; ParticleGravity Example
; -----------------------
; Requires Extended mode.

Graphics3D 640,480,0,2
SetBuffer BackBuffer()

camera=CreateCamera()
PositionEntity camera,0,2,-6
CameraClsColor camera,8,12,24

floor=CreatePlane()
EntityColor floor,30,34,44

; A magic fountain spraying motes upwards
emitter=CreateParticleEmitter(1000)
PositionEntity emitter,0,0.5,0
ParticleEmissionRate emitter,150
ParticleLifetime emitter,2,3
ParticleVelocity emitter,0,3,0,0.5,0.3,0.5
ParticleColor emitter,150,220,255,1,80,120,255,0
ParticleSize emitter,0.1,0.03,0.2
EntityBlend emitter,3

grav_y#=-6

While Not KeyDown(1)

    ; [ / ] change vertical gravity, Space flips it upside down
    If KeyDown(26) And grav_y>-20 Then grav_y=grav_y-0.2
    If KeyDown(27) And grav_y<20 Then grav_y=grav_y+0.2
    If KeyHit(57) Then grav_y=-grav_y

    ; Constant acceleration applied to every particle
    ParticleGravity emitter,0,grav_y,0

    ; Arrow keys move the camera
    If KeyDown(200) Then MoveEntity camera,0,0,0.1
    If KeyDown(208) Then MoveEntity camera,0,0,-0.1
    If KeyDown(203) Then TurnEntity camera,0,1,0
    If KeyDown(205) Then TurnEntity camera,0,-1,0

    ; UpdateWorld also advances the particle simulation
    UpdateWorld
    RenderWorld

    Text 0,0,"Arrow keys: move camera   [ / ] : gravity   Space: flip   Esc: exit"
    Text 0,20,"ParticleGravity emitter,0,"+grav_y+",0"

    Flip

Wend

End