Comparison of 4th generation ("8/16-bit") system hardware

[Kamahl]

It should cause the DMA to pause until the new position is reached if you give it a bigger line number, or will do NOTHING if you give it a line number you are already past.

I was wondering what the effect onscreen would be like, what do you mean by "do nothing"? Not drawing? So it'll leave an empty 16pixel line onscreen? Or will it just draw the old data?

[Chilly Willy]

I was wondering what the effect onscreen would be like, what do you mean by "do nothing"? Not drawing? So it'll leave an empty 16pixel line onscreen? Or will it just draw the old data?

Do nothing means it won't change how it's working - fetching the next couple words of image data on the next horizontal blank. So setting the vpos larger will make it stop drawing the sprite until the new vpos is reached, while setting the vpos smaller won't change the fact that the DMA is running and will keep running until the stop line is reached.

Only changing the hpos has the potential of doing anything more on the current line - setting it larger than the current position will rearm the sprite to show again on the same line. Any other h value is as worthless as setting the vpos smaller.

[Kamahl]

Do nothing means it won't change how it's working - fetching the next couple words of image data on the next horizontal blank. So setting the vpos larger will make it stop drawing the sprite until the new vpos is reached, while setting the vpos smaller won't change the fact that the DMA is running and will keep running until the stop line is reached.

Only changing the hpos has the potential of doing anything more on the current line - setting it larger than the current position will rearm the sprite to show again on the same line. Any other h value is as worthless as setting the vpos smaller.

Ok I understand now, thanks .

[Chilly Willy]

Ok I understand now, thanks .

No problem.

[kool kitty89]

This was never answered:

It doesn't? What did you expect it to say? Clouds and Rooftops are on the same layer, they're not sprites.

EDIT: I'm an idiot , the rooftops are actually on the High priority setting, the clouds are only scroll A, nothing special here.

Huh? The (scrolling/overlapping) clouds and rooftops are still on scroll plane A, right? (so that still doesn't answer the question)

Or are you saying the rooftops on plane B in high priority . . . and emulators display high-priority plane B tiles as part of plane A. (that would also explain some of the odd things I noticed when toggling the layers in ZAMN)

Do emulators display high-priority tiles even on tilemap that's disabled? (that would explain a few other odd cases where something that should be a separate scroll layer appears to actually be on the other layer -like the scrolling BG in BC racers and the scrolling starfield in Duke 3D, or the BG in ZAMN)

[Sik]

That specific emulator lets you disable just low/high priority tiles as if they were another layer. Nothing to do with what the actual hardware does.

[kool kitty89]

That specific emulator lets you disable just low/high priority tiles as if they were another layer. Nothing to do with what the actual hardware does.

Yes, but I wanted to know what issue with the emulator (if any) would make parts of 1 layer remain on-screen even with that entire layer disabled. (which is what I'm apparently seeing in Gens too -looks pretty much identical to what Kamahl's screenshot shows)

Chuck Testa:

[Kamahl]

The plane isn't disabled, only the LOW plane is disabled. They're treated separately on Gens/GS (which was the emulator used to get that screenshot).
If I disable the High Scroll B the rooftops disappear.

I didn't notice that when I took the screenshot either .

[kool kitty89]

The plane isn't disabled, only the LOW plane is disabled. They're treated separately on Gens/GS (which was the emulator used to get that screenshot).
If I disable the High Scroll B the rooftops disappear.

I didn't notice that when I took the screenshot either .

Hmm, then Gens/Gens+ only disables the low priority stuff? (or thinks that high priority plane B is part of plane A -high and low priority)

In any case, shadow would technically work for this situation, right? (plane A having shadow enabled)

[Kamahl]

Hmm, then Gens/Gens+ only disables the low priority stuff? (or thinks that high priority plane B is part of plane A -high and low priority)

In any case, shadow would technically work for this situation, right? (plane A having shadow enabled)

No one should use Gens or Gens+, EVER.
Assuming there's no "weirdness" when it comes to priorities, then yes.

