| 1 | /***************************************************************************\r |
| 2 | adsr.c - description\r |
| 3 | -------------------\r |
| 4 | begin : Wed May 15 2002\r |
| 5 | copyright : (C) 2002 by Pete Bernert\r |
| 6 | email : BlackDove@addcom.de\r |
| 7 | ***************************************************************************/\r |
| 8 | /***************************************************************************\r |
| 9 | * *\r |
| 10 | * This program is free software; you can redistribute it and/or modify *\r |
| 11 | * it under the terms of the GNU General Public License as published by *\r |
| 12 | * the Free Software Foundation; either version 2 of the License, or *\r |
| 13 | * (at your option) any later version. See also the license.txt file for *\r |
| 14 | * additional informations. *\r |
| 15 | * *\r |
| 16 | ***************************************************************************/\r |
| 17 | \r |
| 18 | #include "stdafx.h"\r |
| 19 | \r |
| 20 | #define _IN_ADSR\r |
| 21 | \r |
| 22 | // will be included from spu.c\r |
| 23 | #ifdef _IN_SPU\r |
| 24 | \r |
| 25 | ////////////////////////////////////////////////////////////////////////\r |
| 26 | // ADSR func\r |
| 27 | ////////////////////////////////////////////////////////////////////////\r |
| 28 | \r |
| 29 | static int RateTableAdd[128];\r |
| 30 | static int RateTableSub[128];\r |
| 31 | \r |
| 32 | void InitADSR(void) // INIT ADSR\r |
| 33 | {\r |
| 34 | int lcv, denom;\r |
| 35 | \r |
| 36 | // Optimize table - Dr. Hell ADSR math\r |
| 37 | for (lcv = 0; lcv < 48; lcv++)\r |
| 38 | {\r |
| 39 | RateTableAdd[lcv] = (7 - (lcv&3)) << (11 + 16 - (lcv >> 2));\r |
| 40 | RateTableSub[lcv] = (-8 + (lcv&3)) << (11 + 16 - (lcv >> 2));\r |
| 41 | }\r |
| 42 | \r |
| 43 | for (; lcv < 128; lcv++)\r |
| 44 | {\r |
| 45 | denom = 1 << ((lcv>>2) - 11);\r |
| 46 | \r |
| 47 | RateTableAdd[lcv] = ((7 - (lcv&3)) << 16) / denom;\r |
| 48 | RateTableSub[lcv] = ((-8 + (lcv&3)) << 16) / denom;\r |
| 49 | \r |
| 50 | // XXX: this is wrong, we need more bits..\r |
| 51 | if (RateTableAdd[lcv] == 0)\r |
| 52 | RateTableAdd[lcv] = 1;\r |
| 53 | }\r |
| 54 | }\r |
| 55 | \r |
| 56 | ////////////////////////////////////////////////////////////////////////\r |
| 57 | \r |
| 58 | INLINE void StartADSR(int ch) // MIX ADSR\r |
| 59 | {\r |
| 60 | s_chan[ch].ADSRX.State=0; // and init some adsr vars\r |
| 61 | s_chan[ch].ADSRX.EnvelopeVol=0;\r |
| 62 | }\r |
| 63 | \r |
| 64 | ////////////////////////////////////////////////////////////////////////\r |
| 65 | \r |
| 66 | static void MixADSR(int ch, int ns, int ns_to) // MIX ADSR\r |
| 67 | {\r |
| 68 | int EnvelopeVol = s_chan[ch].ADSRX.EnvelopeVol;\r |
| 69 | int val, rto, level;\r |
| 70 | \r |
| 71 | if (s_chan[ch].bStop) // should be stopped:\r |
| 72 | { // do release\r |
| 73 | val = RateTableSub[s_chan[ch].ADSRX.ReleaseRate * 4];\r |
| 74 | \r |
| 75 | if (s_chan[ch].ADSRX.ReleaseModeExp)\r |
| 76 | {\r |
| 77 | for (; ns < ns_to; ns++)\r |
| 78 | {\r |
| 79 | EnvelopeVol += ((long long)val * EnvelopeVol) >> (15+16);\r |
