borgware-2d/games/tetris/bucket.c

512 lines
14 KiB
C

/**
* \addtogroup tetris
* @{
*/
/**
* @file bucket.c
* @brief Implementation of Tetris' game logic.
* @author Christian Kroll
*/
#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include <stdint.h>
#include "../../compat/pgmspace.h"
#include "../../config.h"
#include "bucket.h"
#include "piece.h"
/***************************
* non-interface functions *
***************************/
/**
* detects if piece collides with s.th. at a given position
* @param pBucket bucket to perform action on
* @param nColumn column where the piece should be moved
* @param nRow row where the piece should be moved
* @return 1 for collision, 0 otherwise
*/
static uint8_t tetris_bucket_collision(tetris_bucket_t *pBucket,
int8_t nCol,
int8_t nRow)
{
// A piece is represented by 16 bits (4 bits per row where the LSB marks the
// left most position). The part of the bucket which is covered by the piece
// is converted to this format (including the bucket borders) so that a
// simple bitwise 'AND' tells us if the piece and the dump overlap.
// only allow coordinates which are within sane ranges
assert(pBucket != NULL);
assert((nCol > -4) && (nCol < pBucket->nWidth));
assert((nRow > -4) && (nRow < pBucket->nHeight));
// left and right borders
uint16_t const nPieceMap = tetris_piece_getBitmap(pBucket->pPiece);
uint16_t nBucketPart = 0;
if (nCol < 0)
{
static uint16_t const nLeftPart[] PROGMEM = {0x7777, 0x3333, 0x1111};
nBucketPart = pgm_read_word(&nLeftPart[nCol + 3]);
}
else if (nCol >= pBucket->nWidth - 3)
{
static uint16_t const nRightPart[] PROGMEM = {0xEEEE, 0xCCCC, 0x8888};
nBucketPart = pgm_read_word(&nRightPart[pBucket->nWidth - nCol - 1]);
}
// lower border
if (nRow > pBucket->nHeight - 4)
{
nBucketPart |= 0xFFFF << ((pBucket->nHeight - nRow) * 4);
}
// return if the piece already collides with the border
if (nPieceMap & nBucketPart)
{
// collision
return 1;
}
// range for inspecting the piece row by row (starting at the bottom)
int8_t const nStart = nRow + tetris_piece_getBottomOffset(nPieceMap);
int8_t const nStop = nRow >= 0 ? nRow : 0;
// mask those blocks which are not covered by the piece
uint16_t const nDumpMask = nCol >= 0 ? 0x000Fu << nCol : 0x000Fu >> -nCol;
// value for shifting blocks to the corresponding part of the piece
int8_t nShift = 12 - nCol - 4 * (nRow + 3 - nStart);
// compare piece with dump
for (int8_t y = nStart; y >= nStop; --y)
{
uint16_t nTemp = pBucket->dump[y] & nDumpMask;
nBucketPart |= nShift >= 0 ? nTemp << nShift : nTemp >> -nShift;
if (nPieceMap & nBucketPart)
{
// collision
return 1;
}
nShift -= 4;
}
// if we reach here, no collision was detected
return 0;
}
/**
* determines if piece is either hovering or gliding and sets the bucket's state
* @param pBucket the bucket we want information from
*/
static void tetris_bucket_hoverStatus(tetris_bucket_t *pBucket)
{
assert(pBucket != NULL);
// status depends on whether the piece touches the dump or not
// NOTE: 0 == TETRIS_BUS_HOVERING, 1 == TETRIS_BUS_GLIDING,
// tetris_bucket_collision(...) either returns 0 or 1
pBucket->status = tetris_bucket_collision(pBucket, pBucket->nColumn,
pBucket->nRow + 1);
}
/****************************
* construction/destruction *
****************************/
tetris_bucket_t *tetris_bucket_construct(int8_t nWidth,
int8_t nHeight)
{
assert((nWidth >= 4) && (nWidth <= TETRIS_BUCKET_MAX_COLUMNS));
assert((nHeight >= 4) && (nHeight <= TETRIS_BUCKET_MAX_ROWS));
// allocating memory
tetris_bucket_t *pBucket =
(tetris_bucket_t *)malloc(sizeof(tetris_bucket_t));
assert(pBucket != NULL);
pBucket->dump = (uint16_t *)calloc((size_t)nHeight, sizeof(uint16_t));
