Sprite multiplexing demo

Prophet (2619)

29-10-2006, 11:34

I've finished a sprite multiplexing demo, showing the workings of several multiplexing algorythms. It manages till 16 mode 1 sprites that can be moved freely to play with them and test the multiplexing methods. Maybe could be useful to anyone looking for this kind of routines and in need of testing :

Sprite multiplexing demo

Keys used:
-------------
Cursor keys: Selects sprite to move vertically.
Space: Aligns all sprites (not reversible!).
0-4 keys: Selects multiplexing method.

You can find more info in this thread from Karoshi's forum (some little explanations about the algorythms) :

www.msxgamesbox.com/karoshi/index.php?topic=427.0

Although it's in the spanish forum, there're lots of english comments! ;)

By PingPong

Prophet (3889)

29-10-2006, 13:01

Good!

What about cpu time spent?
Could you make a msx2 version taking in account 8 spr x scanline?
Are the source free? Can we get them?

By ARTRAG

Enlighted (6844)

29-10-2006, 16:44

This program in mode 1 (mine) is useful to show the differences
between blue and open msx in the management of the 5th sprite

Simply try to have two lines with 5 or more sprites

As mode 1 splits the SAT accordingly to the S0 value
you'll see that the returned S0 value returned by the
two emulators differ!!

Actually I would like to know what is the real behavour of the HW
and which emulator is'nt accurate (maybe none of them..)

try this configuration of sprites on both emulators and you'll see the differences

http://ragozini.googlepages.com/spriteflick.rar

the avi is very short and recorded on BLUE, but it is sufficient to have a glance on the
configuration that shows the differences and reproduce it on OPEN

By ARTRAG

Enlighted (6844)

29-10-2006, 17:13

@pingpong
my code is on karoshi's website

By jltursan

Prophet (2619)

29-10-2006, 19:45

Could you make a msx2 version taking in account 8 spr x scanline?

I think that with very little changes all routines could be adapted to work with 8 sprite planes limit...

Are the source free? Can we get them?

Sure!, the full demo source is here :

www.telefonica.net/web2/msxpage/sprflick.asm

It's in asMSX format; but as usual, it can be easily adapted to any other assembler. Feel free to modify to suit your needs... :)

As ARTRAG says, you'll see the differences between emulators handling the sprite limit. Slowing the emulation speed you'll see also very clearly the inner working of each method.

By AuroraMSX

Paragon (1902)

29-10-2006, 22:10

As ARTRAG says, you'll see the differences between emulators handling the sprite limit.
Can you describe the differences between openMSX, blueMSX and the real thing?
And possibly file a bug report for openMSX?

By ARTRAG

Enlighted (6844)

30-10-2006, 00:05

look at the .avi I posted, run the rom reproducing the
same sprite configuration displayed in the .avi
and compare the two emulators
You'll see that the two emulators does not return the same
S0 value in the same sprite configuration
I cannot be sure, but OPEN seems to return the FIRST 5th sprites it finds in the screen
while BLUE seems to return the last 5th sprite it finds in the screen

IMHO the ideal HW should return the highest hidden plane in the screen
but I am not sure of the behaviour of the real HW

By Manuel

Ascended (18788)

30-10-2006, 16:14

If someone can test this on the real HW, we can see what should be the actual implementation.

By PingPong

Prophet (3889)

30-10-2006, 20:57

I will try on a v9938 if i have time last weekend, but i need a .dsk image (or .com)

By Manuel

Ascended (18788)

30-10-2006, 22:20

Me too

By jltursan

Prophet (2619)

31-10-2006, 00:16

Instead a .com, you can try it under MSXDOS as a .rom using ExecROM. Anyway, I'll build a bin->dsk version the next weekend (and if I feel brave I'll modify it for 8 sprites )