by Liaqat Fayyaz (10 Submissions)
Category: Graphics
Compatability: VB 6.0
Difficulty: Unknown Difficulty
Originally Published: Thu 7th June 2001
Date Added: Mon 8th February 2021
Rating: 
(1 Votes)
Desc: Rendering 3D geometry is much more interesting when dynamic lighting ' is added to the scene. To use lighting in D3D, you must create
API Declarations
'-----------------------------------------------------------------------------
' variables
'-----------------------------------------------------------------------------
Dim g_DX As New DirectX8
Dim g_D3D As Direct3D8 'Used to create the D3DDevice
Dim g_D3DDevice As Direct3DDevice8 'Our rendering device
Dim g_VB As Direct3DVertexBuffer8
' A structure for our custom vertex type
Private Type CUSTOMVERTEX
postion As D3DVECTOR '3d position for vertex
normal As D3DVECTOR 'surface normal for vertex
End Type
' Our custom FVF, which describes our custom vertex structure
Const D3DFVF_CUSTOMVERTEX = (D3DFVF_XYZ Or D3DFVF_NORMAL)
Const g_pi = 3.1415
VBcoders
'
'
' Desc: Rendering 3D geometry is much more interesting when dynamic lighting
' is added to the scene. To use lighting in D3D, you must create one or
' lights, setup a material, and make sure your geometry contains surface
' normals. Lights may have a position, a color, and be of a certain type
' such as directional (light comes from one direction), point (light
' comes from a specific x,y,z coordinate and radiates in all directions)
' or spotlight. Materials describe the surface of your geometry,
' specifically, how it gets lit (diffuse color, ambient color, etc.).
' Surface normals are part of a vertex, and are needed for the D3D's
' internal lighting calculations.
' Name: Form_Load()
Private Sub Form_Load()
Dim b As Boolean
' Allow the form to become visible
Me.Show
DoEvents
' Initialize D3D and D3DDevice
b = InitD3D(Picture1.hWnd)
If Not b Then
MsgBox "Unable to CreateDevice (see InitD3D() source for comments)"
End
End If
' Initialize Vertex Buffer with Geometry
b = InitGeometry()
If Not b Then
MsgBox "Unable to Create VertexBuffer"
End
End If
' Enable Timer to update
Timer1.Enabled = True
End Sub
' Name: Timer1_Timer()
Private Sub Timer1_Timer()
Render
End Sub
' Name: Form_Unload()
Private Sub Form_Unload(Cancel As Integer)
End
End Sub
' Name: InitD3D()
' Desc: Initializes Direct3D
Function InitD3D(hWnd As Long) As Boolean
On Local Error Resume Next
' Create the D3D object
Set g_D3D = g_DX.Direct3DCreate()
If g_D3D Is Nothing Then Exit Function
' Get The current Display Mode format
Dim mode As D3DDISPLAYMODE
g_D3D.GetAdapterDisplayMode D3DADAPTER_DEFAULT, mode
' Set up the structure used to create the D3DDevice. Since we are now
' using more complex geometry, we will create a device with a zbuffer.
' the D3DFMT_D16 indicates we want a 16 bit z buffer but
Dim d3dpp As D3DPRESENT_PARAMETERS
d3dpp.Windowed = 1
d3dpp.SwapEffect = D3DSWAPEFFECT_COPY_VSYNC
d3dpp.BackBufferFormat = mode.Format
d3dpp.BackBufferCount = 1
d3dpp.EnableAutoDepthStencil = 1
d3dpp.AutoDepthStencilFormat = D3DFMT_D16
' Create the D3DDevice
' If you do not have hardware 3d acceleration. Enable the reference rasterizer
' using the DirectX control panel and change D3DDEVTYPE_HAL to D3DDEVTYPE_REF
Set g_D3DDevice = g_D3D.CreateDevice(D3DADAPTER_DEFAULT, D3DDEVTYPE_HAL, hWnd, _
D3DCREATE_SOFTWARE_VERTEXPROCESSING, d3dpp)
If g_D3DDevice Is Nothing Then Exit Function
' Device state would normally be set here
' Turn off culling, so we see the front and back of the triangle
g_D3DDevice.SetRenderState D3DRS_CULLMODE, D3DCULL_NONE
' Turn on the zbuffer
g_D3DDevice.SetRenderState D3DRS_ZENABLE, 1
' Note lighting is on by default
InitD3D = True
End Function
' Name: SetupMatrices()
' Desc: Sets up the world, view, and projection transform matrices.
Sub SetupMatrices()
' The transform Matrix is used to position and orient the objects
' you are drawing
' For our world matrix, we will just rotate the object about the 1 1 1 axis.
Dim matWorld As D3DMATRIX
D3DXMatrixRotationAxis matWorld, vec3(1, 1, 1), Timer / 4
g_D3DDevice.SetTransform D3DTS_WORLD, matWorld
' The view matrix defines the position and orientation of the camera
' Set up our view matrix. A view matrix can be defined given an eye point,
' a point to lookat, and a direction for which way is up. Here, we set the
' eye five units back along the z-axis and up three units, look at the
' origin, and define "up" to be in the y-direction.
