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fixed frame buffer bug

This commit is contained in:
Christian Kroll 2011-05-24 19:28:03 +00:00
parent 3e400e43eb
commit 7b35c18588
1 changed files with 27 additions and 16 deletions
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43
animations/bitmapscroller.c
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@ -54,7 +54,7 @@ static unsigned char bitmap_getAlignedChunk(bitmap_t const *const pBitmap,
unsigned char nChunk = 0xFF;
unsigned char nMask = 1;
unsigned char nAlignment = x % 8;
unsigned char const nAlignment = x % 8;
// we have to go through every bit plane
for (unsigned char i = 0; i < pBitmap->nBitPlanes; ++i)
@ -101,32 +101,43 @@ static void bitmap_drawViewport(bitmap_t const *const pBitmap,
{
assert(nX <= pBitmap->nXDomain);
assert(nY <= pBitmap->nYDomain);
unsigned char nBitmapHwPlanes = (1 << pBitmap->nBitPlanes) - 1;
unsigned char nPlanes = nBitmapHwPlanes > NUMPLANE ?
NUMPLANE : nBitmapHwPlanes;
for (unsigned char y = 0; y < pBitmap->nViewportHeight; ++y)
{
for (unsigned char x = 0; x < pBitmap->nViewportWidth; x += 8)
{
for (unsigned char p = NUMPLANE - nPlanes; p < NUMPLANE; ++p)
for (unsigned char p = NUMPLANE; p--;)
{
// retrieve a chunk which can be copied into the frame buffer
unsigned char nChunk;
#if ((NUM_COLS % 8) != 0)
#if ((NUM_COLS % 8) == 0)
// borg widths which are a multiple of 8 allow for a straight
// forward chunk retrieval
nChunk = bitmap_getAlignedChunk(pBitmap, p, nX + x, nY + y);
#else
// in case the borg width is not a multiple of 8 some shifting
// is required to cover those bits who really affect the display
if ((x + nX) > (8 - NUM_COLS % 8))
{
{
nChunk = bitmap_getAlignedChunk(pBitmap, p,
nX + x - (8 - NUM_COLS % 8), nY + y);
}
else
{
nChunk = bitmap_getAlignedChunk(pBitmap, p,
nX, nY + y) >> (8 - NUM_COLS % 8);
}
#else
nChunk = bitmap_getAlignedChunk(pBitmap, p, nX + x, nY + y);
}
else
{
nChunk = bitmap_getAlignedChunk(pBitmap, p,
nX, nY + y) >> (8 - NUM_COLS % 8);
}
#endif
pixmap[p][y][pBitmap->nChunkCount - 1 - (x / 8)] = nChunk;
// determine correct column within frame buffer
uint8_t const nCol = pBitmap->nChunkCount - 1 - (x / 8);
// copy chunk into corresponding frame buffer plane
pixmap[p][y][nCol] = nChunk;
// if a bit in plane p + 1 is set, the corresponding bit in p
// has to be set as well
if (p < (NUMPLANE - 1))
{
pixmap[p][y][nCol] |= pixmap[p + 1][y][nCol];
}
}
}
}