Chris Aliotta & NeHe's Fog Tutorial (Lesson 16)

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Chris Aliotta & NeHe's Fog Tutorial (Lesson 16)

Post by hagibaba »

This shows how to set up fog in OpenGL.
Press the G key for fog, L key for light, F key for filters, PageUp/PageDown to zoom, and Arrows to rotate cube.
You can get the "Crate.bmp" from the "lesson16.zip" here:
http://nehe.gamedev.net/data/lessons/le ... ?lesson=16

Last edited on 20 Feb 2007.

Code: Select all

;Chris Aliotta & NeHe's Fog Tutorial (Lesson 16)
;http://nehe.gamedev.net
;Credits: Nico Gruener, Dreglor, traumatic
;Author: hagibaba
;Date: 12 Jan 2007
;Note: up-to-date with PB v4.02 (Windows)
;Note: requires a bitmap in path "Data/Crate.bmp"

;Section for standard constants, structures, macros and declarations

XIncludeFile "OpenGL.pbi" ;include the gl.h constants

;wingdi.h constants
#DM_BITSPERPEL=$40000
#DM_PELSWIDTH=$80000
#DM_PELSHEIGHT=$100000

;winuser.h constants
#CDS_FULLSCREEN=4
#DISP_CHANGE_SUCCESSFUL=0
#SC_MONITORPOWER=$F170

Structure AUX_RGBImageRec ;glaux.h structure
 sizeX.l : sizeY.l
 Data.l
EndStructure

Procedure.w LoWord(value.l) ;windef.h macro
 ProcedureReturn (value & $FFFF)
EndProcedure

Procedure.w HiWord(value.l) ;windef.h macro
 ProcedureReturn ((value >> 16) & $FFFF)
EndProcedure

;glaux.lib symbols
!public ___ftoll
!___ftoll dw 0
!public __imp__wsprintfA
!__imp__wsprintfA dw 0

Import "glaux.lib"
 auxDIBImageLoad.l(filename.s) As "_auxDIBImageLoadA@4" ;loads a 24-bit Windows DIB
EndImport

Import "glu32.lib"
 gluPerspective(fovy.d,aspect.d,zNear.d,zFar.d) ;sets up a perspective projection matrix
EndImport

Import "opengl32.lib"
 glClearDepth(depth.d) ;specifies the clear value for the depth buffer
EndImport

;Start of Lesson 16

Global hDC.l ;Private GDI Device Context
Global hRC.l ;Permanent Rendering Context
Global hWnd.l ;Holds Our Window Handle
Global hInstance.l ;Holds The Instance Of The Application

Global Dim keys.b(256) ;Array Used For The Keyboard Routine
Global active.b=#True ;Window Active Flag Set To TRUE By Default
Global fullscreen.b=#True ;Fullscreen Flag Set To Fullscreen Mode By Default

Global light.b ;Lighting ON/OFF
Global lp.b ;L Pressed?
Global fp.b ;F Pressed?
Global gp.b ;G Pressed? ( NEW )

Global xrot.f ;X Rotation
Global yrot.f ;Y Rotation
Global xspeed.f ;X Rotation Speed
Global yspeed.f ;Y Rotation Speed
Global z.f=-5.0 ;Depth Into The Screen

Global Dim LightAmbient.f(4) ;Ambient Light Values
 LightAmbient(0)=0.5 ;red
 LightAmbient(1)=0.5 ;green
 LightAmbient(2)=0.5 ;blue
 LightAmbient(3)=1.0 ;alpha
 
Global Dim LightDiffuse.f(4) ;Diffuse Light Values
 LightDiffuse(0)=1.0 ;red
 LightDiffuse(1)=1.0 ;green
 LightDiffuse(2)=1.0 ;blue
 LightDiffuse(3)=1.0 ;alpha
 
Global Dim LightPosition.f(4) ;Light Position
 LightPosition(0)=0.0 ;x
 LightPosition(1)=0.0 ;y
 LightPosition(2)=2.0 ;z
 LightPosition(3)=1.0 ;w
 
Global filter.l ;Which Filter To Use
Global Dim texture.l(3) ;Storage For 3 Textures

Global Dim fogMode.l(3) ;Storage For Three Types Of Fog ( NEW )
 fogMode(0)=#GL_EXP ;default
 fogMode(1)=#GL_EXP2 ;exponent^2
 fogMode(2)=#GL_LINEAR ;linear
 
Global fogfilter.l=0 ;Which Fog Mode To Use ( NEW )

Global Dim fogColor.FLOAT(4) ;Fog Color ( NEW )
 fogColor(0)\f=0.5 ;red
 fogColor(1)\f=0.5 ;green
 fogColor(2)\f=0.5 ;blue
 fogColor(3)\f=1.0 ;alpha
 
Declare.l WndProc(hWnd.l,uMsg.l,wParam.l,lParam.l) ;Declaration For WndProc

Procedure.l LoadBMP(Filename.s) ;Loads A Bitmap Image

 Protected File.l=#Null ;File Handle
 
 If Filename="" ;Make Sure A Filename Was Given
  ProcedureReturn #Null ;If Not Return NULL
 EndIf
 
 File=ReadFile(#PB_Any,Filename) ;Check To See If The File Exists
 
 If File ;Does The File Exist?
  CloseFile(File) ;Close The Handle
  ProcedureReturn auxDIBImageLoad(Filename) ;Load The Bitmap And Return A Pointer
 EndIf
 
 ProcedureReturn #Null ;If Load Failed Return NULL
 
EndProcedure

Procedure.l LoadGLTextures() ;Load Bitmaps And Convert To Textures

 Protected Status.l=#False ;Status Indicator
 Protected Dim *TextureImage.AUX_RGBImageRec(1) ;Create Storage Space For The Texture
 
 ;Load The Bitmap, Check For Errors, If Bitmap's Not Found Quit
 *TextureImage(0)=LoadBMP("Data/Crate.bmp")
 If *TextureImage(0)
  Status=#True ;Set The Status To TRUE
  
  glGenTextures_(3,@texture(0)) ;Create Three Textures
  
  ;Create Nearest Filtered Texture
  glBindTexture_(#GL_TEXTURE_2D,texture(0))
  glTexParameteri_(#GL_TEXTURE_2D,#GL_TEXTURE_MAG_FILTER,#GL_NEAREST)
  glTexParameteri_(#GL_TEXTURE_2D,#GL_TEXTURE_MIN_FILTER,#GL_NEAREST)
  glTexImage2D_(#GL_TEXTURE_2D,0,3,*TextureImage(0)\sizeX,*TextureImage(0)\sizeY,0,#GL_RGB,#GL_UNSIGNED_BYTE,*TextureImage(0)\Data)
  
