DrawTriangle:
  ;IN: x1,y1,u1,v1,x2,y2,u2,v2,x3,y3,u3,v3
  ;scherm = 96*64

  ld hl, (y1)
  ld de, (y2)
  cpHLDE
  jr c, Y1SmallerThanY2
  ld (y1), de
  ld (y2), hl
  ld hl, (x1)
  ld de, (x2)
  ld (x1), de
  ld (x2), hl
Y1SmallerThanY2:
  ld hl, (y1)
  ld de, (y3)
  cpHLDE
  jr c, Y1SmallerThanY3
  ld (y1), de
  ld (y3), hl
  ld hl, (x1)
  ld de, (x3)
  ld (x1), de
  ld (x3), hl
Y1SmallerThanY3:
  ld hl, (y2)
  ld de, (y3)
  cpHLDE
  jr c, Y2SmallerThanY3
  ld (y2), de
  ld (y3), hl
  ld hl, (x2)
  ld de, (x3)
  ld (x2), de
  ld (x3), hl
Y2SmallerThanY3:


  push IY
  pop hl
  ld (SaveIY), hl
  ld hl, TempFlags
  push hl
  pop IY

  res 0, (IY)	;in bit 0, (IY) wordt opgeslagen bij welke helft het is. 0=eerste helft, 1= tweede helft
  res 1, (IY)	;bit 1, (IY) = interval texturen al berekend

  ld hl, (y2)
  ld de, (y1)
  subFP		;hier gebruikt om 16-bit getallen af te trekken I.P.V. fixed-point getallen
  ld h, l
  ld l, 0
  push hl
  ld hl, (x2)
  ld de, (x1)
  subFP
  ld h, l
  ld l, 0
  pop de
  call DivFP
  ld (dx1), hl
  ld hl, (y3)
  ld de, (y2)
  subFP
  ld h, l
  ld l, 0
  push hl
  ld hl, (x3)
  ld de, (x2)
  subFP
  ld h, l
  ld l, 0
  pop de
  call DivFP
  ld (dx2), hl
  ld hl, (y3)
  ld de, (y1)
  subFP
  ld h, l
  ld l, 0
  push hl
  ld hl, (x3)
  ld de, (x1)
  subFP
  ld h, l
  ld l, 0
  pop de
  call DivFP
  ld (dx3), hl

;  ld hl, (dx1)
;  ld de, (dx3)
;  cpHLDE
;  jr nc, TNoChange
;  ld (dx1), de
;  ld (dx3), hl
;TNoChange:


  ld hl, (x1)
  bit 7, h
  jr z, TPos1
  ld (tx1+1),hl \ ld a, $FF \ ld (tx1),a
  ld (tx2+1),hl \ ld a, $FF \ ld (tx2),a
  jr TEnd1
TPos1:
  ld (tx1+1),hl \ xor a \ ld (tx1),a ;store the 16bit integer at hl into 16.8 fixed point number tx1
  ld (tx2+1),hl \ xor a \ ld (tx2),a
TEnd1:
  ld hl, (y1)
  ld (_ty), hl

  ld hl, (Y1)
  ld de, (y2)
  cpHLDE
  jp z, __TEndLoop

TDrawLoop:

  ;(h,l) (d,e)

;  ld a, (tx1+1)
;  ld h, a
;  ld a, (_ty)
;  ld l, a
;  ld e, a
;  ld a, (tx2+1)
;  ld d, a
;  call DrawLine

;;;;;;;;;;;;;;;;;;;;;;;;;;;;; Horizontal line drawing !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

  ld a, (_ty)
  ld l, a
#comment
  ld hl, (tu1)
  ld (tmpu), hl
  ld hl, (tv1)
  ld (tmpv), hl
  ld hl, (tu2)
  ld (temp2), hl
  ld hl, (tv2)
  ld (temp3), hl
#endcomment
  ld a, (tx2+1)
  ld (temp+1), a
  ld b, a
  ld a, (tx1+1)
  ld (temp), a
  cp b
  jr c, TOrdered
#comment
  ld hl, (tu2)
  ld (tmpu), hl
  ld hl, (tv2)
  ld (tmpv), hl
  ld hl, (tu1)
  ld (temp2), hl
  ld hl, (tv1)
  ld (temp3), hl
#endcomment
  ld a, (tx2+1)
  ld (temp), a
  ld a, (tx1+1)
  ld (temp+1), a
TOrdered:
  ld a, (temp)
  call GetPixel
  ld (mask), a
  ld (pointer), hl
;#comment
  bit 1, (IY)
  jr nz, EndCalc
  ld hl, (tx1)
  ld de, (tx2)
  cpHLDE
  jr z, EndCalc
  ld a, (temp)
  ld h, a
  ld l, 0
  ld a, (temp+1)
  ld d, a
  ld e, 0
  subFP
  push hl
  ld hl, (tmpu)
  ld de, (temp2)
  subFP
  pop de
  call DivFP
  ld (tmpdu), hl
  ld a, (temp)
  ld h, a
  ld l, 0
  ld a, (temp+1)
  ld d, a
  ld e, 0
  subFP
  push hl
  ld hl, (tmpv)
  ld de, (temp3)
  subFP
  pop de
  call DivFP
  ld (tmpdv), hl
EndCalc:
;#endcomment
TPlotLoop:
  ld a, (mask)
  ld hl, (pointer)
  or (hl)
  ld (hl), a

  ld hl, mask
  rrc (hl)
  jr nc, TNoCarry
  ld hl, (pointer)
  inc hl
  ld (pointer), hl
TNoCarry:

