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replaced rand() with bg's random8() and replaced qsort() with my own heapsort function - saving 1.1 kB\!

This commit is contained in:
Christian Kroll 2010-12-19 16:03:37 +00:00
parent 41d9ded12f
commit 1a3e64844c
1 changed files with 55 additions and 18 deletions
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71
games/tetris/variant_bastet.c
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@ -131,26 +131,63 @@ void tetris_bastet_calcPredictedColHeights(tetris_bastet_variant_t *pBastet,
/** /**
* compare function for quick sorting the pieces by score * this function is part of the heapsort algorithm for sorting pieces by score
* @param pa the first value to compare * @param pBastet the Bastet instance whose evaluated pieces should be sorted
* @param pb the second value to compare * @param nRoot start of the sift
* @param nEnd how far down the heap to sift
*/ */
static int tetris_bastet_qsortCompare(void const *pa, static void tetris_bastet_siftDownPieces(tetris_bastet_variant_t *pBastet,
void const *pb) int8_t nRoot,
int8_t nEnd)
{ {
tetris_bastet_scorepair_t *pScorePairA = (tetris_bastet_scorepair_t *)pa; while ((nRoot * 2 + 1) <= nEnd)
tetris_bastet_scorepair_t *pScorePairB = (tetris_bastet_scorepair_t *)pb;
if (pScorePairA->nScore == pScorePairB->nScore)
{ {
return 0; int8_t nChild = nRoot * 2 + 1;
int8_t nSwap = nRoot;
if (pBastet->nPieceScore[nSwap].nScore <
pBastet->nPieceScore[nChild].nScore)
{
nSwap = nChild;
} }
else if (pScorePairA->nScore < pScorePairB->nScore) if ((nChild < nEnd) && (pBastet->nPieceScore[nSwap].nScore <
pBastet->nPieceScore[nChild + 1].nScore))
{ {
return -1; nSwap = nChild + 1;
}
if (nSwap != nRoot)
{
tetris_bastet_scorepair_t scTmp = pBastet->nPieceScore[nRoot];
pBastet->nPieceScore[nRoot] = pBastet->nPieceScore[nSwap];
pBastet->nPieceScore[nSwap] = scTmp;
nRoot = nSwap;
} }
else else
{ {
return 1; return;
}
}
}
/**
* sorts the evaluated pieces by score in ascending order (via heapsort algo)
* @param pBastet the Bastet instance whose evaluated pieces should be sorted
*/
static void tetris_bastet_sortPieces(tetris_bastet_variant_t *pBastet)
{
int8_t const nCount = 7;
// heapify
for (int8_t nStart = nCount / 2 - 1; nStart >= 0; --nStart)
{
tetris_bastet_siftDownPieces(pBastet, nStart, nCount - 1);
}
// sorting the heap
for (int8_t nEnd = nCount - 1; nEnd > 0; --nEnd)
{
tetris_bastet_scorepair_t scTmp = pBastet->nPieceScore[nEnd];
pBastet->nPieceScore[nEnd] = pBastet->nPieceScore[0];
pBastet->nPieceScore[0] = scTmp;
tetris_bastet_siftDownPieces(pBastet, 0, nEnd - 1);
} }
} }
@ -354,6 +391,7 @@ tetris_piece_t* tetris_bastet_choosePiece(void *pVariantData)
// determine the best score for every piece // determine the best score for every piece
tetris_bastet_evaluatePieces(pBastet); tetris_bastet_evaluatePieces(pBastet);
// perturb score (-2 to +2) to avoid stupid tie handling // perturb score (-2 to +2) to avoid stupid tie handling
for (uint8_t i = 0; i < 7; ++i) for (uint8_t i = 0; i < 7; ++i)
{ {
@ -361,8 +399,7 @@ tetris_piece_t* tetris_bastet_choosePiece(void *pVariantData)
} }
// sort pieces by their score in ascending order // sort pieces by their score in ascending order
qsort(pBastet->nPieceScore, 7, sizeof(tetris_bastet_scorepair_t), tetris_bastet_sortPieces(pBastet);
&tetris_bastet_qsortCompare);
// new "preview" piece (AKA "won't give you this one") // new "preview" piece (AKA "won't give you this one")
if (pBastet->pPreviewPiece != NULL) if (pBastet->pPreviewPiece != NULL)
@ -374,11 +411,11 @@ tetris_piece_t* tetris_bastet_choosePiece(void *pVariantData)
TETRIS_PC_ANGLE_0); TETRIS_PC_ANGLE_0);
tetris_piece_t *pPiece = NULL; tetris_piece_t *pPiece = NULL;
uint8_t const nPercent[4] = {75, 92, 98, 100}; uint8_t const nPercent[4] = {191, 235, 250, 255};
uint8_t nRnd = rand() % 100; uint8_t const nRnd = random8();
for (uint8_t i = 0; i < 4; ++i) for (uint8_t i = 0; i < 4; ++i)
{ {
if (nRnd < nPercent[i]) if (nRnd <= nPercent[i])
{ {
// circumvent a trick where the line piece consecutively gets the // circumvent a trick where the line piece consecutively gets the
// lowest score although it removes a line every time // lowest score although it removes a line every time