  ;Create Linear Filtered Texture
  glBindTexture_(#GL_TEXTURE_2D,texture(1))
  glTexParameteri_(#GL_TEXTURE_2D,#GL_TEXTURE_MAG_FILTER,#GL_LINEAR)
  glTexParameteri_(#GL_TEXTURE_2D,#GL_TEXTURE_MIN_FILTER,#GL_LINEAR)
  glTexImage2D_(#GL_TEXTURE_2D,0,3,*TextureImage(0)\sizeX,*TextureImage(0)\sizeY,0,#GL_RGB,#GL_UNSIGNED_BYTE,*TextureImage(0)\Data)
  
  ;Create MipMapped Texture
  glBindTexture_(#GL_TEXTURE_2D,texture(2))
  glTexParameteri_(#GL_TEXTURE_2D,#GL_TEXTURE_MAG_FILTER,#GL_LINEAR)
  glTexParameteri_(#GL_TEXTURE_2D,#GL_TEXTURE_MIN_FILTER,#GL_LINEAR_MIPMAP_NEAREST)
  gluBuild2DMipmaps_(#GL_TEXTURE_2D,3,*TextureImage(0)\sizeX,*TextureImage(0)\sizeY,#GL_RGB,#GL_UNSIGNED_BYTE,*TextureImage(0)\Data)
 EndIf
 
 If *TextureImage(0) ;If Texture Exists
  If *TextureImage(0)\Data ;If Texture Image Exists
   FreeMemory(*TextureImage(0)\Data) ;Free The Texture Image Memory
  EndIf
  FreeMemory(*TextureImage(0)) ;Free The Image Structure
 EndIf
 
 ProcedureReturn Status ;Return The Status
 
EndProcedure

Procedure ReSizeGLScene(width.l,height.l) ;Resize And Initialize The GL Window

 If height=0 : height=1 : EndIf ;Prevent A Divide By Zero Error
 
 glViewport_(0,0,width,height) ;Reset The Current Viewport
 
 glMatrixMode_(#GL_PROJECTION) ;Select The Projection Matrix
 glLoadIdentity_() ;Reset The Projection Matrix
 
 gluPerspective(45.0,Abs(width/height),0.1,100.0) ;Calculate The Aspect Ratio Of The Window
 
 glMatrixMode_(#GL_MODELVIEW) ;Select The Modelview Matrix
 glLoadIdentity_() ;Reset The Modelview Matrix
 
EndProcedure

Procedure.l InitGL() ;All Setup For OpenGL Goes Here

 If LoadGLTextures()=0 ;Jump To Texture Loading Routine
  ProcedureReturn #False ;If Texture Didn't Load Return FALSE
 EndIf
 
 glEnable_(#GL_TEXTURE_2D) ;Enable Texture Mapping
 glShadeModel_(#GL_SMOOTH) ;Enable Smooth Shading
 glClearColor_(0.5,0.5,0.5,1.0) ;We'll Clear To The Color Of The Fog
 glClearDepth(1.0) ;Depth Buffer Setup
 glEnable_(#GL_DEPTH_TEST) ;Enables Depth Testing
 glDepthFunc_(#GL_LEQUAL) ;The Type Of Depth Testing To Do
 glHint_(#GL_PERSPECTIVE_CORRECTION_HINT,#GL_NICEST) ;Really Nice Perspective Calculations
 
 glLightfv_(#GL_LIGHT1,#GL_AMBIENT,LightAmbient()) ;Setup The Ambient Light
 glLightfv_(#GL_LIGHT1,#GL_DIFFUSE,LightDiffuse()) ;Setup The Diffuse Light
 glLightfv_(#GL_LIGHT1,#GL_POSITION,LightPosition()) ;Position The Light
 glEnable_(#GL_LIGHT1) ;Enable Light One
 
 glFogi_(#GL_FOG_MODE,fogMode(fogfilter)) ;Fog Mode
 glFogfv_(#GL_FOG_COLOR,fogColor(0)) ;Set Fog Color
 glFogf_(#GL_FOG_DENSITY,0.35) ;How Dense Will The Fog Be
 glHint_(#GL_FOG_HINT,#GL_DONT_CARE) ;Fog Hint Value
 glFogf_(#GL_FOG_START,1.0) ;Fog Start Depth
 glFogf_(#GL_FOG_END,5.0) ;Fog End Depth
 glEnable_(#GL_FOG) ;Enables GL_FOG
 
 ProcedureReturn #True ;Initialization Went OK
 
EndProcedure

Procedure.l DrawGLScene() ;Here's Where We Do All The Drawing

 glClear_(#GL_COLOR_BUFFER_BIT | #GL_DEPTH_BUFFER_BIT) ;Clear The Screen And The Depth Buffer
 glLoadIdentity_() ;Reset The View
 
 glTranslatef_(0.0,0.0,z) ;Translate Into/Out Of The Screen By z
 
 glRotatef_(xrot,1.0,0.0,0.0) ;Rotate On The X Axis By xrot
 glRotatef_(yrot,0.0,1.0,0.0) ;Rotate On The Y Axis By yrot
 