| 80 | if (EnvelopeVol <= 0)\r |
| 81 | break;\r |
| 82 | \r |
| 83 | ChanBuf[ns] *= EnvelopeVol >> 21;\r |
| 84 | ChanBuf[ns] >>= 10;\r |
| 85 | }\r |
| 86 | }\r |
| 87 | else\r |
| 88 | {\r |
| 89 | for (; ns < ns_to; ns++)\r |
| 90 | {\r |
| 91 | EnvelopeVol += val;\r |
| 92 | if (EnvelopeVol <= 0)\r |
| 93 | break;\r |
| 94 | \r |
| 95 | ChanBuf[ns] *= EnvelopeVol >> 21;\r |
| 96 | ChanBuf[ns] >>= 10;\r |
| 97 | }\r |
| 98 | }\r |
| 99 | \r |
| 100 | if (EnvelopeVol <= 0)\r |
| 101 | goto stop;\r |
| 102 | \r |
| 103 | goto done;\r |
| 104 | }\r |
| 105 | \r |
| 106 | switch (s_chan[ch].ADSRX.State)\r |
| 107 | {\r |
| 108 | case 0: // -> attack\r |
| 109 | rto = 0;\r |
| 110 | if (s_chan[ch].ADSRX.AttackModeExp && EnvelopeVol >= 0x60000000)\r |
| 111 | rto = 8;\r |
| 112 | val = RateTableAdd[s_chan[ch].ADSRX.AttackRate + rto];\r |
| 113 | \r |
| 114 | for (; ns < ns_to; ns++)\r |
| 115 | {\r |
| 116 | EnvelopeVol += val;\r |
| 117 | if (EnvelopeVol < 0)\r |
| 118 | break;\r |
| 119 | \r |
| 120 | ChanBuf[ns] *= EnvelopeVol >> 21;\r |
| 121 | ChanBuf[ns] >>= 10;\r |
| 122 | }\r |
| 123 | \r |
| 124 | if (EnvelopeVol < 0) // overflow\r |
| 125 | {\r |
| 126 | EnvelopeVol = 0x7fffffff;\r |
| 127 | s_chan[ch].ADSRX.State = 1;\r |
| 128 | ns++; // sample is good already\r |
| 129 | goto decay;\r |
| 130 | }\r |
| 131 | break;\r |
| 132 | \r |
| 133 | //--------------------------------------------------//\r |
| 134 | decay:\r |
| 135 | case 1: // -> decay\r |
| 136 | val = RateTableSub[s_chan[ch].ADSRX.DecayRate * 4];\r |
| 137 | level = s_chan[ch].ADSRX.SustainLevel;\r |
| 138 | \r |
| 139 | for (; ns < ns_to; )\r |
| 140 | {\r |
| 141 | EnvelopeVol += ((long long)val * EnvelopeVol) >> (15+16);\r |
| 142 | if (EnvelopeVol < 0)\r |
| 143 | EnvelopeVol = 0;\r |
| 144 | \r |
| 145 | ChanBuf[ns] *= EnvelopeVol >> 21;\r |
| 146 | ChanBuf[ns] >>= 10;\r |
| 147 | ns++;\r |
| 148 | \r |
| 149 | if (((EnvelopeVol >> 27) & 0xf) <= level)\r |
| 150 | {\r |
| 151 | s_chan[ch].ADSRX.State = 2;\r |
| 152 | goto sustain;\r |
| 153 | }\r |
| 154 | }\r |
| 155 | break;\r |
| 156 | \r |
| 157 | //--------------------------------------------------//\r |
| 158 | sustain:\r |
| 159 | case 2: // -> sustain\r |
| 160 | if (s_chan[ch].ADSRX.SustainIncrease)\r |
| 161 | {\r |
| 162 | if (EnvelopeVol >= 0x7fff0000)\r |
| 163 | break;\r |
| 164 | \r |
| 165 | rto = 0;\r |
| 166 | if (s_chan[ch].ADSRX.SustainModeExp && EnvelopeVol >= 0x60000000)\r |
| 167 | rto = 8;\r |
| 168 | val = RateTableAdd[s_chan[ch].ADSRX.SustainRate + rto];\r |
| 169 | \r |
| 170 | for (; ns < ns_to; ns++)\r |
| 171 | {\r |
| 172 | EnvelopeVol += val;\r |
| 173 | if ((unsigned int)EnvelopeVol >= 0x7fe00000)\r |
| 174 | {\r |
| 175 | EnvelopeVol = 0x7fffffff;\r |
| 176 | break;\r |
| 177 | }\r |
| 178 | \r |
| 179 | ChanBuf[ns] *= EnvelopeVol >> 21;\r |
| 180 | ChanBuf[ns] >>= 10;\r |
| 181 | }\r |
| 182 | }\r |
| 183 | else\r |
| 184 | {\r |
| 185 | val = RateTableSub[s_chan[ch].ADSRX.SustainRate];\r |
| 186 | if (s_chan[ch].ADSRX.SustainModeExp)\r |
| 187 | {\r |
