summaryrefslogtreecommitdiff
path: root/libavcodec/cdgraphics.c (plain)
blob: 87ad5e79f441fa7514b3e19817fafbad82a93b90
1/*
2 * CD Graphics Video Decoder
3 * Copyright (c) 2009 Michael Tison
4 *
5 * This file is part of FFmpeg.
6 *
7 * FFmpeg is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
11 *
12 * FFmpeg is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
16 *
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 */
21
22#include "avcodec.h"
23#include "bytestream.h"
24#include "internal.h"
25
26/**
27 * @file
28 * @brief CD Graphics Video Decoder
29 * @author Michael Tison
30 * @see http://wiki.multimedia.cx/index.php?title=CD_Graphics
31 * @see http://www.ccs.neu.edu/home/bchafy/cdb/info/cdg
32 */
33
34/// default screen sizes
35#define CDG_FULL_WIDTH 300
36#define CDG_FULL_HEIGHT 216
37#define CDG_DISPLAY_WIDTH 294
38#define CDG_DISPLAY_HEIGHT 204
39#define CDG_BORDER_WIDTH 6
40#define CDG_BORDER_HEIGHT 12
41
42/// masks
43#define CDG_COMMAND 0x09
44#define CDG_MASK 0x3F
45
46/// instruction codes
47#define CDG_INST_MEMORY_PRESET 1
48#define CDG_INST_BORDER_PRESET 2
49#define CDG_INST_TILE_BLOCK 6
50#define CDG_INST_SCROLL_PRESET 20
51#define CDG_INST_SCROLL_COPY 24
52#define CDG_INST_TRANSPARENT_COL 28
53#define CDG_INST_LOAD_PAL_LO 30
54#define CDG_INST_LOAD_PAL_HIGH 31
55#define CDG_INST_TILE_BLOCK_XOR 38
56
57/// data sizes
58#define CDG_PACKET_SIZE 24
59#define CDG_DATA_SIZE 16
60#define CDG_TILE_HEIGHT 12
61#define CDG_TILE_WIDTH 6
62#define CDG_MINIMUM_PKT_SIZE 6
63#define CDG_MINIMUM_SCROLL_SIZE 3
64#define CDG_HEADER_SIZE 8
65#define CDG_PALETTE_SIZE 16
66
67typedef struct CDGraphicsContext {
68 AVFrame *frame;
69 int hscroll;
70 int vscroll;
71 int transparency;
72} CDGraphicsContext;
73
74static av_cold int cdg_decode_init(AVCodecContext *avctx)
75{
76 CDGraphicsContext *cc = avctx->priv_data;
77
78 cc->frame = av_frame_alloc();
79 if (!cc->frame)
80 return AVERROR(ENOMEM);
81 cc->transparency = -1;
82
83 avctx->width = CDG_FULL_WIDTH;
84 avctx->height = CDG_FULL_HEIGHT;
85 avctx->pix_fmt = AV_PIX_FMT_PAL8;
86
87 return 0;
88}
89
90static void cdg_border_preset(CDGraphicsContext *cc, uint8_t *data)
91{
92 int y;
93 int lsize = cc->frame->linesize[0];
94 uint8_t *buf = cc->frame->data[0];
95 int color = data[0] & 0x0F;
96
97 if (!(data[1] & 0x0F)) {
98 /// fill the top and bottom borders
99 memset(buf, color, CDG_BORDER_HEIGHT * lsize);
100 memset(buf + (CDG_FULL_HEIGHT - CDG_BORDER_HEIGHT) * lsize,
101 color, CDG_BORDER_HEIGHT * lsize);
102
103 /// fill the side borders
104 for (y = CDG_BORDER_HEIGHT; y < CDG_FULL_HEIGHT - CDG_BORDER_HEIGHT; y++) {
105 memset(buf + y * lsize, color, CDG_BORDER_WIDTH);