 glBindTexture_(#GL_TEXTURE_2D,texture(filter)) ;Select A Texture Based On filter
 
 glBegin_(#GL_QUADS) ;Start Drawing Quads
  ;Front Face
  glNormal3f_( 0.0, 0.0, 1.0) ;Normal Pointing Towards Viewer
  glTexCoord2f_(0.0, 0.0) : glVertex3f_(-1.0,-1.0, 1.0) ;Point 1 (Front)
  glTexCoord2f_(1.0, 0.0) : glVertex3f_( 1.0,-1.0, 1.0) ;Point 2 (Front)
  glTexCoord2f_(1.0, 1.0) : glVertex3f_( 1.0, 1.0, 1.0) ;Point 3 (Front)
  glTexCoord2f_(0.0, 1.0) : glVertex3f_(-1.0, 1.0, 1.0) ;Point 4 (Front)
  ;Back Face
  glNormal3f_( 0.0, 0.0,-1.0) ;Normal Pointing Away From Viewer
  glTexCoord2f_(1.0, 0.0) : glVertex3f_(-1.0,-1.0,-1.0) ;Point 1 (Back)
  glTexCoord2f_(1.0, 1.0) : glVertex3f_(-1.0, 1.0,-1.0) ;Point 2 (Back)
  glTexCoord2f_(0.0, 1.0) : glVertex3f_( 1.0, 1.0,-1.0) ;Point 3 (Back)
  glTexCoord2f_(0.0, 0.0) : glVertex3f_( 1.0,-1.0,-1.0) ;Point 4 (Back)
  ;Top Face
  glNormal3f_( 0.0, 1.0, 0.0) ;Normal Pointing Up
  glTexCoord2f_(0.0, 1.0) : glVertex3f_(-1.0, 1.0,-1.0) ;Point 1 (Top)
  glTexCoord2f_(0.0, 0.0) : glVertex3f_(-1.0, 1.0, 1.0) ;Point 2 (Top)
  glTexCoord2f_(1.0, 0.0) : glVertex3f_( 1.0, 1.0, 1.0) ;Point 3 (Top)
  glTexCoord2f_(1.0, 1.0) : glVertex3f_( 1.0, 1.0,-1.0) ;Point 4 (Top)
  ;Bottom Face
  glNormal3f_( 0.0,-1.0, 0.0) ;Normal Pointing Down
  glTexCoord2f_(1.0, 1.0) : glVertex3f_(-1.0,-1.0,-1.0) ;Point 1 (Bottom)
  glTexCoord2f_(0.0, 1.0) : glVertex3f_( 1.0,-1.0,-1.0) ;Point 2 (Bottom)
  glTexCoord2f_(0.0, 0.0) : glVertex3f_( 1.0,-1.0, 1.0) ;Point 3 (Bottom)
  glTexCoord2f_(1.0, 0.0) : glVertex3f_(-1.0,-1.0, 1.0) ;Point 4 (Bottom)
  ;Right face
  glNormal3f_( 1.0, 0.0, 0.0) ;Normal Pointing Right
  glTexCoord2f_(1.0, 0.0) : glVertex3f_( 1.0,-1.0,-1.0) ;Point 1 (Right)
  glTexCoord2f_(1.0, 1.0) : glVertex3f_( 1.0, 1.0,-1.0) ;Point 2 (Right)
  glTexCoord2f_(0.0, 1.0) : glVertex3f_( 1.0, 1.0, 1.0) ;Point 3 (Right)
  glTexCoord2f_(0.0, 0.0) : glVertex3f_( 1.0,-1.0, 1.0) ;Point 4 (Right)
  ;Left Face
  glNormal3f_(-1.0, 0.0, 0.0) ;Normal Pointing Left
  glTexCoord2f_(0.0, 0.0) : glVertex3f_(-1.0,-1.0,-1.0) ;Point 1 (Left)
  glTexCoord2f_(1.0, 0.0) : glVertex3f_(-1.0,-1.0, 1.0) ;Point 2 (Left)
  glTexCoord2f_(1.0, 1.0) : glVertex3f_(-1.0, 1.0, 1.0) ;Point 3 (Left)
  glTexCoord2f_(0.0, 1.0) : glVertex3f_(-1.0, 1.0,-1.0) ;Point 4 (Left)
 glEnd_() ;Done Drawing Quads
 
 xrot+xspeed ;Add xspeed To xrot
 yrot+yspeed ;Add yspeed To yrot
 
 ProcedureReturn #True ;Keep Going
 
EndProcedure

Procedure KillGLWindow() ;Properly Kill The Window

 If fullscreen ;Are We In Fullscreen Mode?
  ChangeDisplaySettings_(#Null,0) ;If So Switch Back To The Desktop
  ShowCursor_(#True) ;Show Mouse Pointer
 EndIf
 
 If hRC ;Do We Have A Rendering Context?
  If wglMakeCurrent_(#Null,#Null)=0 ;Are We Able To Release The DC And RC Contexts?
   MessageBox_(#Null,"Release Of DC And RC Failed.","SHUTDOWN ERROR",#MB_OK | #MB_ICONINFORMATION)
  EndIf
  If wglDeleteContext_(hRC)=0 ;Are We Able To Delete The RC?
   MessageBox_(#Null,"Release Rendering Context Failed.","SHUTDOWN ERROR",#MB_OK | #MB_ICONINFORMATION)
  EndIf
  hRC=#Null ;Set RC To NULL
 EndIf
 
 If hDC And ReleaseDC_(hWnd,hDC)=0 ;Are We Able To Release The DC
  MessageBox_(#Null,"Release Device Context Failed.","SHUTDOWN ERROR",#MB_OK | #MB_ICONINFORMATION)
  hDC=#Null ;Set DC To NULL
 EndIf
 
 If hWnd And DestroyWindow_(hWnd)=0 ;Are We Able To Destroy The Window?
   MessageBox_(#Null,"Could Not Release hWnd.","SHUTDOWN ERROR",#MB_OK | #MB_ICONINFORMATION)
   hWnd=#Null ;Set hWnd To NULL
 EndIf
 
 If UnregisterClass_("OpenGL",hInstance)=0 ;Are We Able To Unregister Class
  MessageBox_(#Null,"Could Not Unregister Class.","SHUTDOWN ERROR",#MB_OK | #MB_ICONINFORMATION)
  hInstance=#Null ;Set hInstance To NULL
 EndIf
 
EndProcedure

;This Code Creates Our OpenGL Window. Parameters Are:
;title - Title To Appear At The Top Of The Window
;width - Width Of The GL Window Or Fullscreen Mode
;height - Height Of The GL Window Or Fullscreen Mode
;bits - Number Of Bits To Use For Color (8/16/24/32)
;fullscreenflag - Use Fullscreen Mode (TRUE) Or Windowed Mode (FALSE)

Procedure.b CreateGLWindow(title.s,width.l,height.l,bits.l,fullscreenflag.b)

 Protected PixelFormat.l ;Holds The Results After Searching For A Match
 Protected wc.WNDCLASS ;Windows Class Structure
 Protected dwExStyle.l ;Window Extended Style
 Protected dwStyle.l ;Window Style
 Protected WindowRect.RECT ;Grabs Rectangle Upper Left / Lower Right Values
 Protected wpos.POINT ;Window position
 
 WindowRect\left=0 ;Set Left Value To 0
 WindowRect\right=width ;Set Right Value To Requested Width
 WindowRect\top=0 ;Set Top Value To 0
 WindowRect\bottom=height ;Set Bottom Value To Requested Height
 
 fullscreen=fullscreenflag ;Set The Global Fullscreen Flag
 
 hInstance=GetModuleHandle_(#Null) ;Grab An Instance For Our Window
 
 wc\style=#CS_HREDRAW | #CS_VREDRAW | #CS_OWNDC ;Redraw On Size, And Own DC For Window
 wc\lpfnWndProc=@WndProc() ;WndProc Handles Messages
 wc\cbClsExtra=0 ;No Extra Window Data
 wc\cbWndExtra=0 ;No Extra Window Data
 wc\hInstance=hInstance ;Set The Instance
 wc\hIcon=LoadIcon_(#Null,#IDI_WINLOGO) ;Load The Default Icon
 wc\hCursor=LoadCursor_(#Null,#IDC_ARROW) ;Load The Arrow Pointer
 wc\hbrBackground=#Null ;No Background Required For GL
 wc\lpszMenuName=#Null ;We Don't Want A Menu
 wc\lpszClassName=@"OpenGL" ;Set The Class Name  
 
 If RegisterClass_(wc)=0 ;Attempt To Register The Window Class
  MessageBox_(#Null,"Failed To Register The Window Class.","ERROR",#MB_OK | #MB_ICONEXCLAMATION)
  ProcedureReturn #False
 EndIf
 
 If fullscreen ;Attempt Fullscreen Mode?
 
