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 Post subject: Re: Powerglove
PostPosted: Sun May 04, 2014 3:42 pm 
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Lazycow wrote:
But first I want to do the double-split. Ok, it's better to do Sprite-0 on top, DPCM on bottom. Wasn't aware of that.

Yeah, the main advantage of using DPCM for the second split is that it fires an interrupt, so even if your logic happens to take more time than expected you'll still be able to do the split without glitches.

DPCM IRQs aren't as simple as they sound though... the sound hardware isn't aligned to the video hardware, so even if you ask for a sample to start playing at the exact same pixel every frame, the IRQ will fire with a variation of up to several scanlines (depending on the frequency of the sample). This means that the DPCM IRQ alone isn't enough for a clean split. Most commercial games that used it for raster effects had the IRQ fire right before a sprite 0 hit, which allowed for proper synchronization with the PPU.

tepples linked to a discovery of his that greatly increases the control you have over when the DMC IRQ fires, but I found the whole thing too complex... to this day I still don't understand it completely. I believe it involves setting up a preliminary IRQ so you can count how long it takes to fire (a time that you waste every frame) and use that count later on to compensate for the misalignment. I was never able to replicate the idea perfectly on my end, and even when the thing was mostly stable I would occasionally (every few seconds or so) get a big timing variation.


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 Post subject: Re: Powerglove
PostPosted: Sun May 04, 2014 4:50 pm 
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tokumaru wrote:
I believe it involves setting up a preliminary IRQ so you can count how long it takes to fire (a time that you waste every frame) and use that count later on to compensate for the misalignment.

Correct. You end up wasting up to 432 cycles, the period of one byte at speed 15. It should be fairly straightforward to get it at least as clean as SMB3's (admittedly glitchy) split, so long as you have a way to test on hardware.


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 Post subject: Re: Powerglove
PostPosted: Fri Sep 19, 2014 10:05 am 
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Image
New mockups! This time, the monsters are build out of 4 8x16 sprites (to get 6 color monsters). The program code has to take care that there are not 2 monsters on the same level when the player comes along. Otherwise it would flicker...

Seems like I won't have enough time to finish the NES version this year. But it is available now for C64, Windows, Mac and Linux. Get it here: http://rgcddev.itch.io/powerglove


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 Post subject: Re: Powerglove
PostPosted: Fri Sep 19, 2014 10:15 pm 
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I tried the Windows version quickly. The presentation is very solid all-around. The game is simplistic, but fun to play. I like the fact that there are separate builds for modern operating systems, and the 3 MB download size.

What's the "shader mode" in the Windows version? It doesn't work on my computer (I have 8800 GTS, so I expected it to work).

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 Post subject: Re: Powerglove
PostPosted: Fri Sep 19, 2014 10:48 pm 
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@thefox: Nice to hear that you like it. I think it would be a nice NES cartridge. Several C64 players mentioned that it gives some kind of "NES feeling" when playing it :D

The shader mode bends the display a bit. (like on a curved CRT monitor) Unfortunately, it does not work with every GFX chip and it's hard to debug if it works on your computer. That's why it is disabled by default. (does not look better than the default mode, anyway)


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 Post subject: Re: Powerglove
PostPosted: Sat Sep 20, 2014 11:41 am 
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Lazycow wrote:
The program code has to take care that there are not 2 monsters on the same level when the player comes along
How does that degrade with the red single-eyed guys? They jump off edges, I thought I remembered getting a pit full of them when playing the C64 build.


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 Post subject: Re: Powerglove
PostPosted: Sat Sep 20, 2014 1:24 pm 
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@lidnariq: Hm... Yes, you are right. There are some rooms which would be problematic and the monster placement would have to be changed a bit. But the red one-eyed "Tap Tap" robo only falls into areas without other robos. (if I remember correctly)

As the 3 additional colors are used in the eyes only, another possibility would be: One robo just closes his eyes if there are too many sprites in a row! (Ha, I like this one)

Wait a minute... if a robo only has 1 eye, then it only needs 3 sprites in one row. Two one-eye robots and a player does not flicker. It is complicated...


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 Post subject: Re: Powerglove
PostPosted: Sat Sep 20, 2014 1:50 pm 
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There's also the room with the two two-eyed red hopping robots, but the idea that they would wink is amusing.


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 Post subject: Re: Powerglove
PostPosted: Sun Sep 21, 2014 10:21 pm 
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Lazycow you've been peddling this on all boards how about you wait until you have a nes build to show instead of including links on every board to your c64,win builds.


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 Post subject: Re: Powerglove
PostPosted: Sun Sep 21, 2014 11:12 pm 
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... you bothered to make an account just to post that?

This is the nesdev forum, not the nesreleases forum...


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 Post subject: Re: Powerglove
PostPosted: Sun Sep 21, 2014 11:32 pm 
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No lidnariq I've made an account because I enjoy 6502 and nes dev and the topics discussed in the forum interest me immensely as there some very profound programmers that reside here.


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 Post subject: Re: Powerglove
PostPosted: Mon Sep 22, 2014 6:20 am 
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lidnariq wrote:
... you bothered to make an account just to post that?

This is the nesdev forum, not the nesreleases forum...

Not to mention this being appropriately on-topic to this forum.


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 Post subject: Re: Powerglove
PostPosted: Mon Sep 22, 2014 9:18 am 
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Yeah the whole point of the Homebrew Projects subforum is for people to show off their work. The fact that a NES version is under development is enough to warrant a thread here.

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 Post subject: Re: Powerglove
PostPosted: Mon Sep 22, 2014 11:39 am 
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Sik wrote:
lidnariq wrote:
... you bothered to make an account just to post that?

This is the nesdev forum, not the nesreleases forum...

Not to mention this being appropriately on-topic to this forum.


Fair enough thefox,as I'm beat on he's never going to port this to nes and Atari 2600 but you guys seem to agree he will, and since I'm a new member unlike you i'll give the programmer(lidnariq an thefox the benefit of the doubt) i'll give in
I apologize LazyCow and hope you do convert the game to nes,2600 best of luck to you
We await your port LazyCow.


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 Post subject: Re: Powerglove
PostPosted: Mon Sep 22, 2014 12:58 pm 
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Oops, didn't want to annoy anyone, I thought you woudn't mind.

Image
Wink test...

Left robo: the hilighting-pixels vanish, too. (but it might not be noticed)
right robo: removed the hilighting pixels. (so the body has 3 colors and the eyes have 3 colors)

In case of a "sprite overflow", only the eyes would have to vanish... (thanks for the inspiration, lidnariq)


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