Zoom Glitch with Sprites - Page 1

Hi there,


i'm in trouble: yes. I got this strange glitch on my sprites.
This is a normal status picture:



And this is what I've got with a stretch:




I'm developing with NeoDevKit from NeoBitz and DatLib.
Since DatLib doesn't support stretch (maybe i'm so rookie that i can't use it as good as it requires with SCB234 function...), i'm using the function from standard DevKit:
change_sprite_zoom(IntroLava.maxWidth +1 , xz, yz, NGX.tileWidth);

Actually i'm trying to manage the clip value (4th argument) to hide that defect, but it's messy and not 100% working , sometime the clip value hides part of the picture.

Anybody has any hint?
I've tried to manipulate the ASM part of this function in the video library, but still didn't get the pie.

Thanks in advance!

Hi,
I just started on the dev NG with datlib.
And I just made rapid tests.

To zoom, I use the function shrink you can see here.
This is the SCB2 part.

"----------------------------------------
https://wiki.neogeodev.org/index.php?title=Sprites

SCB2 (VRAM $8000~$81FF): Shrinking coefficients

SCB2 is used to specify the shrinking values of each sprite.

The lower byte is the vertical shrinking. $FF is full size.

The lower nibble of the upper byte is the horizontal shrinking. $F is full size.
----------------------------------------"

For my part, I can shrink with the Datlib.
X, it goes from 0 to F and Y, from 0 to FF. Like 0xXYY

So in my code, I use "SC234Put (0x8000, 0x1DE);"

So I change the sprite 1 especially horizontally and slightly vertically.
After I add the same function for the following sprites. The sprite 1 has the value 0x8000. 2, 0x8001, etc.

Maybe this can help you.

This was a great post Tonma - thank you a lot for this code snipped.
I tried your sprite shrinking method in my code and it works perfectly.

Thanks, if I can help

Confirmed!!! Thanks a bunch my friend!!!

I got another glitch on the stretch, but it happens only after the USER_ROUTINE (pressing start).



This happens after:

Boot-->AttractMode (Stretch OK)---->add a Coin!---->TItle! (Stretch OK)---->START!--->GAME/GAME OVER--->back to the AttractMode(Stretch Glitch!)

Got to investigate further on that ASM part (i'm scared...).

I don't know yet this part (insert coin, start button). But maybe it's just a tile error in the NG memory.

Before remake the datlib, you could only test with just the text strecher or with a one color background to see if it does not come from a tile that crushes another

Solved.

I actually don't understand why, but I'll share my experience.

I've resized a bit the Canvas size of the Picture and the glitch has gone forever.
Mind you: i didn't gave an hyper gigantic transparent border value to put the "glitched area" brutally off screen, just some 16px more of height.

That's all folks!

Great.

I have sort of things with scrollers. When I don't add transparent zone to have the same size for two scroller picture. I think the NG add random tiles !