Author Topic: clipping  (Read 4007 times)

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Offline ben_g

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clipping
« on: November 04, 2011, 06:59:30 pm »
I'm trying to make my triangle drawing code clipped, but I must be doing something wrong becouse the buffer overflows which corrupts some flags of the OS.

here's the code that should clip horizontally
Code: [Select]
  ld a, (temp)
  bit 7, a
  jr nz, TEndPlot
  cp 95
  jp nc, Clip
temp is the var that contains the x position of the pixel that will be drawn.
TEndPlot is a label that is behind the code to plot the pixel, so jumping to here doesn't draw the current pixel.
Clip is a label that wen jumped too will stop drawing the current scanline, and prepares for the next one.

Here's the code that should clip vertically:
Code: [Select]
  bit 7, a
  jp nz, Clip
  ld a, (_ty)
  cp 64
  ret nc
_ty is the y coordinate of the scanline that will be drawn.
Clip stops the current scanline (so nothing will be drawn) and prepares the next one.
ret obiously ends the drawing routine.

Many thanks in advance.
My projects
 - The Lost Survivors (Unreal Engine) ACTIVE [GameCommandoSquad main project]
 - Oxo, with single-calc multiplayer and AI (axe) RELEASED (screenshot) (topic)
 - An android version of oxo (java)  ACTIVE
 - A 3D collision detection library (axe) RELEASED! (topic)(screenshot)(more recent screenshot)(screenshot of it being used in a tilemapper)
Spoiler For inactive:
- A first person shooter with a polygon-based 3d engine. (z80, will probably be recoded in axe using GLib) ON HOLD (screenshot)
 - A java MORPG. (pc) DEEP COMA(read more)(screenshot)
 - a minecraft game in axe DEAD (source code available)
 - a 3D racing game (axe) ON HOLD (outdated screenshot of asm version)

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Offline Hot_Dog

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Re: clipping
« Reply #1 on: November 07, 2011, 03:37:29 pm »
Can you upload some of your ASM files?  At the moment, it doesn't look like you're doing anything wrong, but if it's a problem of corrupted flags, we can help out more if we can see more of the big picture.  For example, I'm hoping to see where exactly temp and _ty are
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Offline ben_g

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Re: clipping
« Reply #2 on: November 07, 2011, 03:51:02 pm »
Sure I can.

Here is it: http://dl.dropbox.com/u/11215358/invasion.z80
I assembled it with spasm.

BTW: from debugging, I noticed that CmdShadow is never corrupted, and textInverse is corrupted as soon as I press clear.

Here is also what it does in a screenshot:


This is pretty much all information I can give.
My projects
 - The Lost Survivors (Unreal Engine) ACTIVE [GameCommandoSquad main project]
 - Oxo, with single-calc multiplayer and AI (axe) RELEASED (screenshot) (topic)
 - An android version of oxo (java)  ACTIVE
 - A 3D collision detection library (axe) RELEASED! (topic)(screenshot)(more recent screenshot)(screenshot of it being used in a tilemapper)
Spoiler For inactive:
- A first person shooter with a polygon-based 3d engine. (z80, will probably be recoded in axe using GLib) ON HOLD (screenshot)
 - A java MORPG. (pc) DEEP COMA(read more)(screenshot)
 - a minecraft game in axe DEAD (source code available)
 - a 3D racing game (axe) ON HOLD (outdated screenshot of asm version)

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Offline jacobly

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Re: clipping
« Reply #3 on: November 09, 2011, 11:53:35 am »
I think I got it!
Code: [Select]
 ld hl, (SaveIY)
  push hl
  pop IY
^ That code is really important, right?
but what happens if it is clipped off the bottom... then the routine returns at the clipping code
Code: [Select]
 bit 7, a
  jp nz, Clip
  ld a, (_ty)
  cp 6
  ret nc // early return, above code is not run!
This results it iy pointing to flash, which is why the os goes crazy... because it is unable to set any of its own flags O.o
Edit: my mistake, it actually points inside saveSScreen, which still causes problems

P.S. ld iy,(nnnn) and ld (nnnn),iy are both documented instructions...
« Last Edit: November 09, 2011, 12:10:00 pm by jacobly »

Offline ben_g

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Re: clipping
« Reply #4 on: November 09, 2011, 01:37:44 pm »
thanks. That solved clipping at the bottom edge. Now bottom and right edge work. The top and left edges make the triangle look weird and slow down the fps, but nothing is corrupted anymore.
Here is what it does instaed of clipping at the top and left edges:
« Last Edit: November 09, 2011, 04:43:51 pm by ben_g »
My projects
 - The Lost Survivors (Unreal Engine) ACTIVE [GameCommandoSquad main project]
 - Oxo, with single-calc multiplayer and AI (axe) RELEASED (screenshot) (topic)
 - An android version of oxo (java)  ACTIVE
 - A 3D collision detection library (axe) RELEASED! (topic)(screenshot)(more recent screenshot)(screenshot of it being used in a tilemapper)
Spoiler For inactive:
- A first person shooter with a polygon-based 3d engine. (z80, will probably be recoded in axe using GLib) ON HOLD (screenshot)
 - A java MORPG. (pc) DEEP COMA(read more)(screenshot)
 - a minecraft game in axe DEAD (source code available)
 - a 3D racing game (axe) ON HOLD (outdated screenshot of asm version)

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Offline Hot_Dog

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Re: clipping
« Reply #5 on: November 10, 2011, 12:02:02 am »
By the way, this is a pretty sweet program!
There are people who can speak two languages, and they are called bilingual.  There are people who speak three languages and are therefore trilingual.  Then there are people who speak one language, and these people are called Americans.


