Purpose

TTYtris is a stacker ("not tetris") and runs in a terminal, made for a first assignment to my compiler design class to get to know the language we'll be writing a compiler for. Because of technical limitations, there is no gravity and objects only move by your request.

Design Overview

The langauge used to create TTYtris is a stripped down version of C used to teach the basics of compiler design. It is a functional imperative language. It has three data types, int, bool, char, and their one-dimension array counterparts. There is no type cohersion or manual memory management. Arrays are the only type passed by reference. The standard library has output(int), outputc(char), outputb(bool), and outnl(). There is no built in pre-compiler.

To me, I saw this as a challenge. But since Tetris was originally created in 1980's Soviet Russia, I knew it had to be possible.

I've chosen to follow Tetris guidelines as I wanted to create a version that plays similar to other modern stackers. I'm using the Super Rotation System and 7-Bag queue generation. I score B2B's for tetrises and t-spin line clears, as well as give a bonus for combos. It follows a 40 line format, which I chose as I felt that something like marathon wouldn't be as interesting without gravity.

Techniques

First, I've chosen to use the C precompiler to keep the code base clean and simple. Without it everything would have to go into a single, 1800 line long file. I made some use of #defines mainly to add meaning to functions that return an integer.

To create each individual piece, I used a 5x5 sprite system, stored as a int sprite[25]. I chose to use integers instead of chars since it allowed me to both use multi-byte characters in the display and to allowed me to use a bit patterns to represent each rotation. This idea of using layers is later used during frame generation, as I can put the placed blocks on one layer, the current block on a second, and the background on a third. This can then be sent to the outputsprite() function which takes a sprite and its 2d size, and five strings (remember, no multidimensional arrays) to output the sprite.

Conclusion

This was a fun challenge. I ended up writing the bulk of the code in a few days, and the final product really feels like tetris in gameplay.