gzdoom/snes_spc/demo/save_state.c

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/* Loads "test.spc", skips 5 seconds, saves exact emulator state to "state.bin",
hen records 5 seconds to "first.wav". When run again, loads this state back into
emulator and records 5 seconds to "second.wav". These two wave files should
be identical.
Usage: save_state [test.spc]
*/
#include "snes_spc/spc.h"
#include "wave_writer.h"
#include "demo_util.h" /* error(), load_file() */
static SNES_SPC* snes_spc;
void record_wav( const char* path, int secs )
{
/* Start writing wave file */
wave_open( spc_sample_rate, path );
wave_enable_stereo();
while ( wave_sample_count() < secs * spc_sample_rate * 2 )
{
/* Play into buffer */
#define BUF_SIZE 2048
short buf [BUF_SIZE];
error( spc_play( snes_spc, BUF_SIZE, buf ) );
wave_write( buf, BUF_SIZE );
}
wave_close();
}
void state_save( unsigned char** out, void* in, size_t size )
{
memcpy( *out, in, size );
*out += size;
}
void make_save_state( const char* path )
{
/* Load SPC */
long spc_size;
void* spc = load_file( path, &spc_size );
error( spc_load_spc( snes_spc, spc, spc_size ) );
free( spc );
spc_clear_echo( snes_spc );
/* Skip several seconds */
error( spc_play( snes_spc, 5 * spc_sample_rate * 2, 0 ) );
/* Save state to file */
{
static unsigned char state [spc_state_size]; /* buffer large enough for data */
unsigned char* out = state;
spc_copy_state( snes_spc, &out, state_save );
write_file( "state.bin", state, out - state );
}
record_wav( "first.wav", 5 );
}
void state_load( unsigned char** in, void* out, size_t size )
{
memcpy( out, *in, size );
*in += size;
}
void use_save_state()
{
/* Load state into memory */
long state_size;
unsigned char* state = load_file( "state.bin", &state_size );
/* Load into emulator */
unsigned char* in = state;
spc_copy_state( snes_spc, &in, state_load );
assert( in - state <= state_size ); /* be sure it didn't read past end */
record_wav( "second.wav", 5 );
}
int file_exists( const char* path )
{
FILE* file = fopen( path, "rb" );
if ( !file )
return 0;
fclose( file );
return 1;
}
int main( int argc, char** argv )
{
snes_spc = spc_new();
if ( !snes_spc ) error( "Out of memory" );
/* Make new state if it doesn't exist, otherwise load it and
record to wave file */
if ( !file_exists( "state.bin" ) )
make_save_state( (argc > 1) ? argv [1] : "test.spc" );
else
use_save_state();
spc_delete( snes_spc );
return 0;
}