Dim matView As D3DMATRIX
D3DXMatrixLookAtLH matView, vec3(0#, 3#, -5#), _
vec3(0#, 0#, 0#), _
vec3(0#, 1#, 0#)
g_D3DDevice.SetTransform D3DTS_VIEW, matView
' The projection matrix describes the camera's lenses
' For the projection matrix, we set up a perspective transform (which
' transforms geometry from 3D view space to 2D viewport space, with
' a perspective divide making objects smaller in the distance). To build
' a perpsective transform, we need the field of view (1/4 pi is common),
' the aspect ratio, and the near and far clipping planes (which define at
' what distances geometry should be no longer be rendered).
Dim matProj As D3DMATRIX
D3DXMatrixPerspectiveFovLH matProj, g_pi / 4, 1, 1, 1000
g_D3DDevice.SetTransform D3DTS_PROJECTION, matProj
End Sub
' Name: SetupLights()
' Desc: Sets up the lights and materials for the scene.
Sub SetupLights()
Dim col As D3DCOLORVALUE
' Set up a material. The material here just has the diffuse and ambient
' colors set to yellow. Note that only one material can be used at a time.
Dim mtrl As D3DMATERIAL8
With col: .r = 1: .g = 1: .b = 0: .a = 1: End With
mtrl.diffuse = col
mtrl.Ambient = col
g_D3DDevice.SetMaterial mtrl
' Set up a white, directional light, with an oscillating direction.
' Note that many lights may be active at a time (but each one slows down
' the rendering of our scene). However, here we are just using one. Also,
' we need to set the D3DRS_LIGHTING renderstate to enable lighting
Dim light As D3DLIGHT8
light.Type = D3DLIGHT_DIRECTIONAL
light.diffuse.r = 1#
light.diffuse.g = 1#
light.diffuse.b = 1#
light.Direction.x = Cos(Timer * 2)
light.Direction.y = 1#
light.Direction.z = Sin(Timer * 2)
light.Range = 1000#
g_D3DDevice.SetLight 0, light 'let d3d know about the light
g_D3DDevice.LightEnable 0, 1 'turn it on
g_D3DDevice.SetRenderState D3DRS_LIGHTING, 1 'make sure lighting is enabled
' Finally, turn on some ambient light.
' Ambient light is light that scatters and lights all objects evenly
g_D3DDevice.SetRenderState D3DRS_AMBIENT, &H202020
End Sub
' Name: InitGeometry()
' Desc: Creates a vertex buffer and fills it with our vertices.
Function InitGeometry() As Boolean
Dim i As Long
' Initialize three vertices for rendering a triangle
Dim Vertices(100) As CUSTOMVERTEX
Dim VertexSizeInBytes As Long
Dim theta As Single
VertexSizeInBytes = Len(Vertices(0))
' We are algorithmically generating a cylinder
' here, including the normals, which are used for lighting.
' normals are vectors that are of length 1 and point in a direction
' perpendicular to the plane of the triangle the normal belongs to
' In later tutorials we will use d3dx to generate them
For i = 0 To 49
theta = (2 * g_pi * i) / (50 - 1)
Vertices(2 * i + 0).postion = vec3(Sin(theta), -1, Cos(theta))
Vertices(2 * i + 0).normal = vec3(Sin(theta), 0, Cos(theta))
Vertices(2 * i + 1).postion = vec3(Sin(theta), 1, Cos(theta))
Vertices(2 * i + 1).normal = vec3(Sin(theta), 0, Cos(theta))
Next
' Create the vertex buffer.
Set g_VB = g_D3DDevice.CreateVertexBuffer(VertexSizeInBytes * 50 * 2, _
0, D3DFVF_CUSTOMVERTEX, D3DPOOL_DEFAULT)
If g_VB Is Nothing Then Exit Function
' fill the vertex buffer from our array
D3DVertexBuffer8SetData g_VB, 0, VertexSizeInBytes * 100, 0, Vertices(0)
InitGeometry = True
End Function
' Name: Cleanup()
' Desc: Releases all previously initialized objects
Sub Cleanup()
Set g_VB = Nothing
Set g_D3DDevice = Nothing
Set g_D3D = Nothing
End Sub
' Name: Render()
' Desc: Draws the scene
Sub Render()
Dim v As CUSTOMVERTEX
Dim sizeOfVertex As Long
If g_D3DDevice Is Nothing Then Exit Sub
' Clear the backbuffer to a blue color (ARGB = 000000ff)
' Clear the z buffer to 1
g_D3DDevice.Clear 0, ByVal 0, D3DCLEAR_TARGET Or D3DCLEAR_ZBUFFER, &HFF&, 1#, 0
' Begin the scene
g_D3DDevice.BeginScene
' Setup the lights and materials
SetupLights
' Setup the world, view, and projection matrices
SetupMatrices
' Draw the triangles in the vertex buffer
' Note we are now using a triangle strip of vertices
' instead of a triangle list
sizeOfVertex = Len(v)
g_D3DDevice.SetStreamSource 0, g_VB, sizeOfVertex
g_D3DDevice.SetVertexShader D3DFVF_CUSTOMVERTEX
g_D3DDevice.DrawPrimitive D3DPT_TRIANGLESTRIP, 0, (4 * 25) - 2
' End the scene
g_D3DDevice.EndScene
' Present the backbuffer contents to the front buffer (screen)
g_D3DDevice.Present ByVal 0, ByVal 0, 0, ByVal 0
End Sub
' Name: vec3()
' Desc: helper function
Function vec3(x As Single, y As Single, z As Single) As D3DVECTOR
vec3.x = x
vec3.y = y
vec3.z = z
End Function
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