}
+static void encodeSprite(StrBuf *D, enum Mode M, char ColorBits, char ColorMask, char LineBuffer[512],
+ int i, int LastOpaquePixel) {
+/*
+ * The data starts with a byte count. It tells the number of bytes on this
+ * line + 1.
+ * Special case is a count of 1. It will change to next quadrant.
+ * Other special case is 0. It will end the sprite.
+ *
+ * Ordinary data packet. These are bits in a stream.
+ * 1=literal 0=packed
+ * 4 bit count (+1)
+ * for literal you put "count" values
+ * for packed you repeat the value "count" times
+ * Never use packed mode for one pixel
+ * If the last bit on a line is 1 you need to add a byte of zeroes
+ * A sequence 00000 ends a scan line
+ *
+ * All data is high nybble first
+ */
+ char OutBuffer[512]; /* The maximum size is 508 pixels */
+ unsigned char OutIndex = 0;
+ unsigned char V = 0;
+ unsigned W = 0;
+ signed j;
+ signed k;
+
+ switch (M) {
+ case smAuto:
+ case smLiteral:
+ OutIndex = 0;
+ k = 0;
+ for (j = 0; j < i; j++) {
+ /* Fetch next pixel index into pixel buffer */
+ W = (W << ColorBits) | (LineBuffer[j] & ColorMask);
+ k += ColorBits;
+ if (k > 7) {
+ /* The byte is ready */
+ k -= 8;
+ V = (W >> k) & 0xFF;
+ OutBuffer[OutIndex++] = V;
+ if (!OutIndex) {
+ Error ("Sprite is too large for the Lynx");
+ }
+ }
+ }
+ /* Output last bits */
+ if (k != 0) {
+ W = (W << (8-k));
+ k = 0;
+ V = W & 0xFF;
+ OutBuffer[OutIndex++] = V;
+ if (!OutIndex) {
+ Error ("Sprite is too large for the Lynx");
+ }
+ }
+ /* Fix bug in Lynx where the last bit on a line is 1 */
+ if (V & 1) {
+ OutBuffer[OutIndex++] = 0;
+ if (!OutIndex) {
+ Error ("Sprite is too large for the Lynx");
+ }
+ }
+ /* Fix bug in Lynx where the count cannot be 1 */
+ if (OutIndex == 1) {
+ OutBuffer[OutIndex++] = 0;
+ }
+ /* Write the byte count to the end of the scanline */
+ if (OutIndex == 255) {
+ Error ("Sprite is too large for the Lynx");
+ }
+ SB_AppendChar (D, OutIndex+1);
+ /* Write scanline data */
+ for (j = 0; j < OutIndex; j++) {
+ SB_AppendChar (D, OutBuffer[j]);
+ }
+ break;
+ case smPacked:
+ /* Bug workaround: If last bit is 1 and it is in bit0 add a zero byte */
+ /* Note: These extra pixels will be painted also. There is no workaround for this */
+ if (LineBuffer[i - 1] & 0x01) {
+ LineBuffer[i++] = 0;
+ }
+ /* Logical problem workaround: The count can not be 1 so add an extra byte */
+ if (i == 1) {
+ LineBuffer[i++] = 0;
+ }
+ /* Write the byte count for this partial scanline */
+ SB_AppendChar (D, i);
+ for (i = 0; i < LineBuffer[0]; i++) {
+ SB_AppendChar (D, LineBuffer[i]);
+ }
+ break;
+ case smPackedTransparent:
+ break;
+ }
+}
StrBuf* GenLynxSprite (const Bitmap* B, const Collection* A)
/* Generate binary output in Lynx sprite format for the bitmap B. The output
{
enum Mode M;
StrBuf* D;
- unsigned X, Y;
+ signed X, Y;
unsigned OX, OY;
- char LineBuffer[512]; /* The maximum size is 508 pixels */
- char OutBuffer[512]; /* The maximum size is 508 pixels */
char ColorBits;
char ColorMask;
/* Get the sprite mode */
M = GetMode (A);
- /* If the mode wasn't given, fallback to packed */
- if (M == smAuto) {
- M = smLiteral;
- }
-
/* Now check if bitmap indexes are ok */
if (GetBitmapColors (B) > 16) {
Error ("Too many colors for a Lynx sprite");
SB_Realloc (D, 63);
/* Convert the image for quadrant bottom right */
- for (Y = OY; Y < GetBitmapHeight (B); ++Y) {
- unsigned char V = 0;
- unsigned char OutIndex;
- unsigned W = 0;
+ for (Y = OY; Y < (signed)GetBitmapHeight (B); ++Y) {
signed i = 0;
- signed j;
- signed k;
signed LastOpaquePixel = -1;
+ char LineBuffer[512]; /* The maximum size is 508 pixels */
/* Fill the LineBuffer for easier optimisation */
- for (X = OX; X < GetBitmapWidth (B); ++X) {
+ for (X = OX; X < (signed)GetBitmapWidth (B); ++X) {
/* Fetch next bit into byte buffer */
LineBuffer[i] = GetPixel (B, X, Y).Index & ColorMask;
++i;
}
- switch (M) {
- case smLiteral:
- OutIndex = 0;
- for (j = 0; j < i; j++) {
- /* Fetch next pixel index into pixel buffer */
- W = (W << ColorBits) | (LineBuffer[j] & ColorMask);
- k += ColorBits;
- if (k > 7) {
- /* The byte is ready */
- k -= 8;
- V = (W >> k) & 0xFF;
