2D Arrays in Setup and Loop - Problems with the Scope

Projects General Guidance
1

Hi,

let me describe my Project first, so you know what I am up to.
I want to build a digital Go-Board which can replay Games. (Go is played on a 9x9/13x13/19x19 grid by putting black and white stones alternating see: Go (game) - Wikipedia for more information) I already have my 9x9 LED Matrix (WS2812B) ready and want to use the FastLED library.

The common format in which Go-Games are saved is called .sgf and looks something like this: ;B[de];W[fe];B[ee];W[fd];B[ff];W[gf];B[gg];W[fg];B[ef];W[gh];B[hg];W[hh];B[eg];W[fh];B[ge];W[hf]
B is the Black Player, W is the White player and the letters refer to the coordinates on the Board (here a 9x9 Board).
First, I figure out how many moves there are in the game and then create a 2-D array
(byte game[numberOfMoves][2]) to store the individual moves in a numeric form. Here is where I hit my Problem. I obviously want to do the parsing of the Game in the setup() but I want to use it in the Loop(). This results in Problems with the Scope. But I cannot define my Arrays before I know how many moves there are in the game.

My first target ist to display the Game using a Potentiometer (sliding through the game by turning the knob).

Here is my code (i removed some helper functions for accessing the Matrix)

#include <FastLED.h>  // Add Library
// #define NUM_LEDS 81   // Set Number of LEDs
// Params for width and height
const uint8_t kMatrixWidth = 9;
const uint8_t kMatrixHeight = 9;
#define NUM_LEDS (kMatrixWidth * kMatrixHeight)
#define DATA_PIN 6    // Set Data Input pin
#define BRIGHTNESS 64
  
CRGB leds[NUM_LEDS];  // Prepare Memory
CRGB leds_plus_safety_pixel[ NUM_LEDS + 1];

void setup() { 
   FastLED.addLeds<NEOPIXEL, DATA_PIN>(leds, NUM_LEDS);
   FastLED.setBrightness( BRIGHTNESS );
   Serial.begin(9600);
   while (!Serial) {
    ; // wait for serial port to connect. Needed for native USB port only
    
   }
  
   Serial.println("Start analyzing the game...");
   String gameRaw =";B[de];W[fe];B[ee];W[fd];B[ff];W[gf];B[gg];W[fg];B[ef];W[gh];B[hg];W[hh];B[eg];W[fh];B[ge];W[hf];B[he];W[ig];B[fc];W[gd];B[gc];W[hd];B[ed];W[be];B[hc];W[ie];B[bc];W[cg];B[cf];W[bf];B[ch];W[cc];B[cb];W[dg];B[dh];W[bh];B[eh];W[dc];B[bd];W[ec];B[cd];W[fb];B[gb];W[bb];B[eb];W[db];B[fa];W[ca];B[ea];W[da];B[df];W[bg];B[bi];W[ab];B[ah];W[ci];B[di];W[ag];B[ae];W[ac];B[ad];W[ha];B[hb];W[fi];B[ce];W[ai];B[ci];W[ei];B[ah];W[ic];B[ib];W[ai];B[ba];W[aa];B[ah];W[ga];B[ia];W[ai];B[ga];W[id]";
   
   Serial.println("Figuring out the number of moves...");
   int numberOfMoves = gameRaw.length()/6 ;
 
   Serial.print("Moves: ") ;
   Serial.println(numberOfMoves);
 
   
   byte game[numberOfMoves][2];
   Serial.println("Parsing the game...");
    int ascii_a;
    int ascii_b;
    String a;
    String b;
   for (int i = 0; i < numberOfMoves ; i++) {
       a = gameRaw.substring(3+6*i,4+6*i);
       b = gameRaw.substring(4+6*i,5+6*i);

       ascii_a = a[0];
       ascii_b = b[0];
       ascii_a -= 96;
       ascii_b -= 96;
      
       game[i][0] = ascii_a;
       game[i][1] = ascii_b;           
   }

   Serial.println("Parsing complete"); 
  
     
}


void loop()
{

FastLED.clear();
 
for (int i = 0; i < numberOfMoves ; i++) {
  if (i%2 == 0) { 
    playBlack(game[i][0],game[i][1]) ;
    }
  else {
    playWhite(game[i][0],game[i][1]) ;
    }

}


}

void playBlack(uint8_t x, uint8_t y) 
{
    leds[XY(x-1,y-1)] =  CHSV(130,255,100);
        FastLED.show();
        delay(1000);
}

void playWhite(uint8_t x, uint8_t y) 
{
    leds[XY(x-1,y-1)] =  CHSV(0,180,100);
        FastLED.show();
        delay(1000);
}

Any further comments to make the code run smoothly is appreciated very much. A full game of Go is played on 19x19 board and consists of roughly 250 Moves

2

Declare global variables in global scope i.e. outside of functions.

Also don't use String type on ATmega controllers which don't have enough memory.

Readable input is fine for humans but a PITA for controllers. Storing a game can be done by coordinates (pairs of bytes) only. The starting player (b/w) is known and players drop or flip a stone in turn.

Put the moves constant (byte[]) into PROGMEM not into SRAM. If you want to read a game from Serial or SD card you better input and parse the data move by move.

3

So i should just generate an array with an arbitrary length outside the functions? Is there a way to know the number of turn beforehand?

I will handle the game in coordinates, but the given format is the standard in which games are stored. So if i want to review a game it will come in this fileformat.

Using PROGMEM sounds like i good idea. I did not know about that and will read about it.

Thanks for the help!

4

You have to set up all arrays of sufficient size. Forget about dynamic memory with ATmega's.

You only need a board of the intended size (9x9), then read one move after another and execute it.