| 188 | for (; ns < ns_to; ns++)\r |
| 189 | {\r |
| 190 | EnvelopeVol += ((long long)val * EnvelopeVol) >> (15+16);\r |
| 191 | if (EnvelopeVol < 0) \r |
| 192 | goto stop;\r |
| 193 | \r |
| 194 | ChanBuf[ns] *= EnvelopeVol >> 21;\r |
| 195 | ChanBuf[ns] >>= 10;\r |
| 196 | }\r |
| 197 | }\r |
| 198 | else\r |
| 199 | {\r |
| 200 | for (; ns < ns_to; ns++)\r |
| 201 | {\r |
| 202 | EnvelopeVol += val;\r |
| 203 | if (EnvelopeVol < 0) \r |
| 204 | goto stop;\r |
| 205 | \r |
| 206 | ChanBuf[ns] *= EnvelopeVol >> 21;\r |
| 207 | ChanBuf[ns] >>= 10;\r |
| 208 | }\r |
| 209 | }\r |
| 210 | }\r |
| 211 | break;\r |
| 212 | }\r |
| 213 | \r |
| 214 | done:\r |
| 215 | s_chan[ch].ADSRX.EnvelopeVol = EnvelopeVol;\r |
| 216 | return;\r |
| 217 | \r |
| 218 | stop:\r |
| 219 | memset(&ChanBuf[ns], 0, (ns_to - ns) * sizeof(ChanBuf[0]));\r |
| 220 | s_chan[ch].ADSRX.EnvelopeVol = 0;\r |
| 221 | dwChannelOn &= ~(1<<ch);\r |
| 222 | }\r |
| 223 | \r |
| 224 | #endif\r |
| 225 | \r |
| 226 | /*\r |
| 227 | James Higgs ADSR investigations:\r |
| 228 | \r |
| 229 | PSX SPU Envelope Timings\r |
| 230 | ~~~~~~~~~~~~~~~~~~~~~~~~\r |
| 231 | \r |
| 232 | First, here is an extract from doomed's SPU doc, which explains the basics\r |
| 233 | of the SPU "volume envelope": \r |
| 234 | \r |
| 235 | *** doomed doc extract start ***\r |
| 236 | \r |
| 237 | --------------------------------------------------------------------------\r |
| 238 | Voices.\r |
| 239 | --------------------------------------------------------------------------\r |
| 240 | The SPU has 24 hardware voices. These voices can be used to reproduce sample\r |
| 241 | data, noise or can be used as frequency modulator on the next voice.\r |
| 242 | Each voice has it's own programmable ADSR envelope filter. The main volume\r |
| 243 | can be programmed independently for left and right output.\r |
| 244 | \r |
| 245 | The ADSR envelope filter works as follows:\r |
| 246 | Ar = Attack rate, which specifies the speed at which the volume increases\r |
| 247 | from zero to it's maximum value, as soon as the note on is given. The\r |
| 248 | slope can be set to lineair or exponential.\r |
| 249 | Dr = Decay rate specifies the speed at which the volume decreases to the\r |
| 250 | sustain level. Decay is always decreasing exponentially.\r |
| 251 | Sl = Sustain level, base level from which sustain starts.\r |
| 252 | Sr = Sustain rate is the rate at which the volume of the sustained note\r |
| 253 | increases or decreases. This can be either lineair or exponential.\r |
| 254 | Rr = Release rate is the rate at which the volume of the note decreases\r |
| 255 | as soon as the note off is given.\r |
| 256 | \r |
| 257 | lvl |\r |
| 258 | ^ | /\Dr __\r |
| 259 | Sl _| _ / _ \__--- \\r |
| 260 | | / ---__ \ Rr\r |
| 261 | | /Ar Sr \ \\r |
| 262 | | / \\\r |
| 263 | |/___________________\________\r |
| 264 | ->time\r |
| 265 | \r |
| 266 | The overal volume can also be set to sweep up or down lineairly or\r |
| 267 | exponentially from it's current value. This can be done seperately\r |