106 memset(buf + CDG_FULL_WIDTH - CDG_BORDER_WIDTH + y * lsize,
107 color, CDG_BORDER_WIDTH);
108 }
109 }
110}
111
112static void cdg_load_palette(CDGraphicsContext *cc, uint8_t *data, int low)
113{
114 uint8_t r, g, b;
115 uint16_t color;
116 int i;
117 int array_offset = low ? 0 : 8;
118 uint32_t *palette = (uint32_t *) cc->frame->data[1];
119
120 for (i = 0; i < 8; i++) {
121 color = (data[2 * i] << 6) + (data[2 * i + 1] & 0x3F);
122 r = ((color >> 8) & 0x000F) * 17;
123 g = ((color >> 4) & 0x000F) * 17;
124 b = ((color ) & 0x000F) * 17;
125 palette[i + array_offset] = 0xFFU << 24 | r << 16 | g << 8 | b;
126 if (cc->transparency >= 0)
127 palette[cc->transparency] &= 0xFFFFFF;
128 }
129 cc->frame->palette_has_changed = 1;
130}
131
132static int cdg_tile_block(CDGraphicsContext *cc, uint8_t *data, int b)
133{
134 unsigned ci, ri;
135 int color;
136 int x, y;
137 int ai;
138 int stride = cc->frame->linesize[0];
139 uint8_t *buf = cc->frame->data[0];
140
141 ri = (data[2] & 0x1F) * CDG_TILE_HEIGHT + cc->vscroll;
142 ci = (data[3] & 0x3F) * CDG_TILE_WIDTH + cc->hscroll;
143
144 if (ri > (CDG_FULL_HEIGHT - CDG_TILE_HEIGHT))
145 return AVERROR(EINVAL);
146 if (ci > (CDG_FULL_WIDTH - CDG_TILE_WIDTH))
147 return AVERROR(EINVAL);
148
149 for (y = 0; y < CDG_TILE_HEIGHT; y++) {
150 for (x = 0; x < CDG_TILE_WIDTH; x++) {
151 if (!((data[4 + y] >> (5 - x)) & 0x01))
152 color = data[0] & 0x0F;
153 else
154 color = data[1] & 0x0F;
155
156 ai = ci + x + (stride * (ri + y));
157 if (b)
158 color ^= buf[ai];
159 buf[ai] = color;
160 }
161 }
162
163 return 0;
164}
165
166#define UP 2
167#define DOWN 1
168#define LEFT 2
169#define RIGHT 1
170
171static void cdg_copy_rect_buf(int out_tl_x, int out_tl_y, uint8_t *out,
172 int in_tl_x, int in_tl_y, uint8_t *in,
173 int w, int h, int stride)
174{
175 int y;
176
177 in += in_tl_x + in_tl_y * stride;
178 out += out_tl_x + out_tl_y * stride;
179 for (y = 0; y < h; y++)
180 memcpy(out + y * stride, in + y * stride, w);
181}
182
183static void cdg_fill_rect_preset(int tl_x, int tl_y, uint8_t *out,
184 int color, int w, int h, int stride)
185{
186 int y;
187
188 for (y = tl_y; y < tl_y + h; y++)
189 memset(out + tl_x + y * stride, color, w);
190}
191
192static void cdg_fill_wrapper(int out_tl_x, int out_tl_y, uint8_t *out,
193 int in_tl_x, int in_tl_y, uint8_t *in,
194 int color, int w, int h, int stride, int roll)
195{
196 if (roll) {
197 cdg_copy_rect_buf(out_tl_x, out_tl_y, out, in_tl_x, in_tl_y,
198 in, w, h, stride);
199 } else {
200 cdg_fill_rect_preset(out_tl_x, out_tl_y, out, color, w, h, stride);
201 }
202}
203
204static void cdg_scroll(CDGraphicsContext *cc, uint8_t *data,
