Sprite VDP Incompatibilities between MSX-1 and MSX-2

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By Mork

Rookie (18)

Mork's picture

24-06-2022, 17:05

Thank you Micha, that's the solution!
I used another program before that one, which included the command "screen 2,2,0".
Thought that the sprite-settings would be reseted using a new screen-command? oO

By mars2000you

Enlighted (6266)

mars2000you's picture

24-06-2022, 17:15

There are several parameters to the SCREEN instruction. Only the parameters used in a new SCREEN instruction are modified.

https://www.msx.org/wiki/SCREEN

By PingPong

Prophet (3898)

PingPong's picture

26-06-2022, 02:16

Mork wrote:

Hi,
I observed that sprites on a MSX-2 system don´t behave regular in MSX-1 screen modes:
The 4 sprites on a line rule says, that the parts of a fith sprite, which are on a line with the former 4 sprites are suppressed and this is exactly how sprites behave on a MSX-1 system.
However on a MSX-2 system not only the concerned lines of the fith sprites are supressed but the fith sprite at all.
That means, entering the 4 on a line zone the fith sprite vanishes line by line but remains invisible also when parts of the sprite are leaving the zone. The sprite only becomes visible again, when it has left the zone completely.
The same happens with screen 4, concerning the ninth sprite.
Any ideas?

you are wrong. the vdp cannot do this behaviour. to do this the VDP must *remember* the offending sprite between scanlines. that is not the case. Instead the internal vdp state machine work on a scanline basis, it cannot suppress the entire sprite visualization just because one scanline is not displayed

By Mork

Rookie (18)

Mork's picture

27-06-2022, 21:41

Yes, I allready thought, my VDP might be broken... Wink
But Micha found the solution.

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