| 268 | for left and right.\r |
| 269 | \r |
| 270 | Relevant SPU registers:\r |
| 271 | -------------------------------------------------------------\r |
| 272 | $1f801xx8 Attack/Decay/Sustain level\r |
| 273 | bit |0f|0e 0d 0c 0b 0a 09 08|07 06 05 04|03 02 01 00|\r |
| 274 | desc.|Am| Ar |Dr |Sl |\r |
| 275 | \r |
| 276 | Am 0 Attack mode Linear\r |
| 277 | 1 Exponential\r |
| 278 | \r |
| 279 | Ar 0-7f attack rate\r |
| 280 | Dr 0-f decay rate\r |
| 281 | Sl 0-f sustain level\r |
| 282 | -------------------------------------------------------------\r |
| 283 | $1f801xxa Sustain rate, Release Rate.\r |
| 284 | bit |0f|0e|0d|0c 0b 0a 09 08 07 06|05|04 03 02 01 00|\r |
| 285 | desc.|Sm|Sd| 0| Sr |Rm|Rr |\r |
| 286 | \r |
| 287 | Sm 0 sustain rate mode linear\r |
| 288 | 1 exponential\r |
| 289 | Sd 0 sustain rate mode increase\r |
| 290 | 1 decrease\r |
| 291 | Sr 0-7f Sustain Rate\r |
| 292 | Rm 0 Linear decrease\r |
| 293 | 1 Exponential decrease\r |
| 294 | Rr 0-1f Release Rate\r |
| 295 | \r |
| 296 | Note: decay mode is always Expontial decrease, and thus cannot\r |
| 297 | be set.\r |
| 298 | -------------------------------------------------------------\r |
| 299 | $1f801xxc Current ADSR volume\r |
| 300 | bit |0f 0e 0d 0c 0b 0a 09 08 07 06 05 04 03 02 01 00|\r |
| 301 | desc.|ADSRvol |\r |
| 302 | \r |
| 303 | ADSRvol Returns the current envelope volume when\r |
| 304 | read.\r |
| 305 | -- James' Note: return range: 0 -> 32767\r |
| 306 | \r |
| 307 | *** doomed doc extract end *** \r |
| 308 | \r |
| 309 | By using a small PSX proggie to visualise the envelope as it was played,\r |
| 310 | the following results for envelope timing were obtained:\r |
| 311 | \r |
| 312 | 1. Attack rate value (linear mode)\r |
| 313 | \r |
| 314 | Attack value range: 0 -> 127\r |
| 315 | \r |
| 316 | Value | 48 | 52 | 56 | 60 | 64 | 68 | 72 | | 80 |\r |
| 317 | -----------------------------------------------------------------\r |
| 318 | Frames | 11 | 21 | 42 | 84 | 169| 338| 676| |2890|\r |
| 319 | \r |
| 320 | Note: frames is no. of PAL frames to reach full volume (100%\r |
| 321 | amplitude)\r |
| 322 | \r |
| 323 | Hmm, noticing that the time taken to reach full volume doubles\r |
| 324 | every time we add 4 to our attack value, we know the equation is\r |
| 325 | of form:\r |
| 326 | frames = k * 2 ^ (value / 4)\r |
| 327 | \r |
| 328 | (You may ponder about envelope generator hardware at this point,\r |
| 329 | or maybe not... :)\r |
| 330 | \r |
| 331 | By substituting some stuff and running some checks, we get:\r |
| 332 | \r |
| 333 | k = 0.00257 (close enuf)\r |
| 334 | \r |
| 335 | therefore,\r |
| 336 | frames = 0.00257 * 2 ^ (value / 4)\r |
| 337 | If you just happen to be writing an emulator, then you can probably\r |
| 338 | use an equation like:\r |
| 339 | \r |
| 340 | %volume_increase_per_tick = 1 / frames\r |
| 341 | \r |
| 342 | \r |
| 343 | ------------------------------------\r |
| 344 | Pete:\r |
| 345 | ms=((1<<(value>>2))*514)/10000\r |
| 346 | ------------------------------------\r |
| 347 | \r |
| 348 | 2. Decay rate value (only has log mode)\r |
