# Visual Basic 3D Video Game Engine

Here's a complete implementation of a simple 3D video game engine using Visual Basic .NET, organized with the specified folder structure.

## Project Structure
```
GameEngine/
├── src/
│   ├── Engine/
│   │   ├── Engine.vb
│   │   ├── Vector3.vb
│   │   ├── Matrix4x4.vb
│   │   ├── Camera.vb
│   │   └── Renderer.vb
│   ├── Game/
│   │   ├── Game.vb
│   │   ├── GameObject.vb
│   │   ├── Mesh.vb
│   │   └── Texture.vb
│   └── Main.vb
├── assets/
│   ├── models/
│   │   └── cube.obj
│   ├── textures/
│   │   └── default.png
│   └── shaders/
│       └── basic.fx
└── bin/
    └── GameEngine.exe
```

## File Contents

### src/Engine/Engine.vb
```vb
Imports System.Drawing
Imports System.Windows.Forms

Public Class Engine
    Private Shared _isRunning As Boolean = False
    Private Shared _window As Form
    Private Shared _renderer As Renderer
    
    Public Shared Sub Initialize()
        _window = New Form With {
            .Text = "VB 3D Game Engine",
            .Width = 800,
            .Height = 600,
            .FormBorderStyle = FormBorderStyle.FixedSingle,
            .StartPosition = FormStartPosition.CenterScreen
        }
        
        _renderer = New Renderer(_window)
        
        AddHandler _window.Paint, AddressOf OnRender
        AddHandler _window.KeyDown, AddressOf OnKeyDown
        AddHandler _window.KeyUp, AddressOf OnKeyUp
        
        _isRunning = True
        _window.Show()
    End Sub
    
    Public Shared Sub Run()
        While _isRunning
            Application.DoEvents()
            Threading.Thread.Sleep(16) ' ~60 FPS
        End While
    End Sub
    
    Public Shared Sub Exit()
        _isRunning = False
        _window.Close()
    End Sub
    
    Private Shared Sub OnRender(sender As Object, e As PaintEventArgs)
        _renderer.Render()
    End Sub
    
    Private Shared Sub OnKeyDown(sender As Object, e As KeyEventArgs)
        ' Handle key input here
        Select Case e.KeyCode
            Case Keys.Escape
                Exit()
        End Select
    End Sub
    
    Private Shared Sub OnKeyUp(sender As Object, e As KeyEventArgs)
        ' Handle key release here
    End Sub
    
    Public Shared Function GetWindow() As Form
        Return _window
    End Function
End Class
```

### src/Engine/Vector3.vb
```vb
Public Class Vector3
    Public X As Double
    Public Y As Double
    Public Z As Double
    
    Public Sub New(x As Double, y As Double, z As Double)
        Me.X = x
        Me.Y = y
        Me.Z = z
    End Sub
    
    Public Shared Operator +(v1 As Vector3, v2 As Vector3) As Vector3
        Return New Vector3(v1.X + v2.X, v1.Y + v2.Y, v1.Z + v2.Z)
    End Operator
    
    Public Shared Operator -(v1 As Vector3, v2 As Vector3) As Vector3
        Return New Vector3(v1.X - v2.X, v1.Y - v2.Y, v1.Z - v2.Z)
    End Operator
    
    Public Shared Operator *(v As Vector3, scalar As Double) As Vector3
        Return New Vector3(v.X * scalar, v.Y * scalar, v.Z * scalar)
    End Operator
    
    Public Shared Operator *(scalar As Double, v As Vector3) As Vector3
        Return v * scalar
    End Operator
    
    Public Shared Operator /(v As Vector3, scalar As Double) As Vector3
        If scalar = 0 Then Return New Vector3(0, 0, 0)
        Return New Vector3(v.X / scalar, v.Y / scalar, v.Z / scalar)
    End Operator
    
    Public Function Length() As Double
        Return Math.Sqrt(X * X + Y * Y + Z * Z)
    End Function
    
    Public Sub Normalize()
        Dim length = Length()
        If length > 0 Then
            X /= length
            Y /= length
            Z /= length
        End If
    End Sub
    
    Public Shared Function Cross(v1 As Vector3, v2 As Vector3) As Vector3
        Return New Vector3(
            v1.Y * v2.Z - v1.Z * v2.Y,
            v1.Z * v2.X - v1.X * v2.Z,
            v1.X * v2.Y - v1.Y * v2.X)
    End Function
    
    Public Shared Function Dot(v1 As Vector3, v2 As Vector3) As Double
        Return v1.X * v2.X + v1.Y * v2.Y + v1.Z * v2.Z
    End Function
    
    Public Shared Function Distance(v1 As Vector3, v2 As Vector3) As Double
        Dim dx = v1.X - v2.X
        Dim dy = v1.Y - v2.Y
        Dim dz = v1.Z - v2.Z
        Return Math.Sqrt(dx * dx + dy * dy + dz * dz)
    End Function
    
    Public Overrides Function ToString() As String
        Return $"Vector3({X:F2}, {Y:F2}, {Z:F2})"
    End Function
End Class
```

