sunflowerseastar / tetris

yet another tetris

Tetris

lein fig:build # dev - localhost:9500
# http://localhost:9500/figwheel-extra-main/auto-testing

lein fig:min   # build
lein fig:test  # test

Each tetromino starts out as a piece matrix. For example, here are the two piece-matrix-rotations of the piece-type straight:

[;; horizontal
 [[0 0 0 0]
  [0 0 0 0]
  [1 1 1 1]
  [0 0 0 0]]
 [;; vertical
  [0 1 0 0]
  [0 1 0 0]
  [0 1 0 0]
  [0 1 0 0]]]

In order to place a piece matrix on the board, it needs to be translated to xy coordinates for the game board, called coords (using the helper function piece-matrix->coords). A reaction defined as active-piece-coords provides this translation as an ongoing extension of the game state.

In order to know where on the board a given piece matrix should be translated into coords, the piece-matrix->coords needs to know the xy coordinates for the top left square of the piece matrix. As an example, here is the piece matrix for the straight piece type in its zeroth rotation, translated to coordinates on the board with a game board xy position of [0, 0]:

(def piece-matrix [[0 0 0 0]
                   [0 0 0 0]
                   [1 1 1 1]
                   [0 0 0 0]])

(piece-matrix->coords piece-matrix [0 0])
;; => [[0 2] [1 2] [2 2] [3 2]]

;; board coordinates:
;;   012345...
;; 0 ------...
;; 1 ------...
;; 2 ████--...
;; 3 ------...
;; 4 ------...
;; 5 ---...

Notice that [0, 0] cannot not work as a tetromino’s starting point. Rather, the add-piece! function finds the appropriate centering x coordinate, and the y coordinate employs a starting-y-offset to raise it partially above the top of the starting board (so to speak).