Offline annoyingcalc

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Re: clipping
« Reply #6 on: November 10, 2011, 12:08:47 am »
please pm me a compiled version spasm doesnt work for me :(
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Offline ben_g

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Re: clipping
« Reply #7 on: November 10, 2011, 01:14:04 pm »
By the way, this is a pretty sweet program!
Thanks. But please don't use code from it in your own projects yet: Not all code is mine: I used some routines from other people of which most of them are modified to fit the needs of this program, And I want those people and everybody who helped me to to have some credits. And it'll probably be open source anyway when it's done.

please pm me a compiled version spasm doesnt work for me :(
Ok, I'll send you one

EDIT: I just thought that it might be best to put it on the tread itself, for anyone else who wants to run it when spasm doesn't work, so here's the link:
http://dl.dropbox.com/u/11215358/invasion.8xk

btw: you can run around with the arrow keys, and look up/down with [1]/[0]. press [CLEAR] to exit.
« Last Edit: November 10, 2011, 01:32:58 pm by ben_g »
My projects
 - The Lost Survivors (Unreal Engine) ACTIVE [GameCommandoSquad main project]
 - Oxo, with single-calc multiplayer and AI (axe) RELEASED (screenshot) (topic)
 - An android version of oxo (java)  ACTIVE
 - A 3D collision detection library (axe) RELEASED! (topic)(screenshot)(more recent screenshot)(screenshot of it being used in a tilemapper)
Spoiler For inactive:
- A first person shooter with a polygon-based 3d engine. (z80, will probably be recoded in axe using GLib) ON HOLD (screenshot)
 - A java MORPG. (pc) DEEP COMA(read more)(screenshot)
 - a minecraft game in axe DEAD (source code available)
 - a 3D racing game (axe) ON HOLD (outdated screenshot of asm version)

This signature was last updated on 20/04/2015 and may be outdated

Offline ben_g

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Re: clipping
« Reply #8 on: November 16, 2011, 04:26:25 pm »
I have tried several different stuff with my code the last days, but I still can't get clipping right for the top and left edges. It keeps doing random stuff when it needs to clip of those edges.

Here's the full code:
Spoiler For the code:
; ===============================================================
; Alien Invasion
; ===============================================================





;BTW: store 16bit integer hl in 16.8 fixed point var var: ld (var+1),hl \ xor a \ ld (var),a
;   ld hl, (var1) \ ld de, (var2) \ add hl, de \ ld a, (var1+2) \ adc a, 0 \ ld (var1), hl \ ld (var1+2), a
;   als var1 negatief is, doe adc a, $FF ipv. adc a, 0

;         ld hl,(var1) \ ld de, (var2) \ ld a, h \ rla \ sbc a,a \ add hl, de \ ld b, a \ ld a, (var1+2) \ ld (var2), hl \ adc a, b \ ld (var1+2), a




.org $4000

 .db 080h, 00Fh
 .db 000h, 000h, 000h, 000h
 .db 080h, 012h
 .db 001h, 004h
 .db 080h, 021h
 .db 001h
 .db 080h, 031h
 .db 001h
 .db 080h, 048h
 .db "INVASION"
 .db 080h, 081h
 .db 001h
 .db 080h, 090h
 .db 003h, 026h, 009h, 004h
 .db 01Bh, 053h, 00Bh, 079h
 .db 002h, 00Dh, 040h, 0A1h, 06Bh, 099h, 0F6h, 059h, 0BCh, 067h
 .db 0F5h, 085h, 09Ch, 009h, 06Ch, 00Fh, 0B4h, 003h, 09Bh, 0C9h
 .db 003h, 032h, 02Ch, 0E0h, 003h, 020h, 0E3h, 02Ch, 0F4h, 02Dh
 .db 073h, 0B4h, 027h, 0C4h, 0A0h, 072h, 054h, 0B9h, 0EAh, 07Ch
 .db 03Bh, 0AAh, 016h, 0F6h, 077h, 083h, 07Ah, 0EEh, 01Ah, 0D4h
 .db 042h, 04Ch, 06Bh, 08Bh, 013h, 01Fh, 0BBh, 093h, 08Bh, 0FCh
 .db 019h, 01Ch, 03Ch, 0ECh, 04Dh, 0E5h, 075h
 .db 080h, 07Fh
 .db 000h, 000h, 000h, 000h
 .db 000h, 000h, 000h, 000h
 .db 000h, 000h, 000h, 000h
 .db 000h, 000h, 000h, 000h
 .db 000h, 000h, 000h, 000h

.nolist
#include "ti83plus.inc"
.list
#define bcall(label) rst 28h \ .dw label
#define bjump(label) call $50 \ .dw label
#define SubFP xor a \ sbc hl, de
#define cpHLDE or a \ sbc hl, de \ add hl, de
#define gbuf plotsscreen

;;;;;;;;;;;;;;;;;;;;;;;;;; VARIABELEN ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
temp .equ SavesScreen
temp2 .equ temp+2
temp3 .equ temp2+2

Asqr .equ temp3+2
Bsqr .equ Asqr+2
Csqr .equ Bsqr+2
 
xfrom .equ Csqr+2
yfrom .equ xfrom+2
zfrom .equ yfrom+2
xto .equ zfrom+2
yto .equ xto+2
zto .equ yto+2
xup .equ zto+2
yup .equ xup+2
zup .equ yup+2
angle .equ zup+2
xcross .equ angle+1
ycross .equ xcross+2
zcross .equ ycross+2
xpoint .equ zcross+2
ypoint .equ xpoint+2
zpoint .equ ypoint+2
valid .equ zpoint+2
screenX .equ valid+1
screenY .equ screenx+2
screenx2 .equ screeny+2
screeny2 .equ screenx2+2
screenx3 .equ screeny2+2
screeny3 .equ screenx3+2
screenx4 .equ screeny3+2
screeny4 .equ screenx4+2

X .equ screeny4+2
Y .equ X+2
Direction .equ Y+2

x1 .equ Direction+1
y1 .equ x1+2
u1 .equ y1+2
v1 .equ u1+1
x2 .equ v1+1
y2 .equ x2+2
u2 .equ y2+2
v2 .equ u2+1
x3 .equ v2+1
y3 .equ x3+2
u3 .equ y3+2
v3 .equ u3+1

dx1 .equ V3+1
dx2 .equ dx1+2
dx3 .equ dx2+2
dx4 .equ dx3+2

du1 .equ dx4+2
dv1 .equ du1+2
du2 .equ dv1+2
dv2 .equ du2+2
du3 .equ dv2+2
dv3 .equ du3+2
du4 .equ dv3+2
dv4 .equ du4+2

tx1 .equ dv4+2
tx2 .equ tx1+3
tu1 .equ tx2+3
tv1 .equ tu1+2
tu2 .equ tv1+2
tv2 .equ tu2+2
tx12 .equ tv2+2
tx22 .equ tx12+3
tu12 .equ tx22+3
tv12 .equ tu12+2
tu22 .equ tv12+2
tv22 .equ tu22+2
_ty .equ tv22+2
tmpu .equ _ty+2
tmpv .equ tmpu+2
tmpdu .equ tmpv+2
tmpdv .equ tmpdu+2

mask .equ tmpdv+2
pointer .equ mask+1
TempFlags .equ pointer+2
SaveIY .equ TempFlags+1      ;2 bytes
zto2 .equ saveIY+2      ;2 bytes

