1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
|
/* ScummVM - Graphic Adventure Engine
*
* ScummVM is the legal property of its developers, whose names
* are too numerous to list here. Please refer to the COPYRIGHT
* file distributed with this source distribution.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*
* $URL$
* $Id$
*
*/
// Based off ffmpeg's SMC decoder
#include "graphics/video/codecs/smc.h"
#include "common/stream.h"
namespace Graphics {
#define GET_BLOCK_COUNT() \
(opcode & 0x10) ? (1 + stream->readByte()) : 1 + (opcode & 0x0F);
#define ADVANCE_BLOCK() \
{ \
pixelPtr += 4; \
if (pixelPtr >= _surface->w) { \
pixelPtr = 0; \
rowPtr += _surface->w * 4; \
} \
totalBlocks--; \
if (totalBlocks < 0) { \
warning("block counter just went negative (this should not happen)"); \
return _surface; \
} \
}
SMCDecoder::SMCDecoder(uint16 width, uint16 height) {
_surface = new Graphics::Surface();
_surface->create(width, height, 1);
}
const Graphics::Surface *SMCDecoder::decodeImage(Common::SeekableReadStream *stream) {
byte *pixels = (byte *)_surface->pixels;
uint32 numBlocks = 0;
uint32 colorFlags = 0;
uint32 colorFlagsA = 0;
uint32 colorFlagsB = 0;
const uint16 rowInc = _surface->w - 4;
int32 rowPtr = 0;
int32 pixelPtr = 0;
uint32 blockPtr = 0;
uint32 prevBlockPtr = 0;
uint32 prevBlockPtr1 = 0, prevBlockPtr2 = 0;
byte prevBlockFlag = false;
uint32 pixel = 0;
uint32 colorPairIndex = 0;
uint32 colorQuadIndex = 0;
uint32 colorOctetIndex = 0;
uint32 colorTableIndex = 0; // indices to color pair, quad, or octet tables
int32 chunkSize = stream->readUint32BE() & 0x00FFFFFF;
if (chunkSize != stream->size())
warning("MOV chunk size != SMC chunk size (%d != %d); ignoring SMC chunk size", chunkSize, stream->size());
int32 totalBlocks = ((_surface->w + 3) / 4) * ((_surface->h + 3) / 4);
// traverse through the blocks
while (totalBlocks != 0) {
// sanity checks
// make sure stream ptr hasn't gone out of bounds
if (stream->pos() > stream->size()) {
warning("SMC decoder just went out of bounds (stream ptr = %d, chunk size = %d)", stream->pos(), stream->size());
return _surface;
}
// make sure the row pointer hasn't gone wild
if (rowPtr >= _surface->w * _surface->h) {
warning("SMC decoder just went out of bounds (row ptr = %d, size = %d)", rowPtr, _surface->w * _surface->h);
return _surface;
}
byte opcode = stream->readByte();
switch (opcode & 0xF0) {
// skip n blocks
case 0x00:
case 0x10:
numBlocks = GET_BLOCK_COUNT();
while (numBlocks--) {
ADVANCE_BLOCK();
}
break;
// repeat last block n times
case 0x20:
case 0x30:
numBlocks = GET_BLOCK_COUNT();
// sanity check
if (rowPtr == 0 && pixelPtr == 0) {
warning("encountered repeat block opcode (%02X) but no blocks rendered yet", opcode & 0xF0);
break;
}
// figure out where the previous block started
if (pixelPtr == 0)
prevBlockPtr1 = (rowPtr - _surface->w * 4) + _surface->w - 4;
else
prevBlockPtr1 = rowPtr + pixelPtr - 4;
while (numBlocks--) {
blockPtr = rowPtr + pixelPtr;
prevBlockPtr = prevBlockPtr1;
for (byte y = 0; y < 4; y++) {
for (byte x = 0; x < 4; x++)
pixels[blockPtr++] = pixels[prevBlockPtr++];
blockPtr += rowInc;
prevBlockPtr += rowInc;
}
ADVANCE_BLOCK();
}
break;
// repeat previous pair of blocks n times
case 0x40:
case 0x50:
numBlocks = GET_BLOCK_COUNT();
numBlocks *= 2;
// sanity check
if (rowPtr == 0 && pixelPtr < 2 * 4) {
warning("encountered repeat block opcode (%02X) but not enough blocks rendered yet", opcode & 0xF0);
break;
}
// figure out where the previous 2 blocks started
if (pixelPtr == 0)
prevBlockPtr1 = (rowPtr - _surface->w * 4) + _surface->w - 4 * 2;
else if (pixelPtr == 4)
prevBlockPtr1 = (rowPtr - _surface->w * 4) + rowInc;
else
prevBlockPtr1 = rowPtr + pixelPtr - 4 * 2;
if (pixelPtr == 0)
prevBlockPtr2 = (rowPtr - _surface->w * 4) + rowInc;
else
prevBlockPtr2 = rowPtr + pixelPtr - 4;
prevBlockFlag = 0;
while (numBlocks--) {
blockPtr = rowPtr + pixelPtr;
if (prevBlockFlag)
prevBlockPtr = prevBlockPtr2;
else
prevBlockPtr = prevBlockPtr1;
prevBlockFlag = !prevBlockFlag;
for (byte y = 0; y < 4; y++) {
for (byte x = 0; x < 4; x++)
pixels[blockPtr++] = pixels[prevBlockPtr++];
blockPtr += rowInc;
prevBlockPtr += rowInc;
}
ADVANCE_BLOCK();
}
break;
// 1-color block encoding
case 0x60:
case 0x70:
numBlocks = GET_BLOCK_COUNT();
pixel = stream->readByte();