assert(pBucket->dump != NULL);
// setting requested attributes
pBucket->nHeight = pBucket->nFirstTaintedRow = nHeight;
pBucket->nWidth = nWidth;
// bit mask of a full row
pBucket->nFullRow = 0xFFFF >> (16 - pBucket->nWidth);
tetris_bucket_reset(pBucket);
return pBucket;
}
/*******************************
* bucket related functions *
*******************************/
void tetris_bucket_reset(tetris_bucket_t *pBucket)
{
assert(pBucket != NULL);
assert(pBucket->dump != NULL);
pBucket->pPiece = NULL;
pBucket->nColumn = 0;
pBucket->nRow = 0;
pBucket->nRowMask = 0;
pBucket->status = TETRIS_BUS_READY;
// clear dump
memset(pBucket->dump, 0, (size_t)pBucket->nHeight * sizeof(uint16_t));
}
tetris_piece_t *tetris_bucket_insertPiece(tetris_bucket_t *pBucket,
tetris_piece_t *pPiece)
{
assert((pBucket != NULL) && (pPiece != NULL));
// a piece can only be inserted in state TETRIS_BUS_READY
assert(pBucket->status == TETRIS_BUS_READY);
// row mask is now meaningless
pBucket->nRowMask = 0;
// set horizontal start position (in the middle of the top line)
pBucket->nColumn = (pBucket->nWidth - 2) / 2;
// set vertical start position (first piece row with matter at pos. 1)
pBucket->nRow =
1 - tetris_piece_getBottomOffset(tetris_piece_getBitmap(pPiece));
// replace old piece
tetris_piece_t *pOldPiece = pBucket->pPiece;
pBucket->pPiece = pPiece;
// did we already collide with something?
if (tetris_bucket_collision(pBucket, pBucket->nColumn, pBucket->nRow))
{
// game over man, game over!!
pBucket->status = TETRIS_BUS_GAMEOVER;
}
else
{
// bring it on!
tetris_bucket_hoverStatus(pBucket);
}
return pOldPiece;
}
void tetris_bucket_advancePiece(tetris_bucket_t *pBucket)
{
assert(pBucket != NULL);
// a piece can only be lowered if it is hovering or gliding
assert ((pBucket->status == TETRIS_BUS_HOVERING) ||
(pBucket->status == TETRIS_BUS_GLIDING));
// collision detected? check if we can embed the piece into the bucket...
if (tetris_bucket_collision(pBucket, pBucket->nColumn, pBucket->nRow + 1))
{
uint16_t nPieceMap = tetris_piece_getBitmap(pBucket->pPiece);
// determine first row of the piece (skipping empty lines at the top)
int8_t nPieceTop = pBucket->nRow + tetris_piece_getTopRow(nPieceMap);
// Is the bucket filled up?
if (nPieceTop < 0)
{
pBucket->status = TETRIS_BUS_GAMEOVER;
}
else
{
// update value for the first tainted row
pBucket->nFirstTaintedRow = pBucket->nFirstTaintedRow > nPieceTop ?
nPieceTop : pBucket->nFirstTaintedRow;
// embed piece into the dump
int8_t nStopRow = (pBucket->nRow + 3) >= pBucket->nHeight ?
pBucket->nHeight - 1 : pBucket->nRow + 3;
nPieceMap >>= (nPieceTop - pBucket->nRow) * 4;
while (nPieceTop <= nStopRow)
{
uint16_t nTemp = nPieceMap & 0x000F;
pBucket->dump[nPieceTop++] ^= pBucket->nColumn >= 0 ?
nTemp << pBucket->nColumn : nTemp >> -pBucket->nColumn;
nPieceMap >>= 4;
}
// the piece has finally been docked
pBucket->status = TETRIS_BUS_DOCKED;
}
}
else
{
// no collision: piece may continue its travel to the ground...
pBucket->nRow++;
// are we gliding?
tetris_bucket_hoverStatus(pBucket);
}
}
uint8_t tetris_bucket_movePiece(tetris_bucket_t *pBucket,
tetris_bucket_direction_t nDirection)
{
assert(pBucket != NULL);
// a piece can only be moved if it is still hovering or gliding
assert((pBucket->status == TETRIS_BUS_HOVERING) ||
(pBucket->status == TETRIS_BUS_GLIDING));
// only the values of the direction enumeration are allowed
assert((nDirection == TETRIS_BUD_LEFT) || (nDirection = TETRIS_BUD_RIGHT));
if (tetris_bucket_collision(pBucket, pBucket->nColumn + nDirection,
pBucket->nRow) == 0)
{
pBucket->nColumn += nDirection;
// are we gliding?
