Vertex lighting

This code has been declared by its author to be Public Domain code.

Vertex lighting by Ice9

2002

A couple of functions to do vertex lighting for your environment. Thanks to Ravey for giving me the idea. It will allow you to have an unlimited number of lights. Hope it's useful to someone.

Graphics3D 640,480,16
;AmbientLight 0,0,0
For x=1 To 5
	For y= 1 To 5
		For z= 1 To 5
			sphere=CreateSphere( 32 )
			PositionEntity sphere,x*5,y*5,z*5
			ApplyAmbient(sphere,32,32,32)
			ApplyLight(sphere,25,0,0,20,1,255,32,32)
			ApplyLight(sphere,0,0,0,20,1,32,32,255)
			ApplyLight(sphere,12.5,25,0,20,1,32,255,32)				
			ApplyLight(sphere,25,0,15,20,1,32,255,32)
			ApplyLight(sphere,0,0,15,20,1,255,32,32)
			ApplyLight(sphere,12.5,25,15,20,1,32,32,255)
			ApplyLight(sphere,25,0,20,20,1,32,255,255)
			ApplyLight(sphere,0,0,20,20,1,255,255,32)
			ApplyLight(sphere,12.5,25,20,20,1,255,32,255)
			ApplyLight(sphere,12.5,12.5,12.5,20,1,255,255,255)						
			EntityFX sphere,3
		Next
	Next
Next


camera=CreateCamera()
PositionEntity camera,12,12,2
RotateEntity camera,0,0,315

While Not KeyHit(1)		
	UpdateWorld
	RenderWorld
	Flip
Wend


Function ApplyLight(entity,LX#,LY#,LZ#,radius#,flag,Lr,Lg,Lb)
 ;Lambert shading in blitz "by Staton Richardson (Arbitrage)"	
 ;This function is meant for 1 time lighting not realtime	
 ;entity is the entity you wish to light
 ;LX, LY, LZ are the coodinates of the light in world space
 ;Lr, Lg, Lb are the colors of the light
 ;radius is the radius the light affects. Light falls off with distance so half the radius would be half the light
 ;flag tells the function to include the current vertex color for multiple lights 
 
 
 count=CountSurfaces(entity) 
 For n=1 To count
  surf=GetSurface(entity,n) 
  Vcount=CountVertices(surf)-1 
  For v=0 To Vcount          
         xd#=VertexX(surf,v)+EntityX(entity)-LX#
         yd#=VertexY(surf,v)+EntityY(entity)-LY#
         zd#=VertexZ(surf,v)+EntityZ(entity)-LZ#
   mag#=Sqr(xd#*xd# + yd#*yd# + zd#*zd#)
                
   If flag=1
    vcr=VertexRed(surf,v)
    vcg=VertexGreen(surf,v)
    vcb=VertexBlue(surf,v)
   EndIf    
    
   vr=Lr-(Lr/radius)*mag#
   vg=Lg-(Lg/radius)*mag#
   vb=Lb-(Lb/radius)*mag# 
       
   If vr>255 Then vr=255
   If vg>255 Then vg=255
   If vb>255 Then vb=255 
 
   vx#=VertexNX(surf,v)
   vy#=VertexNY(surf,v)
   vz#=VertexNZ(surf,v)
    
   mag#=1/mag#
   LnY#=yd#*mag#*-1
   LnX#=xd#*mag#*-1
   LnZ#=zd#*mag#*-1
    
   Kh#=((vx)*LnX+(vy)*LnY+(vz)*LnZ)
   If kh#>0 
          VertexColor surf,v,vr*Kh#+vcr,vg*Kh#+vcg,vb*Kh#+vcb
   EndIf  
 
  Next   
 Next 
End Function


Function ApplyAmbient(entity,r,g,b)		
	
	count=CountSurfaces(entity)	
	For n=1 To count
		surf=GetSurface(entity,n)	
		Vcount=CountVertices(surf)-1	
		For v=0 To Vcount
        	VertexColor surf,v,r,g,b		
		Next			
	Next

End Function

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