;;;;;;;;;;;;;;; START PROGRAMMA ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

Start:
  di
  ;bcall(_RunIndicOff)
  ;call InitFPS
  call ClearGbuf
  call fastCopy
  ld a, 64*3
  ld (direction), a
  in a,($02)
  rla
  sbc a, a
  out ($20), a
  ;ld l, a
  ;ld h, a

  ld hl, 0
  ld (x), hl
  ld hl, $0200
  ld (y), hl

  ld hl, 0
  ld (x1), hl
  ld (y1), hl
  ld a, 0
  ld (u1), a
  ld (v1), a
  ld (v2), a
  ld (u3), a
  ld a, 8
  ld (u2), a
  ld (v3), a
  ld hl, 40
  ld (x2), hl
  ld (y3), hl
  ld hl, 20
  ld (y2), hl
  ld (x3), hl

  call DrawTriangle
  call FastCopy
  bcall(_GetKey)

  ld hl, 0
  ld (zto2), hl

  ld (saveIY), IY
  ld IY, tempFlags

SpelLus:
  call ClearGBuf
 
#comment
  ld a, $FF
  ld (plotsscreen), a
  ld hl, plotsscreen
  ld de, plotsscreen+1
  ld bc, 767
  ldir
#endcomment

  ld hl, (x)
  ld (xfrom), hl
  ld hl, (y)
  ld (yfrom), hl
  ld hl, 0
  ld (zfrom), hl
  ;ld (zto), hl
  ld a, 64
  ld b, a
  ld a, (direction)
  add a, b
  call SinA
  ld de, (x)
  add hl, de
  ld (xto), hl
  ld a, (direction)
  call SinA
  ld de, (y)
  add hl, de
  ld (yto), hl
  ld hl, $0100
  ld (zup), hl
  ld hl, 0
  ld (xup), hl
  ld (yup), hl
  ld hl, (zto2)
  ld (zto), hl
  call InitView

  ld hl, -$0100
  ld (xpoint), hl
  ld hl, 0
  ld (ypoint), hl
  ld hl, -$0100
  ld (zpoint), hl
  call C3DTo2D
  ld hl, (screenx)
  ld (screenx2), hl
  ld hl, (screeny)
  ld (screeny2), hl
  ld hl, $0100
  ld (xpoint), hl
  ld hl, 0
  ld (ypoint), hl
  ld hl, -$0100
  ld (zpoint), hl
  call C3DTo2D
  ld hl, (screenx)
  ld (screenx3), hl
  ld hl, (screeny)
  ld (screeny3), hl
  ld hl, -$0100
  ld (xpoint), hl
  ld hl, 0
  ld (ypoint), hl
  ld hl, $0100
  ld (zpoint), hl
  call C3DTo2D

  ld hl, (screenx)
  ld (x1), hl
  ld hl, (screeny)
  ld (y1), hl
  ld a, 8
  ld (u1), a
  ld a, 0
  ld (v1), a
  ld hl, (screenx2)
  ld (x2), hl
  ld hl, (screeny2)
  ld (y2), hl
  ld a, 8
  ld (u2), a
  ld a, 8
  ld (v2), a
  ld hl, (screenx3)
  ld (x3), hl
  ld hl, (screeny3)
  ld (y3), hl
  ld a, 0
  ld (u3), a
  ld a, 8
  ld (v3), a

  call DrawTriangle
  ;call FastCopy
  ;call ClearGBuf

  ld hl, -$0100
  ld (xpoint), hl
  ld hl, 0
  ld (ypoint), hl
  ld hl, $0100
  ld (zpoint), hl
  call C3DTo2D
  ld hl, (screenx)
  ld (screenx2), hl
  ld hl, (screeny)
  ld (screeny2), hl
  ld hl, $0100
  ld (xpoint), hl
  ld hl, 0
  ld (ypoint), hl
  ld hl, $0100
  ld (zpoint), hl
  call C3DTo2D
  ld hl, (screenx)
  ld (screenx3), hl
  ld hl, (screeny)
  ld (screeny3), hl
  ld hl, $0100
  ld (xpoint), hl
  ld hl, 0
  ld (ypoint), hl
  ld hl, -$0100
  ld (zpoint), hl
  call C3DTo2D

  ld hl, (screenx)
  ld (x1), hl
  ld hl, (screeny)
  ld (y1), hl
  ld a, 0
  ld (u1), a
  ld a, 8
  ld (v1), a
  ld hl, (screenx2)
  ld (x2), hl
  ld hl, (screeny2)
  ld (y2), hl
  ld a, 8
  ld (u2), a
  ld a, 0
  ld (v2), a
  ld hl, (screenx3)
  ld (x3), hl
  ld hl, (screeny3)
  ld (y3), hl
  ld a, 0
  ld (u3), a
  ld (v3), a

  call DrawTriangle

  call FastCopy

 
  ;knoppen
  ld a, $FE
  out (1), a
  push hl \ pop hl ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
  in a, (1)
  bit 0, a
  call z, MoveBack
  bit 3, a
  call z, MoveForward
  bit 1, a
  call z, TurnLeft
  bit 2, a
  call z, TurnRight

  ld a, %11111101
  out ($01), a
  push hl \ pop hl ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
  in a, ($01)
  bit 6, a
  jp z, Einde

  ld a, $EF
  out (1), a
  push hl
  pop hl
  in a, (1)
  bit 0, a
  call z, LookDown
  bit 1, a
  call z, LookUp

  jp spelLus
 
MoveBack:
  push af
  ld a, (direction)
  ld b, 64
  add a, b
  call SinA
  call NegHL
  ld de, $0A00
  call DivFP
  ld de, (X)
  add hl, de
  ld (X), hl
  ld a, (direction)
  call SinA
  call NegHL
  ld de, $0A00
  call DivFP
  ld de, (Y)
  add hl, de
  ld (Y), hl
  pop af
  ret
MoveForward:
  push af
  ld a, (direction)
  ld b, 64
  add a, b
  call SinA
  ld de, $0A00
  call DivFP
  ld de, (X)
  add hl, de
  ld (X), hl
  ld a, (direction)
  call SinA
  ld de, $0A00
  call DivFP
  ld de, (Y)
  add hl, de
  ld (Y), hl
  pop af
  ret
TurnLeft:
  push af
  ld a, (direction)
  inc a
  ld (direction), a
  pop af
  ret
TurnRight:
  ld a, (direction)
  dec a
  ld (direction), a
  ret
LookUp:
  ld hl, (zto2)
  inc hl
  inc hl
  inc hl
  inc hl
  ld (zto2), hl
  ret
LookDown:
  ld hl, (zto2)
  dec hl
  dec hl
  dec hl
  dec hl
  ld (zto2), hl
  ret