205 AVFrame *new_frame, int roll_over)
206{
207 int color;
208 int hscmd, h_off, hinc, vscmd, v_off, vinc;
209 int y;
210 int stride = cc->frame->linesize[0];
211 uint8_t *in = cc->frame->data[0];
212 uint8_t *out = new_frame->data[0];
213
214 color = data[0] & 0x0F;
215 hscmd = (data[1] & 0x30) >> 4;
216 vscmd = (data[2] & 0x30) >> 4;
217
218 h_off = FFMIN(data[1] & 0x07, CDG_BORDER_WIDTH - 1);
219 v_off = FFMIN(data[2] & 0x0F, CDG_BORDER_HEIGHT - 1);
220
221 /// find the difference and save the offset for cdg_tile_block usage
222 hinc = h_off - cc->hscroll;
223 vinc = v_off - cc->vscroll;
224 cc->hscroll = h_off;
225 cc->vscroll = v_off;
226
227 if (vscmd == UP)
228 vinc -= 12;
229 if (vscmd == DOWN)
230 vinc += 12;
231 if (hscmd == LEFT)
232 hinc -= 6;
233 if (hscmd == RIGHT)
234 hinc += 6;
235
236 if (!hinc && !vinc)
237 return;
238
239 memcpy(new_frame->data[1], cc->frame->data[1], CDG_PALETTE_SIZE * 4);
240
241 for (y = FFMAX(0, vinc); y < FFMIN(CDG_FULL_HEIGHT + vinc, CDG_FULL_HEIGHT); y++)
242 memcpy(out + FFMAX(0, hinc) + stride * y,
243 in + FFMAX(0, hinc) - hinc + (y - vinc) * stride,
244 FFMIN(stride + hinc, stride));
245
246 if (vinc > 0)
247 cdg_fill_wrapper(0, 0, out,
248 0, CDG_FULL_HEIGHT - vinc, in, color,
249 stride, vinc, stride, roll_over);
250 else if (vinc < 0)
251 cdg_fill_wrapper(0, CDG_FULL_HEIGHT + vinc, out,
252 0, 0, in, color,
253 stride, -1 * vinc, stride, roll_over);
254
255 if (hinc > 0)
256 cdg_fill_wrapper(0, 0, out,
257 CDG_FULL_WIDTH - hinc, 0, in, color,
258 hinc, CDG_FULL_HEIGHT, stride, roll_over);
259 else if (hinc < 0)
260 cdg_fill_wrapper(CDG_FULL_WIDTH + hinc, 0, out,
261 0, 0, in, color,
262 -1 * hinc, CDG_FULL_HEIGHT, stride, roll_over);
263
264}
265
266static int cdg_decode_frame(AVCodecContext *avctx,
267 void *data, int *got_frame, AVPacket *avpkt)
268{
269 GetByteContext gb;
270 int buf_size = avpkt->size;
271 int ret;
272 uint8_t command, inst;
273 uint8_t cdg_data[CDG_DATA_SIZE] = {0};
274 AVFrame *frame = data;
275 CDGraphicsContext *cc = avctx->priv_data;
276
277 if (buf_size < CDG_MINIMUM_PKT_SIZE) {
278 av_log(avctx, AV_LOG_ERROR, "buffer too small for decoder\n");
279 return AVERROR(EINVAL);
280 }
281 if (buf_size > CDG_HEADER_SIZE + CDG_DATA_SIZE) {
282 av_log(avctx, AV_LOG_ERROR, "buffer too big for decoder\n");
283 return AVERROR(EINVAL);
284 }
285
286 bytestream2_init(&gb, avpkt->data, avpkt->size);
287
288 if ((ret = ff_reget_buffer(avctx, cc->frame)) < 0)
289 return ret;
290 if (!avctx->frame_number) {
291 memset(cc->frame->data[0], 0, cc->frame->linesize[0] * avctx->height);
292 memset(cc->frame->data[1], 0, AVPALETTE_SIZE);
293 }
294
