Code archives/Graphics/Star field

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Star field by Matty B
(Posted 25 years ago)
Basic 3d Stars 
Const MAX_STAR=5000,STAR_SPEED=2,WIDTH=640,HEIGHT=480

Dim star_x(MAX_STAR),star_y(MAX_STAR),star_z(MAX_STAR)

Graphics WIDTH,HEIGHT
SetBuffer BackBuffer()

setup_stars()

While Not KeyDown(1)
	Cls
	UpdateStar()
	Flip
Wend
End

Function setup_stars()
  	For c=0 To MAX_STAR
	star_x(c)=Rnd(-(WIDTH/2),(WIDTH/2))Shl 8
	star_y(c)=Rnd(-(HEIGHT/2),(HEIGHT/2))Shl 8
    star_z(c)=Rnd(STAR_SPEED,255)
	Next 
End Function

Function UpdateStar()
	For c=0 To MAX_STAR
	star_z(c)=star_z(c)-STAR_SPEED
	If star_z(c)<=STAR_SPEED Then star_z(c)=255
	s_x=(star_x(c)/star_z(c))+(WIDTH/2)
	s_y=(star_y(c)/star_z(c))+(HEIGHT/2)
	col=255-star_z(c)
	Color col,col,col
	Plot s_x,s_y
	Next
End Function

Comments

Tim
(Posted 22 years ago)
anybody knows how to add the stars to a camera with movement ? tried it many times with projectedx but i didn't got it..

CyBeRGoth (John McCubbin)
(Posted 22 years ago)
Nice :)

Try replacing:
Plot s_x,s_y
in the UpdateStar function with:
Rect s_x,s_y,col/50,col/50

give you a nice sense of depth :)

Rob Farley
(Posted 22 years ago)
For a bit of performance boost...

Function UpdateStar()
	LockBuffer BackBuffer()
	For c=0 To MAX_STAR
	star_z(c)=star_z(c)-STAR_SPEED
	If star_z(c)<=STAR_SPEED Then star_z(c)=255
	s_x=(star_x(c)/star_z(c))+(WIDTH/2)
	s_y=(star_y(c)/star_z(c))+(HEIGHT/2)
	col=255-star_z(c)
	If s_x>-1 And s_x<width And s_y>-1 And s_y<height
	argb=(col Or (col Shl 8) Or (col Shl 16) Or ($ff000000))
	WritePixelFast s_x,s_y,argb,BackBuffer()
	EndIf
	
	Next
	UnlockBuffer BackBuffer()
End Function


You'll be able to tell the difference if you change your flip to flip false.

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