| This is a small demo made of parts from my current project. It demonstrates a simple Freelancer-like steering and a planet with atmosphere glow. When you get close to the planet the atmosphere effect shows up and it even includes a check if you are at the dayside or nightside and fades the stars at the dayside. The glowing ring always keeps the same size as the planet. Have fun! Steering: Mouse, Arrows Red Cross: Flight direction Green Box: Target direction SPACE = Wireframe on/off |
AppTitle "Planet Atmosphere Glow Demo" ; by Krischan webmaster(at)jaas.de ; Constants Const ScreenWidth% = 800 ; Screen width Const ScreenHeight% = 600 ; Screen height Const ColorDepth% = 32 ; Color depth Const ScreenMode% = 2 ; Screen Mode Const MouseSpeed# = 0.1 ; Mousespeed Const CameraSmoothness# = 10 ; Smoothness of movement Const Scale# = 12.756 ; Approx. the diameter of earth (1 unit = 1000km) Const GameTime% = 20 ; Game speed Const CursorSize% = 33 ; Size of cursor and crosshair image Const TurnSpeed# = 2.0 ; Turnspeed of player Const RollSpeed# = 1.0 ; Roll speed Const MaxRollAngle# = 20.0 ; Maximum roll angle Const RingDetail% = 60 ; Number of segments ; Glow Color scheme Const R1%=192,G1%=224,B1%=255 ; Surface near color Const R2%=128,G2%=160,B2%=255 ; Surface far color ; Variables Global CameraSpeed# = Scale/10.0 ; Movement speed Global TargetDistance# = 100.0*Scale ; Mousetarget distance to player Global FrameTime = MilliSecs() ; Initialize Frame Timer Global Period% = 1000/75.0 ; Calc frame period (here: 75FPS) ; help variables and objects Global MX%,MY% ; Mouse position Global Player%,MouseTarget%,Cam%,Ship% ; Player Global Cursor%,Cross% ; Images Global Planet%,Light%,Sun%,StarBox% ; Scene objects Global GlowPivot% ; Pivot of Glow Global Glow1%,Glow2% ; Glow rings Global GlowScale# ; Glow scale indicator Global Tween# ; Frame tween Global MoveSpeed# ; movespeed in km/h ; Init 3D Graphics3D ScreenWidth,ScreenHeight,ColorDepth,ScreenMode ; Init Player and Scene InitPlayer() InitScene() ; Center mouse and hide pointer MoveMouse ScreenWidth/2,ScreenHeight/2 HidePointer ; Main loop While Not KeyHit(1) ; Frame tweening Tween#=Float(MilliSecs()-FrameTime)/Float(GameTime) : FrameTime=MilliSecs() ; SPACE = Wireframe If KeyHit(57) Then wf%=1-wf : WireFrame wf ; Get Distance player to planet Local distance#=EntityDistance(Cam,Planet) ; Update atmosphere glow UpdateAtmosphere(distance) ; Attach Starbox to camera PositionEntity StarBox,EntityX(Player),EntityY(Player),EntityZ(Player) ;Sun points To Player PointEntity Sun,Player UpdateWorld RenderWorld ;Move Player Movement(GlowScale,distance) ; Draw cursor and crosshair by chasing the mousetarget CameraProject Cam,EntityX(MouseTarget,1),EntityY(MouseTarget,1),EntityZ(MouseTarget,1) DrawImage Cursor,MX-(CursorSize/2),MY-(CursorSize/2) DrawImage Cross,ProjectedX()-(CursorSize/2),ProjectedY()-(CursorSize/2) ; Statistics Text 0, 0,"Triangles rendered....: "+TrisRendered() Text 0,15,"Distance To Surface...: "+Int((distance-Scale)*1000)+" km" Text 0,30,"Move speed............: "+MoveSpeed+" km/h" Flip 0 Wend End ; The functions that creates the mesh and surface for a ring Function CreateRing(fx%=0,blend%=0) Local a1#,a2#,a3#,a4#,angle% Local v0%,v1%,v2%,v3% Local mesh=CreateMesh() Local surf=CreateSurface(mesh) ; Ring FX If fx>0 Then EntityFX mesh,fx If blend>0 Then EntityBlend mesh,blend Return mesh End Function ; Re-creates the ring vertices and triangles with different values Function UpdateRing(mesh%,radius1#=1.0,radius2#=2.0,segments%=360,r1%=255,g1%=255,b1%=255,alpha1#=1.0,r2%=0,g2%=0,b2%=0,alpha2#=1.0,scale#=0.0) Local