 
Einde:
  ;Key port resetten
  ld a, $FF
  out ($01), a
  call ClearGbuf
  call fastCopy
  ld hl, 0
  ld (CurRow), hl
  ld IY, (saveIY)
  EI
  bjump(_JForceCmdNoChar)
 
Cto0:
  ld c, 0
  pop ix
  ret

;;;;;;;;;;;;;;;; 3D ENGINE ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

;TODO: bereken de zoom
InitView:
  ;call once every frame, before C3DTo2D
  ;IN: The engine's vars
  ;OUT: vars are initialised
  ;DESTROYS: all registers and the engine's variables
  ld hl, (xto)
  ld de, (xfrom)
  SubFP
  ld (xto), hl
  ld hl, (yto)
  ld de, (yfrom)
  SubFP
  ld (yto), hl
  ld hl, (zto)
  ld de, (zfrom)
  SubFP
  ld (zto), hl
  ld de, (xto)
  ld b, d \ ld c, e
  call MulFP
  ld (temp), hl
  ld de, (yto)
  ld b, d \ ld c, e
  call MulFP
  ld de, (temp)
  add hl, de
  ld (temp), hl
  ld de, (zto)
  ld b, d \ ld c, e
  call MulFP
  ld de, (temp)
  add hl, de
  call SqrtFP
  ld (temp), hl
  ld hl, (xto)
  ld de, (temp)
  call DivFP
  ld (xto), hl
  ld hl, (yto)
  ld de, (temp)
  call DivFP
  ld (yto), hl
  ld hl, (zto)
  ld de, (temp)
  call DivFP
  ld (zto), hl
  ld de, (xup)
  ld bc, (xto)
  call MulFP
  ld (temp), hl
  ld de, (yup)
  ld bc, (yto)
  call MulFP
  ld de, (temp)
  add hl, de
  ld (temp), hl
  ld de, (zup)
  ld bc, (zto)
  call MulFP
  ld de, (temp)
  add hl, de
  ld (temp), hl
  ld de, (temp)
  ld bc, (xto)
  call MulFP
  ld d, h \ ld e, l
  ld hl, (xup)
  SubFP
  ld (xup), hl
  ld de, (temp)
  ld bc, (yto)
  call MulFP
  ld d, h \ ld e, l
  ld hl, (yup)
  SubFP
  ld (yup), hl
  ld de, (temp)
  ld bc, (zto)
  call MulFP
  ld d, h \ ld e, l
  ld hl, (zup)
  SubFP
  ld (zup), hl
  ld de, (xup)
  ld b, d \ ld c, e
  call MulFP
  ld (temp), hl
  ld de, (yup)
  ld b, d \ ld c, e
  call MulFP
  ld de, (temp)
  add hl, de
  ld (temp), hl
  ld de, (zup)
  ld b, d \ ld c, e
  call MulFP
  ld de, (temp)
  add hl, de
  call sqrtFP
  ld (temp), hl
  ;Multiply (temp) with the tangent of (angle)/2, which is, in this test program, equal to 1, so we don't need to multiply
  ld hl, (xup)
  ld de, (temp)
  call DivFP
  ld (xup), hl
  ld hl, (yup)
  ld de, (temp)
  call DivFP
  ld (yup), hl
  ld hl, (zup)
  ld de, (temp)
  call DivFP
  ld (zup), hl
  ld de, (yup)
  ld bc, (zto)
  call MulFP
  ld (temp), hl
  ld de, (zup)
  ld bc, (yto)
  call MulFP
  ld d, h \ ld e, l
  ld hl, (temp)
  SubFP
  ld (xcross), hl
  ld de, (zup)
  ld bc, (xto)
  call MulFP
  ld (temp), hl
  ld de, (xup)
  ld bc, (zto)
  call MulFP
  ld d, h \ ld e, l
  ld hl, (temp)
  SubFP
  ld (ycross), hl
  ld de, (xup)
  ld bc, (yto)
  call MulFP
  ld (temp), hl
  ld de, (yup)
  ld bc, (xto)
  call MulFP
  ld d, h \ ld e, l
  ld hl, (temp)
  SubFP
  ld (zcross), hl
  ret
 
C3DTo2D:
  ;IN: xpoint, ypoint and zpoint vars
  ;OUT: screenx and screeny are set to the onscreen coordinates for the point
  ;Will not work if InitView wasn't called before this routine
  ;destroys all registers and xpoint, ypoint and zpoint
  ld hl, (xpoint)
  ld de, (xfrom)
  SubFP
  ld (xpoint), hl
  ld hl, (ypoint)
  ld de, (yfrom)
  SubFP
  ld (ypoint), hl
  ld hl, (zpoint)
  ld de, (zfrom)
  SubFP
  ld (zpoint), hl
  ld de, (xpoint)
  ld bc, (xto)
  call MulFP
  ld (temp), hl
  ld de, (ypoint)
  ld bc, (yto)
  call MulFP
  ld de, (temp)
  add hl, de
  ld (temp), hl
  ld de, (zpoint)
  ld bc, (zto)
  call MulFP
  ld de, (temp)
  add hl, de
  ld (temp), hl
  ;kijk hier of het punt zichtbaar is
  bit 7, h
  jp nz, InValid
 
