398 lines
12 KiB
C
398 lines
12 KiB
C
/*****************************************************************************/
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/* */
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/* lynxsprite.c */
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/* */
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/* Lynx sprite format backend for the sp65 sprite and bitmap utility */
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/* */
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/* */
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/* */
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/* (C) 2012, Ullrich von Bassewitz */
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/* Roemerstrasse 52 */
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/* D-70794 Filderstadt */
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/* EMail: uz@cc65.org */
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/* */
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/* */
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/* This software is provided 'as-is', without any expressed or implied */
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/* warranty. In no event will the authors be held liable for any damages */
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/* arising from the use of this software. */
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/* */
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/* Permission is granted to anyone to use this software for any purpose, */
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/* including commercial applications, and to alter it and redistribute it */
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/* freely, subject to the following restrictions: */
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/* */
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/* 1. The origin of this software must not be misrepresented; you must not */
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/* claim that you wrote the original software. If you use this software */
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/* in a product, an acknowledgment in the product documentation would be */
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/* appreciated but is not required. */
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/* 2. Altered source versions must be plainly marked as such, and must not */
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/* be misrepresented as being the original software. */
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/* 3. This notice may not be removed or altered from any source */
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/* distribution. */
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/* */
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/*****************************************************************************/
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#include <stdlib.h>
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/* common */
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#include "attrib.h"
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#include "print.h"
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/* sp65 */
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#include "attr.h"
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#include "error.h"
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#include "lynxsprite.h"
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/*****************************************************************************/
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/* Data */
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/*****************************************************************************/
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/* Sprite mode */
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enum Mode {
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smAuto,
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smLiteral,
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smPacked,
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smPackedTransparent
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};
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/*****************************************************************************/
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/* Code */
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/*****************************************************************************/
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static enum Mode GetMode (const Collection* A)
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/* Return the sprite mode from the attribute collection A */
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{
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/* Check for a mode attribute */
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const char* Mode = GetAttrVal (A, "mode");
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if (Mode) {
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if (strcmp (Mode, "literal") == 0) {
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return smLiteral;
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} else if (strcmp (Mode, "packed") == 0) {
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return smPacked;
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} else if (strcmp (Mode, "transparent") == 0) {
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return smPackedTransparent;
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} else {
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Error ("Invalid value for attribute `mode'");
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}
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}
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return smAuto;
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}
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static unsigned GetActionPointX (const Collection* A)
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/* Return the sprite mode from the attribute collection A */
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{
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/* Check for a action point x attribute */
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const char* ActionPointX = GetAttrVal (A, "ax");
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if (ActionPointX) {
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return atoi(ActionPointX);
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} else {
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return 0;
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}
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}
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static unsigned GetActionPointY (const Collection* A)
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/* Return the sprite mode from the attribute collection A */
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{
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/* Check for a action point y attribute */
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const char* ActionPointY = GetAttrVal (A, "ay");
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if (ActionPointY) {
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return atoi(ActionPointY);
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} else {
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return 0;
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}
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}
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static void encodeSprite(StrBuf *D, enum Mode M, char ColorBits, char ColorMask, char LineBuffer[512],
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int i, int LastOpaquePixel) {
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/*
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* The data starts with a byte count. It tells the number of bytes on this
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* line + 1.
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* Special case is a count of 1. It will change to next quadrant.
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* Other special case is 0. It will end the sprite.
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*
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* Ordinary data packet. These are bits in a stream.
