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"DMT, DEM, VDXLIGHTING", by nofrontier

Too long for the short title:

- Dynamic Mesh Trail effect, which uses the new VertexAlpha thing,
- Dynamic Environment Mapping, through copyrect and flag 256+64
- And a nice DXlight effect

The Dynamic Mesh Trail original basic functions are by Ben Gillbank, modified along some hour of coding last night.
All the rest is genuine instant from-skratch blitz3d coding.

Enjoy it, mod it, use it, credit me! :)

Code

; b3d Light trails and simple dynamic spherical environment mapping
; Started from the simple demo wrote by Ben Hust
Graphics3D 640,480,16,1
SetBuffer BackBuffer()
SeedRnd 21354
;--------------------------------------------------------------------------
;I normally keep this as an include but it makes it easier if I add it here
;--------------------------------------------------------------------------

Const trail_update=1                    ; trail update frequency (lower number updates more often)
Const maxVerts=20                         ; maximum number of verts per trail object (polygons * 2)

Type trail
     Field id,brush,surface
     Field tdx#[maxVerts], tdy#[maxVerts], tdz#[maxVerts]
     Field update%,alpha#
     Field point1, point2
End Type

;---------------------
;standard camera stoof
;---------------------
camera=CreateCamera()
CameraClsColor camera,0,150,200

;light=CreateLight()
;RotateEntity light,30,0,15
AmbientLight 147,147,147

;get a texture
Gosub gridtex

;---------------------------
;create an object to look at
;---------------------------
ship=CreateSphere(8)
exhaust1=CreateCylinder(8,True,ship)
exhaust2=CreateCylinder(8,True,ship)
ScaleMesh ship,1,1,.5
RotateMesh ship,60,0,180
am=CreateCone(8)
ScaleMesh am,1.05,2.5,.5
RotateMesh am,95,0,0
AddMesh am,ship
FreeEntity am

ScaleEntity exhaust1,0.4,1,0.4          : ScaleEntity exhaust2,0.4,1,0.4
RotateEntity exhaust1,90,0,0          : RotateEntity exhaust2,90,0,0
MoveEntity exhaust1,-1,-1.2,0          : MoveEntity exhaust2,1,-1.2,0

;entitytexture exhaust1,mytexture
;entitytexture exhaust2,mytexture

; give simple first layer texturing to the ship (download texture from:)
EntityTexture ship,grid,0,0
; or comment and use this below:
s=GetSurface(ship,1)
For i=1 To CountVertices(s)
     VertexColor s,i,Rand(1,255),Rand(1,255),Rand(1,255)
Next
;EntityFX ship,2
UpdateNormals ship
EntityShininess ship,.85

; front lights dxlight
clight=CreateLight(2,ship)
MoveEntity clight,0,0,15
RotateEntity clight,15,0,0
LightColor clight,100,150,250
LightConeAngles clight,5,10
LightRange clight,250

; rear trail-dxlight
;tlight=CreateLight(2,ship)
;MoveEntity tlight,0,0,-5:LightColor tlight,150,50,0:LightRange tlight,50

; the envmap itself
envmap=CreateTexture(128,128,256+64+1) ; create an empty texture
TextureBlend envmap,2
; with env spherical flag, And FAST MEM OP for later use
EntityTexture ship,envmap,0,1 ; and assign it to the ship mesh

EntityFX exhaust1,2:s=GetSurface(exhaust1,1)
For i=1 To CountVertices(s)
     c=Rand(150,250)
     VertexColor s,i,c,c,c
Next
EntityFX exhaust2,2:s=GetSurface(exhaust2,1)
For i=1 To CountVertices(s)
     c=Rand(150,250)
     VertexColor s,i,c,c,c
Next

; dynamic env map camera
Global demcam=CreateCamera(ship)
CameraClsColor demcam,0,100,155
CameraViewport demcam,0,0,128,128
CameraZoom demcam,.25

;CameraProjMode demcam,0 ;fasthide the special cam
demcamp=CreateCube(demcam)
EntityColor demcamp,255,200,200
TurnEntity demcam,0,180,0
MoveEntity demcam,0,10,-5 ; put it backward or forward by setting a minus Z or a plus Z

;create a floor
Floor=CreateFace(100,True)
ScaleEntity Floor,500,500,500
EntityTexture Floor,grid
MoveEntity Floor,0,-.5,0

Gosub createobjects

CreateTrail(exhaust1,exhaust2,8)

speed#=1
showcam=False
timer=CreateTimer(50)