| 349 | \r |
| 350 | Decay value range: 0 -> 15\r |
| 351 | \r |
| 352 | Value | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 |\r |
| 353 | ------------------------------------------------\r |
| 354 | frames | | | | | 6 | 12 | 24 | 47 |\r |
| 355 | \r |
| 356 | Note: frames here is no. of PAL frames to decay to 50% volume.\r |
| 357 | \r |
| 358 | formula: frames = k * 2 ^ (value)\r |
| 359 | \r |
| 360 | Substituting, we get: k = 0.00146\r |
| 361 | \r |
| 362 | Further info on logarithmic nature:\r |
| 363 | frames to decay to sustain level 3 = 3 * frames to decay to \r |
| 364 | sustain level 9\r |
| 365 | \r |
| 366 | Also no. of frames to 25% volume = roughly 1.85 * no. of frames to\r |
| 367 | 50% volume.\r |
| 368 | \r |
| 369 | Frag it - just use linear approx.\r |
| 370 | \r |
| 371 | ------------------------------------\r |
| 372 | Pete:\r |
| 373 | ms=((1<<value)*292)/10000\r |
| 374 | ------------------------------------\r |
| 375 | \r |
| 376 | \r |
| 377 | 3. Sustain rate value (linear mode)\r |
| 378 | \r |
| 379 | Sustain rate range: 0 -> 127\r |
| 380 | \r |
| 381 | Value | 48 | 52 | 56 | 60 | 64 | 68 | 72 |\r |
| 382 | -------------------------------------------\r |
| 383 | frames | 9 | 19 | 37 | 74 | 147| 293| 587|\r |
| 384 | \r |
| 385 | Here, frames = no. of PAL frames for volume amplitude to go from 100%\r |
| 386 | to 0% (or vice-versa).\r |
| 387 | \r |
| 388 | Same formula as for attack value, just a different value for k:\r |
| 389 | \r |
| 390 | k = 0.00225\r |
| 391 | \r |
| 392 | ie: frames = 0.00225 * 2 ^ (value / 4)\r |
| 393 | \r |
| 394 | For emulation purposes:\r |
| 395 | \r |
| 396 | %volume_increase_or_decrease_per_tick = 1 / frames\r |
| 397 | \r |
| 398 | ------------------------------------\r |
| 399 | Pete:\r |
| 400 | ms=((1<<(value>>2))*450)/10000\r |
| 401 | ------------------------------------\r |
| 402 | \r |
| 403 | \r |
| 404 | 4. Release rate (linear mode)\r |
| 405 | \r |
| 406 | Release rate range: 0 -> 31\r |
| 407 | \r |
| 408 | Value | 13 | 14 | 15 | 16 | 17 |\r |
| 409 | ---------------------------------------------------------------\r |
| 410 | frames | 18 | 36 | 73 | 146| 292|\r |
| 411 | \r |
| 412 | Here, frames = no. of PAL frames to decay from 100% vol to 0% vol\r |
| 413 | after "note-off" is triggered.\r |
| 414 | \r |
| 415 | Formula: frames = k * 2 ^ (value)\r |
| 416 | \r |
| 417 | And so: k = 0.00223\r |
| 418 | \r |
| 419 | ------------------------------------\r |
| 420 | Pete:\r |
| 421 | ms=((1<<value)*446)/10000\r |
| 422 | ------------------------------------\r |
| 423 | \r |
| 424 | \r |
| 425 | Other notes: \r |
| 426 | \r |
| 427 | Log stuff not figured out. You may get some clues from the "Decay rate"\r |
| 428 | stuff above. For emu purposes it may not be important - use linear\r |
| 429 | approx.\r |
| 430 | \r |
| 431 | To get timings in millisecs, multiply frames by 20.\r |
| 432 | \r |
| 433 | \r |
| 434 | \r |
| 435 | - James Higgs 17/6/2000\r |
| 436 | james7780@yahoo.com\r |
| 437 | \r |