- OutBuffer[OutIndex++] = V;
- if (!OutIndex) {
- Error ("Sprite is too large for the Lynx");
- }
- }
- }
- /* Output last bits */
- if (k != 0) {
- W = (W << (8-k));
- k = 0;
- V = W & 0xFF;
- OutBuffer[OutIndex++] = V;
- if (!OutIndex) {
- Error ("Sprite is too large for the Lynx");
- }
- }
- /* Fix bug in Lynx where the last bit on a line is 1 */
- if (V & 1) {
- OutBuffer[OutIndex++] = 0;
- if (!OutIndex) {
- Error ("Sprite is too large for the Lynx");
- }
- }
- /* Fix bug in Lynx where the count cannot be 1 */
- if (OutIndex == 1) {
- OutBuffer[OutIndex++] = 0;
- }
- /* Write the byte count to the end of the scanline */
- if (OutIndex == 255) {
- Error ("Sprite is too large for the Lynx");
- }
- SB_AppendChar (D, OutIndex+1);
- /* Write scanline data */
- for (j = 0; j < OutIndex; j++) {
- SB_AppendChar (D, OutBuffer[j]);
- }
- break;
- case smPacked:
- /* Bug workaround: If last bit is 1 and it is in bit0 add a zero byte */
- /* Note: These extra pixels will be painted also. There is no workaround for this */
- if (LineBuffer[i - 1] & 0x01) {
- LineBuffer[i++] = 0;
- }
- /* Logical problem workaround: The count can not be 1 so add an extra byte */
- if (i == 1) {
- LineBuffer[i++] = 0;
- }
- /* Write the byte count for this partial scanline */
- SB_AppendChar (D, i);
- for (i = 0; i < LineBuffer[0]; i++) {
- SB_AppendChar (D, LineBuffer[i]);
- }
- break;
- case smPackedTransparent:
- break;
- }
+ encodeSprite(D, M, ColorBits, ColorMask, LineBuffer, i, LastOpaquePixel);
}
if ((OY == 0) && (OX == 0)) {
/* Convert the image for quadrant top right */
for (Y = OY - 1; Y >= 0; --Y) {
- unsigned char V = 0;
- if (M == smLiteral) {
- for (X = OX; X < GetBitmapWidth (B); ++X) {
+ signed i = 0;
+ signed LastOpaquePixel = -1;
+ char LineBuffer[512]; /* The maximum size is 508 pixels */
- /* Fetch next bit into byte buffer */
- V = (V << 4) | (GetPixel (B, X, Y).Index & 0x0f);
+ /* Fill the LineBuffer for easier optimisation */
+ for (X = OX; X < (signed)GetBitmapWidth (B); ++X) {
- /* Store full bytes into the output buffer */
- if ((X & 0x01) == 0x01) {
- SB_AppendChar (D, V);
- V = 0;
- }
+ /* Fetch next bit into byte buffer */
+ LineBuffer[i] = GetPixel (B, X, Y).Index & ColorMask;
+
+ if (LineBuffer[i]) {
+ LastOpaquePixel = i;
}
+ ++i;
}
+
+ encodeSprite(D, M, ColorBits, ColorMask, LineBuffer, i, LastOpaquePixel);
}
/* Next quadrant */
/* Convert the image for quadrant top left */
for (Y = OY - 1; Y >= 0; --Y) {
- unsigned char V = 0;
- if (M == smLiteral) {
- for (X = OX - 1; X >= 0; --X) {
+ signed i = 0;
+ signed LastOpaquePixel = -1;
+ char LineBuffer[512]; /* The maximum size is 508 pixels */
- /* Fetch next bit into byte buffer */
- V = (V << 4) | (GetPixel (B, X, Y).Index & 0x0f);
+ /* Fill the LineBuffer for easier optimisation */
+ for (X = OX - 1; X >= 0; --X) {
- /* Store full bytes into the output buffer */
- if ((X & 0x01) == 0x01) {
- SB_AppendChar (D, V);
- V = 0;
- }
+ /* Fetch next bit into byte buffer */
+ LineBuffer[i] = GetPixel (B, X, Y).Index & ColorMask;
+
+ if (LineBuffer[i]) {
+ LastOpaquePixel = i;
}
+ ++i;
}
+
+ encodeSprite(D, M, ColorBits, ColorMask, LineBuffer, i, LastOpaquePixel);
}
/* Next quadrant */
SB_AppendChar (D, 1);
/* Convert the image for quadrant bottom left */
- for (Y = OY; Y < GetBitmapHeight (B); ++Y) {
- unsigned char V = 0;
- if (M == smLiteral) {
- for (X = OX - 1; X >= 0; --X) {
-
- /* Fetch next bit into byte buffer */
- V = (V << 4) | (GetPixel (B, X, Y).Index & 0x0f);
-
- /* Store full bytes into the output buffer */
- if ((X & 0x01) == 0x01) {
- SB_AppendChar (D, V);
- V = 0;
- }
+ for (Y = OY; Y < (signed)GetBitmapHeight (B); ++Y) {
+ signed i = 0;
+ signed LastOpaquePixel = -1;
+ char LineBuffer[512]; /* The maximum size is 508 pixels */
+
+ /* Fill the LineBuffer for easier optimisation */
+ for (X = OX - 1; X >= 0; --X) {
+
+ /* Fetch next bit into byte buffer */
+ LineBuffer[i] = GetPixel (B, X, Y).Index & ColorMask;
+
+ if (LineBuffer[i]) {
+ LastOpaquePixel = i;
}
+ ++i;
}
+
+ encodeSprite(D, M, ColorBits, ColorMask, LineBuffer, i, LastOpaquePixel);
}
/* End sprite */
projects / cc65 / commitdiff