nesdev.org

It's not about ROY G BIV! :) Eh??? OK thanks to you guys and now have correct sprite transparency effect, but there is one more thing bothering me. If a sprite's pixel is 0 then it has no priority, but if it is 1-3 then it has priority. Is this correct? Also Sprite 0 has a higher priority then Spri...

(Laughs and Laughs and Laughs...) A 6502 is CPU that the NES uses. ROMs contain both code and graphics data and when you load the ROM into it's memory it runs the code from memory. You can us any programming language you want but C/C++ IS the best since almost all emulators use it. Since you seem to...

I second that. When I started to program my emulator, I knew pretty much nothing, and because of that it was a good 4-5 months before I could even get the CPU up and running to about 90% of what it is now. If you insist on writing a NES emulator then write a 6502 emulator. Forget the NES specifics, ...

Argh!!!!!!!

Then in that case, can somebody please explain palettes to me in a post. Please don't refer me to any txt files, I have read them all. Leave no detail out...

Transparency is defined by (0x3F00). So if 0x3F02 has the same value as 0x3F00, is 0x3F02 transparent? I understand what you say about the human eye not being able to see the sprite if it is that same colour as the bg but please try Castlevania and you will see what I mean. Using priorities, they ma...

Bregalad wrote:...so the sprite is invisible, while not techically transparant.

So... What's the difference between the two?

I am going to start writing some ROMs that will test EVERY GODDAMN ASPECT OF THE NES, no matter how tiny or seemingly insignificant. I will start off with the CPU and then move on to the PPU, APU etc. However, I do need your help in ideas for the actual tests. Here is our chance to improve on NEStre...

If the sprite is the same colour as the background, then surely it would be totally transparent and therefore have no priority?

So how does Castlevania make the main character enter the door and go behind the wall when you enter the castle? I have checked and the character remains a fg sprite and there is also a background sprite that is fully transparent which it is supposed to hide behind. If transparency does not affect t...

Quietust's copper.nes also uses the CI bits rather well. 001 B: 074.3% G: 091.5% R: 123.9% 010 B: 088.2% G: 108.6% R: 079.4% 011 B: 065.3% G: 098.0% R: 101.9% 100 B: 127.7% G: 102.6% R: 090.5% 101 B: 097.9% G: 090.8% R: 102.3% 110 B: 100.1% G: 098.7% R: 074.1% 111 B: 075.0% G: 075.0% R: 075.0% How a...

If Sprite 5 and Sprite 20 are drawn in exactly the same place, with 5 behind the bg and 20 in front, and all of Sprite 5's pixels are transparent then does sprite 20 get drawn? In other words if a pixel is transparent then does it count as having a higher priority? The reason that I am asking this i...

ALL scanlines before the main 240 are NOT rendered at all. So only worry about the main 240. The rest are just there for VBlank time when nothing is rendered to the screen. As far as good methods for rendering go, you'll just have to practice programming it yourself. It would be wrong for someone to...

If we set the Red bit so that the screen becomes more red (BGR 001), according to NinTech.txt, becomes 123.9% (23.9 'more red'). If the colour being drawn to the screen is white (0x00FFFFFF) does the red value (0xFF) remain the same or wrap? (Therefore is 0xFF the maximum the colour can be increased...

I think that all we really want for our nes emulators is for the screen to be black. That would be the most neutral colour, i believe. It would also meant that there would be no flickering at the start of a ROM load.

You should check to see whether a button is pressed at the start of a VBlank. When the joypad is strobed then return the bits via 4016.

example;

- Check for input (via directinput)
- start VBlank
- joypad strobe here (then begin to return bits)

Hope this helps.