| 438 | //---------------------------------------------------------------\r |
| 439 | \r |
| 440 | OLD adsr mixing according to james' rules... has to be called\r |
| 441 | every one millisecond\r |
| 442 | \r |
| 443 | \r |
| 444 | long v,v2,lT,l1,l2,l3;\r |
| 445 | \r |
| 446 | if(s_chan[ch].bStop) // psx wants to stop? -> release phase\r |
| 447 | {\r |
| 448 | if(s_chan[ch].ADSR.ReleaseVal!=0) // -> release not 0: do release (if 0: stop right now)\r |
| 449 | {\r |
| 450 | if(!s_chan[ch].ADSR.ReleaseVol) // --> release just started? set up the release stuff\r |
| 451 | {\r |
| 452 | s_chan[ch].ADSR.ReleaseStartTime=s_chan[ch].ADSR.lTime;\r |
| 453 | s_chan[ch].ADSR.ReleaseVol=s_chan[ch].ADSR.lVolume;\r |
| 454 | s_chan[ch].ADSR.ReleaseTime = // --> calc how long does it take to reach the wanted sus level\r |
| 455 | (s_chan[ch].ADSR.ReleaseTime*\r |
| 456 | s_chan[ch].ADSR.ReleaseVol)/1024;\r |
| 457 | }\r |
| 458 | // -> NO release exp mode used (yet)\r |
| 459 | v=s_chan[ch].ADSR.ReleaseVol; // -> get last volume\r |
| 460 | lT=s_chan[ch].ADSR.lTime- // -> how much time is past?\r |
| 461 | s_chan[ch].ADSR.ReleaseStartTime;\r |
| 462 | l1=s_chan[ch].ADSR.ReleaseTime;\r |
| 463 | \r |
| 464 | if(lT<l1) // -> we still have to release\r |
| 465 | {\r |
| 466 | v=v-((v*lT)/l1); // --> calc new volume\r |
| 467 | }\r |
| 468 | else // -> release is over: now really stop that sample\r |
| 469 | {v=0;s_chan[ch].bOn=0;s_chan[ch].ADSR.ReleaseVol=0;s_chan[ch].bNoise=0;}\r |
| 470 | }\r |
| 471 | else // -> release IS 0: release at once\r |
| 472 | {\r |
| 473 | v=0;s_chan[ch].bOn=0;s_chan[ch].ADSR.ReleaseVol=0;s_chan[ch].bNoise=0;\r |
| 474 | }\r |
| 475 | }\r |
| 476 | else \r |
| 477 | {//--------------------------------------------------// not in release phase:\r |
| 478 | v=1024;\r |
| 479 | lT=s_chan[ch].ADSR.lTime;\r |
| 480 | l1=s_chan[ch].ADSR.AttackTime;\r |
| 481 | \r |
| 482 | if(lT<l1) // attack\r |
| 483 | { // no exp mode used (yet)\r |
| 484 | // if(s_chan[ch].ADSR.AttackModeExp)\r |
| 485 | // {\r |
| 486 | // v=(v*lT)/l1;\r |
| 487 | // }\r |
| 488 | // else\r |
| 489 | {\r |
| 490 | v=(v*lT)/l1;\r |
| 491 | }\r |
| 492 | if(v==0) v=1;\r |
| 493 | }\r |
| 494 | else // decay\r |
| 495 | { // should be exp, but who cares? ;)\r |
| 496 | l2=s_chan[ch].ADSR.DecayTime;\r |
| 497 | v2=s_chan[ch].ADSR.SustainLevel;\r |
| 498 | \r |
| 499 | lT-=l1;\r |
| 500 | if(lT<l2)\r |
| 501 | {\r |
| 502 | v-=(((v-v2)*lT)/l2);\r |
| 503 | }\r |
| 504 | else // sustain\r |
| 505 | { // no exp mode used (yet)\r |
| 506 | l3=s_chan[ch].ADSR.SustainTime;\r |
| 507 | lT-=l2;\r |
| 508 | if(s_chan[ch].ADSR.SustainModeDec>0)\r |
| 509 | {\r |
| 510 | if(l3!=0) v2+=((v-v2)*lT)/l3;\r |
| 511 | else v2=v;\r |
| 512 | }\r |
| 513 | else\r |
| 514 | {\r |
| 515 | if(l3!=0) v2-=(v2*lT)/l3;\r |
| 516 | else v2=v;\r |
| 517 | }\r |
| 518 | \r |
| 519 | if(v2>v) v2=v;\r |
| 520 | if(v2<=0) {v2=0;s_chan[ch].bOn=0;s_chan[ch].ADSR.ReleaseVol=0;s_chan[ch].bNoise=0;}\r |
| 521 | \r |
| 522 | v=v2;\r |
| 523 | }\r |
| 524 | }\r |
| 525 | }\r |
| 526 | \r |