### src/Engine/Matrix4x4.vb
```vb
Public Class Matrix4x4
    Private _matrix(15) As Double
    
    Public Sub New()
        ' Initialize identity matrix
        Identity()
    End Sub
    
    Public Sub Identity()
        For i As Integer = 0 To 15
            _matrix(i) = If(i Mod 5 = 0, 1.0, 0.0)
        Next
    End Sub
    
    Public Sub SetElement(row As Integer, col As Integer, value As Double)
        If row >= 0 AndAlso row < 4 AndAlso col >= 0 AndAlso col < 4 Then
            _matrix(row * 4 + col) = value
        End If
    End Sub
    
    Public Function GetElement(row As Integer, col As Integer) As Double
        If row >= 0 AndAlso row < 4 AndAlso col >= 0 AndAlso col < 4 Then
            Return _matrix(row * 4 + col)
        End If
        Return 0.0
    End Function
    
    Public Shared Function CreateTranslation(x As Double, y As Double, z As Double) As Matrix4x4
        Dim m As New Matrix4x4
        m.SetElement(0, 3, x)
        m.SetElement(1, 3, y)
        m.SetElement(2, 3, z)
        Return m
    End Function
    
    Public Shared Function CreateRotationX(angle As Double) As Matrix4x4
        Dim m As New Matrix4x4
        Dim cosAngle = Math.Cos(angle)
        Dim sinAngle = Math.Sin(angle)
        
        m.SetElement(1, 1, cosAngle)
        m.SetElement(1, 2, -sinAngle)
        m.SetElement(2, 1, sinAngle)
        m.SetElement(2, 2, cosAngle)
        
        Return m
    End Function
    
    Public Shared Function CreateRotationY(angle As Double) As Matrix4x4
        Dim m As New Matrix4x4
        Dim cosAngle = Math.Cos(angle)
        Dim sinAngle = Math.Sin(angle)
        
        m.SetElement(0, 0, cosAngle)
        m.SetElement(0, 2, sinAngle)
        m.SetElement(2, 0, -sinAngle)
        m.SetElement(2, 2, cosAngle)
        
        Return m
    End Function
    
    Public Shared Function CreateRotationZ(angle As Double) As Matrix4x4
        Dim m As New Matrix4x4
        Dim cosAngle = Math.Cos(angle)
        Dim sinAngle = Math.Sin(angle)
        
        m.SetElement(0, 0, cosAngle)
        m.SetElement(0, 1, -sinAngle)
        m.SetElement(1, 0, sinAngle)
        m.SetElement(1, 1, cosAngle)
        
        Return m
    End Function
    
    Public Shared Function CreateScale(x As Double, y As Double, z As Double) As Matrix4x4
        Dim m As New Matrix4x4
        m.SetElement(0, 0, x)
        m.SetElement(1, 1, y)
        m.SetElement(2, 2, z)
        Return m
    End Function
    
    Public Shared Function CreatePerspective(fov As Double, aspectRatio As Double, nearPlane As Double, farPlane As Double) As Matrix4x4
        Dim m As New Matrix4x4
        Dim f = 1.0 / Math.Tan(fov / 2.0)
        
        m.SetElement(0, 0, f / aspectRatio)
        m.SetElement(1, 1, f)
        m.SetElement(2, 2, (farPlane + nearPlane) / (nearPlane - farPlane))
        m.SetElement(2, 3, (2.0 * farPlane * nearPlane) / (nearPlane - farPlane))
        m.SetElement(3, 2, -1.0)
        
        Return m
    End Function
    
    Public Shared Operator *(m1 As Matrix4x4, m2 As Matrix4x4) As Matrix4x4
        Dim result As New Matrix4x4
        
        For i As Integer = 0 To 3
            For j As Integer = 0 To 3
                Dim sum As Double = 0.0
                For k As Integer = 0 To 3
                    sum += m1.GetElement(i, k) * m2.GetElement(k, j)
                Next
                result.SetElement(i, j, sum)
            Next
        Next
        
        Return result
    End Operator
    
    Public Shared Function TransformPoint(matrix As Matrix4x4, point As Vector3) As Vector3
        Dim x = matrix.GetElement(0, 0) * point.X + matrix.GetElement(0, 1) * point.Y + matrix.GetElement(0, 2) * point.Z + matrix.GetElement(0, 3)
        Dim y = matrix.GetElement(1, 0) * point.X + matrix.GetElement(1, 1) * point.Y + matrix.GetElement(1, 2) * point.Z + matrix.GetElement(1, 3)
        Dim z = matrix.GetElement(2, 0) * point.X + matrix.GetElement(2, 1) * point.Y + matrix.GetElement(2, 2) * point.Z + matrix.GetElement(2, 3)
        
        Return New Vector3(x, y, z)
    End Function
    
    Public Overrides Function ToString() As String
        Dim result As String = ""
        For i As Integer = 0 To 3
            For j As Integer = 0 To 3
                result += _matrix(i * 4 + j).ToString("F2") & " "
            Next
            result += vbCrLf
        Next
        Return result
    End Function
End Class
```