a1#,a2#,angle% Local v0%,v1%,v2%,v3%,v% ; get and clear the surface Local surf=GetSurface(mesh,1) ClearSurface surf,1,1 ; Limit segments If segments>360 Then segments=360 ; Create ring For angle=0 To segments a1=angle*360.0/segments a2=angle*360.0/segments+180.0/segments ; Calc vertex points v0=AddVertex(surf,radius1*Cos(a1),radius1*Sin(a1),0,0,0) v1=AddVertex(surf,radius2*Cos(a2),radius2*Sin(a2),scale,1,1) ; Color VertexColor surf,v0,r1,g1,b1,alpha1 VertexColor surf,v1,r2,g2,b2,alpha2 Next ; Create Triangles For v=0 To CountVertices(surf)-3 AddTriangle(surf,v,v+1,v+2) Next Return mesh End Function ; Initialize player, camera Function InitPlayer() Local i% ; Player pivot Player=CreatePivot() PositionEntity Player,-Scale*2,0,Scale*2 ; Ship mesh Ship=CreateCube(Player) EntityFX Ship,1 ScaleEntity Ship,0.2,0.05,0.2 PositionEntity Ship,0,-0.5,1.5 EntityOrder Ship,-1000 ; Mousetarget in space MouseTarget=CreatePivot(Ship) MoveEntity MouseTarget,0,0,TargetDistance ; Camera Cam=CreateCamera(Player) PositionEntity Cam,0,0,0 CameraRange Cam,0.01,1000*Scale ; Create cursor image Cursor=CreateImage(CursorSize,CursorSize) SetBuffer ImageBuffer(Cursor) For i=0 To 2 Color 0,Int(255.0/(1+i)),0 Rect i,i,CursorSize-(2*i),CursorSize-(2*i),0 Next ; Create crosshair image Cross=CreateImage(CursorSize,CursorSize) SetBuffer ImageBuffer(Cross) Color 255,0,0 Line (CursorSize-1)/2.0,0,(CursorSize-1)/2.0,CursorSize Line 0,(CursorSize-1)/2.0,CursorSize,(CursorSize-1)/2.0 ; reset buffer and color SetBuffer BackBuffer() Color 255,255,255 End Function ; Initialize scene Function InitScene() Local startex%,i%,col%,rgb% ; Planet Planet=CreateSphere(60) ScaleEntity Planet,Scale,Scale,Scale EntityColor Planet,32,192,64 ; Directional Sunlight Light=CreateLight(1) PositionEntity Light,0,0,-Scale*200 LightRange Light,200*Scale AmbientLight 16,16,16 ; Sun Sun=CreateQuad() ScaleEntity Sun,Scale*10,Scale*10,Scale*10 EntityFX Sun,1 EntityColor Sun,255,255,192 EntityParent Sun,Light PositionEntity Sun,0,0,0 EntityBlend Sun,3 EntityTexture Sun,CreateSunTexture() ; Simple Starbox StarBox=CreateCube() startex=CreateTexture(1024,1024) LockBuffer TextureBuffer(startex) For i=1 To 1000 col=Rand(0,255) rgb=col*$10000+col*$100+col WritePixelFast Rand(0,1023),Rand(0,1023),rgb,TextureBuffer(startex) Next UnlockBuffer TextureBuffer(startex) EntityTexture StarBox,startex ScaleEntity StarBox,10,10,10 EntityOrder StarBox,1 EntityFX StarBox,1 FlipMesh StarBox ; Glow GlowPivot=CreatePivot() Glow1=CreateRing(1+2+16+32,1) Glow2=CreateRing(1+2+16+32,3) EntityParent Glow1,GlowPivot EntityParent Glow2,GlowPivot EntityOrder Glow1,1 EntityOrder Glow2,1 ; Player points to planet first PointEntity Player,Planet TurnEntity Player,0,-20,-90 End Function ; Update atmosphere glow and background color Function UpdateAtmosphere(distance#) Local s2#,s2d#,aa#,bb#,cc# Local angle#,intensity#,clscol#,horizon# ; Calculate ring scale with the help of two right-angled triangles and trigonometry s2#=Scale^2 s2d#=s2/distance GlowScale#=(Sqr(s2+(Scale/Tan(90-(90-(90-ATan(Sqr((distance-(s2d))*(s2d))/(distance-(s2d)))))))^2))/Scale ; Calculcate the sun light angle (1 = exactly between sun and planet, 0 = exactly behind the planet) aa#=EntityDistance(Cam,Planet) bb#=EntityDistance(Planet,Light) cc#=EntityDistance(Cam,Light) angle#=ACos((aa^2+cc^2-bb^2)/(2*aa*cc))/180.0 If angle>1 Then angle=1 If angle<0 Then angle=0 ; Calculate the glow intensity according to sun light angle and distance to planet intensity#=1-(1.0/Exp(GlowScale*angle)) If