[bb] Displacement Mapping by Ziltch [ 1+ years ago ]

Started by BlitzBot, June 29, 2017, 00:28:43

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June 29, 2017, 00:28:43
Title : Displacement Mapping
Author : Ziltch
Posted : 1+ years ago

Description : Here is a displacement mapping function and some routines to show it off.

Function displace(mesh,texture,texsize#=256,amp#=1,wrap=false)

Mesh = the entity you wish to modify
The texture needs to be square ie 256=256x256,512=512x512
amp = The heightmap.
The wrap command is my attempt at handling spheres, etc.

You need lots of vertices in a object for this to look good.  So it not for the polygon shy!

In the example code press the space bar to bumpmap and create simple random landscapes.

The bumpmap function also needs the numcolor and gettetxcol functions if you with to use it in your own code.

Have fun!

Code :
Code (blitzbasic) Select
; Vetex displacment mapping function and example code
; ADAmor Ziltch 2002

Graphics3D 800,600
SetBuffer BackBuffer()

light=CreateLight(2)
PositionEntity light,-1000,50,-10
LightColor     light,255,255,40
light2=CreateLight(2)
PositionEntity light2,1000,50,-10
LightColor     light,55,55,255
light3=CreateLight(2)
PositionEntity light2,0,50,1000
LightColor     light,220,210,55
AmbientLight   125,125,7

Global you = CreatePivot()
PositionEntity you,0,00,-300
cam = CreateCamera(you)
camerarange    cam,1,5000

.createscene

;--cube grid
Global cubegrid = createsquare(51)
PositionEntity cubegrid,0,300,1000
ScaleEntity    cubegrid,2000,200,2000
entitycolor    cubegrid,50,50,150
rotateEntity   cubegrid ,180,0,0

cubegridtex =  gridtex(256,32,12, 70,230,10, 120,50,250)
EntityTexture  cubegrid,cubegridtex,0,1

;--bump plane
Global bumpplane = createsquare(100)
PositionEntity bumpplane ,0,-500,1000
ScaleEntity    bumpplane ,2000,200,2000
entitycolor    bumpplane ,150,50,150

bumptex=CreateTexture(256,256)
spot(bumptex,256,25)
EntityTexture bumpplane,bumptex,0,0

;--bump ball
Global bumpball = createsphere(30)
PositionEntity bumpball ,0,0,1000
ScaleEntity    bumpball ,90,90,90
entitycolor    bumpball ,150,50,150

entityTexture bumpball,cubegridtex,0,0

PointEntity you,cubegrid
rotateentity you,15,0,0

setfont LoadFont("Arial",14,False,False,False)

BumpAlready = false
While Not KeyHit(1)

    spd =  MouseZ()+2  ; mousewheel is speed
    moveyou(spd)

    If KeyHit(57)then
 if (not BumpAlready) Then   ;space for bumpmap
        displace(cubegrid,cubegridtex,256,20)
        displace(bumpplane,bumptex,256,20)
        displace(bumpball,cubegridtex,256,5)
        BumpAlready = true
      else
   freeentity cubegrid
   freeentity bumpplane
   freeentity bumpball
   goto createscene
      end if
    end if

    TurnEntity cubegrid,0,.1,0
    TurnEntity bumpball,-.1,.1,.1
    UpdateNormals cubegrid
 
    RenderWorld
    color 250,250,100
    text 10,10," Hit the SPACEBAR for displacment. Arrows,home,end,endpgup,pgdwn with ctrl for movement. Mouse wheel for speed.  W for Wireframe.  Look in code for more keys"
    Flip
Wend


Function displace(mesh,texture,texsize#=256,amp#=1,wrap=false)

  For sc = 1 To CountSurfaces(mesh)

    surf = GetSurface(mesh,sc)
    If surf = 0 Then
      RuntimeError "Cant find surface to displace with"
      End
    End If
    maxvert = CountVertices(surf)

    For vc = 0 To maxvert-1

       bx#  = VertexX(surf,vc)
       by#  = VertexY(surf,vc)
       bz#  = VertexZ(surf,vc)
       bnx# = VertexNX(surf,vc)
       bny# = VertexNY(surf,vc)
       bnz# = VertexNZ(surf,vc)
       bu#  = VertexU(surf,vc)
       bv#  = VertexV(surf,vc)
       
       If wrap Then
         If (bu = 1)  Then bu = 0
         If (bv =0)  Then bu = 0 : bv = 0
         If (bv =1)  Then bu = 0 : bv = 1
       End If
       
       tx# = bu*texsize
       ty# = bv*texsize
       gettexcol(Texture,tx,ty)
       Cr#=numcolR      ; based off red channel  as this seems to look best

       If (cr > 0) Then
         bxx# = bx + bnx * (Cr/255) * (amp/10)
         byy# = by + bny * (Cr/255) * (amp/10)
         bzz# = bz + bnz * (Cr/255) * (amp/10)
         VertexCoords surf,vc,bxx,byy,bzz
       End If
    Next
  Next
  UpdateNormals mesh
End Function

Global numcolR#,numcolG,numcolB
Function numcolor(num#)
;convert number to r g b values
  numcolR=num  Shr 16 And %11111111
  numcolG=num Shr 8 And %11111111
  numcolB=num And %11111111
End Function