  ld de, (xpoint)
  ld bc, (xcross)
  call MulFP
  ld (temp2), hl
  ld de, (ypoint)
  ld bc, (ycross)
  call MulFP
  ld de, (temp2)
  add hl, de
  ld (temp2), hl
  ld de, (zpoint)
  ld bc, (zcross)
  call MulFP
  ;ld de, (temp2)
  ;ld bc, (zup)
  ;call MulFP
  ld de, (temp2)
  add hl, de
  ld de, (temp)
  call DivFP
  ld (screenx), hl
  ld de, (xpoint)
  ld bc, (xup)
  call MulFP
  ld (temp2), hl
  ld de, (ypoint)
  ld bc, (yup)
  call MulFP
  ld de, (temp2)
  add hl, de
  ld (temp2), hl
  ld de, (zpoint)
  ld bc, (zup)
  call MulFP
  ld de, (temp2)
  add hl, de
  ld de, (temp)
  call DivFP
  ld (screeny), hl
  ld hl, $0100
  ld de, (screenx)
  SubFP
  ld b, h \ ld c, l
  ld de, 48
  call MulFP
  ld (screenx), hl
  ld de, (screeny)
  ld hl, $0100
  SubFP
  ld b, h \ ld c, l
  ld de, 32
  call MulFP
  ld (screeny), hl
  ld a, 1
  ret
InValid:
  ld a, 0
  ret
 

;;;;;;;;;;;;;;;; GRAPHIC ROUTINES ;;;;;;;;;;;;;;;;;;;;;;;;;

DrawLine:   ;(h,l)to(d,e)
  pop ix
  ld c, h
  push bc
  ld c, l
  push bc
  ld c, d
  push bc
  ld l, e
  push ix
 
p_Line:
   .db __LineEnd-$-1
   ld   ix,plotSScreen
   ld   a,l
   pop   hl
   pop   bc
   pop   de
   ex   (sp),hl      ;Called with 3 args pushed.  Using call-back optimization.
   cp   64
   ret   nc
   ld   b,a
   ld   a,e
   cp   64
   ret   nc
   ld   d,l
   ld   l,b

   ld   a,d
   cp   96
   ret   nc
   ld   a,c
   cp   96
   ret   nc

   ld   h,a
   sub   d
   jr   nc,__LineSkipRev
   ex   de,hl
   neg
__LineSkipRev:
   push   af         ; Saving DX (it will be popped into DE below)
   ld   a,d         ; IX+=D/8+E*12 (actually E*4+E*4+E*4)
   rra
   rra
   rra
   and   %00011111
   ld   c,a
   ld   b,0
   add   ix,bc
   ld   a,e
   add   a,a
   add   a,a
   ld   c,a
   add   ix,bc
   add   ix,bc
   add   ix,bc
   ld   a,d         ; Calculating the starting pixel mask
   and   %00000111
   inc   a
   ld   b,a
   ld   a,%00000001
__LineMaskLoop:
   rrca
   djnz   __LineMaskLoop
   ld   c,a
   ld   a,l         ; Calculating delta Y and negating the Y increment if necessary
   sub   e         ; This is the last instruction for which we need the original data
   ld   de,12
   jr   nc,__LineSkipNeg
   ld   de,-12
   neg
__LineSkipNeg:
   pop   hl         ; Recalling DX
   ld   l,a         ; D=DX, E=DY
   cp   h
   jr   c,__LineHoriz      ; Line is rather horizontal than vertical
__LineVert:
   ld   b,l         ; Pixel counter
   inc   b
   rra            ; nc at this point so (A=E/2)
__LineVLoop:
   push   af
   ld   a,(ix+0)
   or   c         ; Writing pixel to current position
   ld   (ix+0),a
   pop   af
   add   ix,de
   sub   h         ; Handling gradient
   jr   nc,__LineVNext
   add   a,l
   rrc   c         ; Rotating mask
   jr   nc,__LineVNext      ; Handling byte boundary
   inc   ix
__LineVNext:
   djnz   __LineVLoop
   ret
__LineHoriz:
   ld   b,h         ; Pixel counter
   inc   b
   ld   a,h         ; Setting up gradient counter
   srl   a
__LineHLoop:
   push   af         ; Saving A
   ld   a,(ix+0)
   or   c         ; Writing pixel to current position
   ld   (ix+0),a
   pop   af         ; Recalling A
   rrc   c         ; Rotating mask
   jr   nc,__LineHSkip      ; Handling byte boundary
   inc   ix
__LineHSkip:
   sub   l         ; Handling gradient
   jr   nc,__LineHNext
   add   a,h
   add   ix,de
__LineHNext:
   djnz __LineHLoop
   ret
__LineEnd:

;;;;;;;;;;;;;;;;;;
;ClearGbuf
;wist de graphics buffer
;
;IN: /
;OUT: wist de graphics buffer
ClearGbuf:
  ld hl, gbuf-12-(-(12*64)+1)
  ld a, $20
  ld c, a
ClearGbufAgain:
  ld b, 64
  inc c
  ld de, -(12*64)+1
  add hl, de
  ld de, 10
ClearGbufLoop:
  add hl, de
  inc hl
  inc hl
  inc de
  ld (hl), $00
  dec de
  djnz ClearGbufLoop
  ld a, c
  cp $2B+1
  jr nz, ClearGbufAgain
  ret
 
;;;;;;;;;;;;;;;;;;
;fastcopy
;IN: /
;OUT: /
;copies the buffer to the screen
fastCopy:
  di
  ld a,$80
  out ($10),a
  ld hl,gbuf-12-(-(12*64)+1)
  ld a,$20
  ld c,a
  inc hl
  dec hl
fastCopyAgain:
  ld b,64
  inc c
  ld de,-(12*64)+1
  out ($10),a
  add hl,de
  ld de,10
fastCopyLoop:
  add hl,de
  inc hl
  inc hl
  inc de
  ld a,(hl)
  out ($11),a
  dec de
  djnz fastCopyLoop
  ld a,c
  cp $2B+1
  jr nz,fastCopyAgain
  ret

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
#comment
  ld hl, (u1)
  ld de, (u2)
  ld (u1), de
  ld (u2), hl
#endComment
  ld a, (u1)
  ld b, a
  ld a, (u2)
  ld (u1), a
  ld a, b
  ld (u2), a
  ld a, (v1)
  ld b, a
  ld a, (v2)
  ld (v1), a
  ld a, b
  ld (v2), a
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
#comment
  ld hl, (u1)
  ld de, (u3)
  ld (u1), de
  ld (u3), hl
#endcomment
  ld a, (u1)
  ld b, a
  ld a, (u3)
  ld (u1), a
  ld a, b
  ld (u3), a
  ld a, (v1)
  ld b, a
  ld a, (v3)
  ld (v1), a
  ld a, b
  ld (v3), a
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
#comment
  ld hl, (u2)
  ld de, (u3)
  ld (u2), de
  ld (u3), hl
#endComment
  ld a, (u2)
  ld b, a
  ld a, (u3)
  ld (u2), a
  ld a, b
  ld (u3), a
  ld a, (v2)
  ld b, a
  ld a, (v3)
  ld (v2), a
  ld a, b
  ld (v3), a
Y2SmallerThanY3:
 

