Imports System.Drawing
Imports System.Windows.Forms
Imports Pilz.Drawing.Drawing3D.OpenGLFactory.CameraN
Imports Pilz.Drawing.Drawing3D.OpenGLFactory.RenderingN
Imports OpenTK
Imports OpenTK.Graphics.OpenGL
Imports Pilz.S3DFileParser
Imports Point = System.Drawing.Point
Imports Color = System.Drawing.Color
Imports System.Windows.Forms.Integration
Imports OpenTK.Mathematics
Imports System.Windows.Input
Imports Key = OpenTK3.Input.Key
Imports OpenTK.Wpf

Namespace PreviewN

    Public Class ModelPreview

        Private WithEvents glControl1 As Wpf.GLWpfControl
        Private WithEvents glControlHost As ElementHost
        Private WithEvents MyCamera As New Camera
        Private ProjMatrix As Matrix4 = Nothing
        Private FOV As Single = 1.048F
        Private camMtx As Matrix4 = Matrix4.Identity
        Private savedCamPos As New Vector3
        Private _isMouseDown As Boolean = False
        Private isDeactivated As Boolean = False
        Private ReadOnly myModels As New Dictionary(Of Object3D, Renderer)
        Private WithEvents RenderTimer As New Timers.Timer(25) With {.AutoReset = True}
        Private _EnableCameraControlling As Boolean = False
        Private finishedLoading As Boolean = False

        Public Property Scaling As Single = 500.0F
        Public Property ClearColor As Color = Color.CornflowerBlue

        Public ReadOnly Property Keyboard As OpenTK3.Input.KeyboardState
            Get
                Return OpenTK3.Input.Keyboard.GetState
            End Get
        End Property

        Public Property EnableCameraControlling As Boolean
            Get
                Return _EnableCameraControlling
            End Get
            Set
                _EnableCameraControlling = Value
                If Value Then
                    If Not RenderTimer.Enabled Then
                        RenderTimer.Start()
                    End If
                ElseIf RenderTimer.Enabled Then
                    RenderTimer.Stop()
                End If
            End Set
        End Property

        Public Property RenderInterval As Double
            Get
                Return RenderTimer.Interval
            End Get
            Set
                RenderTimer.Interval = Value
            End Set
        End Property

        Public ReadOnly Property Camera As Camera
            Get
                Return MyCamera
            End Get
        End Property

        Public ReadOnly Property CameraMatrix As Matrix4
            Get
                Return camMtx
            End Get
        End Property

        Public ReadOnly Property Models As IReadOnlyDictionary(Of Object3D, Renderer)
            Get
                Return myModels
            End Get
        End Property

        Public ReadOnly Property GLControl As Control
            Get
                Return glControlHost
            End Get
        End Property

        Public ReadOnly Property GLControlClient As GLWpfControl
            Get
                Return glControl1
            End Get
        End Property

        Private ReadOnly Property IsStrgPressed As Boolean
            Get
                Dim state = Keyboard
                Return state.IsKeyDown(Key.ControlLeft) OrElse state.IsKeyDown(Key.ControlRight)
            End Get
        End Property

        Private ReadOnly Property IsShiftPressed As Boolean
            Get
                Dim state = Keyboard
                Return state.IsKeyDown(Key.ShiftLeft) OrElse state.IsKeyDown(Key.ShiftRight)
            End Get
        End Property

        Public Property IsMouseDown As Boolean
            Get
                Return _isMouseDown
            End Get
            Set(value As Boolean)
                _isMouseDown = value
                glControlHost.Refresh()
            End Set
        End Property

        Public Sub New()
            Me.New({}, 1.0F)
        End Sub

        Public Sub New(obj As Object3D)
            Me.New(obj, 1.0F)
        End Sub

        Public Sub New(obj As Object3D, scale As Single)
            Me.New({obj}, scale)
        End Sub

        Public Sub New(objs As Object3D(), scale As Single)
            SuspendLayout()

            InitializeComponent()

            'glControl1
            Dim glControl1 As New GLWpfControl
            Dim glControlHost = New ElementHost
            glControlHost.BackColor = Color.Black
            glControlHost.Name = "glControl1"
            glControlHost.Anchor = AnchorStyles.Left Or AnchorStyles.Top Or AnchorStyles.Right Or AnchorStyles.Bottom
            glControlHost.Location = New Point(0, 0)
            glControlHost.Size = Me.ClientSize
            glControlHost.MinimumSize = New Size(600, 120)
            glControlHost.TabIndex = 0
            glControlHost.TabStop = False

