Scrolling Cubes

[kevin]

Scrolling Cubes
Example By SuperMonkey & Uwdesign 8th,July,2004  (Updated Dec/2012)

This PlayBASIC demo renders a rotating cube to an image than rendering that as a tile across the display.

PlayBASIC Code: [Select]

;---------------------------------------------------------------------
;  Example By SuperMonkey & Uwdesign 8th,July,2004  (Updated Dec/2012)
;---------------------------------------------------------------------

Rem create some space for the vertex and face data
Dim points#(8,3)
Dim faces(6,5)
Dim matrix#(3,3)
matrix#(1,1)=1
matrix#(2,2)=1
matrix#(3,3)=1

Rem read in the vertex data
For p = 1 To 8
   points#(p,1) =  ReadData() 
   points#(p,2) =  ReadData() 
   points#(p,3) =  ReadData() 
Next p

Rem read in the face data
For f = 1 To 6
   faces(f,1) = ReadData()
   faces(f,2) = ReadData()
   faces(f,3) = ReadData()
   faces(f,4) = ReadData()
   faces(f,5) = ReadData()
Next f

Rem vertex data

 Data -1,-1,-1
 Data 1,-1,-1
 Data 1,1,-1
 Data -1,1,-1

 Data -1,-1,1
 Data 1,-1,1
 Data 1,1,1
 Data -1,1,1


Rem face data
;right/left
 Data 2,6,7,3, RGB(180,150,230)
 Data 5,1,4,8, RGB(80,100,120)
   
 Data 1,2,3,4, RGB(50,70,90)
 Data 6,5,8,7, RGB(100,140,180)

; top /bot
 Data 5,6,2,1, RGB(0,100,50)
 Data 4,3,7,8, RGB(50,160,100)
 
 
 


Rem some space to put the rotated points
Dim rotated#(8,3)

Rem variables which control the size of the cube
x_scale# = 100.0
y_scale# = 100.0
z_scale# = 100.0
Rem set the initial rotation angles to 0
tilt#=0.0
turn#=0.0
roll#=0.0


   
   CreateShape 1,6,6   
   SetShapeEdge 1,1,1,2
   SetShapeEdge 1,2,2,3
   SetShapeEdge 1,3,3,4
   SetShapeEdge 1,4,4,1

CreateImage 1,50,50


   Repeat
  Cls 0 


   Rem prepare the rotation matrix
   A#=Cos(tilt#) : B#=Sin(tilt#)
   C#=Cos(turn#) : D#=Sin(turn#)
   E#=Cos(roll#) : F#=Sin(roll#)
   AD#=A#*D#
   BD#=B#*D#

; Calc Rotattion Martrix  
    m11#=C#*E#
   m21#=-1*C#*F#
   m31#=D#
   m12#=BD#*E#+A#*F#
   m22#=-1*BD#*F#+A#*E# 
   m32#=-1*B#*C# 

   m13#=-1*AD#*E#+B#*F# 
   m23#=AD#*F#+B#*E#
   m33#=A#*C# 

   Rem rotate all the points using the matrix
   For p=1 To 8
 
    pointx#=points#(p,1)
    pointy#=points#(p,2)
    pointz#=points#(p,3)

      rotated#(p,1) = (m11# * pointx# + m12# * pointy# + m13# * pointz#) * x_scale#
      rotated#(p,2) = (m21# * pointx# + m22# * pointy# + m23# * pointz#) * y_scale#
      rotated#(p,3) = (m31# * pointx# + m32# * pointy# + m33# * pointz#) 
    
      Rem now do the perspective calculation
      z# = rotated#(p,3) + 7.0
      rotated#(p,1) = 25.0 + (rotated#(p,1) ) / z#
      rotated#(p,2) = 25.0 + (rotated#(p,2) )/ z#
  Next p


   RenderToImage 1

   Cls 0
   For f=1 To 6
    Rem p1 -> p4 are the points on the face
    p1# = faces(f,1)
    p2# = faces(f,2)
    p3# = faces(f,3)
    p4# = faces(f,4)
  Col=faces(f,5)
  vx1#=rotated#(p1#,1)
  vy1#=rotated#(p1#,2)

  vx2#=rotated#(p2#,1)
  vy2#=rotated#(p2#,2)
   
  vx3#=rotated#(p3#,1)
  vy3#=rotated#(p3#,2)

   ; Cross product
    If (((vx2#-vx1#)*(vy3#-vy1#))-((vx3#-vx1#)*(vy2#-vy1#)))>0

     Ink col
  ; set the shapes vertex for this quad..
     SetShapeVertex 1,1,vx1#,vy1#
     SetShapeVertex 1,2,vx2#,vy2#
     SetShapeVertex 1,3,vx3#,vy3#
     SetShapeVertex 1,4,rotated#(p4#,1),rotated#(p4#,2)

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[Draco9898]

Yikes, math is evile... :lol:

[Supermonkey]

Cool some of my code is being used. Any chance you can talk me through how to get camera rotation to work?

cheers

Jonny

[kevin]

it doesn't use a camera... all i did was use  PlayBASIC's shape command (a polygon filler)  to connect the edges of your cube (the quad of verts) and draw those verts as a filled the polygon...

it draws one cube to a small image, rather than the screen.. Then tiles this cube across the screen making the effect..  It's a old school demo effect.. Just though it'd be a different way to show off  Shapes...

[Draco9898]

Can you 'shade' shapes? That could be quite useful! or fill these shapes with images?  :lol:

You know the title screen for final fantasy 5 and the text gets rendered inside in? that's what I'm thinking  :D

[kevin]

you can create a negative of a shape that could be used to mask an image.  So it's fairly handy..  

Shading is option too, not for a while though..

[Supermonkey]

it doesn't use a camera... all i did was use PB's shape command

Sorry didn't mean to confuse you, I understood how the code worked I just wondered if you could explain to me how I could impliment camera rotation (if its not too much bother). Maybe I should make a new topic?

cheers

Jonny

[kevin]

oh, i see what you mean .. now :)

that's another subject, make a new thread..  I can give you basics,  it'd take forever to explain it great detail..