CheckersBaseGame

int colorCont = 0;
int[] hues = new int[32];
ArrayList<Piece> pieces = new ArrayList<>();
Piece picked;

void setup(){
    size(800, 800);
    noStroke();
    colorMode(HSB);
    pieces.add(new Piece(0, 0));
}

void draw(){
    drawBoard();
    displayPieces();
    movePicked();
}

void movePicked(){
    if(picked!=null){
        picked.snap(mouseX, mouseY);
    }
}

void mousePressed(){
    setPicked();
}

void mouseReleased(){
    if(picked != null){
        picked.snap(mouseX, mouseY);
        picked = null;
    }
}

void setPicked(){
    for(Piece p : pieces){
        int px = (p.c*100)+50;
        int py = (p.r*100)+50;
        // if dist to center of piece is less than its radius
        if ((Math.pow((mouseX-px), 2) + Math.pow((mouseY-py), 2)) < Math.pow(p.radius, 2)){
            picked = p;
            println("picked in row: " + p.r + " col: " + p.c);
        }
    }
}

void displayPieces(){
    for(Piece p : pieces) p.display();
}

void setColor(int i, int j){
    if((i+j)%2 == 1){
        fill(0);
    }
    else{
        fill(colorCont, 225, 200);
        colorCont = colorCont + 8;
    }
}

void drawBoard(){
    background(0);
    for(int i = 0; i<8; i++){
        for(int j = 0; j<8; j++){
            setColor(i, j);
            
            rect(i*100, j*100, 100, 100, 20);
        }
    }
    colorCont = 0;
}

class Piece{
    int c;
    int r;
    int radius;
    
    Piece(){
        c = 0;
        r = 0;
        radius = 50;
    }
    
    Piece(int a, int b){
        this.c = a;
        this.r = b;
        radius = 50;
    }
    
    void display(){
        fill(255);
        ellipse((c*100)+50, (r*100)+50, 2*radius, 2*radius);
    }
    
    // TODO: fix snap-to-grid
    void snap(float x, float y){
        float row = y/100;
        int rowInt = (int)row;
        float col = x/100;
        int colInt = (int)col;
        
        if(row-rowInt >= 0.8){
            r = rowInt+1;
        }
        else{
            r = rowInt;
        }
        
        if(col-colInt > 0.8){
            c = colInt+1;
        }
        else{
            c = colInt;
        }
        
        if(row > 7){
            r = 7;
        }
        if(col > 7){
            c = 7;
        }
    }
}