tetris_bucket_hoverStatus(pBucket);
return 1;
}
return 0;
}
uint8_t tetris_bucket_rotatePiece(tetris_bucket_t *pBucket,
tetris_piece_rotation_t rotation)
{
assert(pBucket != NULL);
// a piece can only be rotated if it is still hovering or gliding
assert((pBucket->status == TETRIS_BUS_HOVERING) ||
(pBucket->status == TETRIS_BUS_GLIDING));
tetris_piece_rotate(pBucket->pPiece, rotation);
// does the rotated piece collide with something?
if (tetris_bucket_collision(pBucket, pBucket->nColumn, pBucket->nRow))
{
// in that case we revert the rotation
tetris_piece_rotate(pBucket->pPiece, rotation == TETRIS_PC_ROT_CW ?
TETRIS_PC_ROT_CCW : TETRIS_PC_ROT_CW);
return 0;
}
// are we gliding?
tetris_bucket_hoverStatus(pBucket);
return 1;
}
void tetris_bucket_removeCompleteLines(tetris_bucket_t *pBucket)
{
assert(pBucket != NULL);
// rows can only be removed if we are in state TETRIS_BUS_DOCKED
assert(pBucket->status == TETRIS_BUS_DOCKED);
// bit mask (only 4 bits) that tells us if the n-th row after the
// current nRow is complete (n-th bit set to 1, LSB represents nRow itself)
pBucket->nRowMask = 0;
// only consider rows which are affected by the piece (from low to high)
// for incomplete rows, both i and nShiftIndex will be decremented
// for complete rows, only i gets decremented
int8_t nLowestRow = (pBucket->nRow + 3) < pBucket->nHeight ?
pBucket->nRow + 3 : pBucket->nHeight - 1;
int8_t nShiftIndex = nLowestRow;
for (int8_t i = nLowestRow; i >= pBucket->nFirstTaintedRow; --i)
{
// is current row a full row?
if ((pBucket->nFullRow & pBucket->dump[i]) == pBucket->nFullRow)
{
// set corresponding bit for the row mask
pBucket->nRowMask |= 0x01 << (i - pBucket->nRow);
}
else
{
// if nShiftIndex and i differ, the dump has to be shifted
if (i < nShiftIndex)
{
pBucket->dump[nShiftIndex] = pBucket->dump[i];
}
// if there were no completed lines within the range covered by the
// piece, we don't need to look for those any further
else if ((nLowestRow - i) >= 3)
{
break;
}
--nShiftIndex;
}
}
// any completed rows removed?
if (pBucket->nRowMask != 0)
{
// clear space from which the rows have been shifted away
for (int8_t i = nShiftIndex; i >= pBucket->nFirstTaintedRow; --i)
{
pBucket->dump[i] = 0;
}
pBucket->nFirstTaintedRow = nShiftIndex + 1;
}
// ready to get the next piece
pBucket->status = TETRIS_BUS_READY;
}
#ifdef GAME_BASTET
int8_t tetris_bucket_predictDeepestRow(tetris_bucket_t *pBucket,
tetris_piece_t *pPiece,
int8_t nStartRow,
int8_t nColumn)
{
assert(pBucket != NULL);
assert(pPiece != NULL);
assert(nStartRow > TETRIS_BUCKET_INVALID && nStartRow < pBucket->nHeight);
assert(nColumn > TETRIS_BUCKET_INVALID && nColumn < pBucket->nWidth);
// exchange current piece of the bucket (to use its collision detection)
tetris_piece_t *pActualPiece = pBucket->pPiece;
pBucket->pPiece = pPiece;
// skip empty rows at the bottom of the piece which may overlap the dump
uint16_t nMap = tetris_piece_getBitmap(pPiece);
nStartRow -= tetris_piece_getBottomOffset(nMap);
// check if the piece collides with one of the side borders
if (nStartRow >= -3)
{
while (!tetris_bucket_collision(pBucket, nColumn, nStartRow + 1))
{
++nStartRow;
}
// bucket overflow?
