134 lines
3.3 KiB
C
134 lines
3.3 KiB
C
#include <stdlib.h>
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#include <assert.h>
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#include <inttypes.h>
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#include "piece.h"
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#ifdef __AVR__
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#include <avr/pgmspace.h>
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#else
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#define PROGMEM
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#endif
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/*****************************
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* construction/destruction *
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*****************************/
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/* Function: tetris_piece_construct
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* Description: constructs a piece with the given attributes
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* Argument s: shape of the piece (see tetris_piece_shape_t)
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* Argument a: its angle (see tetris_piece_angel_t)
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* Return value: pointer to a newly created piece
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*/
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tetris_piece_t *tetris_piece_construct(tetris_piece_shape_t s,
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tetris_piece_angle_t a)
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{
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tetris_piece_t *p_piece = (tetris_piece_t*) malloc (sizeof(tetris_piece_t));
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assert(p_piece != NULL);
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p_piece->shape = s;
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p_piece->angle = a;
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return p_piece;
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}
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/* Function: tetris_piece_destruct
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* Description: destructs a piece
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* Argument pPc: pointer to the piece to be destructed
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* Return value: void
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*/
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void tetris_piece_destruct(tetris_piece_t *pPc)
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{
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assert(pPc != NULL);
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free(pPc);
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}
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/****************************
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* piece related functions *
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****************************/
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/* Function: tetris_piece_getBitmap
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* Description: returns bitfield representation of the piece
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* Argument pPc: piece from which the bitfield shuld be retrieved
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* Return value: bitfield representation of the piece
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* - nth nibble is nth row of the piece (from upper left)
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* - the LSB of a nibble represents the left side of a row
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*/
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uint16_t tetris_piece_getBitmap(tetris_piece_t *pPc)
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{
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assert(pPc != NULL);
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// Lookup table:
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// A value in an array represents a piece in a specific angle (rotating
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// clockwise from index 0).
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static const uint16_t piece[][4] PROGMEM =
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{{0x0F00, 0x2222, 0x0F00, 0x2222}, // LINE
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{0x4E00, 0x4640, 0x0E40, 0x4C40}, // T
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{0x0660, 0x0660, 0x0660, 0x0660}, // SQUARE
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{0x2E00, 0x88C0, 0x0E80, 0xC440}, // L
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{0x8E00, 0x6440, 0x0E20, 0x44C0}, // LBACK
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{0x6C00, 0x4620, 0x6C00, 0x4620}, // S
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{0xC600, 0x4C80, 0xC600, 0x4C80}}; // Z
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#ifdef __AVR__
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return pgm_read_word(&piece[pPc->shape][pPc->angle]);
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#else
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return piece[pPc->shape][pPc->angle];
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#endif
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}
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/* Function: tetris_piece_rotate
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* Description: rotates a piece
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* Argument pPc: piece to rotate
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* Argument r: type of rotation (see tetris_piece_rotation_t)
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* Return value: void
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*/
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void tetris_piece_rotate(tetris_piece_t *pPc,
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tetris_piece_rotation_t r)
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{
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assert(pPc != NULL);
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// we just rotate through the available angles in the given direction and
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// make wrap arounds where appropriate
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switch (r)
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{
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case TETRIS_PC_ROT_CW:
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if (pPc->angle == TETRIS_PC_ANGLE_270)
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{
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pPc->angle = TETRIS_PC_ANGLE_0;
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}
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else
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{
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++pPc->angle;
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}
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break;
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case TETRIS_PC_ROT_CCW:
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if (pPc->angle == TETRIS_PC_ANGLE_0)
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{
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pPc->angle = TETRIS_PC_ANGLE_270;
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}
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else
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{
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--pPc->angle;
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}
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break;
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}
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}
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/* Function: tetris_piece_change
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* Description: changes the shape of a piece
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* Argument pPc: piece to change
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* Argument shape: the shape of interest
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* Return value: void
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*/
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void tetris_piece_change(tetris_piece_t *pPc,
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tetris_piece_shape_t shape)
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{
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assert(pPc != NULL);
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assert((shape >= 0) && (shape <= TETRIS_PC_Z));
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pPc->shape = shape;
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}
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