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/* Measures performance of blitter, useful for improving a custom blitter.
NOTE: This assumes that the process is getting 100% CPU time; you might need to
arrange for this or else the performance will be reported lower than it really is. */
#include "nes_ntsc.h"
#include <stdlib.h>
#include <stdio.h>
#include <time.h>
enum { in_width = 256 };
enum { in_height = 240 };
enum { out_width = NES_NTSC_OUT_WIDTH( in_width ) };
enum { out_height = in_height };
struct data_t
{
nes_ntsc_t ntsc;
unsigned char in [ in_height] [ in_width];
unsigned short out [out_height] [out_width];
};
static int time_blitter( void );
int main()
{
struct data_t* data = (struct data_t*) malloc( sizeof *data );
if ( data )
{
/* fill with random pixel data */
int y;
for ( y = 0; y < in_height; y++ )
{
int x;
for ( x = 0; x < in_width; x++ )
data->in [y] [x] = rand() >> 4 & 0x1F;
}
printf( "Timing nes_ntsc...\n" );
fflush( stdout );
nes_ntsc_init( &data->ntsc, 0 );
/* measure frame rate */
while ( time_blitter() )
{
nes_ntsc_blit( &data->ntsc, data->in [0], in_width, 0,
in_width, in_height, data->out [0], sizeof data->out [0] );
}
free( data );
}
getchar();
return 0;
}
static int time_blitter( void )
{
int const duration = 4; /* seconds */
static clock_t end_time;
static int count;
if ( !count )
{
clock_t time = clock();
while ( clock() == time ) { }
if ( clock() - time > CLOCKS_PER_SEC )
{
/* clock increments less-often than once every second */
printf( "Insufficient time resolution\n" );
return 0;
}
end_time = clock() + CLOCKS_PER_SEC * duration;
}
else if ( clock() >= end_time )
{
int rate = count / duration;
printf( "Performance: %d frames per second, which would use %d%% CPU at 60 FPS\n",
rate, 60 * 100 / rate );
return 0;
}
count++;
return 1;
}
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