BoundsMax, piece.LocalTransform, out bounds);
+    }
+
+    public bool TryGetSelectedPieceWorldBounds(out ViewportBounds bounds)
+    {
+        var selectedPiece = SelectedPiece;
+        if (selectedPiece == null)
+        {
+            bounds = default;
+            return false;
+        }
+
+        return TryGetPieceWorldBounds(selectedPiece, out bounds);
+    }
+
+    public bool TryGetSceneWorldBounds(out ViewportBounds bounds)
+    {
+        var hasBounds = false;
+        var min = new Vector3(float.PositiveInfinity, float.PositiveInfinity, float.PositiveInfinity);
+        var max = new Vector3(float.NegativeInfinity, float.NegativeInfinity, float.NegativeInfinity);
+
+        foreach (var piece in _pieces)
+        {
+            if (!TryGetPieceWorldBounds(piece, out var pieceBounds))
+                continue;
+
+            min = Vector3.Min(min, pieceBounds.Min);
+            max = Vector3.Max(max, pieceBounds.Max);
+            hasBounds = true;
+        }
+
+        bounds = hasBounds ? new ViewportBounds(min, max) : default;
+        return hasBounds;
+    }
+
     public static ViewportScene CreateDefaultCubeScene(GpuMesh cubeMesh, GpuMesh gridMesh)
     {
         var scene = new ViewportScene
@@ -50,4 +90,36 @@ public sealed class ViewportScene
 
         return scene;
     }
+
+    private static bool TryTransformBounds(
+        Vector3 localMin,
+        Vector3 localMax,
+        Matrix4x4 transform,
+        out ViewportBounds bounds)
+    {
+        var corners = new[]
+        {
+            new Vector3(localMin.X, localMin.Y, localMin.Z),
+            new Vector3(localMax.X, localMin.Y, localMin.Z),
+            new Vector3(localMin.X, localMax.Y, localMin.Z),
+            new Vector3(localMax.X, localMax.Y, localMin.Z),
+            new Vector3(localMin.X, localMin.Y, localMax.Z),
+            new Vector3(localMax.X, localMin.Y, localMax.Z),
+            new Vector3(localMin.X, localMax.Y, localMax.Z),
+            new Vector3(localMax.X, localMax.Y, localMax.Z),
+        };
+
+        var min = new Vector3(float.PositiveInfinity, float.PositiveInfinity, float.PositiveInfinity);
+        var max = new Vector3(float.NegativeInfinity, float.NegativeInfinity, float.NegativeInfinity);
+
+        foreach (var corner in corners)
+        {
+            var world = Vector3.Transform(corner, transform);
+            min = Vector3.Min(min, world);
+            max = Vector3.Max(max, world);
+        }
+
+        bounds = new ViewportBounds(min, max);
+        return true;
+    }
 }

NResUI/Rendering/Viewport/ViewportSelection.cs

@@ -14,28 +14,24 @@ public static class ViewportSelection
             return -1;
 
         var aspect = viewportSize.X / viewportSize.Y;
-        var fovRadians = ViewportCamera.ToRadians(60.0f);
+        var fovRadians = ViewportCamera.ToRadians(ViewportCamera.FieldOfViewDegrees);
         var tanHalfFov = MathF.Tan(fovRadians * 0.5f);
 
         var ndcX = (2.0f * localMouse.X / viewportSize.X) - 1.0f;
         var ndcY = 1.0f - (2.0f * localMouse.Y / viewportSize.Y);
 
-        var rayOriginWorld = new Vector3(0.0f, 0.0f, camera.Distance);
-        var rayDirectionWorld = Vector3.Normalize(new Vector3(
-            ndcX * aspect * tanHalfFov,
-            ndcY * tanHalfFov,
-            -1.0f));
-
-        var sceneRotation = camera.GetSceneRotationMatrix();
+        var rayOriginWorld = camera.GetEyePosition();
+        var rayDirectionWorld = Vector3.Normalize(
+            camera.GetForwardDirection() +
+            camera.GetRightDirection() * (ndcX * aspect * tanHalfFov) +
+            camera.GetUpDirection() * (ndcY * tanHalfFov));
 
         var bestPieceId = -1;
         var bestDistance = float.PositiveInfinity;
 
         foreach (var piece in scene.Pieces)
         {
-            var model = piece.LocalTransform * sceneRotation;
-
-            if (!Matrix4x4.Invert(model, out var inverseModel))
+            if (!Matrix4x4.Invert(piece.LocalTransform, out var inverseModel))
                 continue;
 
             var rayOriginLocal = Vector3.Transform(rayOriginWorld, inverseModel);