ref: 817945120f025fcf8d90222bb767dafb0f847e5d
dir: /opl/examples/droplay.c/
// // Copyright(C) 2005-2014 Simon Howard // // 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. // // DESCRIPTION: // Demonstration program for OPL library to play back DRO // format files. // #include <stdio.h> #include <stdlib.h> #include <string.h> #include "SDL.h" #include "opl.h" #define HEADER_STRING "DBRAWOPL" #define ADLIB_PORT 0x388 void WriteReg(unsigned int reg, unsigned int val) { int i; // This was recorded from an OPL2, but we are probably playing // back on an OPL3, so we need to enable the original OPL2 // channels. Doom does this already, but other games don't. if ((reg & 0xf0) == OPL_REGS_FEEDBACK) { val |= 0x30; } OPL_WritePort(OPL_REGISTER_PORT, reg); for (i=0; i<6; ++i) { OPL_ReadPort(OPL_REGISTER_PORT); } OPL_WritePort(OPL_DATA_PORT, val); for (i=0; i<35; ++i) { OPL_ReadPort(OPL_REGISTER_PORT); } } void ClearAllRegs(void) { int i; for (i=0; i<=0xff; ++i) { WriteReg(i, 0x00); } } void Init(void) { if (SDL_Init(SDL_INIT_TIMER) < 0) { fprintf(stderr, "Unable to initialise SDL timer\n"); exit(-1); } if (!OPL_Init(ADLIB_PORT)) { fprintf(stderr, "Unable to initialise OPL layer\n"); exit(-1); } } void Shutdown(void) { OPL_Shutdown(); } struct timer_data { int running; FILE *fstream; }; void TimerCallback(void *data) { struct timer_data *timer_data = data; int delay; if (!timer_data->running) { return; } // Read data until we must make a delay. for (;;) { int reg, val; // End of file? if (feof(timer_data->fstream)) { timer_data->running = 0; return; } reg = fgetc(timer_data->fstream); val = fgetc(timer_data->fstream); // Register value of 0 or 1 indicates a delay. if (reg == 0x00) { delay = val; break; } else if (reg == 0x01) { val |= (fgetc(timer_data->fstream) << 8); delay = val; break; } else { WriteReg(reg, val); } } // Schedule the next timer callback. OPL_SetCallback(delay * OPL_MS, TimerCallback, timer_data); } void PlayFile(char *filename) { struct timer_data timer_data; int running; char buf[8]; timer_data.fstream = fopen(filename, "rb"); if (timer_data.fstream == NULL) { fprintf(stderr, "Failed to open %s\n", filename); exit(-1); } if (fread(buf, 1, 8, timer_data.fstream) < 8) { fprintf(stderr, "failed to read raw OPL header\n"); exit(-1); } if (strncmp(buf, HEADER_STRING, 8) != 0) { fprintf(stderr, "Raw OPL header not found\n"); exit(-1); } fseek(timer_data.fstream, 28, SEEK_SET); timer_data.running = 1; // Start callback loop sequence. OPL_SetCallback(0, TimerCallback, &timer_data); // Sleep until the playback finishes. do { OPL_Lock(); running = timer_data.running; OPL_Unlock(); SDL_Delay(100 * OPL_MS); } while (running); fclose(timer_data.fstream); } int main(int argc, char *argv[]) { if (argc < 2) { printf("Usage: %s <filename>\n", argv[0]); exit(-1); } Init(); PlayFile(argv[1]); ClearAllRegs(); Shutdown(); return 0; }