  Protected dmScreenSettings.DEVMODE ;Device Mode
  dmScreenSettings\dmSize=SizeOf(DEVMODE) ;Size Of The Devmode Structure
  dmScreenSettings\dmFields=#DM_BITSPERPEL | #DM_PELSWIDTH | #DM_PELSHEIGHT ;bit flags to specify the members of DEVMODE that were initialized
  dmScreenSettings\dmBitsPerPel=bits ;Selected Bits Per Pixel
  dmScreenSettings\dmPelsWidth=width ;Selected Screen Width in pixels
  dmScreenSettings\dmPelsHeight=height ;Selected Screen Height in pixels
  
  ;Try To Set Selected Mode And Get Results. Note: CDS_FULLSCREEN Gets Rid Of Start Bar
  If ChangeDisplaySettings_(dmScreenSettings,#CDS_FULLSCREEN)<>#DISP_CHANGE_SUCCESSFUL
   ;If The Mode Fails, Offer Two Options. Quit Or Use Windowed Mode
   If MessageBox_(#Null,"The Requested Fullscreen Mode Is Not Supported By"+Chr(10)+"Your Video Card. Use Windowed Mode Instead?","NeHe GL",#MB_YESNO | #MB_ICONEXCLAMATION)=#IDYES
    fullscreen=#False ;Windowed Mode Selected.  Fullscreen = FALSE
   Else
    ;Pop Up A Message Box Letting User Know The Program Is Closing
    MessageBox_(#Null,"Program Will Now Close.","ERROR",#MB_OK | #MB_ICONSTOP)
    ProcedureReturn #False
   EndIf
  EndIf
  
 EndIf
 
 If fullscreen ;Are We Still In Fullscreen Mode?
  dwExStyle=#WS_EX_APPWINDOW ;Window Extended Style
  dwStyle=#WS_POPUP ;Windows Style
  ShowCursor_(#False) ;Hide Mouse Pointer
 Else
  dwExStyle=#WS_EX_APPWINDOW | #WS_EX_WINDOWEDGE ;Window Extended Style
  dwStyle=#WS_OVERLAPPEDWINDOW ;Windows Style
 EndIf
 
 AdjustWindowRectEx_(WindowRect,dwStyle,#False,dwExStyle) ;Adjust Window To True Requested Size
 
 If fullscreen=0 ;if not fullscreen mode calculate screen centered window
  wpos\x=(GetSystemMetrics_(#SM_CXSCREEN)/2)-((WindowRect\right-WindowRect\left)/2)
  wpos\y=(GetSystemMetrics_(#SM_CYSCREEN)/2)-((WindowRect\bottom-WindowRect\top)/2)
 EndIf
 
 ;CreateWindowEx_(Extended Window Style, Class Name, Window Title, Window Style, Window X Position, Window Y Position, Width, Height, No Parent Window, No Menu, Instance, No Creation Data)
 hWnd=CreateWindowEx_(dwExStyle,"OpenGL",title,dwStyle | #WS_CLIPSIBLINGS | #WS_CLIPCHILDREN,wpos\x,wpos\y,WindowRect\right-WindowRect\left,WindowRect\bottom-WindowRect\top,#Null,#Null,hInstance,#Null)
 If hWnd=0
  KillGLWindow() ;Reset The Display
  MessageBox_(#Null,"Window Creation Error.","ERROR",#MB_OK | #MB_ICONEXCLAMATION)
  ProcedureReturn #False
 EndIf
 
 Protected pfd.PIXELFORMATDESCRIPTOR ;pfd Tells Windows How We Want Things To Be
 pfd\nSize=SizeOf(PIXELFORMATDESCRIPTOR) ;Size Of This Structure
 pfd\nVersion=1 ;Version Number
 pfd\dwFlags=#PFD_SUPPORT_OPENGL | #PFD_DOUBLEBUFFER | #PFD_DRAW_TO_WINDOW ;Format Must Support Window, OpenGL, Double Buffering
 pfd\iPixelType=#PFD_TYPE_RGBA ;Request An RGBA Format
 pfd\cColorBits=bits ;Select Our Color Depth
 pfd\cRedBits=0 ;Color Bits Ignored
 pfd\cRedShift=0
 pfd\cGreenBits=0
 pfd\cGreenShift=0
 pfd\cBlueBits=0
 pfd\cBlueShift=0
 pfd\cAlphaBits=0 ;No Alpha Buffer
 pfd\cAlphaShift=0 ;Shift Bit Ignored
 pfd\cAccumBits=0 ;No Accumulation Buffer
 pfd\cAccumRedBits=0 ;Accumulation Bits Ignored
 pfd\cAccumGreenBits=0
 pfd\cAccumBlueBits=0
 pfd\cAccumAlphaBits=0
 pfd\cDepthBits=16 ;16Bit Z-Buffer (Depth Buffer)
 pfd\cStencilBits=0 ;No Stencil Buffer
 pfd\cAuxBuffers=0 ;No Auxiliary Buffer
 pfd\iLayerType=#PFD_MAIN_PLANE ;Main Drawing Layer
 pfd\bReserved=0 ;Reserved
 pfd\dwLayerMask=0 ;Layer Masks Ignored
 pfd\dwVisibleMask=0
 pfd\dwDamageMask=0
 
 hDC=GetDC_(hWnd)
 If hDC=0 ;Did We Get A Device Context?
  KillGLWindow() ;Reset The Display
  MessageBox_(#Null,"Can't Create A GL Device Context.","ERROR",#MB_OK | #MB_ICONEXCLAMATION)
  ProcedureReturn #False
 EndIf
 
 PixelFormat=ChoosePixelFormat_(hDC,pfd)
 If PixelFormat=0 ;Did Windows Find A Matching Pixel Format?
  KillGLWindow() ;Reset The Display
  MessageBox_(#Null,"Can't Find A Suitable PixelFormat.","ERROR",#MB_OK | #MB_ICONEXCLAMATION)
  ProcedureReturn #False
 EndIf
 
 If SetPixelFormat_(hDC,PixelFormat,pfd)=0 ;Are We Able To Set The Pixel Format?
  KillGLWindow() ;Reset The Display
  MessageBox_(#Null,"Can't Set The PixelFormat.","ERROR",#MB_OK | #MB_ICONEXCLAMATION)
  ProcedureReturn #False
 EndIf
 
 hRC=wglCreateContext_(hDC)
 If hRC=0 ;Are We Able To Get A Rendering Context?
  KillGLWindow() ;Reset The Display
  MessageBox_(#Null,"Can't Create A GL Rendering Context.","ERROR",#MB_OK | #MB_ICONEXCLAMATION)
  ProcedureReturn #False
 EndIf
 
 If wglMakeCurrent_(hDC,hRC)=0 ;Try To Activate The Rendering Context
  KillGLWindow() ;Reset The Display
  MessageBox_(#Null,"Can't Activate The GL Rendering Context.","ERROR",#MB_OK | #MB_ICONEXCLAMATION)
  ProcedureReturn #False
 EndIf
 
