[Scummvm-cvs-logs] SF.net SVN: scummvm: [30096] scummvm/trunk/engines/lure
dreammaster at users.sourceforge.net
dreammaster at users.sourceforge.net
Mon Dec 31 06:57:11 CET 2007
Revision: 30096
http://scummvm.svn.sourceforge.net/scummvm/?rev=30096&view=rev
Author: dreammaster
Date: 2007-12-30 21:57:11 -0800 (Sun, 30 Dec 2007)
Log Message:
-----------
Added support for decoding EGA screens
Modified Paths:
--------------
scummvm/trunk/engines/lure/decode.cpp
scummvm/trunk/engines/lure/decode.h
Modified: scummvm/trunk/engines/lure/decode.cpp
===================================================================
--- scummvm/trunk/engines/lure/decode.cpp 2007-12-31 05:56:22 UTC (rev 30095)
+++ scummvm/trunk/engines/lure/decode.cpp 2007-12-31 05:57:11 UTC (rev 30096)
@@ -24,6 +24,7 @@
*/
#include "lure/decode.h"
+#include "lure/lure.h"
#include "lure/memory.h"
#include "lure/luredefs.h"
#include "common/endian.h"
@@ -50,13 +51,20 @@
}
byte PictureDecoder::DSSI(bool incr) {
- byte result = dataIn[dataPos];
+ if (dataPos > dataIn->size())
+ error("PictureDecoder went beyond end of source data");
+
+ byte result = (dataPos == dataIn->size()) ? 0 :
+ dataIn->data()[dataPos];
if (incr) ++dataPos;
return result;
}
byte PictureDecoder::ESBX(bool incr) {
- byte result = dataIn[dataPos2];
+ if (dataPos2 >= dataIn->size())
+ error("PictureDecoder went beyond end of source data");
+
+ byte result = dataIn->data()[dataPos2];
if (incr) ++dataPos2;
return result;
}
@@ -75,22 +83,147 @@
return result;
}
-void PictureDecoder::swap(uint16 &v1, uint16 &v2) {
- uint16 vTemp;
- vTemp = v1;
- v1 = v2;
- v2 = vTemp;
+// decode
+// Decodes a compressed Lure of the Temptress screen
+
+MemoryBlock *PictureDecoder::decode(MemoryBlock *src, uint32 maxOutputSize) {
+ bool isEGA = LureEngine::getReference().isEGA();
+ return isEGA ? egaDecode(src, maxOutputSize) : vgaDecode(src, maxOutputSize);
}
-// decode_data
-// Takes care of decoding compressed Lure of the Temptress data
+// egaDecode
+// Takes care of decoding a compressed EGA screen
-MemoryBlock *PictureDecoder::decode(MemoryBlock *src, uint32 maxOutputSize) {
+#define READ_BIT_DX { bitFlag = (dx & 0x8000) != 0; dx <<= 1; if (--bitCtr == 0) { dx = (dx & 0xff00) | DSSI(); bitCtr = 8; } }
+#define READ_BITS(loops) for (int ctr = 0; ctr < loops; ++ctr) READ_BIT_DX
+
+MemoryBlock *PictureDecoder::egaDecode(MemoryBlock *src, uint32 maxOutputSize) {
MemoryBlock *dest = Memory::allocate(maxOutputSize);
+ byte popTable[32 + 128];
+ uint8 al;
+ bool bitFlag;
// Set up initial states
- dataIn = src->data();
+ dataIn = src;
+ dataPos = 6;
+
+ uint16 dx = READ_BE_UINT16(src->data() + dataPos);
+ dataPos += sizeof(uint16);
+ int bitCtr = 8;
+
+ // Decode the colour popularity table
+
+ for (int nibbleCtr = 0; nibbleCtr < 32; ++nibbleCtr) {
+ for (int byteCtr = 0; byteCtr < 128; byteCtr += 32) {
+ popTable[nibbleCtr + byteCtr] = dx >> 11;
+ READ_BITS(5);
+ }
+ }
+
+ // ok, on to the real thing
+
outputOffset = 0;
+ al = dx >> 11;
+ writeByte(dest, al);
+ READ_BITS(5);
+
+ uint16 tableOffset = al;
+ uint8 v = 0;
+
+ for (;;) {
+ READ_BIT_DX
+
+ if (!bitFlag) {
+ // Get the favourite colour
+ v = popTable[tableOffset];
+
+ } else {
+
+ READ_BIT_DX
+
+ if (bitFlag) {
+ // Get another bit
+ READ_BIT_DX
+
+ if (bitFlag) {
+ // We have no favourite. Could this be a repeat?