intensity<0 Then intensity=0 If intensity>1 Then intensity=1 ; Calculate the horizon glow scale multiplicator horizon#=1-(1.2/Exp(GlowScale*angle/2.0)) If horizon<0 Then horizon=0 If horizon>1 Then horizon=1 ; Update ring intensity according to sun light angle and distance to planet UpdateRing(Glow1,0.6*Scale,0.01*Scale,RingDetail,R1*intensity,G1*intensity,B1*intensity,angle,R2*(angle-intensity),G2*(angle-intensity),B2*(angle-intensity), 0,Scale/3.0) UpdateRing(Glow2,(1.0-(horizon/10.0))*Scale,(1.05+(horizon/10.0))*Scale,RingDetail,R1*intensity,G1*intensity,B1*intensity,1.0-horizon,R2*angle,G2*angle,B2*angle,0,horizon*2) ; Scale the rings and always point to player ScaleEntity GlowPivot,GlowScale,GlowScale,GlowScale PointEntity GlowPivot,Player ; Calculate the background color to simulate atmosphere penetration clscol#=(1-(5.0/Exp(GlowScale*angle/2.0)))*intensity If clscol<0 Then clscol=0 If clscol>1 Then clscol=1 CameraClsColor Cam,R2*clscol,G2*clscol,B2*clscol ; Change Starbox alpha EntityAlpha StarBox,1-clscol End Function ; Player movement Function Movement(scale#,distance#) Local roll#,mox#,moz#,cx#,cz# Local t1#,t2# ; get mouse position MX=MouseX() MY=MouseY() ; Movement with speed limit cx=(KeyDown(205)-KeyDown(203))*CameraSpeed cz=(KeyDown(200)-KeyDown(208))*CameraSpeed ; Arrow left/right = roll If KeyDown(203) Then roll=RollSpeed If KeyDown(205) Then roll=-RollSpeed ; Normalize Mouse position (-1 to +1) t1=Normalize(MY,0,ScreenHeight,-1,1) t2=Normalize(MX,0,ScreenWidth,1,-1) ; Slower cursor movement in the center of the screen ;If t1<0 Then t1=(Abs(t1)^2.0)*-1 Else t1=t1^2.0 ;If t2<0 Then t2=(Abs(t2)^2.0)*-1 Else t2=t2^2.0 ; Rotate ship mesh and turn player pivot RotateEntity Ship,t1*MaxRollAngle,t2*MaxRollAngle,t2*MaxRollAngle*2 TurnEntity Player,t1*TurnSpeed*Tween,t2*TurnSpeed*Tween,roll*TurnSpeed*Tween ; Move the player forward/backward MoveEntity Player,0,0,(cz*1.0/(scale)^3)*Tween ; Calculate actual movespeed MoveSpeed#=(cz*1.0/(scale)^3)*3600000 End Function ; Normalize a value Function Normalize#(value#=128.0,value_min#=0.0,value_max#=255.0,norm_min#=0.0,norm_max#=1.0) Return ((value-value_min)/(value_max-value_min))*(norm_max-norm_min)+norm_min End Function Function CreateQuad() ; Create mesh and surface Local mesh%=CreateMesh() Local surf%=CreateSurface(mesh) ; Add vertices Local v0%=AddVertex(surf, 1.0, 1.0, 0.0, 0.0, 0.0 ) ; upper left Local v1%=AddVertex(surf, -1.0, 1.0, 0.0, 1.0, 0.0 ) ; upper right Local v2%=AddVertex(surf, -1.0, -1.0, 0.0, 1.0, 1.0 ) ; lower right Local v3%=AddVertex(surf, 1.0, -1.0, 0.0, 0.0, 1.0 ) ; lower left ; Connect vertices AddTriangle surf,v0,v1,v2 AddTriangle surf,v0,v2,v3 Return mesh End Function ; Create a simple sun texture Function CreateSunTexture() Local tex%=CreateTexture(512,512,2) Local tb%=TextureBuffer(tex) Local i#,j%,col%,rgb% SetBuffer tb LockBuffer tb ; Intensity steps For j=0 To 255 ; Exponential falloff col=Int((1.0/Exp(j*0.075))*100000000) If col>255 Then col=255 rgb=col*$1000000+col*$10000+col*$100+col ; Draw circles For i=0 To 360 Step 0.1 WritePixelFast 256+(Sin(i)*j),256+(Cos(i)*j),rgb,tb Next Next UnlockBuffer tb SetBuffer BackBuffer() Return tex End Function |
If angle>1 Then angle=1 If angle<0 Then angle=0
If angle Then lastangle#=angle# Local s2#,s2d#,aa#,bb#,cc# ... If Not angle And lastangle<0.5 Then angle=0.01 If Not angle And lastangle>0.5 Then angle=0.99 If angle<0.01 Then angle=0.01 If angle>0.99 Then angle=0.99
PositionEntity Player,0,0,Scale*3
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