Problem with FIIIus

mabauti · Post by **mabauti** » Wed Aug 24, 2005 7:14 am

I have a probem with FFIIIus.

The guiding hand is showed complete on the lower action

The guiding hand is half showed on the middle action
http://i18.photobucket.com/albums/b145/mabauti/ff3.png

The guiding hand is not showed on the upper action.

Is this "normal" ?
what can I do?

byuu · Post by **byuu** » Wed Aug 24, 2005 8:16 am

Is this "normal" ?

Nope.

what can I do?

You can modify ZSNES' RTO (range/time over) sprite support to load the first 34 tiles in reverse order from the first 32 sprites on a scanline (e.g. start with sprite #31 and work your way downwards). It goes in the opposite direction currently (starts with the tiles in the first sprite), which causes invisible "sprites" stored before the cursor in the sprite list to be loaded first, thus eating up all available tiles that the PPU can render in one scanline, and not rendering the cursor.

Perhaps a visual example will help. In the below screenshots, 128 16x16 sprites are drawn on the same line, the first at X=0, the second at X=1, etc.

If we were to grab the first 32 sprites, and then go backwards, each 16x16 sprite would contain 2 8x8 tiles. We would thus grab the next 17 sprites (17*2=34). So 32-17=15, so the first 15 sprites would not be rendered. Which just so happens, given the X spacing of 1 pixel per tile, there are 15 blank pixels at the leftmost side in the correct screenshot.
You can apply this logic in reverse to see what the incorrect screenshot is doing wrong.

The left screenshot is correct, the right screenshot was taken from ZSNES 08/22 WIP. Ignore the slight hue difference, the left screenshot was taken with a color curve applied to the image.

And here's a sample program + source that can help you identify when you have the emulation corrected.

Have fun.

mabauti · Post by **mabauti** » Wed Aug 24, 2005 8:59 am

Yeah byuusan u r right. The emulation is not correct. I'll be trying to adjust that issue Thanks

creaothceann · Post by **creaothceann** » Wed Aug 24, 2005 9:40 am

mabauti wrote:I'll be trying to adjust that issue

That's the spirit!

mabauti · Post by **mabauti** » Thu Aug 25, 2005 12:16 am

Ok.

I loaded the rto with Zsnes , but I can't see any other screen than the two blocks (I tried all the keyboard and the gamepad). Should I watch other? ... I can't find the range/time over sprite support screen.

Btw I have trying with all the speed options...result: negative

TIA

p.s. I'm using Zsnes WIP 8_22 (latest)

Clements · Post by **Clements** » Thu Aug 25, 2005 1:00 am

This is a problem for the ZSNES team to solve, or an eagar programmer with the skills and motivation required. I believe byuu already solved this problem for his own bsnes emulator, and is providing the info to help with the fix.

Post by **grinvader** » Thu Aug 25, 2005 11:13 am

As Clements said, you can't "adjust" rto in zsnes unless you have immense x86 asm skills.

mabauti · Post by **mabauti** » Thu Aug 25, 2005 10:23 pm

oops , sorry my mistake.

I'll try with the rto.asm archive.

mabauti · Post by **mabauti** » Thu Aug 25, 2005 10:47 pm

byuu · Post by **byuu** » Thu Aug 25, 2005 11:53 pm

Clements is correct. I thought it might be fun to post the correct technical solution for any interested ZSNES developers (pagefault) here.

You can try running FF3 on SNES9x in the mean time, if you want. It handles sprite rendering (more) correctly. Not looking for an "emulator X is better" discussion, just saying...