Save coordinates in array doesn't work?

LuigiPlayIt · November 2017

Hello,

I'm quite new to programming and we have to create the game Snake with processing for School. But the snake is always 2 parts long no matter how big the snake size variable is. I hope you can help me out. (ignore the german names :P)

//Variables
int swidth = 20;  //snake width
int sheight = 20; //snake height
int xpos = 200; //Snake position
int ypos = 200;
int dir = 0; //direction: 0 = up, 1 = right, 2 = down, 3 = left
int slength = 5; //snake length

//Arrays
int[] xSchlange = new int[50]; //X Position Snake
int[] ySchlange = new int[50]; //Y Position Snake

void setup(){
   size(400,400);
   frameRate(8);
   background(255);
   stroke(0);
   zeichneGitter(); //draw grid
   xSchlange[0] = xpos;
   ySchlange[0] = ypos;
}

void draw(){
   zeichneGitter();
   steuerung();
   schlangeZeichnen();
   fill(0); 
}
void zeichneGitter(){ //draw grid
   background(255);
   stroke(0);
   for(int i = 0; i < 20; i++){ //X lines 
      line(0, i*20, 400, i*20);  
   }
   for(int i = 0; i < 20; i++){ //Y lines
      line(i*20, 0, i*20, 400);  
   } 
}

void steuerung(){ //controls
   if(dir == 0){
       ySchlange[0] = ySchlange[0] - 20;
   }else if(dir == 1){
       xSchlange[0] = xSchlange[0] + 20;
   }else if(dir == 2){
       ySchlange[0] = ySchlange[0] + 20;
   }else if(dir == 3){
       xSchlange[0] = xSchlange[0] - 20;
   } 
}

void schlangeZeichnen(){ //draw snake
    for(int i = 0; i <= slength; i++){
      rect(xSchlange[i], ySchlange[i], swidth, sheight);
    }
    for(int i = 0; i <= slength; i++){
       xSchlange[i + 1] = xSchlange[i];
       ySchlange[i + 1] = ySchlange[i];
    }
} 

void keyPressed(){
   if(key == 'W' || key == 'w'){  //WASD controls
      dir = 0; 
   }else if(key == 'S' || key == 's'){
      dir = 2;
   }else if(key == 'A' || key == 'a'){
      dir = 3; 
   }else if(key == 'D' || key == 'd'){
      dir = 1; 
   }
}

kfrajer · December 2017

Instead of making the snake longer, you should focus in working on the snake in the grid. Then, you could add the extra code. The trick is to shuffle the positions of the body of the array by one "backwards" and then update the head.

Please also study for loops... your conditions were wrong which leads to bugs in your programs.

also check in the reference: rectMode()

Kf

final int kUP=0;
final int kDOWN=2;
final int kLEFT=3;
final int kRIGHT=1;


int swidth = 20;  //snake width
int sheight = 20; //snake height
int xpos = 200; //Snake position
int ypos = 200;
int dir = 0; //direction: 0 = up, 1 = right, 2 = down, 3 = left
int slength = 5; //snake length

int deltax=0;
int deltay=0;

//Arrays
int[] xSchlange = new int[50]; //X Position Snake
int[] ySchlange = new int[50]; //Y Position Snake

void setup() {
  size(400, 400);
  frameRate(8);
  background(255);
  stroke(0);
  rectMode(CENTER);
  xpos = ypos = 200;
  for (int i = 0; i < slength; i++) {    
    xSchlange[i] = xpos-swidth/2;
    ySchlange[i] = ypos+i*sheight-sheight/2;
  }
  fill(0);
  key='w';
  keyPressed();
}

void draw() {
  zeichneGitter();
  steuerung();
  schlangeZeichnen();
}

void zeichneGitter() { //draw grid
  background(255);
  stroke(0);
  for (int i = 0; i < 20; i++) { 
    line(0, i*20, 400, i*20);
    line(i*20, 0, i*20, 400);
  }
}

void steuerung() { //controls

  for (int i=slength-1;i>0; i--) {
    xSchlange[i]=xSchlange[i-1];
    ySchlange[i]=ySchlange[i-1]+sheight*0;
  }

  xSchlange[0] = xSchlange[0] + deltax;
  ySchlange[0] = ySchlange[0] + deltay;
}

void schlangeZeichnen() { //draw snake
  for (int i = 0; i < slength; i++) {
    rect(xSchlange[i], ySchlange[i], swidth, sheight);
  }
} 



void keyPressed() {
  deltax=deltay=0;
  if (key == 'W' || key == 'w') {  //WASD controls
    dir = kUP;
    deltay=-sheight;
  } else if (key == 'S' || key == 's') {
    dir = kDOWN;
    deltay=sheight;
  } else if (key == 'A' || key == 'a') {
    dir = kLEFT;
    deltax=-swidth;
  } else if (key == 'D' || key == 'd') {
    dir = kRIGHT;
    deltax=swidth;
  }
}

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Save coordinates in array doesn't work?

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