            Me.glControl1 = glControl1
            Me.glControlHost = glControlHost

            Dim controlSettings As New GLWpfControlSettings With
            {
                .RenderContinuously = False,
                .GraphicsProfile = Windowing.Common.ContextProfile.Compatability
            }
            glControl1.Start(controlSettings)

            glControlHost.Child = glControl1
            Controls.Add(glControlHost)

            Scaling = scale

            ProjMatrix = Matrix4.CreatePerspectiveFieldOfView(FOV, glControlHost.Width / glControlHost.Height, 100.0F, 100000.0F)

            ResumeLayout()

            MyCamera.SetCameraMode(CameraMode.FLY, camMtx)
            MyCamera.UpdateMatrix(camMtx)

            For Each obj As Object3D In objs
                AddModel(obj)
            Next

            finishedLoading = True
        End Sub

        Public Sub UpdateOrbitCamera()
            If Camera.IsOrbitCamera Then
                Camera.UpdateOrbitCamera(camMtx)
            End If
        End Sub

        Public Sub UpdateView()
            If glControlHost.Enabled AndAlso finishedLoading Then
                Invoke(Sub() InvalidateGL())
            End If
        End Sub

        Private Sub InvalidateGL()
            glControl1.InvalidateVisual()
            glControlHost.Invalidate()
        End Sub

        Public Function AddModel(obj As Object3D) As Renderer
            Dim rndr As New Renderer(obj)
            AddModel(rndr)
            Return rndr
        End Function

        Public Sub AddModel(rndr As Renderer)
            myModels.Add(rndr.Model, rndr)
        End Sub

        Public Sub HandlesOnShown(sender As Object, e As EventArgs) Handles MyBase.Shown
            RenderModels()
            InvalidateGL()
        End Sub

        Public Sub RenderModels()
            For Each rndr As Renderer In myModels.Values
                RenderModel(rndr)
            Next
        End Sub

        Public Sub RenderModel(rndr As Renderer)
            If myModels.Values.Contains(rndr) Then
                rndr.ModelScaling = Scaling
                rndr.RenderModel()
            End If
        End Sub

        Private Sub glControl1_Load() Handles glControl1.Ready
            GL.Enable(EnableCap.Blend)
            GL.BlendFunc(BlendingFactor.SrcAlpha, BlendingFactor.OneMinusSrcAlpha)

            GL.Enable(EnableCap.DepthTest)
            GL.DepthFunc(DepthFunction.Lequal)

            GL.Enable(EnableCap.Texture2D)
            GL.Enable(EnableCap.AlphaTest)
            GL.AlphaFunc(AlphaFunction.Gequal, 0.5F)

            GL.Enable(EnableCap.CullFace)
        End Sub

        Public Sub HandlesOnActivated(sender As Object, e As EventArgs) Handles Me.Activated
            If isDeactivated Then
                isDeactivated = False
            End If
        End Sub

        Public Sub HandlesOnDeactivate(sender As Object, e As EventArgs) Handles Me.Deactivate
            isDeactivated = True
        End Sub

        Private Sub RenderTimer_Elapsed(sender As Object, e As Timers.ElapsedEventArgs) Handles RenderTimer.Elapsed
            If Not isDeactivated Then
                MoveCameraViaWASDQE()
            End If
        End Sub

        Public Sub HandlesOnPaint(renderTime As TimeSpan) Handles glControl1.Render
            GL.ClearColor(ClearColor)
            GL.Clear(ClearBufferMask.ColorBufferBit Or ClearBufferMask.DepthBufferBit)
            GL.LoadIdentity()
            GL.MatrixMode(MatrixMode.Projection)
            GL.LoadMatrix(ProjMatrix)
            GL.MatrixMode(MatrixMode.Modelview)
            GL.LoadMatrix(camMtx)

            For Each rndr As Renderer In myModels.Values
                If rndr.HasRendered Then
                    rndr.DrawModel(RenderMode.FillOutline)
                End If
            Next

            GL.End()
            GL.Finish()

            'glControl1.SwapBuffers()
        End Sub

        Private Sub glControl1_Resize(sender As Object, e As EventArgs) Handles glControlHost.Resize
            'glControl1.Context.Update(glControl1.WindowInfo)
            GL.Viewport(0, 0, glControlHost.Width, glControlHost.Height)
            ProjMatrix = Matrix4.CreatePerspectiveFieldOfView(FOV, glControlHost.Width / glControlHost.Height, 100.0F, 100000.0F)
            InvalidateGL()
        End Sub

