.NET 3D Examples - Printable Version

Code

Imports System.Drawing.Graphics

Imports System.Drawing.Color

Imports System.Drawing.Brush

Imports System.Drawing.Point



Public Class Main

    Protected m_timer As Timer

    Protected m_vertices(8) As Point3D

    Protected m_faces(6, 4) As Integer

    Protected m_colors(6) As Color

    Protected m_brushes(6) As Brush

    Protected m_angle As Integer



    Private Sub Main_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

      ' Enable double-buffering to eliminate flickering.

      Me.SetStyle(ControlStyles.AllPaintingInWmPaint, True)

      Me.SetStyle(ControlStyles.OptimizedDoubleBuffer, True)



      InitCube()



      ' Create the timer.

      m_timer = New Timer()



      ' Set the timer interval to 25 milliseconds. This will give us 1000/25 ~ 40 frames per second.

      m_timer.Interval = 25



      ' Set the callback for the timer.

      AddHandler m_timer.Tick, AddressOf AnimationLoop



      ' Start the timer.

      m_timer.Start()

    End Sub



    Private Sub InitCube()

      ' Create the cube vertices.

      m_vertices = New Point3D() {

             New Point3D(-1, 1, -1),

             New Point3D(1, 1, -1),

             New Point3D(1, -1, -1),

             New Point3D(-1, -1, -1),

             New Point3D(-1, 1, 1),

             New Point3D(1, 1, 1),

             New Point3D(1, -1, 1),

             New Point3D(-1, -1, 1)}



      ' Create an array representing the 6 faces of a cube. Each face is composed by indices to the vertex array

      ' above.

      m_faces = New Integer(,) {{0, 1, 2, 3}, {1, 5, 6, 2}, {5, 4, 7, 6}, {4, 0, 3, 7}, {0, 4, 5, 1}, {3, 2, 6, 7}}



      ' Define the colors of each face.

      m_colors = New Color() {Color.BlueViolet, Color.Cyan, Color.Green, Color.Yellow, Color.Violet, Color.LightSkyBlue}



      ' Create the brushes to draw each face. Brushes are used to draw filled polygons.

      For i = 0 To 5

      m_brushes(i) = New SolidBrush(m_colors(i))

      Next

    End Sub



    Private Sub AnimationLoop()

      ' Forces the Paint event to be called.

      Me.Invalidate()



      ' Update the variable after each frame.

      m_angle += 1

    End Sub



    Private Sub Main_Paint(ByVal sender As Object, ByVal e As System.Windows.Forms.PaintEventArgs) Handles Me.Paint

      Dim t(8) As Point3D

      Dim f(4) As Integer

      Dim v As Point3D

      Dim avgZ(6) As Double

      Dim order(6) As Integer

      Dim tmp As Double

      Dim iMax As Integer



      ' Clear the window

      e.Graphics.Clear(Color.LightBlue)



      ' Transform all the points and store them on the "t" array.

      For i = 0 To 7

      Dim b As Brush = New SolidBrush(Color.White)

      v = m_vertices(i)

      t(i) = v.RotateX(m_angle).RotateY(m_angle).RotateZ(Me.m_angle)

      t(i) = t(i).Project(Me.ClientSize.Width, Me.ClientSize.Height, 256, 4)

      Next



      ' Compute the average Z value of each face.

      For i = 0 To 5

      avgZ(i) = (t(m_faces(i, 0)).Z + t(m_faces(i, 1)).Z + t(m_faces(i, 2)).Z + t(m_faces(i, 3)).Z) / 4.0

      order(i) = i

      Next



      ' Next we sort the faces in descending order based on the Z value.

      ' The objective is to draw distant faces first. This is called 

      ' the PAINTERS ALGORITHM. So, the visible faces will hide the invisible ones.

      ' The sorting algorithm used is the SELECTION SORT.

      For i = 0 To 4

      iMax = i

      For j = i + 1 To 5

            If avgZ(j) > avgZ(iMax) Then

            iMax = j

            End If

      Next

      If iMax <> i Then

            tmp = avgZ(i)

            avgZ(i) = avgZ(iMax)

            avgZ(iMax) = tmp



            tmp = order(i)

            order(i) = order(iMax)

            order(iMax) = tmp

      End If

      Next



      ' Draw the faces using the PAINTERS ALGORITHM (distant faces first, closer faces last).

      For i = 0 To 5

      Dim points() As Point

      Dim index As Integer = order(i)

      points = New Point() {

            New Point(CInt(t(m_faces(index, 0)).X), CInt(t(m_faces(index, 0)).Y)),

            New Point(CInt(t(m_faces(index, 1)).X), CInt(t(m_faces(index, 1)).Y)),

            New Point(CInt(t(m_faces(index, 2)).X), CInt(t(m_faces(index, 2)).Y)),

            New Point(CInt(t(m_faces(index, 3)).X), CInt(t(m_faces(index, 3)).Y))

      }

      e.Graphics.FillPolygon(m_brushes(index), points)

      Next

    End Sub

End Class

Code

Option Explicit On



Public Class Point3D

    Protected m_x As Double, m_y As Double, m_z As Double



    Public Sub New(ByVal x As Double, ByVal y As Double, ByVal z As Double)

      Me.X = x

      Me.Y = y

      Me.Z = z

    End Sub



    Public Property X() As Double

      Get

      Return m_x

      End Get

      Set(ByVal value As Double)

      m_x = value

      End Set

    End Property



    Public Property Y() As Double

      Get

      Return m_y

      End Get

      Set(ByVal value As Double)

      m_y = value

      End Set

    End Property



    Public Property Z() As Double

      Get

      Return m_z

      End Get

      Set(ByVal value As Double)

      m_z = value

      End Set

    End Property



    Public Function RotateX(ByVal angle As Integer) As Point3D

      Dim rad As Double, cosa As Double, sina As Double, yn As Double, zn As Double



      rad = angle * Math.PI / 180

      cosa = Math.Cos(rad)

      sina = Math.Sin(rad)

      yn = Me.Y * cosa - Me.Z * sina

      zn = Me.Y * sina + Me.Z * cosa

      Return New Point3D(Me.X, yn, zn)

    End Function



    Public Function RotateY(ByVal angle As Integer) As Point3D

      Dim rad As Double, cosa As Double, sina As Double, Xn As Double, Zn As Double



      rad = angle * Math.PI / 180

      cosa = Math.Cos(rad)

      sina = Math.Sin(rad)

      Zn = Me.Z * cosa - Me.X * sina

      Xn = Me.Z * sina + Me.X * cosa



      Return New Point3D(Xn, Me.Y, Zn)

    End Function



    Public Function RotateZ(ByVal angle As Integer) As Point3D

      Dim rad As Double, cosa As Double, sina As Double, Xn As Double, Yn As Double



      rad = angle * Math.PI / 180

      cosa = Math.Cos(rad)

      sina = Math.Sin(rad)

      Xn = Me.X * cosa - Me.Y * sina

      Yn = Me.X * sina + Me.Y * cosa

      Return New Point3D(Xn, Yn, Me.Z)

    End Function



    Public Function Project(ByVal viewWidth, ByVal viewHeight, ByVal fov, ByVal viewDistance)

      Dim factor As Double, Xn As Double, Yn As Double

      factor = fov / (viewDistance + Me.Z)

      Xn = Me.X * factor + viewWidth / 2

      Yn = Me.Y * factor + viewHeight / 2

      Return New Point3D(Xn, Yn, Me.Z)

    End Function

End Class