[Sik]

Hmm, then Gens/Gens+ only disables the low priority stuff? (or thinks that high priority plane B is part of plane A -high and low priority)

No, it doesn't think that high priority plane B is part of plane A, it's just treating it like its own layer =/

In any case, shadow would technically work for this situation, right? (plane A having shadow enabled)

Shadow isn't enabled for specific "planes", it's enabled overall. I assume you mean having all the plane A tiles high priority so they default to normal lighting? (if in a given pixel both planes are low priority, then that pixel is shadowed by default unless a sprite overrides it)

[kool kitty89]

No, it doesn't think that high priority plane B is part of plane A, it's just treating it like its own layer =/

I checked, and Gens+ definitely displays high priority tiles of the back layer as part of the top plane in some cases (including crusader of centy), hence my confusion. (if you disable plane B in Crusader of Centy, the rooftops remain even though they're part of plane B -likewise, if you disable plane A, the roofs and clouds both disappear) I'll stick to Gens/GS from now on for such tests.

Shadow isn't enabled for specific "planes", it's enabled overall. I assume you mean having all the plane A tiles high priority so they default to normal lighting? (if in a given pixel both planes are low priority, then that pixel is shadowed by default unless a sprite overrides it)

I meant the clouds cloud effect be solid and using shadow rather than a dithered mesh. (those dithered shadows are the only things on plane A) Shadow isn't good for colored shadows (let alone multicolor/multi-shade translucent objects), but this case fits perfectly for shadow. (the clouds on plane A are at the highest priority on-screen -except for the sprites in the status display- and the cloud shadows are the only things being displayed on plane A)

[Sik]

I checked, and Gens+ definitely displays high priority tiles of the back layer as part of the top plane in some cases (including crusader of centy), hence my confusion. (if you disable plane B in Crusader of Centy, the rooftops remain even though they're part of plane B -likewise, if you disable plane A, the roofs and clouds both disappear) I'll stick to Gens/GS from now on for such tests.

Hint: if you see "low" and "high" when you can disable layers, to remove an entire plane you need to disable both (e.g. "low plane A" and "high plane A").

I meant the clouds cloud effect be solid and using shadow rather than a dithered mesh. (those dithered shadows are the only things on plane A) Shadow isn't good for colored shadows (let alone multicolor/multi-shade translucent objects), but this case fits perfectly for shadow. (the clouds on plane A are at the highest priority on-screen -except for the sprites in the status display- and the cloud shadows are the only things being displayed on plane A)

Wouldn't work, this kind of shadow has tile granularity (I know I have mentioned using this technique before, but that involved using raster effects to collapse tiles to single lines and then making extremely horizontal clouds to compensate for the lack of granularity horizontally). If you want something like this, you need sprites, and those sprites will hide any other sprites under them (so they only show the tilemaps under them).

[kool kitty89]

Hint: if you see "low" and "high" when you can disable layers, to remove an entire plane you need to disable both (e.g. "low plane A" and "high plane A").

Gens and Gens+ don't have those options in the "layers" section of video, just A, B, and sprite. (no priority)

Wouldn't work, this kind of shadow has tile granularity (I know I have mentioned using this technique before, but that involved using raster effects to collapse tiles to single lines and then making extremely horizontal clouds to compensate for the lack of granularity horizontally). If you want something like this, you need sprites, and those sprites will hide any other sprites under them (so they only show the tilemaps under them).

Tilemap shadow effects are only on a per-tile basis, not per-pixel? (you can't have a pattern of shadow and transparent -let alone other color- pixels within a tile?)

[Kamahl]

Tilemap shadow effects are only on a per-tile basis, not per-pixel? (you can't have a pattern of shadow and transparent -let alone other color- pixels within a tile?)

I asked a similar question earlier in the thread, either Chilly didn't understand my question or there's some confusion going on .