  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
  bit 7, h
  ld h, l
  ld l, 0
  jr z,$+3 \ dec l
  push hl
  ld hl, (x2)
  ld de, (x1)
  subFP
  bit 7, h
  ld h, l
  ld l, 0
  jr z,$+3 \ dec l
  pop de
  call DivFP
  ld (dx1), hl
  ld hl, (y3)
  ld de, (y2)
  subFP
  bit 7, h
  ld h, l
  ld l, 0
  jr z,$+3 \ dec l
  push hl
  ld hl, (x3)
  ld de, (x2)
  subFP
  bit 7, h
  ld h, l
  ld l, 0
  jr z,$+3 \ dec l
  pop de
  call DivFP
  ld (dx2), hl
  ld hl, (y3)
  ld de, (y1)
  subFP
  bit 7, h
  ld h, l
  ld l, 0
  jr z,$+3 \ dec l
  push hl
  ld hl, (x3)
  ld de, (x1)
  subFP
  bit 7, h
  ld h, l
  ld l, 0
  jr z,$+3 \ dec l
  pop de
  call DivFP
  ld (dx3), hl


  ld hl, (y2)
  ld de, (y1)
  subFP
  bit 7, h
  ld h, l
  ld l, 0
  jr z,$+3 \ dec l
  push hl
  ld a, (u2)
  ld h, a
  ld l, 0
  ld a, (u1)
  ld d, a
  ld e, 0
  subFP
  ;ld h, l
  ;ld l, 0
  pop de
  call DivFP
  ld (du1), hl
  ld hl, (y3)
  ld de, (y2)
  subFP
  bit 7, h
  ld h, l
  ld l, 0
  jr z,$+3 \ dec l
  push hl
  ld a, (u3)
  ld h, a
  ld l, 0
  ld a, (u2)
  ld d, a
  ld e, 0
  subFP
  ;ld h, l
  ;ld l, 0
  pop de
  call DivFP
  ld (du2), hl
  ld hl, (y3)
  ld de, (y1)
  subFP
  bit 7, h
  ld h, l
  ld l, 0
  jr z,$+3 \ dec l
  push hl
  ld a, (u3)
  ld h, a
  ld l, 0
  ld a, (u1)
  ld d, a
  ld e, 0
  subFP
  ;ld h, l
  ;ld l, 0
  pop de
  call DivFP
  ld (du3), hl


  ld hl, (y2)
  ld de, (y1)
  subFP
  bit 7, h
  ld h, l
  ld l, 0
  jr z,$+3 \ dec l
  push hl
  ld a, (v2)
  ld h, a
  ld l, 0
  ld a, (v1)
  ld d, a
  ld l, 0
  subFP
  ;ld h, l
  ;ld l, 0
  pop de
  call DivFP
  ld (dv1), hl
  ld hl, (y3)
  ld de, (y2)
  subFP
  bit 7, h
  ld h, l
  ld l, 0
  jr z,$+3 \ dec l
  push hl
  ld a, (v3)
  ld h, a
  ld l, 0
  ld a, (v2)
  ld d, a
  ld e, 0
  subFP
  ;ld h, l
  ;ld l, 0
  pop de
  call DivFP
  ld (dv2), hl
  ld hl, (y3)
  ld de, (y1)
  subFP
  bit 7, h
  ld h, l
  ld l, 0
  jr z,$+3 \ dec l
  push hl
  ld a, (v3)
  ld h, a
  ld l, 0
  ld a, (v1)
  ld d, a
  ld e, 0
  subFP
  ;ld h, l
  ;ld l, 0
  pop de
  call DivFP
  ld (dv3), hl

  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 a, (u1)
  ld h, a
  ld l, 0
  ld (tu1), hl
  ld (tu2), hl
  ld a, (v1)
  ld h, a
  ld l, 0
  ld (tv1), hl
  ld (tv2), hl

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

TDrawLoop:
  ld a, (_ty)
  ld d, a

  bit 7, a
  jp nz, Clip
  ld a, (_ty)
  cp 64
  ret nc

  ld hl, (tu1)
  ld (tmpu), hl
  ld hl, (tv1)
  ld (tmpv), hl
  ld hl, (tu2)
  ld (temp2), hl
  ld hl, (tv2)
  ld (temp3), hl
  ld a, (tx2+1)
  ld (temp+1), a
  ld b, a
  ld a, (tx1+1)
  ld (temp), a
  cp b
  jr c, TOrdered
  ld hl, (tu2)
  ld (tmpu), hl
  ld hl, (tv2)
  ld (tmpv), hl
  ld hl, (tu1)
  ld (temp2), hl
  ld hl, (tv1)
  ld (temp3), hl
  ld a, (tx2+1)
  ld (temp), a
  ld a, (tx1+1)
  ld (temp+1), a
TOrdered:
  ld l, d
  ld a, (temp)
  call GetPixel
  ld (mask), a
  ld (pointer), hl

  bit 1, (IY)
  jr nz, TPlotLoop
  ld hl, (tx1)
  ld de, (tx2)
  cpHLDE
  jr z, TPlotLoop
  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
  set 1, (IY)


TPlotLoop:

  ld a, (temp)
  bit 7, a
  jr nz, TEndPlot
  cp 96
  jp nc, Clip

  ld a, (tmpv+1)
  ld hl, texture
  add a, l
  ld l, a

  ld a, (tmpu+1)
  ld b, a
  inc b
  ld a, (hl)
TshiftLoop:
  rla
  djnz   TshiftLoop

  ;push af
 
  ld a, (mask)
  ld hl, (pointer)
  jr c, TSetPixel

TResPixel:
  ;ld a, b
  cpl
  and (hl)
  ld (hl), a
  jr TEndPlot

TSetPixel:
  ;ld a, b
  or (hl)
  ld (hl), a

TEndPlot:

