I ported this over from some BB code I found in the archives. I also tried to package it up nicely into a type. Never used it for much as I think it had too many limitations. You can change the color and intensity of the shadow though which did make some interesting effects.
You will have to point it to a texture for the scene sphere which is receiving the shadow, and add some code to replace the mouse handling code in my toolbox.bmx file.
EDIT: Added the function I made to zero the normals on an object so it would render flat. Yeah I probably could just hide the light temporarily, but this was fun.
Import sidesign.minib3d
'
' A shadow system for miniB3D.
'
' Based a realtime shadow system by
' Mikkel Fredborg found in the code archives of BlitzBasic.com
'
Type TShadow3D
Field viewCam:TCamera,shadowCam:TCamera
Field targetObj:TEntity
Field scene:TMesh
Field sceneMesh:TMesh
Field sceneOrig:TMesh
Field shadowSurf:TSurface
Field shadowZoom:Float = 1.75 'Adjust to your liking.
Field shadowLight:TEntity
Field red:Int = 0
Field green:Int = 0
Field blue:Int = 0
Field texSize:Int = 512
Field shadowTex:TTexture,shadowBrush:TBrush
Field lastx:Float,lasty:Float,lastz:Float
Field lastpitch:Float,lastyaw:Float,lastroll:Float
Field resetAmbientRed:Int,resetAmbientGreen:Int,resetAmbientBlue:Int
Field blur:Int = 0
Field shadowStaticDist:Float = 20.0 'units from the targetObj
Method changeColor(r:Int = 0,g:Int = 0,b:Int = 0)
Self.red = r
Self.green = g
Self.blue = b
End Method
Method changeLight(lit:TEntity = Null)
If lit = Null Then Return
Self.shadowLight = lit
End Method
Method changeTarget(tar:TEntity = Null)
If tar = Null Then Return
Self.targetObj = tar
End Method
Method setAmbient(r:Int,g:Int,b:Int)
resetAmbientRed:Int = r
resetAmbientGreen:Int = g
resetAmbientBlue:Int = b
End Method
Method changeViewCam(cam:TCamera = Null)
If cam = Null Then Return
Self.viewCam = cam
End Method
Method changeScene(sc:TMesh = Null)
If sc = Null Then Return
Self.scene = sc
End Method
Method update()
HideEntity Self.sceneMesh
HideEntity Self.sceneOrig
?Debug
Local tarDist:Float = EntityDistance(Self.targetObj,Self.shadowCam)
Print tarDist
?
shadowZoom = tarDist / 10.0
If shadowZoom > 1.75 Then shadowZoom = 1.75
If shadowZoom < 0.05 Then shadowZoom = 0.05
If blur=0 'Need to figure out a good way to blur this thing.
AmbientLight(red,green,blue)
ShowEntity Self.shadowCam
CameraZoom Self.shadowCam,shadowZoom
PointEntity(Self.shadowCam,targetObj)
RenderWorld()
EndIf
BackBufferToTex(Self.shadowTex,0,0)
AmbientLight(resetAmbientRed,resetAmbientGreen,resetAmbientBlue)
' Show shadow meshes
ShowEntity Self.sceneMesh
Local x:Float = EntityX(shadowLight,True)
Local y:Float = EntityY(shadowLight,True)
Local z:Float = EntityZ(shadowLight,True)
Local pitch:Float = EntityPitch(shadowLight,True)
Local yaw:Float = EntityYaw(shadowLight,True)
Local roll:Float = EntityRoll(shadowLight,True)
' Remove backfacing triangles
If x<>Self.lastx Or y<>Self.lasty Or z<>Self.lastz Or pitch<>Self.lastpitch Or yaw<>Self.lastyaw Or roll<>Self.lastroll