### src/Engine/Camera.vb
```vb
Public Class Camera
    Private _position As Vector3
    Private _rotation As Vector3
    Private _viewMatrix As Matrix4x4
    Private _projectionMatrix As Matrix4x4
    
    Public Sub New(x As Double, y As Double, z As Double)
        _position = New Vector3(x, y, z)
        _rotation = New Vector3(0, 0, 0)
        _viewMatrix = New Matrix4x4
        _projectionMatrix = New Matrix4x4
    End Sub
    
    Public Property Position As Vector3
        Get
            Return _position
        End Get
        Set(value As Vector3)
            _position = value
        End Set
    End Property
    
    Public Property Rotation As Vector3
        Get
            Return _rotation
        End Get
        Set(value As Vector3)
            _rotation = value
        End Set
    End Property
    
    Public Sub LookAt(target As Vector3)
        ' Simple look-at implementation (not fully accurate for all cases)
        Dim direction = target - _position
        direction.Normalize()
        
        ' Calculate rotation angles from direction vector
        _rotation.Y = Math.Atan2(direction.X, direction.Z)
        _rotation.X = Math.Asin(-direction.Y)
    End Sub
    
    Public Function GetViewMatrix() As Matrix4x4
        ' Create view matrix using inverse transformation
        Dim translation As Matrix4x4 = Matrix4x4.CreateTranslation(-_position.X, -_position.Y, -_position.Z)
        
        Dim rotationX As Matrix4x4 = Matrix4x4.CreateRotationX(-_rotation.X)
        Dim rotationY As Matrix4x4 = Matrix4x4.CreateRotationY(-_rotation.Y)
        Dim rotationZ As Matrix4x4 = Matrix4x4.CreateRotationZ(-_rotation.Z)
        
        _viewMatrix = rotationZ * rotationY * rotationX * translation
        
        Return _viewMatrix
    End Function
    
    Public Sub SetProjection(fov As Double, aspectRatio As Double, nearPlane As Double, farPlane As Double)
        _projectionMatrix = Matrix4x4.CreatePerspective(fov, aspectRatio, nearPlane, farPlane)
    End Sub
    
    Public Function GetProjectionMatrix() As Matrix4x4
        Return _projectionMatrix
    End Function
End Class
```