+ al = dx >> 11;
+ READ_BITS(5);
+
+ if (al == popTable[tableOffset]) {
+ // Repeat 16 bits
+ uint16 numLoops = dx & 0xff00;
+ READ_BITS(8);
+ numLoops |= (dx >> 8);
+ READ_BITS(8);
+
+ if (numLoops == 0)
+ // Finished decoding
+ break;
+ writeBytes(dest, al, numLoops);
+ continue;
+
+ } else if (al == popTable[tableOffset + 32]) {
+ // Repeat 8 bits
+ writeBytes(dest, tableOffset, dx >> 8);
+ READ_BITS(8);
+ continue;
+
+ } else if (al == popTable[tableOffset + 64]) {
+ // Repeat 6 bits
+ writeBytes(dest, tableOffset, dx >> 10);
+ READ_BITS(6);
+ continue;
+
+ } else if (al == popTable[tableOffset + 96]) {
+ // Repeat 5 bits
+ writeBytes(dest, tableOffset, dx >> 11);
+ READ_BITS(5);
+ continue;
+
+ } else {
+ // It's a new colour
+ v = al;
+ }
+
+ } else {
+ // Fourth favourite
+ v = popTable[tableOffset + 96];
+ }
+
+ } else {
+ // Get another bit
+ READ_BIT_DX
+
+ if (bitFlag) {
+ // Third favourite
+ v = popTable[tableOffset + 64];
+ } else {
+ // Second favourite
+ v = popTable[tableOffset + 32];
+ }
+ }
+ }
+
+ tableOffset = v;
+ writeByte(dest, v);
+ }
+
+ // Resize the output to be the number of outputed bytes and return it
+ if (outputOffset < dest->size()) dest->reallocate(outputOffset);
+
+ return dest;
+}
+
+// vgaDecode
+// Takes care of decoding a compressed vga screen
+
+MemoryBlock *PictureDecoder::vgaDecode(MemoryBlock *src, uint32 maxOutputSize) {
+ MemoryBlock *dest = Memory::allocate(maxOutputSize);
+
+ // Set up initial states
+ dataIn = src;
+ outputOffset = 0;
dataPos = READ_LE_UINT32(dataIn + 0x400);
dataPos2 = 0x404;
@@ -107,7 +240,7 @@
if (shlCarry()) goto Loc761;
decrCtr();
if (shlCarry()) goto Loc759;
- AL = dataIn[BP];
+ AL = dataIn->data()[BP];
Loc758:
writeByte(dest, AL);
@@ -128,17 +261,17 @@
decrCtr();
if (shlCarry()) goto Loc764;
- AL = dataIn[BP+1];
+ AL = dataIn->data()[BP+1];
goto Loc758;
Loc764:
- AL = dataIn[BP+2];
+ AL = dataIn->data()[BP+2];
goto Loc758;
Loc765:
decrCtr();
if (shlCarry()) goto Loc767;
- AL = dataIn[BP+3];
+ AL = dataIn->data()[BP+3];
goto Loc758;
Loc767:
Modified: scummvm/trunk/engines/lure/decode.h
===================================================================
--- scummvm/trunk/engines/lure/decode.h 2007-12-31 05:56:22 UTC (rev 30095)
+++ scummvm/trunk/engines/lure/decode.h 2007-12-31 05:57:11 UTC (rev 30096)
@@ -34,7 +34,7 @@
class PictureDecoder {
private:
- byte *dataIn;
+ MemoryBlock *dataIn;
uint32 BP;
uint32 dataPos, dataPos2;
uint32 outputOffset;
@@ -47,9 +47,11 @@
byte ESBX(bool incr = true);
void decrCtr();
bool shlCarry();
- void swap(uint16 &v1, uint16 &v2);
+
+ MemoryBlock *egaDecode(MemoryBlock *src, uint32 maxOutputSize);
+ MemoryBlock *vgaDecode(MemoryBlock *src, uint32 maxOutputSize);
public:
- MemoryBlock *decode(MemoryBlock *src, uint32 maxOutputSize = SCREEN_SIZE);
+ MemoryBlock *decode(MemoryBlock *src, uint32 maxOutputSize = SCREEN_SIZE + 1);
};
class AnimationDecoder {
This was sent by the SourceForge.net collaborative development platform, the world's largest Open Source development site.
More information about the Scummvm-git-logs
mailing list