;#comment
  ld hl, (tmpu)
  ld de, (tmpdu)
  add hl, de
  ld (tmpu), hl
  ld hl, (tmpv)
  ld de, (tmpdv)
  add hl, de
  ld (tmpv), hl
;#endcomment

  ld a, (temp+1)
  ld b, a
  ld a, (temp)
  ld hl, temp
  inc (hl)
  cp b
  jr nz, TPlotLoop

;  ld hl, (tx1)
;  ld de, (dx1)
;  add hl, de
;  ld a, (tx1+2)
;  bit 7, d
;  jr z, TPos2
;  adc a, $FF
;  jr Tend2
;TPos2:
;  adc a, 0
;TEnd2:
;  ld (tx1), hl
;  ld (tx1+2), a

;  ld hl,(tx1) \ ld de, (dx1) \ ld a, d \ rla \ sbc a,a \ add hl, de \ ld b, a \ ld a, (tx1+2) \ adc a, b \ ld (tx1+2), a \ ld (tx1), hl

;  ld hl, (tx1)
;  ld de, (dx1)
;  ld a,(tx1+2)
;  bit 7, d
;  jr nz, __Substract1
;  add hl, de
;  jr nc, __End1
;  inc a
;  ld (tx1+2), a
;  jr __End1
;__Substract1:
;  call NegDE
;  or a
;  sbc hl, de
;  jr nc, __End1
;  dec a
;  ld (tx1+2), a
;__End1:
;  ld (tx1), hl

  ld hl,(tx1)
  ld de, (dx1)
  ld a, d
  rla
  sbc a, a
  ld b, a
  add hl, de
  ld (tx1), hl
  ld a, (tx1+2)
  adc a, b
  ld (tx1+2), a

;  ld hl, (tx2)
;  ld de, (dx3)
;  add hl, de
;  ld a, (tx2+2)
;  bit 7, d
;  jr z, TPos3
;  adc a, $FF
;  jr Tend3
;TPos3:
;  adc a, 0
;TEnd3:
;  ld (tx2), hl
;  ld (tx2+2), a

;  ld hl,(tx2) \ ld de, (dx3) \ ld a, d \ rla \ sbc a,a \ add hl, de \ ld b, a \ ld a, (tx2+2) \ adc a, b \ ld (tx2+2), a \ ld (tx2), hl

;  ld hl, (tx2)
;  ld de, (dx3)
;  ld a,(tx2+2)
;  bit 7, d
;  jr nz, __Substract2
;  add hl, de
;  jr nc, __End2
;  inc a
;  ld (tx2+2), a
;  jr __End2
;__Substract2:
;  call NegDE
;  or a
;  sbc hl, de
;  jr nc, __End2
;  dec a
;  ld (tx2+2), a
;__End2:
;  ld (tx2), hl

  ld hl,(tx2)
  ld de, (dx3)
  ld a, d
  rla
  sbc a, a
  ld b, a
  add hl, de
  ld (tx2), hl
  ld a, (tx2+2)
  adc a, b
  ld (tx2+2), a



  ld hl, (_ty)
  inc hl
  ld (_ty), hl
  ld de, (y2)
  cpHLDE
  jp c, TDrawLoop

  bit 0, (IY)
  jr nz, _TEnd
__TEndLoop:

  ;Begin tweede keer tekenen:

  ld hl, (y2)
  ld (_ty), hl

  ld hl, (y3)
  ld (y2), hl
  ld hl, (dx2)
  ld (dx1), hl

  ld hl, (x2)
  bit 7, h
  jr nz, TPos4
  ld (tx1+1),hl \ ld a, $FF \ ld (tx1),a
  jr TEnd4
TPos4:
  ld (tx1+1),hl \ xor a \ ld (tx1),a
Tend4:

  set 0, (IY)

  jp TDrawLoop

_TEnd:

  ld hl, (SaveIY)
  push hl
  pop IY

  ret



getPixel:
   ld   h, 0
   ld   d, h
   ld   e, l

   add   hl, hl
   add   hl, de
   add   hl, hl
   add   hl, hl

   ld   e, a
   srl   e
   srl   e
   srl   e
   add   hl, de

   ld   de, PlotSScreen
   add   hl, de

   and   7
   ld   b, a
   ld   a, $80
   ret   z

   rrca
   djnz   $-1
   ret