Function gettexcol(tex,x,y)
; get results from numcolR, numcolG, numcolB
  SetBuffer TextureBuffer(tex)
  LockBuffer TextureBuffer(tex)
  numcolor(ReadPixelFast(x,y))
  UnlockBuffer TextureBuffer(tex)
  SetBuffer BackBuffer()
End Function




;------ VVVV  these functions are just to create an example bdisplacement map    VVVV

Function createsquare(segs#=5,parent=0)

    mesh=CreateMesh( parent )
    surf=CreateSurface( mesh )

    l# =-.5
    b# = -.5
    tvc= 0

;create all the vertices first
    Repeat
 u# = l + .5
 v# = b + .5
      AddVertex surf,l,0,b,u,v
      tvc=tvc + 1
      l = l + 1/segs
      If l > .5 Then
        l = -.5
        b = b + 1/segs
      End If
    Until b > .5

    vc# =0

    ;create polys
    vc# =0
    Repeat

      AddTriangle (surf,vc,vc+segs+1,vc+segs+2)
      AddTriangle (surf,vc,vc+segs+2,vc+1)

      vc = vc + 1
      tst# =  ((vc+1) /(segs+1)) -Int ((vc+1) /(segs+1))

      If (vc > 0) And (tst=0) Then
        vc = vc + 1
      End If

    Until vc=>tvc-segs-1
    UpdateNormals mesh
    Return mesh

End Function


Function moveyou(spd=1)

    If  KeyDown( 205 ) Then
      If KeyDown(157) Then
        MoveEntity you,spd,0,0    ; ctrl -> straff right
      Else
       TurnEntity you,0,-2,0      ; -> turn right
      End If
    End If
    If  KeyDown( 203 ) Then
      If KeyDown(157) Then
        MoveEntity you,-spd,0,0   ; ctrl <- straff left
      Else
        TurnEntity you,0,2,0      ; <- turn left
      End If
    End If
    If  KeyDown( 199 ) Then
      If KeyDown(157) Then
        TurnEntity you,0,0,2      ; ctrl home roll left
      Else
        TurnEntity you,-2,0,0     ; home  pitch left
      End If
    End If

    If  KeyDown( 207 ) Then
      If KeyDown(157) Then
        TurnEntity you,0,0,-2     ; ctrl end roll right
      Else
        TurnEntity you,2,0,0      ; end roll right
      End If
    End If

    If  MouseDown(1) Or KeyDown( 200 )  Then MoveEntity you,0,0,spd  ; up arrow forward
    If MouseDown(2) Or KeyDown( 208 ) Then MoveEntity you,0,0,-spd   ; down arrow back
    If KeyDown(201) Then MoveEntity you,0,spd,0  ; pgup raise
    If KeyDown(209) Then MoveEntity you,0,-spd,0 ; pgdown lower

    If KeyHit( 17) Then wf = Not wf : WireFrame wf  ;w for wireframe

    If KeyHit(68) Then  ; F10 for snapshot
       If sscnt = 0 Then sscnt = 1000
       sscnt = sscnt + 1
       SaveBuffer(FrontBuffer(),"snapshot"+Right(Str(sscnt),3)+".bmp")
    End If

    If KeyHit(36) Then joy = Not joy   ; j key for joystick
    If joy Then
      jyaw#=-JoyXDir()
      jpitch#=-JoyYDir()
      TurnEntity you,jpitch,jyaw,0
      If JoyDown(7) Then MoveEntity you,0,0,spd
      If JoyDown(8) Then MoveEntity you,0,0,-spd

    End If
   
End Function
Global WF,joy


Function  spot(tex,texsize,numspots,clstrue=true)

SetBuffer  TextureBuffer(tex)

  if clstrue then
 color 0,0,0
    Rect 0,0,texsize,texsize,1
  end if

lockbuffer TextureBuffer(tex)
  for sc = 1 to numspots
    spotsize=Rand(25,64): if spotsize >60 then spotsize=spotsize*2
    rx=Rand(spotsize+1,texsize-spotsize)
    ry=Rand(spotsize+1,texsize-spotsize)
    For a# = 1 To spotsize-1 step 1
 i# = 0
while i < 360
 sx=sin(i)*a+rx
 sy=cos(i)*a+ry
i = i + .5
 rc=readpixel(sx,sy,texturebuffer(tex))

  numcolor(rc)
   nr#=(abs (sin((a-1)/4))*(spotsize-a)*2+numcolR*.9)mod 255

        nc=Colornum(nr,numcolG+1,numcolB+1)
        writepixelfast sx,sy,nc
      wend

    Next
next

unlockbuffer TextureBuffer(tex)
SetBuffer BackBuffer()

End Function



Function colornum(r,g,b)
 return ((r Shl 16) + (g Shl 8) + b)
End Function



Function gridtex(s=256,st=128,width=16,colr=0,colg=0,colb=0,backcolr=0,backcolg=0,backcolb=0)
  tex=CreateTexture(s,s)
  SetBuffer TextureBuffer(tex)
  Color backcolr,backcolg,backcolb
  Rect 0,0,s,s,1
  a = 0
  i#=s/260
  Repeat
    Color colr,colg,colb
    For w= 0 To width-1
      Line a+w,0,a+w,s
      Line 0,a+w,s,a+w
    Next
    a = a + st
  Until a => s
  SetBuffer BackBuffer()
  Return tex

End Function

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