| 527 | //----------------------------------------------------// \r |
| 528 | // ok, done for this channel, so increase time\r |
| 529 | \r |
| 530 | s_chan[ch].ADSR.lTime+=1; // 1 = 1.020408f ms; \r |
| 531 | \r |
| 532 | if(v>1024) v=1024; // adjust volume\r |
| 533 | if(v<0) v=0; \r |
| 534 | s_chan[ch].ADSR.lVolume=v; // store act volume\r |
| 535 | \r |
| 536 | return v; // return the volume factor\r |
| 537 | */\r |
| 538 | \r |
| 539 | \r |
| 540 | //-----------------------------------------------------------------------------\r |
| 541 | //-----------------------------------------------------------------------------\r |
| 542 | //-----------------------------------------------------------------------------\r |
| 543 | \r |
| 544 | \r |
| 545 | /*\r |
| 546 | -----------------------------------------------------------------------------\r |
| 547 | Neill Corlett\r |
| 548 | Playstation SPU envelope timing notes\r |
| 549 | -----------------------------------------------------------------------------\r |
| 550 | \r |
| 551 | This is preliminary. This may be wrong. But the model described herein fits\r |
| 552 | all of my experimental data, and it's just simple enough to sound right.\r |
| 553 | \r |
| 554 | ADSR envelope level ranges from 0x00000000 to 0x7FFFFFFF internally.\r |
| 555 | The value returned by channel reg 0xC is (envelope_level>>16).\r |
| 556 | \r |
| 557 | Each sample, an increment or decrement value will be added to or\r |
| 558 | subtracted from this envelope level.\r |
| 559 | \r |
| 560 | Create the rate log table. The values double every 4 entries.\r |
| 561 | entry #0 = 4\r |
| 562 | \r |
| 563 | 4, 5, 6, 7,\r |
| 564 | 8,10,12,14,\r |
| 565 | 16,20,24,28, ...\r |
| 566 | \r |
| 567 | entry #40 = 4096...\r |
| 568 | entry #44 = 8192...\r |
| 569 | entry #48 = 16384...\r |
| 570 | entry #52 = 32768...\r |
| 571 | entry #56 = 65536...\r |
| 572 | \r |
| 573 | increments and decrements are in terms of ratelogtable[n]\r |
| 574 | n may exceed the table bounds (plan on n being between -32 and 127).\r |
| 575 | table values are all clipped between 0x00000000 and 0x3FFFFFFF\r |
| 576 | \r |
| 577 | when you "voice on", the envelope is always fully reset.\r |
| 578 | (yes, it may click. the real thing does this too.)\r |
| 579 | \r |
| 580 | envelope level begins at zero.\r |
| 581 | \r |
| 582 | each state happens for at least 1 cycle\r |
| 583 | (transitions are not instantaneous)\r |
| 584 | this may result in some oddness: if the decay rate is uberfast, it will cut\r |
| 585 | the envelope from full down to half in one sample, potentially skipping over\r |
| 586 | the sustain level\r |
| 587 | \r |
| 588 | ATTACK\r |
| 589 | ------\r |
| 590 | - if the envelope level has overflowed past the max, clip to 0x7FFFFFFF and\r |
| 591 | proceed to DECAY.\r |
| 592 | \r |
| 593 | Linear attack mode:\r |
| 594 | - line extends upward to 0x7FFFFFFF\r |
| 595 | - increment per sample is ratelogtable[(Ar^0x7F)-0x10]\r |
| 596 | \r |
| 597 | Logarithmic attack mode:\r |
| 598 | if envelope_level < 0x60000000:\r |
