The purpose of this modification to NES Tetris is to assist learning the DAS (Delayed Auto Shift) method of playing. An unfavourable DAS charge value (0-9) is visualized by changing the color of the background from dark gray to something else:
- During entry delay: red
- Pressing
leftorrightjust after entry delay: yellow - All other times: bright gray
The original statistics have been replaced. The topmost number is now total piece count since game start. The remaining numbers represent how many pieces each color has appeared for, shown as the percentage of total piece count.
Pressing select during play turns on visualization of all DAS charge values during entry delay, using blue for 10-15 and green for 16.
Pre-built IPS mod files are available in the releases section of GitHub. They must be applied to the USA Tetris ROM:
Database match: Tetris (USA)
Database: No-Intro: Nintendo Entertainment System (v. 20180803-121122)
File SHA-1: 77747840541BFC62A28A5957692A98C550BD6B2B
File CRC32: 6D72C53A
ROM SHA-1: FD9079CB5E8479EB06D93C2AE5175BFCE871746A
ROM CRC32: 1394F57E
You can use Hasher-js or ROM
Hasher to verify your ROM matches.
It is generally okay if the "ROM" checksum matches, but the "File" checksum
differs. But note that make test will fail.
You only need to build if you are making changes or want to try out changes that have not yet been included in a release.
Dependencies (should be in PATH):
- Flips. Flips 1.31 is fine
- cc65. Starting in Debian 10
(Buster) and Ubuntu 18.04 (Bionic) a package is available via
sudo apt install cc65. The Fedora package is available viasudo dnf install cc65. Arch Linux has an AUR package available. - GNU Make. Windows users can use
make.exe(just the one file) from thebin/folder ofmake-*-without-guile-w32-bin.zipavailable at ezwinports - GNU Coreutils and Sed. These are standard on Linux. On Windows they are
provided by Git for Windows when using
the "Git Bash" command line. Note that it uses a Unix directory structure;
the Windows directory structure is within the
/c/directory
On Windows, to modify your PATH, run SystemPropertiesAdvanced.exe. On the
"Advanced" tab click "Environment Variables" and then change Path in your
"User variables" and hit Okay. You will need to restart any terminals for the
changes to take effect.
Manual prep:
- Copy tetris ROM to
tetris.nesin thesimpledastrainerfolder. If the iNES header is different than mentioned above you can still use the ROM, but you need to adjust the header intetris.sto match your rom to make$ make testhappy.
Use $ make to build artifacts into build/, which includes disassembling
into build/tetris-PRG.s. $ make test verifies the reassembled version
matches the original. The mod will be generated at build/simpledastrainer.ips
and will have been applied to build/simpledastrainer.nes.
tetris-PRG.info is the location for all tetris ROM knowledge. It is used to disassemble tetris into build/tetris-PRG.s. tetris.s and tetris.nes.info contain the pieces to reassemble tetris into a iNES file. Reassembly is able to output debug information.
The main debug output is the .lbl file. It is basic and just contains the labels with their addresses, so doesn't have any more information than tetris-PRG.info. However, it is easy to parse so the file format is used for several other tasks; it is transformed into build/tetris.inc using sed and can be read directly by the Lua testing tools.
NES and IPS files are output directly by the linker, because our .s files define the headers for the formats and the .cfg files specify the ordering of the headers/chunks. The linker is fairly well suited to the job and provides the ability to mix-and-match source files when generating an IPS file, only needing to manually sort the hunks. It is useful to have understanding of the IPS format and how it works. It is basically the simplest possible patch format, only supporting 1:1 replacing, so should be easy to learn.
The Nesdev Wiki has good resources for the various file formats. The .info file format is described in the da65 (disassembler) documentation. The .cfg file format is described in the ld65 (linker) documentation.
This project is based on TAUS (the Actually Useful Statistics Tetris mod) which among other things provides an infrastructure for creating NES Tetris modifications.