Iterating over an unsigned char array bit by bit.

Projects Programming
1

Hi.
I am working with some LED matrices to try to make Game of Life and I am having a problem with my program. Currently I am only using a single matrix.
I have this array which I use to store the current state of the matrix in:

unsigned char buffer[8] = { B00000000,
                            B00000000,
                            B00101000,
                            B00000000,
                            B00010000,
                            B00000000,
                            B00000000,
                            B00000011
                          };

Now I want to iterate over each bit in the array from position 0,0 (upper left corner) down to 7,7 (lower right corner) bit by bit.
The reason I want to do this is because for every LED I have to check the neighbooring LEDs if they are on or off.

Does someone know a way to do this? I don't mind changing the structure of how I store the state of the matrix.

Thanks.

EDIT:
The ideal solution I was hoping for is something like this:

for(int i = 0; i < 8; i++) {
for(int y = 0; y < 8; y++){
bit currentBit = buffer[i][y];
// Here would be the logic where I check the bits around the currentBit.
// if(buffer[i-1][y] == 1) then something and so on....

}
}
2

You need two nested loops, one to iterate over the bytes in your array and another to iterate over the bits in each byte.

3

Or use mask and shift (or divide and modulo) operations to allow a single index to access both bytes and bits.

4

You are close...

bit currentBit = bitRead(buffer[i],y);
5

My BitBool library makes this easy.

BitBool< 64, true > buffer ={ B00000000,
                        B00000000,
                        B00101000,
                        B00000000,
                        B00010000,
                        B00000000,
                        B00000000,
                        B00000011
                      };
void setup() {
  Serial.begin( 9600 );
  
  for( char i = 0 ; i < buffer.BitCount ; ++i ){
    Serial.print( buffer[ i ], DEC );
  }  
}

void loop() {}
6

EDIT: Removed comment about pYro_65 code. It compiles.

DavidOConnor: That does not want to compile. It gives me:

LCDemoMatrixWorking.ino: In function 'void test()':
LCDemoMatrixWorking:242: error: 'bit' was not declared in this scope
LCDemoMatrixWorking:242: error: expected `;' before 'currentBit'
7

I guess I assumed you had typedef'ed bit. Use byte instead.

8

Thanks. The bitRead function did the trick.