 ShowWindow_(hWnd,#SW_SHOW) ;Show The Window
 SetForegroundWindow_(hWnd) ;Slightly Higher Priority
 SetFocus_(hWnd) ;Sets Keyboard Focus To The Window
 ReSizeGLScene(width,height) ;Set Up Our Perspective GL Screen
 
 If InitGL()=0 ;Initialize Our Newly Created GL Window
  KillGLWindow() ;Reset The Display
  MessageBox_(#Null,"Initialization Failed.","ERROR",#MB_OK | #MB_ICONEXCLAMATION)
  ProcedureReturn #False
 EndIf
 
 ProcedureReturn #True ;Success
 
EndProcedure

Procedure.l WndProc(hWnd.l,uMsg.l,wParam.l,lParam.l)

 Select uMsg ;Check For Windows Messages
 
  Case #WM_ACTIVATE ;Watch For Window Activate Message
   If HiWord(wParam)=0 ;Check Minimization State
    active=#True ;Program Is Active
   Else
    active=#False ;Program Is No Longer Active
   EndIf
   ProcedureReturn 0 ;Return To The Message Loop
   
  Case #WM_SYSCOMMAND ;Intercept System Commands
   Select wParam ;Check System Calls
    Case #SC_SCREENSAVE ;Screensaver Trying To Start?
     ProcedureReturn 0 ;Prevent From Happening
    Case #SC_MONITORPOWER ;Monitor Trying To Enter Powersave?
     ProcedureReturn 0 ;Prevent From Happening
   EndSelect
   
  Case #WM_CLOSE ;Did We Receive A Close Message?
   PostQuitMessage_(0) ;Send A Quit Message 
   ProcedureReturn 0 ;Jump Back
   
  Case #WM_KEYDOWN ;Is A Key Being Held Down?
   keys(wParam)=#True ;If So, Mark It As TRUE
   ProcedureReturn 0 ;Jump Back
   
  Case #WM_KEYUP ;Has A Key Been Released?
   keys(wParam)=#False ;If So, Mark It As FALSE
   ProcedureReturn 0 ;Jump Back
   
  Case #WM_SIZE ;Resize The OpenGL Window
   ReSizeGLScene(LoWord(lParam),HiWord(lParam)) ;LoWord=Width, HiWord=Height
   ProcedureReturn 0 ;Jump Back
   
 EndSelect
 
 ;Pass All Unhandled Messages To DefWindowProc
 ProcedureReturn DefWindowProc_(hWnd,uMsg,wParam,lParam)
 
EndProcedure

Procedure.l WinMain() ;Main Program

 Protected msg.MSG ;Windows Message Structure
 Protected done.b ;Bool Variable To Exit Loop
 
 ;Ask The User Which Screen Mode They Prefer
 If MessageBox_(#Null,"Would You Like To Run In Fullscreen Mode?","Start FullScreen?",#MB_YESNO | #MB_ICONQUESTION)=#IDNO
  fullscreen=#False ;Windowed Mode
 EndIf
 
 If CreateGLWindow("Chris Aliotta & NeHe's Fog Tutorial",640,480,16,fullscreen)=0 ;Create The Window
  ProcedureReturn 0 ;Quit If Window Was Not Created
 EndIf
 
 While done=#False ;Loop That Runs While done=FALSE
 
  If PeekMessage_(msg,#Null,0,0,#PM_REMOVE) ;Is There A Message Waiting?
  
   If msg\message=#WM_QUIT ;Have We Received A Quit Message?
    done=#True ;If So done=TRUE
   Else ;If Not, Deal With Window Messages
    TranslateMessage_(msg) ;Translate The Message
    DispatchMessage_(msg) ;Dispatch The Message
   EndIf
   
  Else ;If There Are No Messages
  
   ;Draw The Scene. Watch For ESC Key And Quit Messages From DrawGLScene()
   If (active And DrawGLScene()=0) Or keys(#VK_ESCAPE) ;Active? Was There A Quit Received?
   
    done=#True ;ESC or DrawGLScene Signalled A Quit
    
   Else ;Not Time To Quit, Update Screen
   
    SwapBuffers_(hDC) ;Swap Buffers (Double Buffering)
    
    If keys(#VK_L) And lp=0 ;L Key Being Pressed Not Held?
     lp=#True ;lp Becomes TRUE
     light=~light & 1 ;Toggle Light TRUE/FALSE
     If light=0 ;If Not Light
      glDisable_(#GL_LIGHTING) ;Disable Lighting
     Else ;Otherwise
      glEnable_(#GL_LIGHTING) ;Enable Lighting
     EndIf
    EndIf
    If keys(#VK_L)=0 ;Has L Key Been Released?
     lp=#False ;If So, lp Becomes FALSE
    EndIf
    
    If keys(#VK_F) And fp=0 ;Is F Key Being Pressed?
     fp=#True ;fp Becomes TRUE
     filter+1 ;filter Value Increases By One
     If filter>2 ;Is Value Greater Than 2?
      filter=0 ;If So, Set filter To 0
     EndIf
    EndIf
    If keys(#VK_F)=0 ;Has F Key Been Released?
     fp=#False ;If So, fp Becomes FALSE
    EndIf
    
    If keys(#VK_PRIOR) ;Is Page Up Being Pressed?
     z-0.02 ;If So, Move Into The Screen
    EndIf
    If keys(#VK_NEXT) ;Is Page Down Being Pressed?
     z+0.02 ;If So, Move Towards The Viewer
    EndIf
    
    If keys(#VK_UP) And xspeed>-0.5 ;Is Up Arrow Being Pressed?
     xspeed-0.01 ;If So, Decrease xspeed
    EndIf
    If keys(#VK_DOWN) And xspeed<0.5 ;Is Down Arrow Being Pressed?
     xspeed+0.01 ;If So, Increase xspeed
    EndIf
    If keys(#VK_RIGHT) And yspeed<0.5 ;Is Right Arrow Being Pressed?
     yspeed+0.01 ;If So, Increase yspeed
    EndIf
    If keys(#VK_LEFT) And yspeed>-0.5 ;Is Left Arrow Being Pressed?
     yspeed-0.01 ;If So, Decrease yspeed
    EndIf
    
    If keys(#VK_G) And gp=0 ;Is The G Key Being Pressed?
     gp=#True ;gp Is Set To TRUE
     fogfilter+1 ;Increase fogfilter By One
     If fogfilter>2 ;Is fogfilter Greater Than 2?
      fogfilter=0 ;If So, Set fogfilter To 0
     EndIf
     glFogi_(#GL_FOG_MODE,fogMode(fogfilter)) ;Fog Mode
    EndIf
    If keys(#VK_G)=0 ;Has The G Key Been Released?
     gp=#False ;If So, gp Is Set To FALSE
    EndIf
    
