1 /* 2 * Definitions for Tetris. 3 */ 4 5 /* 6 * The display (`board') is composed of 23 rows of 12 columns of characters 7 * (numbered 0..22 and 0..11), stored in a single array for convenience. 8 * Columns 1 to 10 of rows 1 to 20 are the actual playing area, where 9 * shapes appear. Columns 0 and 11 are always occupied, as are all 10 * columns of rows 21 and 22. Rows 0 and 22 exist as boundary areas 11 * so that regions `outside' the visible area can be examined without 12 * worrying about addressing problems. 13 */ 14 15 /* the board */ 16 #define B_COLS 12 17 #define B_ROWS 23 18 #define B_SIZE (B_ROWS * B_COLS) 19 20 typedef unsigned char cell; 21 cell board[B_SIZE]; /* 1 => occupied, 0 => empty */ 22 23 /* the displayed area (rows) */ 24 #define D_FIRST 1 25 #define D_LAST 22 26 27 /* the active area (rows) */ 28 #define A_FIRST 1 29 #define A_LAST 21 30 31 /* 32 * Minimum display size. 33 */ 34 #define MINROWS 23 35 #define MINCOLS 40 36 37 int Rows, Cols; /* current screen size */ 38 39 /* 40 * Translations from board coordinates to display coordinates. 41 * As with board coordinates, display coordiates are zero origin. 42 */ 43 #define RTOD(x) ((x) - 1) 44 #define CTOD(x) ((x) * 2 + (((Cols - 2 * B_COLS) >> 1) - 1)) 45 46 /* 47 * A `shape' is the fundamental thing that makes up the game. There 48 * are 7 basic shapes, each consisting of four `blots': 49 * 50 * X.X X.X X.X 51 * X.X X.X X.X.X X.X X.X.X X.X.X X.X.X.X 52 * X X X 53 * 54 * 0 1 2 3 4 5 6 55 * 56 * Except for 3 and 6, the center of each shape is one of the blots. 57 * This blot is designated (0,0). The other three blots can then be 58 * described as offsets from the center. Shape 3 is the same under 59 * rotation, so its center is effectively irrelevant; it has been chosen 60 * so that it `sticks out' upward and leftward. Except for shape 6, 61 * all the blots are contained in a box going from (-1,-1) to (+1,+1); 62 * shape 6's center `wobbles' as it rotates, so that while it `sticks out' 63 * rightward, its rotation---a vertical line---`sticks out' downward. 64 * The containment box has to include the offset (2,0), making the overall 65 * containment box range from offset (-1,-1) to (+2,+1). (This is why 66 * there is only one row above, but two rows below, the display area.) 67 * 68 * The game works by choosing one of these shapes at random and putting 69 * its center at the middle of the first display row (row 1, column 5). 70 * The shape is moved steadily downward until it collides with something: 71 * either another shape, or the bottom of the board. When the shape can 72 * no longer be moved downwards, it is merged into the current board. 73 * At this time, any completely filled rows are elided, and blots above 74 * these rows move down to make more room. A new random shape is again 75 * introduced at the top of the board, and the whole process repeats. 76 * The game ends when the new shape will not fit at (1,5). 77 * 78 * While the shapes are falling, the user can rotate them counterclockwise 79 * 90 degrees (in addition to moving them left or right), provided that the 80 * rotation puts the blots in empty spaces. The table of shapes is set up 81 * so that each shape contains the index of the new shape obtained by 82 * rotating the current shape. Due to symmetry, each shape has exactly 83 * 1, 2, or 4 rotations total; the first 7 entries in the table represent 84 * the primary shapes, and the remaining 12 represent their various 85 * rotated forms. 86 */ 87 struct shape { 88 int rot; /* index of rotated version of this shape */ 89 int off[3]; /* offsets to other blots if center is at (0,0) */ 90 }; 91 92 extern struct shape shapes[]; 93 #define randshape() (&shapes[random() % 7]) 94 95 /* 96 * Shapes fall at a rate faster than once per second. 97 * 98 * The initial rate is determined by dividing 1 million microseconds 99 * by the game `level'. (This is at most 1 million, or one second.) 100 * Each time the fall-rate is used, it is decreased a little bit, 101 * depending on its current value, via the `faster' macro below. 102 * The value eventually reaches a limit, and things stop going faster, 103 * but by then the game is utterly impossible. 104 */ 105 long fallrate; /* less than 1 million; smaller => faster */ 106 #define faster() (fallrate -= fallrate / 3000) 107 108 /* 109 * Game level must be between 1 and 9. This controls the initial fall rate 110 * and affects scoring. 111 */ 112 #define MINLEVEL 1 113 #define MAXLEVEL 9 114 115 /* 116 * Scoring is as follows: 117 * 118 * When the shape comes to rest, and is integrated into the board, 119 * we score one point. If the shape is high up (at a low-numbered row), 120 * and the user hits the space bar, the shape plummets all the way down, 121 * and we score a point for each row it falls (plus one more as soon as 122 * we find that it is at rest and integrate it---until then, it can 123 * still be moved or rotated). 124 */ 125 int score; /* the obvious thing */ 126 127 char key_msg[100]; 128 129 int fits_in __P((struct shape *, int)); 130 void place __P((struct shape *, int, int)); 131 void stop __P((char *)); 132