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Diffstat (limited to 'opl/examples/droplay.c')
| -rw-r--r-- | opl/examples/droplay.c | 217 |
1 files changed, 217 insertions, 0 deletions
diff --git a/opl/examples/droplay.c b/opl/examples/droplay.c new file mode 100644 index 00000000..36f5c3c0 --- /dev/null +++ b/opl/examples/droplay.c @@ -0,0 +1,217 @@ +// Emacs style mode select -*- C++ -*- +//----------------------------------------------------------------------------- +// +// Copyright(C) 2009 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. +// +// 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., 59 Temple Place - Suite 330, Boston, MA +// 02111-1307, USA. +// +// DESCRIPTION: +// Demonstration program for OPL library to play back DRO +// format files. +// +//----------------------------------------------------------------------------- + + +#include <stdio.h> +#include <stdlib.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, 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); + } 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; +} + |