   EndIf
   
   If keys(#VK_F1) ;Is F1 Being Pressed?
    keys(#VK_F1)=#False ;If So Make Key FALSE
    KillGLWindow() ;Kill Our Current Window
    fullscreen=~fullscreen & 1 ;Toggle Fullscreen / Windowed Mode
    ;Recreate Our OpenGL Window
    If CreateGLWindow("Chris Aliotta & NeHe's Fog Tutorial",640,480,16,fullscreen)=0
     ProcedureReturn 0 ;Quit If Window Was Not Created
    EndIf
   EndIf
   
  EndIf
  
 Wend
 
 ;Shutdown
 KillGLWindow() ;Kill The Window
 End ;Exit The Program
 
EndProcedure

WinMain() ;run the main program

Last edited by hagibaba on Sun Jul 01, 2007 11:15 pm, edited 9 times in total.
PB
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Joined: Fri Apr 25, 2003 5:24 pm

Re: Chris Aliotta & NeHe's Fog Tutorial (Lesson 16)

Post by PB »

While I haven't done game programming, I just wanted to thank you for
posting all your tutorials here. I will (hopefully) get around to studying them
all one day.
I compile using 5.31 (x86) on Win 7 Ultimate (64-bit).
"PureBasic won't be object oriented, period" - Fred.
User avatar
netmaestro
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Posts: 8425
Joined: Wed Jul 06, 2005 5:42 am
Location: Fort Nelson, BC, Canada

Post by netmaestro »

Great job! The fog looks so realistic. Thanks for sharing.

p.s. Why is their crate.bmp not 24bit RGB color? It needs to be converted before it shows correctly, I dunno why they're distributing the graphic in that format. :?:
BERESHEIT
hagibaba
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Location: UK
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Post by hagibaba »

PB, thanks for the feedback.

netmaestro, actually this was an easy one. It doesn't take much code to add fog in OpenGL.

The "Crate.bmp" is 8-bit because the tutorials were originally written using the glAux.dll which can load 8-bit and 24-bit bitmaps.
I couldn't get that code working so I used the "glAux replacement" code which uses LoadImage_() and that only loads 24-bit bitmaps.
I would like to write a better bitmap loading procedure some time, as loading 8-bit bmps is very useful.
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Post by Mistrel »

I get an invalid memory access error when I try to compile this with PB 4.1. :(
mpz
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Re: Chris Aliotta & NeHe's Fog Tutorial (Lesson 16)

Post by mpz »

Hello,

next code actualised for x86/x64, PB 5.73.

you can choose a purebasic texture or get the original from the internet

P.S:I think the code can work with linux and mac Osx too.


Greetings Michael

C Code and texture
iamyaker.googlepages.com/16_Fog.rar

Code: Select all

;Chris Aliotta & NeHe's Fog Tutorial (Lesson 16)
;http://nehe.gamedev.net 
;https://nehe.gamedev.net/tutorial/cool_looking_fog/19001/
;Credits: Nico Gruener, Dreglor, traumatic, hagibaba
;Author: MPz
;Date: 04 Oct 2021
;Note: up-to-date with PB v5.73 (Windows)

UsePNGImageDecoder() 

Global light.b ;Lighting ON/OFF
Global lp.b ;L Pressed?
Global fp.b ;F Pressed?
Global gp.b ;G Pressed? ( NEW )

Global xrot.f ;X Rotation
Global yrot.f ;Y Rotation
Global xspeed.f ;X Rotation Speed
Global yspeed.f ;Y Rotation Speed
Global z.f=-5.0 ;Depth Into The Screen

Global Dim LightAmbient.f(4) ;Ambient Light Values
 LightAmbient(0)=0.5 ;red
 LightAmbient(1)=0.5 ;green
 LightAmbient(2)=0.5 ;blue
 LightAmbient(3)=1.0 ;alpha
 
Global Dim LightDiffuse.f(4) ;Diffuse Light Values
 LightDiffuse(0)=1.0 ;red
 LightDiffuse(1)=1.0 ;green
 LightDiffuse(2)=1.0 ;blue
 LightDiffuse(3)=1.0 ;alpha
 
Global Dim LightPosition.f(4) ;Light Position
 LightPosition(0)=0.0 ;x
 LightPosition(1)=0.0 ;y
 LightPosition(2)=2.0 ;z
 LightPosition(3)=1.0 ;w
 
Global filter.l ;Which Filter To Use
Global Dim texture.l(3) ;Storage For 3 Textures

Global Dim fogMode.l(3) ;Storage For Three Types Of Fog ( NEW )
 fogMode(0)=#GL_EXP ;default
 fogMode(1)=#GL_EXP2 ;exponent^2
 fogMode(2)=#GL_LINEAR ;linear
 
Global fogfilter.l=0 ;Which Fog Mode To Use ( NEW )

Global Dim fogColor.FLOAT(4) ;Fog Color ( NEW )
 fogColor(0)\f=0.5 ;red
 fogColor(1)\f=0.5 ;green
 fogColor(2)\f=0.5 ;blue
 fogColor(3)\f=1.0 ;alpha

Procedure LoadGLTextures(Names.s)
  
  LoadImage(0, Names) ; Load texture with name
  *pointer = EncodeImage(0, #PB_ImagePlugin_BMP,0 ,24 );  
  FreeImage(0)
  	
  glGenTextures_(3, @Texture(0));                  // Create Three Textures

  ;// Create Nearest Filtered Texture
  glBindTexture_(#GL_TEXTURE_2D, Texture(0));
  glTexParameteri_(#GL_TEXTURE_2D,#GL_TEXTURE_MAG_FILTER,#GL_NEAREST); // ( NEW )
  glTexParameteri_(#GL_TEXTURE_2D,#GL_TEXTURE_MIN_FILTER,#GL_NEAREST); // ( NEW )
  glTexImage2D_(#GL_TEXTURE_2D, 0, 3,PeekL(*pointer+18), PeekL(*pointer+22), 0, #GL_BGR_EXT, #GL_UNSIGNED_BYTE, *pointer+54);
  ;// Create Linear Filtered Texture
  glBindTexture_(#GL_TEXTURE_2D, Texture(1));
  glTexParameteri_(#GL_TEXTURE_2D,#GL_TEXTURE_MAG_FILTER,#GL_LINEAR);
  glTexParameteri_(#GL_TEXTURE_2D,#GL_TEXTURE_MIN_FILTER,#GL_LINEAR);
  glTexImage2D_(#GL_TEXTURE_2D, 0, 3, PeekL(*pointer+18),PeekL(*pointer+22), 0, #GL_BGR_EXT, #GL_UNSIGNED_BYTE, *pointer+54);
  ;// Create MipMapped Texture
  glBindTexture_(#GL_TEXTURE_2D, Texture(2));
  glTexParameteri_(#GL_TEXTURE_2D,#GL_TEXTURE_MAG_FILTER,#GL_LINEAR);
  glTexParameteri_(#GL_TEXTURE_2D,#GL_TEXTURE_MIN_FILTER,#GL_LINEAR_MIPMAP_NEAREST); // ( NEW )
  gluBuild2DMipmaps_(#GL_TEXTURE_2D, 3, PeekL(*pointer+18),PeekL(*pointer+22), #GL_BGR_EXT, #GL_UNSIGNED_BYTE, *pointer+54); // ( NEW )
  