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* 1=literal 0=packed
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* 4 bit count (+1)
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* for literal you put "count" values
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* for packed you repeat the value "count" times
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* Never use packed mode for one pixel
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* If the last bit on a line is 1 you need to add a byte of zeroes
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* A sequence 00000 ends a scan line
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*
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* All data is high nybble first
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*/
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char OutBuffer[512]; /* The maximum size is 508 pixels */
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unsigned char OutIndex = 0;
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unsigned char V = 0;
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unsigned W = 0;
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signed j;
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signed k;
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switch (M) {
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case smAuto:
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case smLiteral:
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OutIndex = 0;
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k = 0;
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for (j = 0; j < i; j++) {
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/* Fetch next pixel index into pixel buffer */
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W = (W << ColorBits) | (LineBuffer[j] & ColorMask);
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k += ColorBits;
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if (k > 7) {
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/* The byte is ready */
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k -= 8;
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V = (W >> k) & 0xFF;
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OutBuffer[OutIndex++] = V;
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if (!OutIndex) {
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Error ("Sprite is too large for the Lynx");
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}
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}
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}
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/* Output last bits */
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if (k != 0) {
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W = (W << (8-k));
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k = 0;
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V = W & 0xFF;
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OutBuffer[OutIndex++] = V;
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if (!OutIndex) {
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Error ("Sprite is too large for the Lynx");
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}
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}
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/* Fix bug in Lynx where the last bit on a line is 1 */
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if (V & 1) {
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OutBuffer[OutIndex++] = 0;
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if (!OutIndex) {
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Error ("Sprite is too large for the Lynx");
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}
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}
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/* Fix bug in Lynx where the count cannot be 1 */
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if (OutIndex == 1) {
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OutBuffer[OutIndex++] = 0;
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}
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/* Write the byte count to the end of the scanline */
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if (OutIndex == 255) {
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Error ("Sprite is too large for the Lynx");
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}
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SB_AppendChar (D, OutIndex+1);
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/* Write scanline data */
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for (j = 0; j < OutIndex; j++) {
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SB_AppendChar (D, OutBuffer[j]);
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}
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break;
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case smPacked:
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/* Bug workaround: If last bit is 1 and it is in bit0 add a zero byte */
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/* Note: These extra pixels will be painted also. There is no workaround for this */
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if (LineBuffer[i - 1] & 0x01) {
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LineBuffer[i++] = 0;
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}
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/* Logical problem workaround: The count can not be 1 so add an extra byte */
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if (i == 1) {
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LineBuffer[i++] = 0;
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}
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/* Write the byte count for this partial scanline */
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SB_AppendChar (D, i);
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for (i = 0; i < LineBuffer[0]; i++) {
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SB_AppendChar (D, LineBuffer[i]);
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}
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break;
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case smPackedTransparent:
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break;
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}
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}
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StrBuf* GenLynxSprite (const Bitmap* B, const Collection* A)
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/* Generate binary output in Lynx sprite format for the bitmap B. The output
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* is stored in a string buffer (which is actually a dynamic char array) and
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* returned.
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*
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* The Lynx will draw 4 quadrants:
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* - Down right
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* - Up right
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* - Up left
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* - Down left
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*
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* The sprite will end with a byte 0.
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*/
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{
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enum Mode M;
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StrBuf* D;
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signed X, Y;
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unsigned OX, OY;
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char ColorBits;
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char ColorMask;
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/* Action point of the sprite */
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OX = GetActionPointX (A);
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OY = GetActionPointY (A);
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if (OX >= GetBitmapWidth (B)) {
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Error ("Action point X cannot be larger than bitmap width");
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}
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if (OY >= GetBitmapHeight (B)) {
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Error ("Action point Y cannot be larger than bitmap height");
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}
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/* Output the image properties */
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Print (stdout, 1, "Image is %ux%u with %u colors%s\n",
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GetBitmapWidth (B), GetBitmapHeight (B), GetBitmapColors (B),