ClearSurface Self.shadowSurf
n_surfs = CountSurfaces(Self.sceneOrig)
For s = 1 To n_surfs
surf = GetSurface(Self.sceneOrig,s)
n_tris = CountTriangles(surf)-1
For t = 0 To n_tris
v0 = TriangleVertex(surf,t,0)
v1 = TriangleVertex(surf,t,1)
v2 = TriangleVertex(surf,t,2)
ex0# = VertexX(surf,v1) - VertexX(surf,v0)
ey0# = VertexY(surf,v1) - VertexY(surf,v0)
ez0# = VertexZ(surf,v1) - VertexZ(surf,v0)
ex1# = VertexX(surf,v2) - VertexX(surf,v0)
ey1# = VertexY(surf,v2) - VertexY(surf,v0)
ez1# = VertexZ(surf,v2) - VertexZ(surf,v0)
' Triangle normal
nx# = ey0# * ez1# - ez0# * ey1#
ny# = ez0# * ex1# - ex0# * ez1#
nz# = ex0# * ey1# - ey0# * ex1#
' Transform it compared To light
TFormNormal nx#,ny#,nz#,Self.sceneOrig,Self.shadowLight
If TFormedZ()<0.0
nv0 = AddVertex(Self.shadowSurf,VertexX(surf,v0),VertexY(surf,v0),VertexZ(surf,v0))
nv1 = AddVertex(Self.shadowSurf,VertexX(surf,v1),VertexY(surf,v1),VertexZ(surf,v1))
nv2 = AddVertex(Self.shadowSurf,VertexX(surf,v2),VertexY(surf,v2),VertexZ(surf,v2))
AddTriangle Self.shadowSurf,nv0,nv1,nv2
EndIf
Next
Next
EndIf
' Calculate uv's
n_verts = CountVertices(Self.shadowSurf)-1
For v = 0 To n_verts
'Original Working Code
TFormPoint VertexX(Self.shadowSurf,v),VertexY(Self.shadowSurf,v),VertexZ(Self.shadowSurf,v),Self.sceneMesh,0
CameraProject shadowCam,TFormedX(),TFormedY(),TFormedZ()
Local viewX = ProjectedX(),viewY=ProjectedY()
If viewX < 0 Then viewX = 0
If viewX > texSize Then viewX = texSize
If viewY < 0 Then viewY = 0
If viewY > texSize Then viewY = texSize
'Rem WORKING
tu:Float = Float(ProjectedX())/Float(texSize)
tv:Float = 1.0-(Float(ProjectedY())/Float(texSize))
If tu > 1.0 Then tu = 1.0
If tu < 0.0 Then tu = 0.0
If tv > 1.0 Then tv = 1.0
If tv < 0.0 Then tv = 0.0
VertexTexCoords Self.shadowSurf,v,tu,tv
'EndRem
Next
' Update positions
Self.lastx = x
Self.lasty = y
Self.lastz = z
Self.lastpitch = pitch
Self.lastyaw = yaw
Self.lastroll = roll
HideEntity Self.shadowCam
End Method
Method cleanup()
'TO DO
End Method
Method init()
'texture init
ClearTextureFilters
Self.shadowTex = CreateTexture(Self.texSize,Self.texSize,1+2+4+16+32+256)
TextureBlend shadowTex,1
Self.shadowBrush = CreateBrush()
BrushColor(shadowBrush,red,green,blue)
BrushBlend shadowBrush,1
BrushFX shadowBrush,1
BrushTexture shadowBrush,shadowTex
'mesh and surface init
Self.sceneMesh = CopyMesh(Self.scene)
Self.shadowSurf = CreateSurface(Self.sceneMesh)
EntityColor(sceneMesh,255,255,255)
FlipMesh(sceneMesh)
EntityFX(scene,16)
'Entity blend modes 1 = Alpha, 2 = Mul, 3 = Add
EntityBlend(Self.sceneMesh,2)
PaintSurface Self.shadowSurf,Self.shadowBrush
Self.sceneOrig = CopyMesh(Self.scene)
'Camera init
Self.shadowCam = CreateCamera(shadowLight)
PositionEntity(shadowCam,EntityX(shadowLight),EntityY(shadowLight),EntityZ(shadowLight))
PointEntity(shadowLight,targetObj)
PointEntity(shadowCam,targetObj)
CameraProjMode shadowCam,1
CameraRange shadowCam,1.0,65000.0
CameraClsColor shadowCam,255,255,255
CameraViewport shadowCam,0,0,texSize,texSize