| 599 | - line extends upward to 0x60000000\r |
| 600 | - increment per sample is ratelogtable[(Ar^0x7F)-0x10]\r |
| 601 | else:\r |
| 602 | - line extends upward to 0x7FFFFFFF\r |
| 603 | - increment per sample is ratelogtable[(Ar^0x7F)-0x18]\r |
| 604 | \r |
| 605 | DECAY\r |
| 606 | -----\r |
| 607 | - if ((envelope_level>>27)&0xF) <= Sl, proceed to SUSTAIN.\r |
| 608 | Do not clip to the sustain level.\r |
| 609 | - current line ends at (envelope_level & 0x07FFFFFF)\r |
| 610 | - decrement per sample depends on (envelope_level>>28)&0x7\r |
| 611 | 0: ratelogtable[(4*(Dr^0x1F))-0x18+0]\r |
| 612 | 1: ratelogtable[(4*(Dr^0x1F))-0x18+4]\r |
| 613 | 2: ratelogtable[(4*(Dr^0x1F))-0x18+6]\r |
| 614 | 3: ratelogtable[(4*(Dr^0x1F))-0x18+8]\r |
| 615 | 4: ratelogtable[(4*(Dr^0x1F))-0x18+9]\r |
| 616 | 5: ratelogtable[(4*(Dr^0x1F))-0x18+10]\r |
| 617 | 6: ratelogtable[(4*(Dr^0x1F))-0x18+11]\r |
| 618 | 7: ratelogtable[(4*(Dr^0x1F))-0x18+12]\r |
| 619 | (note that this is the same as the release rate formula, except that\r |
| 620 | decay rates 10-1F aren't possible... those would be slower in theory)\r |
| 621 | \r |
| 622 | SUSTAIN\r |
| 623 | -------\r |
| 624 | - no terminating condition except for voice off\r |
| 625 | - Sd=0 (increase) behavior is identical to ATTACK for both log and linear.\r |
| 626 | - Sd=1 (decrease) behavior:\r |
| 627 | Linear sustain decrease:\r |
| 628 | - line extends to 0x00000000\r |
| 629 | - decrement per sample is ratelogtable[(Sr^0x7F)-0x0F]\r |
| 630 | Logarithmic sustain decrease:\r |
| 631 | - current line ends at (envelope_level & 0x07FFFFFF)\r |
| 632 | - decrement per sample depends on (envelope_level>>28)&0x7\r |
| 633 | 0: ratelogtable[(Sr^0x7F)-0x1B+0]\r |
| 634 | 1: ratelogtable[(Sr^0x7F)-0x1B+4]\r |
| 635 | 2: ratelogtable[(Sr^0x7F)-0x1B+6]\r |
| 636 | 3: ratelogtable[(Sr^0x7F)-0x1B+8]\r |
| 637 | 4: ratelogtable[(Sr^0x7F)-0x1B+9]\r |
| 638 | 5: ratelogtable[(Sr^0x7F)-0x1B+10]\r |
| 639 | 6: ratelogtable[(Sr^0x7F)-0x1B+11]\r |
| 640 | 7: ratelogtable[(Sr^0x7F)-0x1B+12]\r |
| 641 | \r |
| 642 | RELEASE\r |
| 643 | -------\r |
| 644 | - if the envelope level has overflowed to negative, clip to 0 and QUIT.\r |
| 645 | \r |
| 646 | Linear release mode:\r |
| 647 | - line extends to 0x00000000\r |
| 648 | - decrement per sample is ratelogtable[(4*(Rr^0x1F))-0x0C]\r |
| 649 | \r |
| 650 | Logarithmic release mode:\r |
| 651 | - line extends to (envelope_level & 0x0FFFFFFF)\r |
| 652 | - decrement per sample depends on (envelope_level>>28)&0x7\r |
| 653 | 0: ratelogtable[(4*(Rr^0x1F))-0x18+0]\r |
| 654 | 1: ratelogtable[(4*(Rr^0x1F))-0x18+4]\r |
| 655 | 2: ratelogtable[(4*(Rr^0x1F))-0x18+6]\r |
| 656 | 3: ratelogtable[(4*(Rr^0x1F))-0x18+8]\r |
| 657 | 4: ratelogtable[(4*(Rr^0x1F))-0x18+9]\r |
| 658 | 5: ratelogtable[(4*(Rr^0x1F))-0x18+10]\r |
| 659 | 6: ratelogtable[(4*(Rr^0x1F))-0x18+11]\r |
| 660 | 7: ratelogtable[(4*(Rr^0x1F))-0x18+12]\r |
| 661 | \r |
| 662 | -----------------------------------------------------------------------------\r |
| 663 | */\r |
| 664 | \r |
| 665 | // vim:shiftwidth=1:expandtab\r |