101 lines
3.3 KiB
C++
101 lines
3.3 KiB
C++
/**
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* Furnace Tracker - multi-system chiptune tracker
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* Copyright (C) 2021-2024 tildearrow and contributors
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*/
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#include "fileOpsCommon.h"
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class DivEngine;
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//PDX 8-bit OKI ADPCM sample bank
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/* File format
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The file starts with a header with 96 8-byte pairs, with each pair containing offset and length of ADPCM data chunks for each note value, like so:
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[[byte pointer to sample in file -- 32-bit unsigned integer (4 bytes)] [empty: $0000 -- 16-bit integer] [length of sample, amount in bytes -- 16-bit unsigned integer] ×96] [ADPCM data] EOF
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The first sample (1) is mapped to 0x80 (= the lowest note within MXDRV) and the last sample (96) is mapped to 0xDF (= the highest note within MXDRV).
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Samples are encoded in 4-bit OKI ADPCM encoded nibbles, where each byte contains 2 nibbles: [nibble 2 << 4 || nibble 1]
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Unfortunately, sample rates for each samples are not defined within the .PDX file and have to be set manually with the appropriate command for that at play-time */
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#define PDX_BANK_SIZE 96
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#define PDX_SAMPLE_RATE 16000
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typedef struct
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{
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unsigned int start_pointer;
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unsigned short sample_length;
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} PDX_HEADER;
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#define UNUSED(x) (void)(x)
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void DivEngine::loadPDX(SafeReader& reader, std::vector<DivSample*>& ret, String& stripPath)
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{
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try
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{
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reader.seek(0, SEEK_SET);
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PDX_HEADER headers[PDX_BANK_SIZE];
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for(int i = 0; i < PDX_BANK_SIZE; i++)
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{
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headers[i].start_pointer = (unsigned int)reader.readI_BE();
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unsigned short empty = (unsigned short)reader.readS_BE(); //skip 1st 2 bytes
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UNUSED(empty);
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headers[i].sample_length = (unsigned short)reader.readS_BE();
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}
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for(int i = 0; i < PDX_BANK_SIZE; i++)
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{
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if(headers[i].start_pointer != 0 && headers[i].sample_length != 0)
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{
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DivSample* s = new DivSample;
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s->rate = PDX_SAMPLE_RATE;
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s->centerRate = PDX_SAMPLE_RATE;
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s->depth = DIV_SAMPLE_DEPTH_VOX;
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s->init(headers[i].sample_length * 2);
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reader.seek((int)headers[i].start_pointer, SEEK_SET);
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int sample_pos = 0;
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for(unsigned short j = 0; j < headers[i].sample_length; j++)
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{
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unsigned char curr_byte = (unsigned char)reader.readC();
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curr_byte = (curr_byte << 4) | (curr_byte >> 4);
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s->dataVOX[sample_pos] = curr_byte;
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sample_pos++;
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}
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ret.push_back(s);
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logI("pdx: start %d len %d", headers[i].start_pointer, headers[i].sample_length);
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}
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}
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}
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catch (EndOfFileException& e)
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{
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lastError=_("premature end of file");
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logE("premature end of file");
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}
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} |