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

  ld hl, (tmpu)
  ld de, (tmpdu)
  add hl, de
  ld (tmpu), hl
  ld hl, (tmpv)
  ld de, (tmpdv)
  add hl, de
  ld (tmpv), hl

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

  bit 0, (IY)
  jr nz, aaaa
  res 1, (IY)
aaaa:

Clip:

  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)
  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, (tu1)
  ld de, (du1)
  add hl, de
  ld (tu1), hl
  ld hl, (tu2)
  ld de, (du3)
  add hl, de
  ld (tu2), hl

  ld hl, (tv1)
  ld de, (dv1)
  add hl, de
  ld (tv1), hl
  ld hl, (tv2)
  ld de, (dv3)
  add hl, de
  ld (tv2), hl


  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, (du2)
  ld (du1), hl
  ld hl, (dv2)
  ld (dv1), 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:

  ld a, (u2)
  ld h, a
  ld l, 0
  ld (tu1), hl
  ld a, (v2)
  ld h, a
  ld l, 0
  ld (tv1), hl

  set 0, (IY)

  jp TDrawLoop

_TEnd:

  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
 


;;;;;;;;;;;;;;;;;;;;;;;;;; MATH ROUTINES ;;;;;;;;;;;;;;;;;;;;;;;;;;;

 
SqrtA:
   LD   (Asqr),A
   SRL   A
   JR   DataOver
DataOver:
   LD   (Bsqr),A
   LD   B,A
   LD   (Csqr),A
iterate:
   LD   A,(Bsqr)
   ld     b, a
   LD   a,(Asqr)
   LD   D,A
   LD   E,B
dividedbyEreturnA:
   RL   D
   RLA
   SUB   E
   JR   nc,$+3
   ADD   A,E
   LD   E,A
   LD   A,D
   CPL
   push af      ;1
   LD   a,(Bsqr)
   ld b, a
   pop af         ;0
   ADD   A,B
   SRL   A
   LD   (Bsqr),A
   LD   a,(Bsqr)
   ld b, a
   LD   A,(Csqr)
   DEC   A
   CP   B
   JR   z,done
   push af      ;1
   LD   (Csqr),a
   ld b, a
   pop af         ;0
   JR   iterate
done:
   LD   A,(Bsqr)
   RET
 
;SubFP:
;  ;substracts 2 16-bit fixed-point numbers
;  ;IN: hl, de
;  ;OUT: hl - de in hl
;  ;DESTROYS: a, hl
;  or   a   ;clear carry flag
;  sbc   hl, de
;  ret
 
Div16By8:
  ;divides a 16-bit number by an 8-bit number
  ;IN: hl and d
  ;OUT: hl = hl/d, remainder = a
  ;DESTROYS: a, b, c, d, hl
  xor a
  ld b, 16
_D16b8Loop:
  add hl, hl
  rla
  jr c, _D16b8Overflow
  cp d
  jr c, _D16b8Skip
_D16b8Overflow:
  sub b
  inc l
_D16b8Skip:
  djnz _D16b8Loop
  ret

 
MulFP:
  ;Multiplies 2 16bit fixed-point numbers
  ;IN: de, bc
  ;OUT: de * bc in hl
  ;DESTROYS: af, bc, de, hl
  bit 7, d
  jr nz, _MulFP_FirstNeg
  bit 7, b
  jr nz, _MulFP_AnsNeg
  jr z, _MulFP_AnsPos
_MulFP_FirstNeg:
  bit 7, b
  jr nz, _MulFP_AnsPos
_MulFP_AnsNeg:
  ld a, 1
  push af         ;1
  jr _MulFP_Cont
_MulFP_AnsPos:
  ld a, 0
  push af         ;1
_MulFP_Cont:
  bit 7, b
  jr z, _MulFP_BCPos
  call NegBC
_MulFP_BCPos:
  bit 7, d
  jr z, _MulFP_DEPos
  call NegDE
_MulFP_DEPos:
  ld hl,0
  ld a,16
Mul16Loop:
  add hl,hl
  rl e
  rl d
  jp nc,NoMul16
  add hl,bc
  jp nc,NoMul16
  inc de
NoMul16:
  dec a
  jp nz,Mul16Loop

  ld l, h
  ld h, e
  pop af         ;0
  cp 1
  call z, NegHL
  ret
 
;adding fixed-point numbers:
;load one of the numbers in hl, and the other in an other 16-bit register.
;then, do: add hl, <register>

DivFP:
  ;IN: hl, de
  ;OUT: hl = hl / de
  ;DESTROYS: af, hl, bc, d
  bit 7, d
  jr nz, _DivFP_FirstNeg
  bit 7, h
  jr nz, _DivFP_AnsNeg
  jr z, _DivFP_AnsPos
_DivFP_FirstNeg:
  bit 7, h
  jr nz, _DivFP_AnsPos
_DivFP_AnsNeg:
  ld a, 1
  push af
  jr _DivFP_Cont
_DivFP_AnsPos:
  ld a, 0
  push af
_DivFP_Cont:
  bit 7, h
  jr z, _DivFP_HLPos
  call NegHL
_DivFP_HLPos:
  bit 7, d
  jr z, _DivFP_DEPos
  call NegDE
_DivFP_DEPos
  ld a, h
  ld h, l
  ld l, 0
  push hl ;INPUTS: ahl = dividend de = divisor   ;1
  pop ix ;OUTPUTS: ahl = quotient de = divisor   ;0
  ld hl,0
  ld b,24
_Div24by16loop:
  add ix,ix
  rla
  adc hl,hl
  jr c,_Div24by16setbit
  or a
  sbc hl,de
  add hl,de
  jr c,_Div24by16skip
_Div24by16setbit:
  or a
  sbc hl,de
  inc ix
_Div24by16skip:
  djnz _Div24by16loop
  push ix         ;1
  pop hl         ;0