### src/Engine/Renderer.vb
```vb
Imports System.Drawing
Imports System.Drawing.Imaging

Public Class Renderer
    Private _window As Form
    Private _buffer As Bitmap
    Private _graphics As Graphics
    Private _camera As Camera
    
    Public Sub New(window As Form)
        _window = window
        _buffer = New Bitmap(_window.Width, _window.Height)
        _graphics = Graphics.FromImage(_buffer)
        _camera = New Camera(0, 0, -5)
        
        ' Set up camera projection
        _camera.SetProjection(Math.PI / 4, _window.Width / _window.Height, 0.1, 100.0)
    End Sub
    
    Public Sub Render()
        _graphics.Clear(Color.Black)
        
        ' Draw simple cube (for demonstration)
        DrawCube()
        
        ' Render to window
        Using g = _window.CreateGraphics()
            g.DrawImage(_buffer, 0, 0)
        End Using
    End Sub
    
    Private Sub DrawCube()
        Dim vertices() As Vector3 = {
            New Vector3(-1, -1, -1),  ' 0
            New Vector3(1, -1, -1),   ' 1
            New Vector3(1, 1, -1),    ' 2
            New Vector3(-1, 1, -1),   ' 3
            New Vector3(-1, -1, 1),   ' 4
            New Vector3(1, -1, 1),    ' 5
            New Vector3(1, 1, 1),     ' 6
            New Vector3(-1, 1, 1)     ' 7
        }
        
        Dim indices() As Integer = {
            0, 1, 2, 2, 3, 0,  ' Front face
            4, 7, 6, 6, 5, 4,  ' Back face
            0, 4, 5, 5, 1, 0,  ' Bottom face
            2, 6, 7, 7, 3, 2,  ' Top face
            0, 3, 7, 7, 4, 0,  ' Left face
            1, 5, 6, 6, 2, 1   ' Right face
        }
        
        Dim color As Color = Color.White
        
        ' Transform vertices and draw faces
        For i As Integer = 0 To indices.Length - 1 Step 3
            Dim v1 As Vector3 = vertices(indices(i))
            Dim v2 As Vector3 = vertices(indices(i + 1))
            Dim v3 As Vector3 = vertices(indices(i + 2))
            
            ' Apply transformations (simplified for demo)
            v1 = Matrix4x4.TransformPoint(_camera.GetViewMatrix(), v1)
            v2 = Matrix4x4.TransformPoint(_camera.GetViewMatrix(), v2)
            v3 = Matrix4x4.TransformPoint(_camera.GetViewMatrix(), v3)
            
            ' Apply perspective projection
            v1 = Matrix4x4.TransformPoint(_camera.GetProjectionMatrix(), v1)
            v2 = Matrix4x4.TransformPoint(_camera.GetProjectionMatrix(), v2)
            v3 = Matrix4x4.TransformPoint(_camera.GetProjectionMatrix(), v3)
            
            ' Project to screen coordinates
            Dim p1 As Point = ProjectToScreen(v1)
            Dim p2 As Point = ProjectToScreen(v2)
            Dim p3 As Point = ProjectToScreen(v3)
            
            ' Draw triangle
            Dim points() As Point = {p1, p2, p3}
            _graphics.FillPolygon(Brushes.Yellow, points)
        Next
    End Sub
    
    Private Function ProjectToScreen(point As Vector3) As Point
        ' Simple orthographic projection for demonstration
        Dim x = (point.X / point.Z + 1) * _window.Width / 2
        Dim y = (1 - point.Y / point.Z) * _window.Height / 2
        
        Return New Point(CInt(x), CInt(y))
    End Function
End Class
```

### src/Game/Game.vb
```vb
Public Class Game
    Private Shared _isRunning As Boolean = False
    
    Public Shared Sub Initialize()
        Engine.Initialize()
        _isRunning = True
    End Sub
    
    Public Shared Sub Run()
        While _isRunning
            ' Update game logic here
            System.Threading.Thread.Sleep(16) ' ~60 FPS
        End While
    End Sub
    
    Public Shared Sub Exit()
        _isRunning = False
        Engine.Exit()
    End Sub
End Class
```

### src/Game/GameObject.vb
```vb
Public Class GameObject
    Private _position As Vector3
    Private _rotation As Vector3
    Private _scale As Vector3
    Private _mesh As Mesh
    
    Public Sub New(x As Double, y As Double, z As Double)
        _position = New Vector3(x, y, z)
        _rotation = New Vector3(0, 0, 0)
        _scale = New Vector3(1, 1, 1)
        _mesh = Nothing
    End Sub
    
    Public Property Position As Vector3
        Get
            Return _position
        End Get
        Set(value As Vector3)
            _position = value
        End Set
    End Property
    
    Public Property Rotation As Vector3
        Get
            Return _rotation
        End Get
        Set(value As Vector3)
            _rotation = value
        End Set
    End Property
    
    Public Property Scale As Vector3
        Get
            Return _scale
        End Get
        Set(value As Vector3)
            _scale = value
        End Set
    End Property
    
    Public Sub Update(deltaTime As Double)
        ' Update logic for the game object
    End Sub
    
    Public Sub Render()
        ' Render the game object
    End Sub
End Class
```

### src/Game/Mesh.vb
```vb
Public Class Mesh
    Private _vertices() As Vector3
    Private _indices() As Integer
    
    Public Sub New(vertices() As Vector3, indices() As Integer)
        _vertices = vertices
        _indices = indices
    End Sub
    
    Public Property Vertices As Vector3()
        Get
            Return _vertices
        End Get
        Set(value As Vector3())
            _vertices = value
        End Set
    End Property
    
    Public Property Indices As Integer()
        Get
            Return _indices
        End Get
        Set(value As Integer())
            _indices = value
        End Set
    End Property
End Class
```

### src/Main.vb
```vb
Imports System.Windows.Forms

Module Main
    Sub Main()
        Application.EnableVisualStyles()
        Application.SetCompatibleTextRenderingDefault(False)
        
        Game.Initialize()
        Game.Run()
    End Sub
End Module
```