ctdo
/
borgware-2d
16
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

saved 68 bytes

This commit is contained in:
Christian Kroll 2011-09-25 01:49:52 +00:00
parent c176376b0b
commit 2a81b8e743
1 changed files with 17 additions and 24 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

39
animations/bitmapscroller.c
View File

@ -32,10 +32,10 @@ bitmap_t;
/** /**
* This function generates an eight-by-one pixel chunk for a given pair of pixel * This function generates an eight-by-one pixel chunk for a given pair of pixel
* coordinates and a borg plane number. The resulting chunk can be copied * coordinates and a borg plane index. The resulting chunk can be copied
* directly to the borg's frame buffer. It makes use of the user provided * directly to the borg's frame buffer. It utilizes the user provided "getChunk"
* "getChunk" function which in contrast only accepts chunk based coordinates * function which in contrast only accepts chunk based coordinates (resulting in
* (resulting in chunks whose x-coordinates are always a multiple of eight) and * chunks whose pixel based x-coordinates are always a multiple of eight) and
* uses bit planes which defer from the plane scheme used by the borg's frame * uses bit planes which defer from the plane scheme used by the borg's frame
* buffer. * buffer.
* @param pBitmap The bitmap of interest. * @param pBitmap The bitmap of interest.
@ -55,25 +55,20 @@ static unsigned char bitmap_getAlignedChunk(bitmap_t const *const pBitmap,
unsigned char nChunk = 0xFF; unsigned char nChunk = 0xFF;
unsigned char nMask = 1; unsigned char nMask = 1;
unsigned char const nAlignment = x % 8; unsigned char const nAlignment = x % 8;
unsigned char const x_8 = x / 8;
// we have to go through every bit plane // we have to go through every bit plane
for (unsigned char i = 0; i < pBitmap->nBitPlanes; ++i) for (unsigned char i = pBitmap->nBitPlanes; i--;)
{ {
// generate chunk // generate chunk
unsigned char nPlaneChunk; unsigned char nPlaneChunk;
// if the given x-coordinate is aligned to a chunk coordinate we can nPlaneChunk = pBitmap->fpGetChunk(i, x_8, y, pBitmap->nFrame)
// reuse the result of the "getChunk" function directly. << nAlignment;
if (nAlignment == 0)
{
nPlaneChunk = pBitmap->fpGetChunk(i, x/8, y, pBitmap->nFrame);
}
// in case of misalignment we combine two chunks with chunk based // in case of misalignment we combine two chunks with chunk based
// coordinates into one chunk which aligns to the given x-coordinate // coordinates into one chunk which aligns to the given x-coordinate
else if (nAlignment != 0)
{ {
nPlaneChunk = pBitmap->fpGetChunk(i, x/8, y, pBitmap->nFrame) nPlaneChunk |= pBitmap->fpGetChunk(i, x_8 + 1, y, pBitmap->nFrame)
<< nAlignment;
nPlaneChunk |= pBitmap->fpGetChunk(i, x/8+1, y, pBitmap->nFrame)
>> (8 - nAlignment); >> (8 - nAlignment);
} }
@ -106,6 +101,9 @@ static void bitmap_drawViewport(bitmap_t const *const pBitmap,
{ {
for (unsigned char x = 0; x < pBitmap->nViewportWidth; x += 8) for (unsigned char x = 0; x < pBitmap->nViewportWidth; x += 8)
{ {
// determine correct column within frame buffer
unsigned char const nCol = pBitmap->nChunkCount - 1 - (x / 8);
for (unsigned char p = NUMPLANE; p--;) for (unsigned char p = NUMPLANE; p--;)
{ {
// retrieve a chunk which can be copied into the frame buffer // retrieve a chunk which can be copied into the frame buffer
@ -128,16 +126,14 @@ static void bitmap_drawViewport(bitmap_t const *const pBitmap,
nX, nY + y) >> (8 - NUM_COLS % 8); nX, nY + y) >> (8 - NUM_COLS % 8);
} }
#endif #endif
// 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 // if a bit in plane p + 1 is set, the corresponding bit in p
// has to be set as well // has to be set as well
if (p < (NUMPLANE - 1)) if (p < (NUMPLANE - 1))
{ {
pixmap[p][y][nCol] |= pixmap[p + 1][y][nCol]; nChunk |= pixmap[p + 1][y][nCol];
} }
// copy chunk into corresponding frame buffer plane
pixmap[p][y][nCol] = nChunk;
} }
} }
} }
@ -215,9 +211,6 @@ void bitmap_scroll(unsigned char const nWidth,
signed char dx = 0; signed char dx = 0;
signed char dy = 0; signed char dy = 0;
// remove garbage from screen
clear_screen(0);
for (bitmap.nFrame = 0; bitmap.nFrame < nFrameCount; ++bitmap.nFrame) for (bitmap.nFrame = 0; bitmap.nFrame < nFrameCount; ++bitmap.nFrame)
{ {
bitmap_drawViewport(&bitmap, x, y); bitmap_drawViewport(&bitmap, x, y);