  FreeMemory(*pointer)
  
EndProcedure

Procedure ReSizeGLScene(width.l,height.l) ;Resize And Initialize The GL Window

 If height=0 : height=1 : EndIf ;Prevent A Divide By Zero Error
 
 ResizeGadget(0, 0, 0, width, height)
 
 glViewport_(0,0,width,height) ;Reset The Current Viewport
 
 glMatrixMode_(#GL_PROJECTION) ;Select The Projection Matrix
 glLoadIdentity_() ;Reset The Projection Matrix
 
 gluPerspective_(45.0,Abs(width/height),0.1,100.0) ;Calculate The Aspect Ratio Of The Window
 
 glMatrixMode_(#GL_MODELVIEW) ;Select The Modelview Matrix
 glLoadIdentity_() ;Reset The Modelview Matrix
 
EndProcedure

Procedure.l InitGL() ;All Setup For OpenGL Goes Here

 glEnable_(#GL_TEXTURE_2D) ;Enable Texture Mapping
 glShadeModel_(#GL_SMOOTH) ;Enable Smooth Shading
 glClearColor_(0.5,0.5,0.5,1.0) ;We'll Clear To The Color Of The Fog
 glClearDepth_(1.0) ;Depth Buffer Setup
 glEnable_(#GL_DEPTH_TEST) ;Enables Depth Testing
 glDepthFunc_(#GL_LEQUAL) ;The Type Of Depth Testing To Do
 glHint_(#GL_PERSPECTIVE_CORRECTION_HINT,#GL_NICEST) ;Really Nice Perspective Calculations
 
 glLightfv_(#GL_LIGHT1,#GL_AMBIENT,LightAmbient()) ;Setup The Ambient Light
 glLightfv_(#GL_LIGHT1,#GL_DIFFUSE,LightDiffuse()) ;Setup The Diffuse Light
 glLightfv_(#GL_LIGHT1,#GL_POSITION,LightPosition()) ;Position The Light
 glEnable_(#GL_LIGHT1) ;Enable Light One
 
 glFogi_(#GL_FOG_MODE,fogMode(fogfilter)) ;Fog Mode
 glFogfv_(#GL_FOG_COLOR,fogColor(0)) ;Set Fog Color
 glFogf_(#GL_FOG_DENSITY,0.35) ;How Dense Will The Fog Be
 glHint_(#GL_FOG_HINT,#GL_DONT_CARE) ;Fog Hint Value
 glFogf_(#GL_FOG_START,1.0) ;Fog Start Depth
 glFogf_(#GL_FOG_END,5.0) ;Fog End Depth
 glEnable_(#GL_FOG) ;Enables GL_FOG
 
 ProcedureReturn #True ;Initialization Went OK
 
EndProcedure

Procedure DrawScene(Gadget)
  
 SetGadgetAttribute(Gadget, #PB_OpenGL_SetContext, #True)
  
 glClear_(#GL_COLOR_BUFFER_BIT | #GL_DEPTH_BUFFER_BIT) ;Clear The Screen And The Depth Buffer
 glLoadIdentity_() ;Reset The View
 
 glTranslatef_(0.0,0.0,z) ;Translate Into/Out Of The Screen By z
 
 glRotatef_(xrot,1.0,0.0,0.0) ;Rotate On The X Axis By xrot
 glRotatef_(yrot,0.0,1.0,0.0) ;Rotate On The Y Axis By yrot
 
 glBindTexture_(#GL_TEXTURE_2D,texture(filter)) ;Select A Texture Based On filter
 
 glBegin_(#GL_QUADS) ;Start Drawing Quads
  ;Front Face
  glNormal3f_( 0.0, 0.0, 1.0) ;Normal Pointing Towards Viewer
  glTexCoord2f_(0.0, 0.0) : glVertex3f_(-1.0,-1.0, 1.0) ;Point 1 (Front)
  glTexCoord2f_(1.0, 0.0) : glVertex3f_( 1.0,-1.0, 1.0) ;Point 2 (Front)
  glTexCoord2f_(1.0, 1.0) : glVertex3f_( 1.0, 1.0, 1.0) ;Point 3 (Front)
  glTexCoord2f_(0.0, 1.0) : glVertex3f_(-1.0, 1.0, 1.0) ;Point 4 (Front)
  ;Back Face
  glNormal3f_( 0.0, 0.0,-1.0) ;Normal Pointing Away From Viewer
  glTexCoord2f_(1.0, 0.0) : glVertex3f_(-1.0,-1.0,-1.0) ;Point 1 (Back)
  glTexCoord2f_(1.0, 1.0) : glVertex3f_(-1.0, 1.0,-1.0) ;Point 2 (Back)
  glTexCoord2f_(0.0, 1.0) : glVertex3f_( 1.0, 1.0,-1.0) ;Point 3 (Back)
  glTexCoord2f_(0.0, 0.0) : glVertex3f_( 1.0,-1.0,-1.0) ;Point 4 (Back)
  ;Top Face
  glNormal3f_( 0.0, 1.0, 0.0) ;Normal Pointing Up
  glTexCoord2f_(0.0, 1.0) : glVertex3f_(-1.0, 1.0,-1.0) ;Point 1 (Top)
  glTexCoord2f_(0.0, 0.0) : glVertex3f_(-1.0, 1.0, 1.0) ;Point 2 (Top)
  glTexCoord2f_(1.0, 0.0) : glVertex3f_( 1.0, 1.0, 1.0) ;Point 3 (Top)
  glTexCoord2f_(1.0, 1.0) : glVertex3f_( 1.0, 1.0,-1.0) ;Point 4 (Top)
  ;Bottom Face
  glNormal3f_( 0.0,-1.0, 0.0) ;Normal Pointing Down
  glTexCoord2f_(1.0, 1.0) : glVertex3f_(-1.0,-1.0,-1.0) ;Point 1 (Bottom)
  glTexCoord2f_(0.0, 1.0) : glVertex3f_( 1.0,-1.0,-1.0) ;Point 2 (Bottom)
  glTexCoord2f_(0.0, 0.0) : glVertex3f_( 1.0,-1.0, 1.0) ;Point 3 (Bottom)
  glTexCoord2f_(1.0, 0.0) : glVertex3f_(-1.0,-1.0, 1.0) ;Point 4 (Bottom)
  ;Right face
  glNormal3f_( 1.0, 0.0, 0.0) ;Normal Pointing Right
  glTexCoord2f_(1.0, 0.0) : glVertex3f_( 1.0,-1.0,-1.0) ;Point 1 (Right)
  glTexCoord2f_(1.0, 1.0) : glVertex3f_( 1.0, 1.0,-1.0) ;Point 2 (Right)
  glTexCoord2f_(0.0, 1.0) : glVertex3f_( 1.0, 1.0, 1.0) ;Point 3 (Right)
  glTexCoord2f_(0.0, 0.0) : glVertex3f_( 1.0,-1.0, 1.0) ;Point 4 (Right)
  ;Left Face
  glNormal3f_(-1.0, 0.0, 0.0) ;Normal Pointing Left
  glTexCoord2f_(0.0, 0.0) : glVertex3f_(-1.0,-1.0,-1.0) ;Point 1 (Left)
  glTexCoord2f_(1.0, 0.0) : glVertex3f_(-1.0,-1.0, 1.0) ;Point 2 (Left)
  glTexCoord2f_(1.0, 1.0) : glVertex3f_(-1.0, 1.0, 1.0) ;Point 3 (Left)
  glTexCoord2f_(0.0, 1.0) : glVertex3f_(-1.0, 1.0,-1.0) ;Point 4 (Left)
 glEnd_() ;Done Drawing Quads
 