Repeat

WaitTimer(timer)

If KeyDown(200) move#=move#+.25               ;Forwards
     If KeyDown(208) move#=move#-.25               ;Backward
     If KeyDown(205) turn#=turn#-4               ;Left
     If KeyDown(203) turn#=turn#+4               ;Right
     If KeyHit(17) wire=Not(wire):WireFrame wire
     If KeyHit(2) showcam=Not(showcam)
     move=move*.9
     
     RotateEntity ship,0,turn,0
     MoveEntity ship,0,0,move
     
     ;hide
     CameraProjMode camera,0
     CameraProjMode demcam,1

EntityAlpha ship,0
     EntityAlpha exhaust1,0
     EntityAlpha exhaust2,0
     
     ;render
     PointEntity demcam,ship
     
     RenderWorld     
     CopyRect 0,0,128,128,0,0,BackBuffer(),TextureBuffer(envmap)
          
     EntityAlpha ship,1
     EntityAlpha exhaust1,1
     EntityAlpha exhaust2,1
     
     CameraProjMode camera,1
     If Not(SHOWCAM) CameraProjMode demcam,0
     
     
     update_camera(ship,camera,5,3)     
     updatetrails
     
     UpdateWorld()
     RenderWorld()
     
     Flip

Until KeyHit(1)

End

.gridtex

grid=CreateTexture(64,64,1+8)
     
     SetBuffer TextureBuffer(grid)
     Color 255,255,255      : Rect 0,0,64,64
     Color 255,0,0           : Rect 0,0,64,64,False
     Color 155,155,155     : Rect 32,32,64,64,False
     ScaleTexture grid,.1,.1
     
     SetBuffer BackBuffer()

Return

.createobjects

;create some (20x20=400) objects to variate the surrounding environ
For i=1 To 20
     For l=1 To 20
          ot%=Rand(1,20) ;randomize object type
          Select ot%
               Case 1
                    o=CreateCube()
                    ScaleEntity o,1,5,1
                    EntityColor o,0,50,100
               Case 2
                    o=CreateSphere(5)
                    ScaleEntity o,3,5,3
                    EntityColor o,50,220,150
                    EntityAlpha o,.5
                    EntityFX o,4
               Case 3
                    o=CreateCone(6)
                    ScaleEntity o,2,5,2
                    EntityColor o,50,150,20
               Case 4
                    o=CreateCylinder(6,1)
                    ScaleEntity o,1,5,1
                    EntityColor o,150,100,0
               Case 5
                    o=CreateSphere(8)
                    ScaleEntity o,1,5,1
                    EntityColor o,250,100,0
                    EntityShininess o,.75
               Default
                    o=CreatePivot()               
          End Select
          PositionEntity o,(i-10)*25,2.5,(l-10)*25
     Next
Next

Return

;Creates a single sided face segmented
Function CreateFace(segs=1,double=False,parent=0)
    mesh=CreateMesh( parent )
    surf=CreateSurface( mesh )
    stx#=-.5
    sty#=stx
    stp#=Float(1)/Float(segs)
    y#=sty
    For a=0 To segs
        x#=stx
        v#=a/Float(segs)
        For b=0 To segs
            u#=b/Float(segs)
            AddVertex(surf,x,0,y,u,v) ; swap these for a different start orientation
            x=x+stp
        Next
        y=y+stp
    Next
    For a=0 To segs-1
        For b=0 To segs-1
            v0=a*(segs+1)+b:v1=v0+1
            v2=(a+1)*(segs+1)+b+1:v3=v2-1
            AddTriangle( surf,v0,v2,v1 )
            AddTriangle( surf,v0,v3,v2 )
        Next
    Next
    UpdateNormals mesh
    If double=True Then EntityFX mesh,16
    Return mesh
End Function

;-----------------
;update all trails
;-----------------
Function UpdateTrails()
     
Local x#,y#,z#

;loop through all trails
For t.trail = Each trail

; Move the trail pieces along.
     t\update=t\update+1 : If t\update=trail_update Then t\update=0

;update                    
     If t\update=0
          For i=2 To CountVertices(t\surface)-1
               t\tdx[i] = (VertexX(t\surface,i-2) - VertexX(t\surface,i))/trail_update
               t\tdy[i] = (VertexY(t\surface,i-2) - VertexY(t\surface,i))/trail_update
               t\tdz[i] = (VertexZ(t\surface,i-2) - VertexZ(t\surface,i))/trail_update
               t\alpha=1.0-Float(i)/10
               If t\alpha<0 Then t\alpha=0
               VertexColor t\surface,i,255-i*10,(20-i)*5,i*15,t\alpha
          Next
     End If

