Spot Light

[kevin]

Here's a bit of spot light effect.  The effect is drawing a full screen tile map to one FX image,  then draw some inverted (sort) gouraud triangles to a second image.  The pair are then merged during the blit image process.  It's certainly a bit of huge  mouthful for my trusty duron 800mhz,  but should be more than viable on faster machines.     This one's an MMX only effect.  

The effect is running full screen here, you could selectively limit it to only blit the 'visible region' with a bit of clever coding.

[kevin]

Here's an update of the light map feature.  Now it can be used to add blended coloured lights.  While not express on my duron 800, it's a pretty effect :)

Available in PB1.29

[kevin]

require PB1.29

PlayBASIC Code: [Select]

   w=640
   h=480
   If ScreenModeExist(w,h,32)=False
  Cls 0
  Print "Sorry This Demo Requires A 32 bit Colour Screen Mode"
  Print "press any key to close"
  Sync
  WaitKey
  End   
   EndIf
   OpenScreen w,h,32,2


; Create an FX copy of the display
   FXScreen  =NewImage(GetScreenWidth(),GetScreenHeight()) 
   PrepareFXImage FXscreen


; Create BlitIMage's blend surface. 
   w=GetScreenWidth()
   h=GetScreenHeight()
   BlendFXScreen=NewImage(w,h) 
   PrepareFXImage BlendFXscreen
   SetBlitImageBuffer BlendFXscreen
   RenderToImage BlendFXScreen
   ShadeBox 0,0,w,h,RndRGB(),RndRGB(),RndRGB(),RndRGB()



  Gosub CReateMapStuff



   RenderToImage FXscreen
   
; create a camera.  This camera will attach itself to the current image
; which will be the FX screen  
   CreateCamera 1
   CameraCls 1,Off



   WhiteLIghtColour=$ffffff


   NumbOflights=5

   Dim Balls(   NumbOflights)
   
   balls(1)=Make_SpotLight($ff7f3f)
   For lp=2 To NUmbOFlights
  balls(lp)=Make_SpotLight(RndRGB())
   Next

   Type tLight
     X#,Y#
     Xdir#,Ydir#
     Angle#
     Sprite 
     RadiusX
     RadiusY
   EndType
   Dim Lights(NumbOflights) As tlight


   For lp=1 To NumbOflights
  x=Rnd(GetScreenWidth())
  y=Rnd(GetScreenHeight())
  lights(lp).x#=x
  lights(lp).y#=y
  lights(lp).angle#=Rnd(360)
  lights(lp).RadiusX=RndRange(50,160)
  lights(lp).RadiusY=RndRange(50,160)
  If lp=1
    ThisBall=1
  Else
     ThisBall=RndRange(1,NumbOflights)  
  EndIf
  ThisLight=NewSprite(x,y,balls(ThisBall))
  CenterSpriteHandle ThisLight
  SpriteDrawMode ThisLight,2+16
  ScaleSprite ThisLIght,rndrange(1,5)
  lights(lp).sprite=ThisLIght
   Next 


   ShowControls=Timer()+10000

   
Do

  ; Tell pPB to capture the following drawn items to the scene buffer
     CaptureToScene
        ; clear the buffer
     ClsScene
        ; draw our map to the scene buffer
     DrawMap thisMap,1,0,0
     DrawCamera 1


     RenderToImage BlendFXScreen

     FadeAngle#=WrapAngle(FadeAngle#,2)
     Cls RGBFade(WhiteLightColour,50+Sin(FadeAngle#)*50)     

     If MouseButton()
    WhiteLIghtColour=RndRGB()
     EndIf      

     xpos=MouseX()
     ypos=MouseY()

     For lp=2 To NumbOflights
    x#=lights(lp).x#
    y#=lights(lp).y#
     
    angle#=WrapAngle(lights(lp).Angle#,5)
    lights(lp).Angle=Angle#
    x#=x#+CosRadius(angle#,lights(lp).RadiusX)
    y#=y#+SinRadius(angle#,lights(lp).RadiusY)
    PositionSprite Lights(lp).sprite,x#,y#
    DrawSprite Lights(lp).sprite
     Next

     PositionSprite Lights(1).sprite,xpos,ypos
     DrawSprite Lights(1).sprite

     angle#=WrapAngle(angle#,1)

     RenderToScreen

    BlitImageAlphaMultImage(Fxscreen,0,0,BlendFXscreen)

  ; if the demo has been running for less than 10 second then show
  ; the controls message
      If ShowControls>Timer()
        CenterText GetScreenWidth()/2,GetScreenHeight()/2,"Use Arrows to Scroll Window"
      EndIf

  ; updtae the map animations
     UpdateMapAnims Thismap


     c$=str$(rgbR(WhiteLIghtColour))+","
     c$=c$+str$(rgbG(WhiteLIghtColour))+","
     c$=c$+str$(rgbB(WhiteLIghtColour))


Login required to view complete source code

[kevin]

I've updated the Multiply Blit mode to support 16bit 565 mode (mmx + none mmx).  Resulting in a nice 40-45 FPS effect.  Very useful on my duron 800mhz machine.  Which should mean it'll be very useful for you guys too.  

I've also added 16bit support to Alpha Blit Merge subtract + Addition..  

Anyway here's a screenie..

[kevin]

I've now added 16bit (565) support  Alpha ADD/blendimage.  Bellow is variant of the previous spotlight demo.  This time the light map is being added to to the source image.  The circle in the middle is a being masked off the lightmap.  Creates a rather cool by product..

[Jeku]

Wow, this looks really neat!

[2dman]

"of huge mouthful for my trusty duron 800mhz..."

800mhz is probably too HIGH of a spec if you're going for the casual game market. You should spec your development end on very low end machines. No sense giving us all these wonderful fx if it takes a fast cpu to render them. In that case we'll just use a hardware accelerated engine like PBFX, right?

[kevin]

800mhz is probably too HIGH of a spec if you're going for the casual game market. You should spec your development end on very low end machines. No sense giving us all these wonderful fx if it takes a fast cpu to render  them.

 Sigh,  damn if do, damned if we don't.    

 Fill rate is proportional. Slow clock speeds/videos card & bus speeds obviously have a lower throughput.   Thus, users should spec their demos/games at the appropriate resolution/screen depth for the system their targeting.   Irrespective of design, there can be no guarantee's on any PC.    

In that case we'll just use a hardware accelerated engine like PBFX, right? 

 Not necessarily, since PBFX opposite end of the spectrum..