CameraZoom shadowCam,shadowZoom '<--- This may need changing depending on the scene And light position
End Method
EndType
Function killNormals(ent:TMesh)
numSurf:Int =CountSurfaces(ent)
For s = 1 To numSurf
currSurf:TSurface = GetSurface(ent,s)
numVerts:Int = CountVertices(currSurf)-1
For v = 0 To numVerts
VertexNormal(currSurf,v,0.0,0.0,0.0)
Next
Next
End Function
Local width=1280,height=720,depth=32,mode=0,rate=30
Graphics3D width,height,depth,mode,rate
HideMouse
AmbientLight 0,0,0
SeedRnd MilliSecs()
Global bob = CreateCube(10)
PositionEntity(bob,0,0,0)
Global scene = CreateSphere(18)
EntityColor(scene,255,255,255)
EntityFX(scene,0)
sceneTex = LoadTexture("512x512grid.png")
EntityTexture(scene,sceneTex)
ScaleMesh(scene,50,50,50)
PositionEntity(scene,0,0,0)
FlipMesh(scene)
Global light = CreateLight()
LightRange(light,2000)
RotateEntity light,0,0,0
PositionEntity light,0,0,-10
PointEntity light,bob
sphere = CreateSphere(light)
ScaleEntity(sphere,1,1,1)
EntityColor(sphere,255,255,255)
PositionEntity(sphere,EntityX(light),EntityY(light),EntityZ(light))
EntityFX(sphere,1)
Global camera1 = CreateCamera()
CameraClsColor(camera1,100,100,255)
PositionEntity(camera1,4,4,-15)
RotateEntity(camera1,-15,180,0)
Global shadow:TShadow3D = New TShadow3D
shadow.changeScene(scene)
shadow.changeColor(255,255,255)
shadow.changeTarget(bob)
shadow.changeViewCam(camera1)
shadow.changeLight(light)
shadow.setAmbient(64,64,64)
shadow.init()
spd# = 20.0 / Float(rate) 'units / sec
zoom# = 1.0
a:Float = 0.0
b:Float = 0.0
mxs:Float = 0.0
mys:Float = 0.0
mouse:TMouse = New TMouse
'A hacky way of clearing the shininess from my model.
Local renderme:TMesh = CopyMesh(bob)
PositionEntity(renderme,EntityX(bob),EntityY(bob),EntityZ(bob))
Local renderbrush = CreateBrush()
BrushColor(renderbrush,128,128,128)
BrushShininess(renderbrush,0.0)
BrushBlend renderbrush,1
BrushAlpha renderbrush,1.0
BrushFX renderbrush,16
PaintMesh(renderme,renderbrush)
killNormals(renderme)
Repeat
MoveEntity camera1,(KeyDown(KEY_D)-KeyDown(KEY_A))*spd,0,(KeyDown(KEY_W)-KeyDown(KEY_S))*spd
PositionEntity light,EntityX(light)+((KeyDown(KEY_RIGHT)-KeyDown(KEY_LEFT))*spd),EntityY(light)+((KeyDown(KEY_UP)-KeyDown(KEY_DOWN))*spd),EntityZ(light)+((KeyDown(KEY_1)-KeyDown(KEY_2))*spd)
PointEntity light,bob
PositionEntity sphere,EntityX(light),EntityY(light),EntityZ(light)
PointEntity sphere,light
mxs=mxs-(mouse.MouseXSpeed()/2.0)
mys=mys+(mouse.MouseYSpeed()/2.0)
TurnEntity camera1,mys,mxs,0
mxs = 0.0
mys = 0.0
mouse.update()
mouse.flush()
b = b + (45.0/Float(rate)) 'degrees per second
a# = a- (45.0/Float(rate))
RotateEntity bob,b,b,0
RotateEntity renderme,b,b,0
HideEntity scene
CameraProjMode camera1,0
HideEntity camera1
HideEntity sphere
HideEntity bob
ShowEntity renderme
shadow.update()
ShowEntity bob
ShowEntity scene
ShowEntity sphere
HideEntity renderme
CameraProjMode camera1,1
ShowEntity camera1
RenderWorld()
BeginMax2D()
EndMax2D()
Flip
Until KeyHit(KEY_ESCAPE)
End
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