295 command = bytestream2_get_byte(&gb);
296 inst = bytestream2_get_byte(&gb);
297 inst &= CDG_MASK;
298 bytestream2_skip(&gb, 2);
299 bytestream2_get_buffer(&gb, cdg_data, sizeof(cdg_data));
300
301 if ((command & CDG_MASK) == CDG_COMMAND) {
302 switch (inst) {
303 case CDG_INST_MEMORY_PRESET:
304 if (!(cdg_data[1] & 0x0F))
305 memset(cc->frame->data[0], cdg_data[0] & 0x0F,
306 cc->frame->linesize[0] * CDG_FULL_HEIGHT);
307 break;
308 case CDG_INST_LOAD_PAL_LO:
309 case CDG_INST_LOAD_PAL_HIGH:
310 if (buf_size - CDG_HEADER_SIZE < CDG_DATA_SIZE) {
311 av_log(avctx, AV_LOG_ERROR, "buffer too small for loading palette\n");
312 return AVERROR(EINVAL);
313 }
314
315 cdg_load_palette(cc, cdg_data, inst == CDG_INST_LOAD_PAL_LO);
316 break;
317 case CDG_INST_BORDER_PRESET:
318 cdg_border_preset(cc, cdg_data);
319 break;
320 case CDG_INST_TILE_BLOCK_XOR:
321 case CDG_INST_TILE_BLOCK:
322 if (buf_size - CDG_HEADER_SIZE < CDG_DATA_SIZE) {
323 av_log(avctx, AV_LOG_ERROR, "buffer too small for drawing tile\n");
324 return AVERROR(EINVAL);
325 }
326
327 ret = cdg_tile_block(cc, cdg_data, inst == CDG_INST_TILE_BLOCK_XOR);
328 if (ret) {
329 av_log(avctx, AV_LOG_ERROR, "tile is out of range\n");
330 return ret;
331 }
332 break;
333 case CDG_INST_SCROLL_PRESET:
334 case CDG_INST_SCROLL_COPY:
335 if (buf_size - CDG_HEADER_SIZE < CDG_MINIMUM_SCROLL_SIZE) {
336 av_log(avctx, AV_LOG_ERROR, "buffer too small for scrolling\n");
337 return AVERROR(EINVAL);
338 }
339
340 if ((ret = ff_get_buffer(avctx, frame, AV_GET_BUFFER_FLAG_REF)) < 0)
341 return ret;
342
343 cdg_scroll(cc, cdg_data, frame, inst == CDG_INST_SCROLL_COPY);
344 av_frame_unref(cc->frame);
345 ret = av_frame_ref(cc->frame, frame);
346 if (ret < 0)
347 return ret;
348 break;
349 case CDG_INST_TRANSPARENT_COL:
350 cc->transparency = cdg_data[0] & 0xF;
351 break;
352 default:
353 break;
354 }
355
356 if (!frame->data[0]) {
357 ret = av_frame_ref(frame, cc->frame);
358 if (ret < 0)
359 return ret;
360 }
361 *got_frame = 1;
362 } else {
363 *got_frame = 0;
364 }
365
366 return avpkt->size;
367}
368
369static av_cold int cdg_decode_end(AVCodecContext *avctx)
370{
371 CDGraphicsContext *cc = avctx->priv_data;
372
373 av_frame_free(&cc->frame);
374
375 return 0;
376}
377
378AVCodec ff_cdgraphics_decoder = {
379 .name = "cdgraphics",
380 .long_name = NULL_IF_CONFIG_SMALL("CD Graphics video"),
381 .type = AVMEDIA_TYPE_VIDEO,
382 .id = AV_CODEC_ID_CDGRAPHICS,
383 .priv_data_size = sizeof(CDGraphicsContext),
384 .init = cdg_decode_init,
385 .close = cdg_decode_end,
386 .decode = cdg_decode_frame,
387 .capabilities = AV_CODEC_CAP_DR1,
388};
389
generated by cgit at 2024-05-17 01:48:30 (GMT)