For i=2 To CountVertices(t\surface)-1
          VertexCoords(t\surface,i,VertexX(t\surface,i)+t\tdx[i],VertexY(t\surface,i)+t\tdy[i],VertexZ(t\surface,i)+t\tdz[i])
     Next
     
     ;position the first two verts at the back of the ship
     VertexCoords(t\surface,0,EntityX(t\point1,1),EntityY(t\point1,1),EntityZ(t\point1,1))
     VertexCoords(t\surface,1,EntityX(t\point2,1),EntityY(t\point2,1),EntityZ(t\point2,1))
     
Next
               
End Function

;---------------------
;create a trail object
;---------------------
Function CreateTrail(point1,point2,polys=20,startalpha#=1.0)

Local x#,y#,z#
     
     t.trail=New trail

;create mesh and set properties
     t\id = CreateMesh()
     t\brush = CreateBrush()
     BrushBlend t\brush,3
     BrushFX t\brush,2+16
     t\surface = CreateSurface(t\id,t\brush)
     t\alpha=1.0
     
     ;check there are two trail strat points
     If point1=False Then RuntimeError "must specify 'point1' for one side of the trail" Else t\point1=point1
     If point2=False Then RuntimeError "must specify 'point2' for one side of the trail" Else t\point2=point2
     
     ;mid pount between two trial objects
     x=(EntityX(t\point1,1)+EntityX(t\point2,1))/2
     y=(EntityY(t\point1,1)+EntityY(t\point2,1))/2
     z=(EntityZ(t\point1,1)+EntityZ(t\point2,1))/2

;create polygons
     For i=0 To polys
          AddVertex t\surface,x,y,z,Float(i)/Float(polys),1,0
          AddVertex t\surface,x,y,z,Float(i)/Float(polys),0,0
          VertexNormal t\surface,i,0,-1,0
          VertexNormal t\surface,i+1,0,-1,0
          
          If i>0
               AddTriangle t\surface,i*2,i*2-1,i*2-2
               AddTriangle t\surface,i*2,i*2+1,i*2-1
          End If
     Next
     
End Function

;--------------------------------
;free trail and delete trail type
;--------------------------------
Function free_trail(id)

For t.trail=Each trail
          If t\id=id
               FreeEntity t\id
               Delete t
          EndIf
     Next
     
     Return True
     
End Function

;----------------------------------------------------------------------
;These are just handy functions that have nothing to do with the trails
;----------------------------------------------------------------------

;---------------------------------------
;a chase cam for use in 3rd person games
;---------------------------------------
Function update_camera(character,camera,distance#,height#,angle=180)

;get player values
     px#=EntityX(character)
     py#=EntityY(character)
     pz#=EntityZ(character)
     
     pa#=EntityYaw(character)+angle
     
     ;get camera values
     cx#=EntityX(camera)
     cy#=EntityY(camera)
     cz#=EntityZ(camera)
     
     ;If EntityDistance(camera,character)>Float(distance*1.5) EntityType camera,c_none
     
     ;work out new values
     cx=curvevalue(cx,newxvalue(px,pa,distance),6)
     cy=curvevalue(cy,py+height,7)
     cz=curvevalue(cz,newzvalue(pz,pa,distance),6)

;update camera position

If MouseDown(1)
          PositionEntity camera,px,py+7,pz+5
          MoveEntity camera,MouseXSpeed()/10,0,MouseYSpeed()/10
          PointEntity camera,character
     Else
          PositionEntity camera,cx,cy,cz
          PointEntity camera,character
     EndIf
     
     ;EntityType camera,c_camera
     
End Function

;--------------------
;curve value function
;--------------------
Function CurveValue#(current#,destination#,amount)

current=current+((destination-current)/amount)
     If current<0.01 And current>-0.01 Then current=0
     Return current

End Function

;---------
;newxvalue
;---------
Function NewXValue#(current#,ang#,dist#)

Return current-Sin(ang)*dist

End Function

;---------
;newyvalue
;---------
Function NewYValue#(current#,ang#,dist#)

Return current+Sin(ang)*dist

End Function

;---------
;newzvalue
;---------
Function NewZValue#(current#,ang#,dist#)

Return current+Cos(ang)*dist

End Function

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