void Copy_Chunk( FILE *fp )
{
uint32_t x, y;
unsigned char pixel_data;
/* A copy chunk just has 64000 bytes of data to pop
straight to video memory */
for( y = 0; y < 200; y++ )
{
for( x = 0; x < 320; x++ )
{
fread( &pixel_data, sizeof( unsigned char ), 1, fp );
DB_Fast_Pixel( x, y, pixel_data );
}
}
}
void Copy_Chunk_Ram( uint8_t *file_buffer, uint32_t *file_pos )
{
long x, y;
unsigned char pixel_data;
/* A copy chunk just has 64000 bytes of data to pop
straight to video memory */
for( y = 0; y < 200; y++ )
{
for( x = 0; x < 320; x++ )
{
pixel_data = file_buffer[ (*file_pos)++ ];
DB_Fast_Pixel( x, y, pixel_data );
}
}
} /* End of Copy_Chunk_Ram() */
void Delta_Chunk_Ram( uint8_t *file_buffer, uint32_t *file_pos )
{
unsigned long line_index; /* Number of lines processed */
unsigned long pixel_index = 0; /* Number of pixels processed */
short lines_to_skip; /* Number of lines to skip */
unsigned short number_lines; /* Number of lines encoded for frame */
unsigned char num_packets; /* Number of packets in line */
unsigned long packet_index; /* Index for loop */
unsigned char skip_count; /* Number of xpixels to skip */
char packet_type; /* Type of delta encoding */
unsigned char pixel_data; /* One pixel to put on screen */
unsigned long byte_count; /* Index for loop */
long x, y;
unsigned long i;
unsigned char *temp_buffer;
/* Get the y position we start on */
temp_buffer = (unsigned char *)&lines_to_skip;
for( i = 0; i < sizeof( short ); i++ )
temp_buffer[i] = file_buffer[ (*file_pos)++ ];
/* Get the number of lines encoded */
temp_buffer = (unsigned char *)&number_lines;
for( i = 0; i < sizeof( short ); i++ )
temp_buffer[i] = file_buffer[ (*file_pos)++ ];
x = y = 0;
y += lines_to_skip; /* Move to line lines_to_skip */
for( line_index = 0; line_index < number_lines; line_index++ )
{
num_packets = file_buffer[ (*file_pos)++ ];
for( packet_index = 0; packet_index < num_packets; packet_index++ )
{
/* Get number of x pixels to skip on this packet */
skip_count = file_buffer[ (*file_pos)++ ];
/* Get type of packet encoding */
packet_type = file_buffer[ (*file_pos)++ ];
x += skip_count; /* Add the skip count to our x value */
/* If packet type is positive, copy packet_type
number of pixels from the file to the screen... */
if( packet_type > 0 )
{
for( byte_count = 0; byte_count < (unsigned long)packet_type; byte_count++ )
{
pixel_data = file_buffer[ (*file_pos)++ ];
pixel_index++;
DB_Fast_Pixel( x, y, pixel_data );
x++;
}
}
/* If packet type is negative, take its absolute value,
and replicate one byte from the file packet_type
times */
else
{
packet_type = -packet_type;
pixel_data = file_buffer[ (*file_pos)++ ];
for( byte_count = 0; byte_count < (unsigned long)packet_type; byte_count++ )
{
pixel_index++;
DB_Fast_Pixel( x, y, pixel_data );
x++;
}
} /* End if else */
} /* End for packet index */
y++; /* Move to next line */
x = 0; /* Move to beginning of line */
} /* End for line index */
} /* End of Delta_Chunk_Ram() */
/* Delta chunk is the most common type of chunk...
it contains the changes in the image from the last
frame */
void Delta_Chunk( FILE *fp )
{
uint32_t line_index; /* Number of lines processed */
uint32_t pixel_index = 0; /* Number of pixels processed */
uint32_t pos; /* Position in file */
int16_t lines_to_skip; /* Number of lines to skip */
uint16_t number_lines; /* Number of lines encoded for frame */
uint8_t num_packets; /* Number of packets in line */
uint32_t packet_index; /* Index for loop */
uint8_t skip_count; /* Number of xpixels to skip */
int8_t packet_type; /* Type of delta encoding */
uint8_t pixel_data; /* One pixel to put on screen */
uint32_t byte_count; /* Index for loop */
int32_t x, y;
pos = ftell( fp ); /* Record our position in the file */
/* Get the y position we start on */
fread( &lines_to_skip, sizeof(int16_t), 1, fp );
/* Get the number of lines encoded */
fread( &number_lines, sizeof(int16_t), 1, fp );
x = y = 0;
y += lines_to_skip; /* Move to line lines_to_skip */
for( line_index = 0; line_index < number_lines; line_index++ )
{
fread( &num_packets, sizeof( unsigned char ), 1, fp );
for( packet_index = 0; packet_index < num_packets; packet_index++ )
{
/* Get number of x pixels to skip on this packet */
fread( &skip_count, sizeof( unsigned char ), 1, fp );
/* Get type of packet encoding */
fread( &packet_type, sizeof( char ), 1, fp );
x += skip_count; /* Add the skip count to our x value */
/* If packet type is positive, copy packet_type
number of pixels from the file to the screen... */
if( packet_type > 0 )
{
for( byte_count = 0; byte_count < (uint32_t)packet_type; byte_count++ )
{
fread( &pixel_data, sizeof( char ), 1, fp );
pixel_index++;
DB_Fast_Pixel( x, y, pixel_data );
x++;
}
}
/* If packet type is negative, take its absolute value,
and replicate one byte from the file packet_type
times */
else
{
packet_type = -packet_type;
fread( &pixel_data, sizeof(char), 1, fp );
for( byte_count = 0; byte_count < (uint32_t)packet_type; byte_count++ )
{
pixel_index++;
DB_Fast_Pixel( x, y, pixel_data );
x++;
}
} /* End if else */
} /* End for packet index */
y++; /* Move to next line */
x = 0; /* Move to beginning of line */
} /* End for line index */
} /* End of delta_chunk */
