Contents

Particle Explosion Effect

Added on 1/17/2001

Compatibilities:
behavior Mac Shockwave

This item has not yet been rated

Attach this behavior to a single sprite on the stage. Then open the behavior properties and specify how many copies of the sprite should be created. Click anywhere to trigger explosion

Download PC Source    Download Mac Source

on getBehaviorDescription me
  txt=""
  txt=txt & "This is a particle effects demo. "
  txt=txt & "Based on code by Andre LaMothe. "
  txt=txt & "Author:  adam@papakane.com "
  txt=txt & "Site:  http://www.papakane.com "
  return txt
end

-- Author-defined properties.
property pNumParticles
property pLifeSpan
property pGravity
property pUseFade
property pSound
property pUseMouseScript

-- Other properties.
property pSpr, pMbr
property pParticles

------------------------------------------------------------
-- getPropertyDescriptionList
------------------------------------------------------------
on getPropertyDescriptionList me

  --•
  if not(the currentSpriteNum) then exit -->

  --•
  props=[:]
  props[#pNumParticles]=[#comment:"Number of particles", #format:#integer, #range:[#min:1, #max:100], #default:50]
  props[#pLifeSpan]=[#comment:"Lifespan (milliseconds)", #format:#integer, #range:[#min:0, #max:5000], #default:5000]
  props[#pGravity]=[#comment:"Gravity vector", #format:#list, #default:[0,0.5]]
  props[#pUseFade]=[#comment:"Fade out", #format:#boolean, #default:false]
  props[#pSound]=[#comment:"Sound", #format:#sound, #default:0]
  props[#pUseMouseScript]=[#comment:"Steal mouse down script", #format:#boolean, #default:true]
  return props

end

------------------------------------------------------------
-- beginSprite
------------------------------------------------------------
on beginSprite me

  --•
  pSpr=sprite(me.spriteNum)
  pMbr=pSpr.member

  --•
  if pUseMouseScript then
    the mouseDownScript="sprite(" & me.spriteNum & ").mouseDown()"
  end if

  --•
  me.mReset()

end

------------------------------------------------------------
-- mReset
------------------------------------------------------------
on mReset me

  --•
  pParticles=[]
  repeat with i=1 to pNumParticles
    particle=[:]
    particle[#pState]=#dead
    particle[#pSpr]=sprite(me.mCreateSprite())
    particle[#pStartTime]=0
    particle[#pAge]=0
    particle[#pX]=0
    particle[#pY]=0
    particle[#pXV]=0
    particle[#pYV]=0
    particle[#pLifeSpan]=pLifeSpan
    pParticles.add(particle)
  end repeat

end

------------------------------------------------------------
-- prepareFrame
------------------------------------------------------------
on prepareFrame me

  repeat with i=1 to pParticles.count

    -- Bail if this particle is dead.
    if pParticles[i].pState=#dead then
      pParticles[i].pSpr.loc=point(-1000,-1000)
      next repeat -->
    end if

    -- Add gravity.
    pParticles[i].pXV=pParticles[i].pXV + pGravity[1]
    pParticles[i].pYV=pParticles[i].pYV + pGravity[2]

    -- Otherwise, move particle one step.
    pParticles[i].pX=pParticles[i].pX+pParticles[i].pXV
    pParticles[i].pY=pParticles[i].pY+pParticles[i].pYV

    -- Test if particle is off screen.
    if me.mOffstage(point(pParticles[i].pX,pParticles[i].pY)) then
      pParticles[i].pState=#dead
      next repeat -->
    end if

    -- Test if particle has died of old age
    pParticles[i].pAge=the milliseconds - pParticles[i].pStartTime
    if pParticles[i].pAge >= pParticles[i].pLifeSpan then
      pParticles[i].pState=#dead
      next repeat -->
    end if

    -- Set ink.
    pParticles[i].pSpr.ink=33

    -- Set particle fade amount.
    if pUseFade then
      fadeRatio=float(pParticles[i].pAge) / pParticles[i].pLifeSpan
      blendRatio=1 - fadeRatio
      curBlend=blendRatio * 100
      pParticles[i].pSpr.blend=curBlend
    end if

    -- Draw particle posiiton.
    pParticles[i].pSpr.loc=point(pParticles[i].pX, pParticles[i].pY)

  end repeat

end

------------------------------------------------------------
-- exitFrame
------------------------------------------------------------
on exitFrame me
  go to the frame
end

------------------------------------------------------------
-- mouseDown
------------------------------------------------------------
on mouseDown me
  me.mStart()
end

------------------------------------------------------------
-- mStart
------------------------------------------------------------
on mStart me

  -- Bail if any particles are still alive.
  repeat with i=1 to pParticles.count

    -- Bail if this particle is already alive.
    -- if pParticles[i].pState=#alive then exit-->

  end repeat

  --•
  sound(1).play(pSound)

  --•
  repeat with i=1 to pParticles.count

    -- Explosion happens where user clicked.
    pParticles[i].pX=the mouseH
    pParticles[i].pY=the mouseV

    -- Look, it's a new born particle!
    pParticles[i].pAge=0
    pParticles[i].pStartTime=the milliseconds

    -- Compute random trajectory angle (in damn radians).
    angle=random(360) * pi/180.0

    -- Compute random trajectory velocity.
    vel=2 + random(4)

    -- Set (and show) initial particle velocity.
    pParticles[i].pXV=cos(angle) * vel
    pParticles[i].pYV=sin(angle) * vel

    -- Start particle on its way.
    pParticles[i].pState=#alive

  end repeat

end

------------------------------------------------------------
-- mOffstage
-- checks to see if a specified point is offstage.
------------------------------------------------------------
on mOffstage (me, pt)
  ptRect=rect(pt[1], pt[2], pt[1]+1, pt[2]+1)
  stageRect=(the stage).drawRect
  if intersect(ptRect, stageRect) = rect(0,0,0,0) then
    return true
  else
    return false
  end if
end

------------------------------------------------------------
-- mCreateSprite
------------------------------------------------------------
on mCreateSprite me

  -- Walk through channels 'till we find an open one.
  repeat with chan=1 to the lastChannel
    if sprite(chan).memberNum=0 then
      openChan=chan
      exit repeat
    end if
  end repeat

  -- Place member into empty score channel
  puppetSprite chan, true
  sprite(openChan).forecolor=255
  sprite(openChan).loc=point(random(640), random(480))
  sprite(openChan).member=pMbr

  --•
  return openChan
end

Contact

MMI
36 South Court Sq
Suite 300
Newnan, GA 30263
USA

Send e-mail