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BitmapIsIndexed (B)? " (indexed)" : "");
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/* Get the sprite mode */
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M = GetMode (A);
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/* Now check if bitmap indexes are ok */
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if (GetBitmapColors (B) > 16) {
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Error ("Too many colors for a Lynx sprite");
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}
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ColorBits = 4;
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ColorMask = 0x0f;
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if (GetBitmapColors (B) < 9) {
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ColorBits = 3;
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ColorMask = 0x07;
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}
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if (GetBitmapColors (B) < 5) {
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ColorBits = 2;
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ColorMask = 0x03;
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}
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if (GetBitmapColors (B) < 3) {
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ColorBits = 1;
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ColorMask = 0x01;
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}
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/* Create the output buffer and resize it to the required size. */
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D = NewStrBuf ();
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SB_Realloc (D, 63);
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/* Convert the image for quadrant bottom right */
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for (Y = OY; Y < (signed)GetBitmapHeight (B); ++Y) {
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signed i = 0;
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signed LastOpaquePixel = -1;
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char LineBuffer[512]; /* The maximum size is 508 pixels */
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/* Fill the LineBuffer for easier optimisation */
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for (X = OX; X < (signed)GetBitmapWidth (B); ++X) {
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/* Fetch next bit into byte buffer */
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LineBuffer[i] = GetPixel (B, X, Y).Index & ColorMask;
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if (LineBuffer[i]) {
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LastOpaquePixel = i;
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}
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++i;
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}
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encodeSprite(D, M, ColorBits, ColorMask, LineBuffer, i, LastOpaquePixel);
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}
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if ((OY == 0) && (OX == 0)) {
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/* Trivial case only one quadrant */
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/* Mark end of sprite */
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SB_AppendChar (D, 0);
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/* Return the converted bitmap */
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return D;
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}
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/* Next quadrant */
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SB_AppendChar (D, 1);
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/* Convert the image for quadrant top right */
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for (Y = OY - 1; Y >= 0; --Y) {
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signed i = 0;
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signed LastOpaquePixel = -1;
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char LineBuffer[512]; /* The maximum size is 508 pixels */
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/* Fill the LineBuffer for easier optimisation */
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for (X = OX; X < (signed)GetBitmapWidth (B); ++X) {
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/* Fetch next bit into byte buffer */
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LineBuffer[i] = GetPixel (B, X, Y).Index & ColorMask;
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if (LineBuffer[i]) {
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LastOpaquePixel = i;
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}
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++i;
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}
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encodeSprite(D, M, ColorBits, ColorMask, LineBuffer, i, LastOpaquePixel);
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}
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if (OX == 0) {
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/* Special case only two quadrants */
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/* Mark end of sprite */
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SB_AppendChar (D, 0);
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/* Return the converted bitmap */
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return D;
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}
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/* Next quadrant */
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SB_AppendChar (D, 1);
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/* Convert the image for quadrant top left */
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for (Y = OY - 1; Y >= 0; --Y) {
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signed i = 0;
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signed LastOpaquePixel = -1;
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char LineBuffer[512]; /* The maximum size is 508 pixels */
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/* Fill the LineBuffer for easier optimisation */
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for (X = OX - 1; X >= 0; --X) {
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/* Fetch next bit into byte buffer */
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LineBuffer[i] = GetPixel (B, X, Y).Index & ColorMask;
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if (LineBuffer[i]) {
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LastOpaquePixel = i;
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}
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++i;
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}
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encodeSprite(D, M, ColorBits, ColorMask, LineBuffer, i, LastOpaquePixel);
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}
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/* Next quadrant */
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SB_AppendChar (D, 1);
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/* Convert the image for quadrant bottom left */
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for (Y = OY; Y < (signed)GetBitmapHeight (B); ++Y) {
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signed i = 0;
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signed LastOpaquePixel = -1;
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char LineBuffer[512]; /* The maximum size is 508 pixels */
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/* Fill the LineBuffer for easier optimisation */
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for (X = OX - 1; X >= 0; --X) {
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/* Fetch next bit into byte buffer */
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LineBuffer[i] = GetPixel (B, X, Y).Index & ColorMask;
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if (LineBuffer[i]) {
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LastOpaquePixel = i;
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}
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++i;
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}
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encodeSprite(D, M, ColorBits, ColorMask, LineBuffer, i, LastOpaquePixel);
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}
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/* End sprite */
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SB_AppendChar (D, 0);
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/* Return the converted bitmap */
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return D;
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}
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