Archive for the retro Category

Email and file server is down

Posted in hacks, homebrew, NES2PCE, retro on October 17, 2015 by pcedev

My server account got suspended cause I didn’t pay the bill. Hopefully I can get it back online in the next few days.

I’ve been messing with PCE hardware this weekend. Also looking over what projects are due, what needs attention, and what is going to be put on the back burner (for time resource reasons).

That and just some gaming on the SGX+SCD. I was playing SMB (nes2pce) and realized I could optimized some of the nes2pce PPU emulation code. Anytime the cpu writes to vram, the internal emulation code has to do all these checks to make sure it’s transferring data to the right area (and how to interpret that data). I needed this because I found games could just load PPU tile, sprite, and tilemap stuffs all in one shot.

Of course this slows things down having to do all these checks. Sometimes it puts what would normally be the cpu in vblank time, into the start of active display. I figured one way to speed this up, is to have dedicated $2007 write functions. NES games tend to setup strings of data into a buffer to be updated during vblank (because game logic is processed during active display). This means it’s very rare that a string of data will cross a tile bank into a nametable area, etc. So for those areas of code, I could potentially use the faster and specific $2007 write functions.

Nes2pce code was never meant as general emulation for NES games to run on the PCE. It was to get the game up and running close as possible, to help the transition of replacing the original NES sprite and map routines into native PCE stuffs. Though none of the nes2pce stuffs I’ve released have these changes.

Ideally, the sprite and map routines should be hacked for direct PCE writes, by passing some of the PPU emulation. So the optimization I listed it kind of counter intuitive to the goal of nes2pce. But I just don’t have the time to alter each game for these kinds of changes. I used to have that kind of time, but I squandered it :/ Eventually, I will have that kind of time again – but will people really care about nes stuffs on PCE by then? One example is Dragon Warrior. It’s the first RPG I’ve ever played, so I have nostalgia for it. I’ve already hacked the map routines somewhat. The game is simple enough to keep modifying. But should I really put my time into it? This is the dilemma I’m faced with nes2pce.

Anyway, just thinking out loud.

Spriggan Mark 2 first draft teaser

Posted in retro, shmup, translations on April 12, 2014 by pcedev

Translation is entering into the final phase (draft revisions and such). Dubbing should start soon.

On a side note:
This game was re-released for Wii virtual console in Japan, so I’m assuming some active company still holds the rights for this game. If anyone has experience with contacting companies (particularly Japanese companies) and negotiating licenses, please shoot me an email. I wouldn’t mind making this official, if the cost of the license is reasonable (or however that works).

Posted in Audio, hacks, Megaman, NES2PCE, retro with tags , , , , , , , , , , , , , , , , on February 8, 2014 by pcedev

More Megaman 1 stuff.

Maaaannnn. Talk about a pain. Principle and execution; two very different things. What should have been a very easy upgrade to the load room graphics hook/code, ended up being a nightmare. It broke a lot of stuff that I already had in place. So, some other stuff got changed/upgraded (mostly OAM->SAT conversion). But it’s done and working. Finally. All the enemy sprites for Cutman stage are up and running. All converted to native PCE format. I worked out how to handle the palettes for those enemies too. You know, you don’t realize how much 16 subpalettes just for sprites – is incredibly large for that era. It makes things sooo much easier, and the fact that I still have another set of 16 just for the BG graphics – this is gonna be easy. Wily Wars on the MD/Gen, uses 7+1 colors for sprites. That how the extend the 4 subpalettes to be more than 4. 8 colors for a sprite, isn’t so bad for Megaman style design. BUT WE ARE GOING THE FULL 15 COLORS PER SPRITE! Yeah, baby. I purposely added colors to the sprites, even if you can see them – lol. I wanna have a few screens in the game, surpass the 100+ color count mark.

Anyway, things are coming along. I’m working on the ‘start stage sprite’ load routine, which is different than the load-room-sprites (not sure why). I’ll have something to show off when that’s finished.

Posted in hacks, Megaman, NES2PCE, retro on February 4, 2014 by pcedev

No title to the post. Megaman stuffs…

Anyway, I got all the sprites for Cutman’s stage done. That is to say, all the new sprite sheets are in order. Hacking the room loading routine is next. I’ve already traced through it more times than I care to admit. I might be pretty fluent in 65x, but that doesn’t reading/understanding someone else’ code is easy.

The game makes it easy though. The game breaks down a sprite/palette load for a given room, over about 40 frames. That slow pan up or down, left or right, it’s updating vram sprites (which is why all sprites except megaman/score/powermeter are turned off). The game divides a level into 16k banks. There’s a variable for ‘currentlevel’; the game grabs this, maps it, uses the ‘current room’ as an index, and reads from a table (this table is in every level and in the same spot, just different values corresponding to the level), then maps in the tile bank and transfers to vram. All my hook needs to do, is get ‘currentlevel’ and ‘currentroom’, and the rest is just loading my own graphics to vram.

That part is fairly easy. The problem I’m running into now, is that there’s no room left in the ’emulation’ bank. There is where all the apu/ppu/mapper emulation code is. Since this is a fixed bank, this is also where my hack code and tables are. As of yesterday, I had to move all the enemy sprite sheets (object information, not the cell data) to another bank. Even with that, I’m left with 500bytes free in that 8k bank. So now I’m tasked with creating a second ‘library’ bank for code, and move non essential code to there (APU reg write code, PPU reg write code). I’m taking a note from the NES games, and duplicating the TIMER and VDC/NMI code into the second lib bank at the same place. That way when I swap in the far bank, the interrupt code still behaves as normal.

Eventually, I’ll won’t be needing the APU and PPU emulation code anymore. Actually, I soon plan to convert the sound FX in the game to a different format. Something along the lines of VGM format. That is to say, the sound FX will be streaming port writes at 1/60 tick (anything higher seems wasteful). It takes up very little room, compresses easily (and light on cpu resource), and allows me to make new sound FX outside of any music/sound engine design (and I don’t have to worry about a new PCE sound engine having legacy support too). Though OAM emulation will probably be the first to go. Once all the sprites have been converted over, I won’t need NES OAM (SAT) emulation anymore. That’ll free up a little bit of cpu resource. The tilemap code will probably be one of the last to go, leaving the game completely native PCE in execution (albeit limited to game logic).

But back to the ‘currentlevel’ and ‘currentgame’ variables. Knowing these two, I can create new stages. I just need to hook the bank changing routine for the higher level #’s. I want to add in two more Robot Master levels. Not MM: Powered Up levels, but something unique to this PCE version. That also means two new items or weapons. I figured I’ll probably make them ‘item-ish’ rather than weapons, as that would be harder to balance the game with new weapons. Or maybe new ‘moves’, like slide and charge power shot (you won’t need to ‘equip’ them). I do want to make a weapon/function that’s equivalent to ‘enery tanks’ in later MM games. I figured something along the lines of; convert weapon energy to health. And depending on the difficulty of the game setting, will be the ratio of transfer from energy to health.