while (numBlocks--) {
blockPtr = rowPtr + pixelPtr;
for (byte y = 0; y < 4; y++) {
for (byte x = 0; x < 4; x++)
pixels[blockPtr++] = pixel;
blockPtr += rowInc;
}
ADVANCE_BLOCK();
}
break;
// 2-color block encoding
case 0x80:
case 0x90:
numBlocks = (opcode & 0x0F) + 1;
// figure out which color pair to use to paint the 2-color block
if ((opcode & 0xF0) == 0x80) {
// fetch the next 2 colors from bytestream and store in next
// available entry in the color pair table
for (byte i = 0; i < CPAIR; i++) {
pixel = stream->readByte();
colorTableIndex = CPAIR * colorPairIndex + i;
_colorPairs[colorTableIndex] = pixel;
}
// this is the base index to use for this block
colorTableIndex = CPAIR * colorPairIndex;
colorPairIndex++;
// wraparound
if (colorPairIndex == COLORS_PER_TABLE)
colorPairIndex = 0;
} else
colorTableIndex = CPAIR * stream->readByte();
while (numBlocks--) {
colorFlags = stream->readUint16BE();
uint16 flagMask = 0x8000;
blockPtr = rowPtr + pixelPtr;
for (byte y = 0; y < 4; y++) {
for (byte x = 0; x < 4; x++) {
if (colorFlags & flagMask)
pixel = colorTableIndex + 1;
else
pixel = colorTableIndex;
flagMask >>= 1;
pixels[blockPtr++] = _colorPairs[pixel];
}
blockPtr += rowInc;
}
ADVANCE_BLOCK();
}
break;
// 4-color block encoding
case 0xA0:
case 0xB0:
numBlocks = (opcode & 0x0F) + 1;
// figure out which color quad to use to paint the 4-color block
if ((opcode & 0xF0) == 0xA0) {
// fetch the next 4 colors from bytestream and store in next
// available entry in the color quad table
for (byte i = 0; i < CQUAD; i++) {
pixel = stream->readByte();
colorTableIndex = CQUAD * colorQuadIndex + i;
_colorQuads[colorTableIndex] = pixel;
}
// this is the base index to use for this block
colorTableIndex = CQUAD * colorQuadIndex;
colorQuadIndex++;
// wraparound
if (colorQuadIndex == COLORS_PER_TABLE)
colorQuadIndex = 0;
} else
colorTableIndex = CQUAD * stream->readByte();
while (numBlocks--) {
colorFlags = stream->readUint32BE();
// flag mask actually acts as a bit shift count here
byte flagMask = 30;
blockPtr = rowPtr + pixelPtr;
for (byte y = 0; y < 4; y++) {
for (byte x = 0; x < 4; x++) {
pixel = colorTableIndex + ((colorFlags >> flagMask) & 0x03);
flagMask -= 2;
pixels[blockPtr++] = _colorQuads[pixel];
}
blockPtr += rowInc;
}
ADVANCE_BLOCK();
}
break;
// 8-color block encoding
case 0xC0:
case 0xD0:
numBlocks = (opcode & 0x0F) + 1;
// figure out which color octet to use to paint the 8-color block
if ((opcode & 0xF0) == 0xC0) {
// fetch the next 8 colors from bytestream and store in next
// available entry in the color octet table
for (byte i = 0; i < COCTET; i++) {
pixel = stream->readByte();
colorTableIndex = COCTET * colorOctetIndex + i;
_colorOctets[colorTableIndex] = pixel;
}
// this is the base index to use for this block
colorTableIndex = COCTET * colorOctetIndex;
colorOctetIndex++;
// wraparound
if (colorOctetIndex == COLORS_PER_TABLE)
colorOctetIndex = 0;
} else
colorTableIndex = COCTET * stream->readByte();
while (numBlocks--) {
/*
For this input of 6 hex bytes:
01 23 45 67 89 AB
Mangle it to this output:
flags_a = xx012456, flags_b = xx89A37B
*/
// build the color flags
byte flagData[6];
stream->read(flagData, 6);
colorFlagsA = ((READ_BE_UINT16(flagData) & 0xFFF0) << 8) | (READ_BE_UINT16(flagData + 2) >> 4);
colorFlagsB = ((READ_BE_UINT16(flagData + 4) & 0xFFF0) << 8) | ((flagData[1] & 0xF) << 8) |
((flagData[3] & 0xF) << 4) | (flagData[5] & 0xf);
colorFlags = colorFlagsA;
// flag mask actually acts as a bit shift count here
byte flagMask = 21;
blockPtr = rowPtr + pixelPtr;
for (byte y = 0; y < 4; y++) {
// reload flags at third row (iteration y == 2)
if (y == 2) {
colorFlags = colorFlagsB;
flagMask = 21;
}
for (byte x = 0; x < 4; x++) {
pixel = colorTableIndex + ((colorFlags >> flagMask) & 0x07);
flagMask -= 3;
pixels[blockPtr++] = _colorOctets[pixel];
}
blockPtr += rowInc;
}
ADVANCE_BLOCK();
}
break;
// 16-color block encoding (every pixel is a different color)
case 0xE0:
numBlocks = (opcode & 0x0F) + 1;
while (numBlocks--) {
blockPtr = rowPtr + pixelPtr;
for (byte y = 0; y < 4; y++) {
for (byte x = 0; x < 4; x++)
pixels[blockPtr++] = stream->readByte();
blockPtr += rowInc;
}
ADVANCE_BLOCK();
}
break;
case 0xF0:
warning("0xF0 opcode seen in SMC chunk (contact the developers)");
break;
}
}
return _surface;
}
} // End of namespace Graphics
|