 xrot+xspeed ;Add xspeed To xrot
 yrot+yspeed ;Add yspeed To yrot
 
 SetGadgetAttribute(Gadget, #PB_OpenGL_FlipBuffers, #True)
EndProcedure

Procedure CreateGLWindow(title.s,WindowWidth.l,WindowHeight.l,bits.l=16,fullscreenflag.b=0,Vsync.b=0)
  
  If InitKeyboard() = 0 Or InitSprite() = 0 Or InitMouse() = 0
    MessageRequester("Error", "Can't initialize Keyboards or Mouse", 0)
    End
  EndIf

  If fullscreenflag
    hWnd = OpenWindow(0, 0, 0, WindowWidth, WindowHeight, title, #PB_Window_BorderLess|#PB_Window_Maximize )
    OpenWindowedScreen(WindowID(0), 0, 0,WindowWidth(0),WindowHeight(0)) 
  Else  
    hWnd = OpenWindow(0, 1, 1, WindowWidth, WindowHeight, title,#PB_Window_MinimizeGadget |  #PB_Window_MaximizeGadget | #PB_Window_SizeGadget ) 
    OpenWindowedScreen(WindowID(0), 1, 1, WindowWidth,WindowHeight) 
  EndIf
  
  If bits = 24
    OpenGlFlags + #PB_OpenGL_24BitDepthBuffer
  EndIf
  
  If Vsync = 0
    OpenGlFlags + #PB_OpenGL_NoFlipSynchronization
  EndIf
  
  OpenGLGadget(0, 0, 0, WindowWidth(0),WindowHeight(0),OpenGlFlags)
  
  SetActiveGadget(0) 
  
  ReSizeGLScene(WindowWidth(0),WindowHeight(0))
  ;hDC = GetDC_(hWnd)
  
EndProcedure

CreateGLWindow("Chris Aliotta & NeHe's Fog Tutorial (Lesson 16)",640,480,16,0)

InitGL()

LoadGLTextures(#PB_Compiler_Home + "examples/3d/Data/Textures/Caisse.png")
;LoadGLTextures("Data/Crate.bmp") ; -> Original from http://nehe.gamedev.net

Repeat

  Repeat 
    Event = WindowEvent()
    
    Select Event
      Case #PB_Event_CloseWindow
        Quit = 1
      Case #PB_Event_SizeWindow  
        ReSizeGLScene(WindowWidth(0),WindowHeight(0)) ;LoWord=Width, HiWord=Height
    EndSelect
  
  Until Event = 0
  
  ExamineKeyboard()
        
  If KeyboardPushed(#PB_Key_Escape)    ; // push ESC key
    Quit = 1                           ; // This is the end
  EndIf
  
  If KeyboardPushed(#PB_Key_L) And lp=0 ;L Key Being Pressed Not Held?
    lp=#True ;lp Becomes TRUE
    light=~light & 1 ;Toggle Light TRUE/FALSE
    If light=0 ;If Not Light
      glDisable_(#GL_LIGHTING) ;Disable Lighting
    Else ;Otherwise
      glEnable_(#GL_LIGHTING) ;Enable Lighting
    EndIf
  EndIf
   
  If Not KeyboardPushed(#PB_Key_L) ;Has L Key Been Released?
    lp=#False ;If So, lp Becomes FALSE
  EndIf
    
  If KeyboardPushed(#PB_Key_F) And fp=0 ;Is F Key Being Pressed?
      fp=#True ;fp Becomes TRUE
      filter+1 ;filter Value Increases By One
      If filter>2 ;Is Value Greater Than 2?
        filter=0 ;If So, Set filter To 0
      EndIf
  EndIf
    
  If Not KeyboardPushed(#PB_Key_F) ;Has F Key Been Released?
      fp=#False ;If So, fp Becomes FALSE
  EndIf
    
  If KeyboardPushed(#PB_Key_PageUp) ;Is Page Up Being Pressed?
      z-0.02 ;If So, Move Into The Screen
  EndIf
    
  If KeyboardPushed(#PB_Key_PageDown) ;Is Page Down Being Pressed?
      z+0.02 ;If So, Move Towards The Viewer
  EndIf
    
  If KeyboardPushed(#PB_Key_Up) And xspeed>-0.5 ;Is Up Arrow Being Pressed?
      xspeed-0.01 ;If So, Decrease xspeed
  EndIf
    
  If KeyboardPushed(#PB_Key_Down) And xspeed<0.5 ;Is Down Arrow Being Pressed?
     xspeed+0.01 ;If So, Increase xspeed
  EndIf
    
  If KeyboardPushed(#VK_RIGHT) And yspeed<0.5 ;Is Right Arrow Being Pressed?
     yspeed+0.01 ;If So, Increase yspeed
  EndIf
    
  If KeyboardPushed(#VK_LEFT) And yspeed>-0.5 ;Is Left Arrow Being Pressed?
     yspeed-0.01 ;If So, Decrease yspeed
  EndIf
    
  If KeyboardPushed(#VK_G) And gp=0 ;Is The G Key Being Pressed?
     gp=#True ;gp Is Set To TRUE
     fogfilter+1 ;Increase fogfilter By One
     If fogfilter>2 ;Is fogfilter Greater Than 2?
        fogfilter=0 ;If So, Set fogfilter To 0
     EndIf
     glFogi_(#GL_FOG_MODE,fogMode(fogfilter)) ;Fog Mode
  EndIf
    
  If Not KeyboardPushed(#VK_G) ;Has The G Key Been Released?
     gp=#False ;If So, gp Is Set To FALSE
  EndIf
  
  DrawScene(0)
  Delay(10)
Until Quit = 1

Working on - MP3D Library - PB 5.73 version ready for download
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