if (nStartRow < 0 && ((0xFFFF >> (((4 + nStartRow) * 4))) & nMap))
{
nStartRow = TETRIS_BUCKET_INVALID;
}
}
// restore actual bucket piece
pBucket->pPiece = pActualPiece;
return nStartRow;
}
int8_t tetris_bucket_predictCompleteLines(tetris_bucket_t *pBucket,
tetris_piece_t *pPiece,
int8_t nRow,
int8_t nColumn)
{
assert(pBucket != NULL);
assert(pPiece != NULL);
assert(nRow > TETRIS_BUCKET_INVALID && nRow < pBucket->nHeight);
assert(nColumn > TETRIS_BUCKET_INVALID && nColumn < pBucket->nWidth);
// initialization
int8_t nCompleteRows = 0;
uint16_t nPieceMap = tetris_piece_getBitmap(pPiece);
int8_t nStartRow = nRow;
int8_t const nStopRow = (nRow + 3) >= pBucket->nHeight ?
pBucket->nHeight - 1 : nRow + 3;
if (nRow < 0)
{
nPieceMap >>= -nRow * 4;
nStartRow = 0;
}
for (int8_t y = nStartRow; y <= nStopRow; ++y)
{
uint16_t nTemp = nPieceMap & 0x000F;
nTemp = nColumn >= 0 ? nTemp << nColumn : nTemp >> -nColumn;
if ((pBucket->dump[y] ^ nTemp) == pBucket->nFullRow)
{
++nCompleteRows;
}
nPieceMap >>= 4;
}
return nCompleteRows;
}
uint16_t* tetris_bucket_predictBottomRow(tetris_bucket_iterator_t *pIt,
tetris_bucket_t *pBucket,
tetris_piece_t *pPiece,
int8_t nRow,
int8_t nColumn)
{
assert(pIt != NULL);
assert(pBucket != NULL);
assert(pPiece != NULL);
assert(nRow > TETRIS_BUCKET_INVALID && nRow < pBucket->nHeight);
assert(nColumn > TETRIS_BUCKET_INVALID && nColumn < pBucket->nWidth);
pIt->pBucket = pBucket;
pIt->nCurrentRow = pBucket->nHeight - 1;
pIt->nRowBuffer = 0;
pIt->nPieceMap = tetris_piece_getBitmap(pPiece);
// determine sane start and stop values for the piece's row indices
pIt->nPieceTopRow = nRow + tetris_piece_getTopRow(pIt->nPieceMap);
pIt->nPieceBottomRow = nRow + tetris_piece_getBottomOffset(pIt->nPieceMap);
if (pIt->nPieceBottomRow >= pBucket->nHeight)
{
pIt->nPieceBottomRow = pBucket->nHeight - 1;
}
// accelerate detection of full rows
pIt->nPieceMap <<= (nRow + 3 - pIt->nPieceBottomRow) * 4;
pIt->nShift = nColumn - 12;
// don't return any trailing rows which are empty, so we look for a stop row
pIt->nStopRow = pBucket->nFirstTaintedRow < pIt->nPieceTopRow ?
pBucket->nFirstTaintedRow : pIt->nPieceTopRow;
pIt->nStopRow = pIt->nStopRow < 0 ? 0 : pIt->nStopRow;
return tetris_bucket_predictNextRow(pIt);
}
uint16_t* tetris_bucket_predictNextRow(tetris_bucket_iterator_t *pIt)
{
assert(pIt != NULL);
if (pIt->nCurrentRow >= pIt->nStopRow)
{
uint16_t nTemp = 0;
// embed piece if it is there
if ((pIt->nCurrentRow <= pIt->nPieceBottomRow) &&
(pIt->nCurrentRow >= pIt->nPieceTopRow))
{
nTemp = pIt->nPieceMap & 0xF000;
nTemp = pIt->nShift >= 0 ?
nTemp << pIt->nShift : nTemp >> -pIt->nShift;
pIt->nPieceMap <<= 4;
}
pIt->nRowBuffer = pIt->pBucket->dump[pIt->nCurrentRow--] | nTemp;
// don't return full (and therefore removed) rows
if (pIt->nRowBuffer == pIt->pBucket->nFullRow)
{
// recursively determine next (?) row instead
return tetris_bucket_predictNextRow(pIt);
}
// row isn't full
else
{
return &pIt->nRowBuffer;
}
}
else
{
return NULL;
}
}
#endif /* GAME_BASTET */
/*@}*/