More Ramblings from a Los Angeles Programmer

February 20, 2007

Update on NES Emulator

Filed under: coding, technology — Tags: — Josh DeWald @ 6:20 pm

I went 2 or 3 weeks without doing much on the emulator, but the time I have spent has been modestly productive. It’s that type of productivity though where I’ve spent most of the time within single methods fixing bugs and optimizing. I have the Name/Attribute Table mirroring working mostly. I literally swapped a value and suddenly Mario began looking significantly better. There were actually quite a bit of other code changes (which allowed screen scrolling to work properly) but I had the mirroring wrong which made the wrong sprites show up most of the time.

Oddly, “fixing” the mirroring made it so that Metal Gear doesn’t work properly, so I need to look into that. I believe that I’ve done Vertical mirroring incorrectly, but I actually suspect some other logic that determines what memory address to look for objects at.

I’ve fully redone the way that the internal rendering works. Using the documentation available, I’ve made it much closer to how the real PPU functions in loading the addresses from the latches at the start of screen rendering while also allowing some bits to be modified *during* rendering. This is actually what makes scrolling work. The downside is that it makes the logic a bit harder to understand because previously I did a more human-readable version of the logic but it was also more naive. I’d like to find a compromise between “here’s what’s happening” while allowing for mid-rendering writes.

Anyhow, here are some new screenshots:

mario demo 1mario demo 2

Again, there are definite flaws in it (what’s up with the green shading in the middle?) but I think it’s a significant improvement from the previous version. I still haven’t fixed the “bottom pixel” issue ont he sprites which is why there are lines running through them. That’s also why the bottom is cut off from the top status bar (which I only got working yesterday by properly implementing the “Sprite 0” detection which I previously had a completely naive version of). I also did a quick fix to get the transparent pixels working.

I’m not sure when I should move onto sound… I’m getting a little anxious but feel that I should probably get Mario actually playing! For some reason it won’t actually start. Bot Pacman and Metal Gear will start once I hit the START key, but I cannot get Super Mario Brothers to leave the demo mode. Very strange.

I played a full game of Othello last night against the computer, I think I beat it but it was a close game!

As before, want to do a shoutout. There is a good compendium of available documentation that’s been made into a nice color PDF available at from parodius written by Patrick Diskin. I think they also have emulators that actually work 🙂 In addition to NES-specific docs, it has a great introduction to how the 6502 functions which probably would ahve been useful when I was writing the core.

This is exactly how I see Myspace

Filed under: daily life, technology — Josh DeWald @ 9:50 am

EXTRALIFE – Web comic for geeks, gamers, and stuff like that


February 14, 2007

Ding dong the Wicked Witch is Dead!

Filed under: technology — Josh DeWald @ 9:51 am

Boing Boing: Blu-Ray AND HD-DVD broken – processing keys extracted

One of the /.  commentors took the words right out of my mouth, “props to some unpaid hackers spending a few weaks to crack something that probably had millions of R&D hours spent creating”. The DRM schemes are useless and are just a waste of money to the industry. People buy DVDs. Believe it or not, media industry, but we like to get a nice shiny box from Best Buy (or wherever)  and pop it into our player and watch in it’s glory. Those who are just going to download it using BitTorrent or Limewire or such are going to do it anyways, and you didn’t just lose a purchase. Even those people will buy the movies they really care about.

All you’re doing with your inane “protection” is slowing down fair use. If I want to buy a movie and watch it on my iPod, that is my decision. I purchased it, now leave me alone to watch my video. What you see as different “distribution channels” are nothing more than viewing channels.

The music industry seems to be mostly waking up to this fact, and at least one of the labels is considering releasing un-handcuffed MP3s for the music listening public.  I would imagine that this is beginning to sound like a broken record (pun non intended) to the music and film industries, but the world at large can and will download your content for free if they so choose. Most will happily pay for their content. Frankly, it’s a lot easier to make a legal purchase than search and wait for a long dowload (that then fails, oh, there’s another one!) so you can then play it on your 17″ screen. When you buy it legally and put it into your player you know it’s going to work. The average user does not want to deal with codec issues and the like. But those who can, will. Even the “technically savvy” people will legally purchase the content happily so that they can turn around and rip under their Fair Use priveleges to watch on their latest batter-guzzling gadget. Just let them!

I truly wish I had the time and cryptographic no-how to do what these guys are doing. I would love to get into trouble for a DMCA violation.

So all I have to say now to the Industry is: Stop wasting your time trying to “protect” your content. Focus your energies on making a quality product that people want to buy. We’re plopping down $20, $30, $40 on what amounts to 2 hours of entertainment. That’s more than most people make in that 2 hours. Make it worth our worthwhile.

February 8, 2007

“This is what Im talking about”

Filed under: daily life, uk life — Josh DeWald @ 11:54 am

The Long Tail: This is what Im talking about

Maybe it’s the music, but this kinda brought chills.

In other news, thanks to all the people asking me how the weather in England has been… woke up to a couple of inches of snow a la Los Angeles a couple of weeks ago. Snow in Green Park

Damn the weather, we will still make it to London tonight to see Wicked!

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