Function Distance#(x1#, y1#, z1#, x2#, y2#, z2#)
Return Sqr((x1 - x2) ^ 2 + (y1 - y2) ^ 2 + (z1 - z2) ^ 2)
End Function

Graphics3D 1024, 768, 32, 2
SetBuffer BackBuffer()
SeedRnd MilliSecs()

;Globs
Dim xval(20)
Dim yval(20)

Global CamX# = .5
Global CamY# = .5
Global CamZ# = -1

Global ProjX
Global ProjY

;Types
Type Polygon
  Field x1#, y1#, z1#
  Field x2#, y2#, z2#
  Field x3#, y3#, z3#
  Field col1, col2, col3
  Field distance
End Type

;Camera
Global Cam = CreateCamera()
PositionEntity Cam, 0, 0, -7
CameraRange Cam, .00000001, 1000000000

;Model
;Vorne(bei der Camera)
CreatePolygon(0, 0, 0,   1, 0, 0,   1, 1, 0)
CreatePolygon(0, 0, 0,   0, 1, 0,   1, 1, 0)
;Hintern(von der camera Weg)
CreatePolygon(0, 0, 1,   1, 0, 1,   1, 1, 1)
CreatePolygon(0, 0, 1,   0, 1, 1,   1, 1, 1)
;Links
CreatePolygon(0, 0, 0,   0, 0, 1,   0, 1, 1)
CreatePolygon(0, 0, 0,   0, 1, 0,   0, 1, 1)
;Rechts
CreatePolygon(1, 0, 0,   1, 0, 1,   1, 1, 1)
CreatePolygon(1, 0, 0,   1, 1, 0,   1, 1, 1)
;Unten
CreatePolygon(0, 0, 1,   1, 0, 1,   1, 0, 0)
CreatePolygon(0, 0, 1,   0, 0, 0,   1, 0, 0)
;Oben
CreatePolygon(0, 1, 1,   1, 1, 1,   1, 1, 0)
CreatePolygon(0, 1, 1,   0, 1, 0,   1, 1, 0)

While Not KeyHit(1)
  If KeyDown(17) Or KeyDown(200) Then CamZ# = CamZ# + .05
  If KeyDown(31) Or KeyDown(208) Then CamZ# = CamZ# - .05
  If KeyDown(30) Or KeyDown(203) Then CamX# = CamX# - .05
  If KeyDown(32) Or KeyDown(205) Then CamX# = CamX# + .05
  Render()
  Flip
Wend
End

Function Render()
  SortPolys()
  Cls
  For p.Polygon = Each Polygon
    ProjCam(p\x1#, p\y1#, p\z1#): xx1 = ProjX: yy1 = ProjY
    ProjCam(p\x2#, p\y2#, p\z2#): xx2 = ProjX: yy2 = ProjY
    ProjCam(p\x3#, p\y3#, p\z3#): xx3 = ProjX: yy3 = ProjY
    If (xx1 <> 0 Or yy1 <> 0) And (xx2 <> 0 Or yy2 <> 0) And (xx3 <> 0 Or yy3 <> 0) Then
      Color p\col1, p\col2, p\col3
      DrawTriangle(xx1, yy1, xx2, yy2, xx3, yy3)
      DrawTriangle(xx1, yy1, xx3, yy3, xx2, yy2)
      DrawTriangle(xx2, yy2, xx1, yy1, xx3, yy3)
      DrawTriangle(xx2, yy2, xx3, yy3, xx1, yy1)
      DrawTriangle(xx3, yy3, xx1, yy1, xx2, yy2)
      DrawTriangle(xx3, yy3, xx2, yy2, xx1, yy1)
    EndIf
  Next
  Color 255, 255, 255
End Function

Function SortPolys()
For p.Polygon = Each Polygon
  xm# = (p\x1# + p\x2# + p\x3#) / 3
  ym# = (p\y1# + p\y2# + p\y3#) / 3
  zm# = (p\z1# + p\z2# + p\z3#) / 3
  p\distance = Distance(CamX#, CamY#, CamZ#, xm#, ym#, zm#)
Next
SortType()
End Function

Function ProjCam(x#, y#, z#)
tx# = x# - CamX#
ty# = y# - CamY#
tz# = z# - CamZ#
ProjX = GraphicsWidth() / 2 * tx# / tz# + GraphicsWidth() / 2
ProjY = GraphicsHeight() / 2 - GraphicsWidth() / 2 * ty# / tz#
End Function

Function CreatePolygon(x1#, y1#, z1#, x2#, y2#, z2#, x3#, y3#, z3#)
p.Polygon = New Polygon
p\x1# = x1#
p\y1# = y1#
p\z1# = z1#
p\x2# = x2#
p\y2# = y2#
p\z2# = z2#
p\x3# = x3#
p\y3# = y3#
p\z3# = z3#
p\col1 = Rand(50, 255)
p\col2 = Rand(50, 255)
p\col3 = Rand(50, 255)
End Function

Function DrawTriangle(x0, y0, x1, y1, x2, y2)
xval(0) = x0
yval(0) = y0
xval(1) = x1
yval(1) = y1
xval(2) = x2
yval(2) = y2
width = GraphicsWidth()
height = GraphicsHeight()
b = 3 - 1
y = yval(0)
While c <> b
  c = c + 1
  yy = yval(c)
  If yy < y And y = yy Then d = c
Wend
c = d
t = c
While y < height
  If y = yval(c)
    While y = yval(c)
      x0 = xval(c) Shl 16
      c = c + 1
      If c > b Then c = a
      If c = t Then Return
      If y > yval(c) Then Return
    Wend
    h = yval(c) - y
    g0 = ((xval(c) Shl 16) - x0) / h
  EndIf
  If y = yval(d) Then
    While y = yval(d)
      x1 = xval(d) Shl 16
      d = d - 1
      If d < a Then d = b
      If y > yval(d) Then Return
    Wend
    h = yval(d) - y
    g1 = ((xval(d) Shl 16) - x1) / h
  EndIf
  x = x1 Sar 16
  w = ((x0 Sar 16) - x) + 1
  If (w > 0 And y > -1 And x < width And x + w > 0) Then
    If x < 0 w = w + x x = 0
    If x + w > width w = width - x
    Rect x, y, w, 1
  EndIf
  x0 = x0 + g0
  x1 = x1 + g1
  y = y + 1
Wend
End Function

Function SortType()
For Liste.Polygon = Each Polygon: gs = gs + 1 : Next
bs = 1
Repeat
  Liste.Polygon = Last Polygon
  Insert Liste Before First Polygon
  Liste.Polygon = First Polygon
  points_1 = Liste\distance
  X = 1
  bs = bs + 1
  Repeat
    If bs = x Then Exit
    Liste.Polygon = After Liste
    X = X + 1
    If points_1 < Liste\distance Then
      Insert Liste Before Before Liste
      Liste.Polygon = After Liste
    Else
      Exit
    End If
  Forever
Until gs = bs
End Function


Function Distance#(x1#, y1#, z1#, x2#, y2#, z2#)
Return Sqr((x1 - x2) ^ 2 + (y1 - y2) ^ 2 + (z1 - z2) ^ 2)
End Function