According to MSX Tech. Handbook, LMMM copies have the following parameters:

Quote:

MXS: select the source memory 0 = VRAM, 1 = expansion RAM MXD: select the destination memory 0 = VRAM, 1 = expansion RAM SX: source origin X-coordinate (0 to 511) SY: source origin Y-coordinate (0 to 1023) NX: number of dots to be transferred in X direction (0 to 511) NY: number of dots to be transferred in Y direction (0 to 1023) DIX: direction of NX from the origin 0 = right, 1 = left DIY: direction of NY from the origin 0 = below, 1 = above DX: destination origin X-coordinate (0 to 511) DY: destination origin Y-coordinate (0 to 1023)

So, what's the use of DIX and DIY? Can it actually mirror a copy?
In my pascal routines I tried setting both to 0/1 but got no changes whatsoever...

Any clues from the "wise ones"?

DIX and DIY are for line drawing. The line draw only accept positive values for NX and NY and NY<NX. With DIX/Y you can make it draw in any direction.

It probably makes a difference when copying blocks where the destination overlaps the source. Not using it is also a valid feature though

Here is simple example on BASIC, that uses DIX and DIY on VDP to deltapack the picture:

10 SCREEN 8
20 BLOAD"PICTURE.PIC",S
30 A$=INPUT$(1)
40 ' 2D deltapack picture with VDP
50 COPY (1,0)-(255,211) TO (0,0),,XOR
60 COPY (0,1)-(255,211) TO (0,0),,XOR
70 A$=INPUT$(1)
80 ' Unpack picture to original format
90 COPY (0,211)-(255,0) TO (0,210),,XOR
100 COPY (255,0)-(0,211) TO (254,0),,XOR
110 A$=INPUT$(1)

DIX and DIY are used for rotational copying. From BASIC it's only used by a copy from an array of a file. The parameter directly writes DIX and DIY.

COPY array,direction TO (DX,DY)
COPY "filename.ext",direction TO (DX,DY)

A use of DIX and DIY is in the Xak II - Rising of The Red Moon intro, when the game title is displayed where the lower part is a stretched version of the last line.

BiFi, you must be kidding, right?

ain't it simple.. these copy commands do the same:

copy a block (width=10, height=20) from 50,100 to 150,200

SX= 50, SY= 100
NX= 10, NY= 20
DIX= 0, DIY= 0
DX= 150, DY= 200

SX= 60, SY= 120
NX= 10, NY= 20
DIX= 1, DIY= 1
DX= 160, DY= 220

The first copies the block starting from the upper left, the second from right/bottom.
what's the difference? -> when copying overlapping source/destination (a scroller for example)
when scrolling from right to left DIX/DIY can both be 0, but copying form left to right DIX must be 1. just figure it out...

It seems that in BASIC/NBASIC this copy-thing shows up... I tried to make a left-to-right scroller once, which worked in BASIC... With the CALL TURBO ON statement, it went all wrong. Apparently, XBASIC (which is wrapped in NBASIC) doesn't set the DIX/DIY flags accordingly and it all goes haywire...

Feature request: please fix this in NBASIC?

Quote:

DIX and DIY are used for rotational copying. From BASIC it's only used by a copy from an array of a file. The parameter directly writes DIX and DIY. COPY array,direction TO (DX,DY) COPY "filename.ext",direction TO (DX,DY) A use of DIX and DIY is in the Xak II - Rising of The Red Moon intro, when the game title is displayed where the lower part is a stretched version of the last line.

!!!!!!!!!!!!!

Man, I REALLY need to understand how this works. Just for you guys to know... I am thinking about doing BARBARIAN for MSX2 (the fighting one, from CPC, not the one that already exists on MSX1).

I already have the barbarian graphic ripped, but it takes a full VRAM page - just for the player. I would use another page for the enemy, and another for background and buffer (on scr5, of course)

So, I need to be able to mirror "shapes" on the fly, otherwise this game project/idea will never be completed...

The copy routines from Lammassari that I modified and use on MSXPad do have the DIX and DIY parameters, but I get no results from them... maybe only when copying from RAM they would work?

DIX/Y don't mirror the graphics, they just specify from which start point and in which direction the copy is executed. This is handy if you need to do a copy where the source and destination coordinates overlap. Nothing as exciting as mirroring tho. I guess that when you're doing logical copies from RAM you could idd use this to mirror the graphics by reading the source data in the original direction and having a reversed DIX/Y, but it would probably be just as easy to keep DIX/Y normal and read the source data in reverse if you're working with RAM...

the problem is that DIX&DIY in VRAM-VRAM copies are both used for the source and the destination,
so no mirror is possible in this way.

Actually the only way to mirror a a block with DIX/DIY is to use RAM->VRAM commands
Accordingly to DIX you get an horizontal mirror of the block stored in RAM

BUT!!

Pay attention!!! In scr5/6/7 you must use logical commands (LMMC) or the bytes will
be copyed as they are (i.e. unmirrored) with the results you can immegine.

Hmmm... so I have to change my routines to copy from RAM, and also do some timing test to see if the game will be possible...

SLotman: I think you should not copy trought RAM as it is VERY slow. Better to keep the data on RAM or use loop to mirror graphics with VDP. On SCREEN 5 mirror loop is quite heavy as you can not use hispeed commands.

D-Tail: You must have had some other problem. COPY command works just fine on XBASIC. You may for example try the deltapack routine with following changes:

25 _TURBO ON
30 IF INKEY$="" THEN 30
70 IF INKEY$="" THEN 70
110 IF INKEY$="" THEN 110