  pop af
  cp 1
  call z, NegHL
  ret
 
SinA:
  ;calculates the sine of a as a fixed point number
  ;IN: a
  ;OUT: hl = sin(a)
    LD     h, 0
    LD     l, a
    add hl, hl
    LD     DE, sine_table
    ADD    HL, DE
    LD     A, (HL)
    INC    HL
    LD     H, (HL)
    LD     L, A
    RET
sine_table:
.dw    0, 6, 13, 19, 25, 31, 38, 44, 50, 56, 62, 68, 74, 80, 86, 92, 98, 104, 109, 115, 121, 126, 132, 137, 142
.dw    147, 152, 157, 162, 167, 172, 177, 181, 185, 190, 194, 198, 202, 206, 209, 213, 216, 220, 223, 226, 229, 231, 234
.dw    237, 239, 241, 243, 245, 247, 248, 250, 251, 252, 253, 254, 255, 255, 256, 256, 256, 256, 256, 255, 255, 254, 253
.dw    252, 251, 250, 248, 247, 245, 243, 241, 239, 237, 234, 231, 229, 226, 223, 220, 216, 213, 209, 206, 202, 198, 194
.dw    190, 185, 181, 177, 172, 167, 162, 157, 152, 147, 142, 137, 132, 126, 121, 115, 109, 104, 98, 92, 86, 80, 74, 68
.dw    62, 56, 50, 44, 38, 31, 25, 19, 13, 6, 0, -6, -13, -19, -25, -31, -38, -44, -50, -56, -62, -68, -74, -80, -86, -92
.dw    -98, -104, -109, -115, -121, -126, -132, -137, -142, -147, -152, -157, -162, -167, -172, -177, -181, -185, -190
.dw    -194, -198, -202, -206, -209, -213, -216, -220, -223, -226, -229, -231, -234, -237, -239, -241, -243, -245, -247
.dw    -248, -250, -251, -252, -253, -254, -255, -255, -256, -256, -256, -256, -256, -255, -255, -254, -253, -252, -251
.dw    -250, -248, -247, -245, -243, -241, -239, -237, -234, -231, -229, -226, -223, -220, -216, -213, -209, -206, -202
.dw    -198, -194, -190, -185, -181, -177, -172, -167, -162, -157, -152, -147, -142, -137, -132, -126, -121, -115, -109
.dw    -104, -98, -92, -86, -80, -74, -68, -62, -56, -50, -44, -38, -31, -25, -19, -13, -6
 
SqrtFP:
;#####################################################
;square root of fixed point hl
;input: hl
;output: hl=sqrt(hl)

sqrt_hl:
   ld   a, l
   ld   l, h
   ld   de, 0040h   ; 40h appends "01" to D
   ld   h, d
   
   ld   b, 7
   
   ; need to clear the carry beforehand
   or   a
   
_loopz:
   sbc   hl, de
   jr   nc, $+3
   add   hl, de
   ccf
   rl   d
   rla
   adc   hl, hl
   rla
   adc   hl, hl
   
   djnz   _loopz
   
   sbc   hl, de      ; optimised last iteration
   ccf
   rl   d

   ld   h, d
   xor   a
   ld   b, 4
shiftLoopz:
   srl   h
   rra
   djnz   shiftLoopz
   ld   l, a
   ret
 
NegHL:
   xor a
   sub l
   ld l,a
   sbc a,a
   sub h
   ld h,a
   ret

NegBC:
   xor a
   sub c
   ld c,a
   sbc a,a
   sub b
   ld b,a
   ret

NegDE:
   xor a
   sub e
   ld e,a
   sbc a,a
   sub d
   ld d,a
   ret
 
;;;;;;;;;;;;;;;;;;;;;;;;;; OTHER ROUTINES ;;;;;;;;;;;;;;;;;;;;;;;;;;

;###################################
calcFPS:
fpsCounter   equ   $+1
   ld   a, 00
   inc   a
   ld   (fpsCounter), a

   in   a, (04)
   bit   5, a
   jr   z, didntChange
initFPS:
   ld   a, $47
   out   ($30), a
   xor   a
   out   ($31), a
   ld   a, 8
   out   ($32), a
   ld   a, (fpsCounter)
   ld   (fpsFinal), a
   xor   a
   ld   (fpsCounter), a
didntChange:
fpsFinal   equ   $+1
   ld   a, 00
   ret



;;;;;;;;;;;;;;;;;;;;;;;;;;;; Textures ;;;;;;;;;;;;;;;;;;;;;;;;;
Texture:
.db %11111111
.db %11010101
.db %10101011
.db %11010101
.db %10101011
.db %11010101
.db %10101011
.db %11111111
   
.end
« Last Edit: November 17, 2011, 01:45:36 pm by ben_g »
My projects
 - The Lost Survivors (Unreal Engine) ACTIVE [GameCommandoSquad main project]
 - Oxo, with single-calc multiplayer and AI (axe) RELEASED (screenshot) (topic)
 - An android version of oxo (java)  ACTIVE
 - A 3D collision detection library (axe) RELEASED! (topic)(screenshot)(more recent screenshot)(screenshot of it being used in a tilemapper)
Spoiler For inactive:
- A first person shooter with a polygon-based 3d engine. (z80, will probably be recoded in axe using GLib) ON HOLD (screenshot)
 - A java MORPG. (pc) DEEP COMA(read more)(screenshot)
 - a minecraft game in axe DEAD (source code available)
 - a 3D racing game (axe) ON HOLD (outdated screenshot of asm version)

This signature was last updated on 20/04/2015 and may be outdated

Offline aeTIos

  • Nonbinary computing specialist
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Re: clipping
« Reply #9 on: November 17, 2011, 01:38:46 pm »
D: Code + spoiler in chrome
I'm not a nerd but I pretend:

Offline ben_g

  • Hey cool I can set a custom title now :)
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Re: clipping
« Reply #10 on: November 17, 2011, 01:46:26 pm »
D: Code + spoiler in chrome
I replaced the [code] tags with [tt] tags. I hope that's better.
« Last Edit: November 17, 2011, 04:11:25 pm by ben_g »
My projects
 - The Lost Survivors (Unreal Engine) ACTIVE [GameCommandoSquad main project]
 - Oxo, with single-calc multiplayer and AI (axe) RELEASED (screenshot) (topic)
 - An android version of oxo (java)  ACTIVE
 - A 3D collision detection library (axe) RELEASED! (topic)(screenshot)(more recent screenshot)(screenshot of it being used in a tilemapper)
Spoiler For inactive:
- A first person shooter with a polygon-based 3d engine. (z80, will probably be recoded in axe using GLib) ON HOLD (screenshot)
 - A java MORPG. (pc) DEEP COMA(read more)(screenshot)
 - a minecraft game in axe DEAD (source code available)
 - a 3D racing game (axe) ON HOLD (outdated screenshot of asm version)

This signature was last updated on 20/04/2015 and may be outdated