        Private Sub glControl1_Wheel(sender As Object, e As Windows.Input.MouseWheelEventArgs) Handles glControl1.MouseWheel
            MyCamera.ResetMouseStuff()
            MyCamera.UpdateCameraMatrixWithScrollWheel(CInt(Math.Truncate(e.Delta * (If(IsShiftPressed, 3.5F, 1.5F)))), camMtx)
            savedCamPos = MyCamera.Position
            InvalidateGL()
        End Sub

        Private Sub glControl1_MouseDown(ByVal sender As Object, ByVal e As Windows.Input.MouseButtonEventArgs) Handles glControl1.MouseDown
            IsMouseDown = True
            savedCamPos = MyCamera.Position
        End Sub

        Private Sub glControl1_MouseLeave(ByVal sender As Object, ByVal e As EventArgs) Handles glControl1.MouseLeave, glControl1.MouseUp
            MyCamera.ResetMouseStuff()
            IsMouseDown = False
        End Sub

        Private Sub glControl1_MouseMove(ByVal sender As Object, ByVal e As Windows.Input.MouseEventArgs) Handles glControl1.MouseMove
            If e.LeftButton = MouseButtonState.Pressed Then
                Dim pos = e.GetPosition(glControl1)
                If IsShiftPressed Then
                    MyCamera.UpdateCameraOffsetWithMouse(savedCamPos, pos.X, pos.Y, glControl1.Width, glControl1.Height, camMtx)
                Else
                    MyCamera.UpdateCameraMatrixWithMouse(pos.X, pos.Y, camMtx)
                End If
                InvalidateGL()
            End If
        End Sub

        Public Sub MoveCameraViaWASDQE()
            Dim moveSpeed As Integer = Convert.ToInt32(Math.Round((If(IsShiftPressed, 60, 30)) * (MyCamera.CamSpeedMultiplier), 0))
            Dim allowCamMove As Boolean = Not (IsMouseDown AndAlso IsShiftPressed)
            Dim state = Keyboard

            If allowCamMove Then
                If state.IsKeyDown(Key.W) Then
                    'camera.Move(moveSpeed, moveSpeed, camMtx)
                    MyCamera.UpdateCameraMatrixWithScrollWheel(moveSpeed, camMtx)
                    savedCamPos = MyCamera.Position
                End If
                If state.IsKeyDown(Key.S) Then
                    'camera.Move(-moveSpeed, -moveSpeed, camMtx)
                    MyCamera.UpdateCameraMatrixWithScrollWheel(-moveSpeed, camMtx)
                    savedCamPos = MyCamera.Position
                End If
                If state.IsKeyDown(Key.A) Then
                    'camera.Move(-moveSpeed, 0, camMtx)
                    MyCamera.UpdateCameraOffsetDirectly(-moveSpeed, 0, camMtx)
                End If
                If state.IsKeyDown(Key.D) Then
                    'camera.Move(moveSpeed, 0, camMtx)
                    MyCamera.UpdateCameraOffsetDirectly(moveSpeed, 0, camMtx)
                End If
                If state.IsKeyDown(Key.E) Then
                    'camera.Move(0, -moveSpeed, camMtx)
                    MyCamera.UpdateCameraOffsetDirectly(0, -moveSpeed, camMtx)
                End If
                If state.IsKeyDown(Key.Q) Then
                    'camera.Move(0, moveSpeed, camMtx)
                    MyCamera.UpdateCameraOffsetDirectly(0, moveSpeed, camMtx)
                End If
            End If
        End Sub

        Private Sub Camera_NeedSelectedObject(sender As Object, e As Camera.NeedSelectedObjectEventArgs) Handles MyCamera.NeedSelectedObject
            e.Points = Nothing
        End Sub

        Private Sub MyCamera_PerspectiveChanged(sender As Object, e As EventArgs) Handles MyCamera.PerspectiveChanged
            UpdateView()
        End Sub

        Private Sub ModelPreview_FormDisposed(sender As Object, e As EventArgs) Handles Me.Disposed
            For Each rndr As Renderer In myModels.Values
                rndr.ReleaseBuffers()
            Next
        End Sub

    End Class

End Namespace