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Need someone to help me with altering title screen on game
http://forums.nesdev.com/viewtopic.php?f=21&t=11352
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Author:  highfuel90 [ Thu Jun 19, 2014 9:49 pm ]
Post subject:  Need someone to help me with altering title screen on game

Hello everyone,

I need some help creating a title screen alteration
With Doki Doki Yuuenchi to say: Crazyland. I tried
Using tile editor pro but its too scrambled to make
Anything out. I believe it needs to be done in a hex editor?
Anyway if anyone can help me im willing to pay for services too.

Author:  tokumaru [ Fri Jun 20, 2014 12:25 am ]
Post subject:  Re: Need someone to help me with altering title screen on ga

A tile editor is necessary for you to draw the new graphics over the tiles that won't be used anymore. Then you need to change the mapping of the tiles, which specifies which tiles are drawn where using which palettes. The way this information is stored in the ROM varies from game to game, so you usually have to do a bit of debugging to figure out where it comes from and how it's encoded. More often than not, screens are compressed in some way, since raw tile map data is pretty large.

You'll need an emulator with good debugging capabilities, like FCEUX. You'll have to check which name table the title screen is drawn on, and then set up a write breakpoint to that name table. The breakpoint will cause the emulation to pause when a write to the memory you specified happens, so you'll be able to step through the program and see where the data being written is being copied from. If it's from ROM, you'll have to study the code to see what kind of processing is being made to the data to figure out how it's encoded, so you can encode the new data using the same format. If it's from RAM, you'll have to set up a breakpoint to the RAM location in question to see how the data got there, and so on.

You can also completely ignore the data encoding/compression used by the game and hack in you'r own routine to draw the title screen, so you'll be able to encode the data however you want.

Author:  psycopathicteen [ Sat Jun 21, 2014 12:45 pm ]
Post subject:  Re: Need someone to help me with altering title screen on ga

Convert it from RGB to YUV. Convert UV to phase and amplitude. Quantize the colors to 4 luma levels, 12 phases and 2 amplitudes.

Author:  tokumaru [ Sat Jun 21, 2014 1:16 pm ]
Post subject:  Re: Need someone to help me with altering title screen on ga

psycopathicteen wrote:
Convert it from RGB to YUV. Convert UV to phase and amplitude. Quantize the colors to 4 luma levels, 12 phases and 2 amplitudes.

Wrong thread?

Author:  psycopathicteen [ Sat Jun 21, 2014 2:01 pm ]
Post subject:  Re: Need someone to help me with altering title screen on ga

tokumaru wrote:
psycopathicteen wrote:
Convert it from RGB to YUV. Convert UV to phase and amplitude. Quantize the colors to 4 luma levels, 12 phases and 2 amplitudes.

Wrong thread?


How did that happen?

Author:  koitsu [ Sat Jun 21, 2014 3:32 pm ]
Post subject:  Re: Need someone to help me with altering title screen on ga

Being human is how it happened. Next!

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