Pacman

Programming Questions

nic.vande..

in Programming Questions • 4 months ago

Hello I am trying to create Pacman the game and I am stuck. I am starting to work on the consumables but I keep getting a null pointer error. I am using a PSape function with an array to create the two different kinds of eatables. It seems when ever the shape function tries to call on the array eats[] it returns a NPR. There is a good chance this is relatively simple but I figured I would ask.

Also, apologies if I am not posting to a specific layout, I am relatively knew to coding and this forum.

//declare varibales
GameControl gc;
Map map;
void setup() {
size(640, 480);
gc= new GameControl();
map= new Map();
imageMode(CENTER);
}//setup
void draw() {
println("x-axis "+gc.plyr.x);
println("y-axis "+gc.plyr.y);
map.display();
gc.runGame();
}//draw
void keyPressed() {
if (keyCode==LEFT) {
if (map.collideMap(gc.plyr.x-20, gc.plyr.y)) {
gc.plyr.move(0);
}//checking true or false boolean
}//move left
if (keyCode==RIGHT) {
if (map.collideMap(gc.plyr.x+20, gc.plyr.y)) {
gc.plyr.move(1);
}
}//move right
if (keyCode==UP) {
if (map.collideMap(gc.plyr.x, gc.plyr.y-20)) {
gc.plyr.move(2);
}
}//move up
if (keyCode==DOWN) {
if (map.collideMap(gc.plyr.x, gc.plyr.y+20)) {
gc.plyr.move(3);
}
}//move down
}//keypressed
class Collectables {
int xpos, ypos, numofcirc, circsize, circ2size, spacing;
int startx, starty;
PShape[] eats;
Collectables (int x, int y) {
startx= x;
starty= y;
numofcirc= 2;
circsize= 5;
circ2size=15;
spacing= 10;
eats = new PShape[2];
eats[0] = createShape (ELLIPSE, 118, 54, circ2size, circ2size);
eats[0] = createShape (ELLIPSE, 518, 54, circ2size, circ2size);
eats[0] = createShape (ELLIPSE, 118, 334, circ2size, circ2size);
eats[0] = createShape (ELLIPSE, 518, 334, circ2size, circ2size);
eats[1] = createShape (ELLIPSE, 100, 50, circsize, circsize);
}//constructor
void display () {
/*for (int i=1; i<=numofcirc; i++) {
for (int j=1; j<=numofcirc; j++) {
xpos=startx+(i*spacing);
ypos=starty+(j*spacing);
fill(255);
stroke(0);
ellipse(xpos, ypos, circsize, circsize);
}//j loop
}//i loop */
noStroke();
shape(eats[1]);
shape(eats[2]);
}//display
}//class end
class GameControl {
Player plyr;
Collectables clct;
PImage pacman;
ArrayList collItems;
int score;
PFont scoreText;
GameControl () {
startGame();
}//constructor
void runGame() {
/*for (int j=0; j<collItems.size();j++) {
checkCollision(plyr, (Collectables)collItems.get(j), j);
}
for (int i=0; i<collItems.size();i++) {
Collectables tempC;
tempC=(Collectables)collItems.get(i);
tempC.display();
} */
plyr.display();
this.displayScore();
for (int i=0; i<collItems.size();i++) {
clct=(Collectables)collItems.get(i);
clct.display();
}
}//runGame
void startGame() {
plyr= new Player(318, 254, 10);
pacman= loadImage("pacman_LEFT_open.png");
imageMode(CENTER);
score=0;
scoreText = loadFont("Arial-BoldMT-15.vlw");
collItems = new ArrayList();
for (int i=0; i<20;i++) {
collItems.add(new Collectables(120, 20));
}
}//startGame
void adjScore (int amount) {
score+=amount;
}
void displayScore () {
textFont(scoreText);
text(score, 20, 80);
}
/* void checkCollision(Player pl, Collectables cl, int index) {
if (keyPressed==LEFT) {
if (map.collideMap(gc.plyr.x-20, gc.plyr.y)) {
gc.plyr.move(0);
}//checking true or false boolean
}//move left
if (keyPressed==RIGHT) {
if (map.collideMap(gc.plyr.x+20, gc.plyr.y)) {
gc.plyr.move(1);
}
}//move right
if (keyPressed==UP) {
if (map.collideMap(gc.plyr.x, gc.plyr.y-20)) {
gc.plyr.move(2);
}
}//move up
if (keyPressed==DOWN) {
if (map.collideMap(gc.plyr.x, gc.plyr.y+20)) {
gc.plyr.move(3);
}
}//move down
}//checkCollision */
}//class end
class Map {
boolean[][] collisionMap;
PImage colMap= loadImage("pacman_collisionmap.gif");
PImage blankMap;
Map () {
blankMap= loadImage("pacman_blankmap.png");
}//constructor
void display() {
image(blankMap, width/2, height/2);
imageMode(CENTER);
}//display
boolean collideMap(float x, float y) {
color black= color(0);
color white= color(255);
color c=colMap.get((int)x, (int)y);
//this if statement decides the state when the collision map is black or white
if (c==black) {
return false;
}
else {
return true;
}
}//end ColMap
}//class end
class Player {
int frames;
float x, y, speed;
int direction;
PImage[] pacman;
int state;
Player (float _x, float _y, float _s) {
x= _x;
y= _y;
speed= _s;
frames=8;
direction=3;
state=1;
pacman = new PImage[frames];
pacman[0]= loadImage("pacman_LEFT_open.png");
pacman[1]= loadImage("pacman_LEFT_closed.png");
pacman[2]= loadImage("pacman_RIGHT_open.png");
pacman[3]= loadImage("pacman_RIGHT_closed.png");
pacman[4]= loadImage("pacman_UP_open.png");
pacman[5]= loadImage("pacman_UP_closed.png");
pacman[6]= loadImage("pacman_DOWN_open.png");
pacman[7]= loadImage("pacman_DOWN_closed.png");
}//constructor
void display () {
imageMode(CENTER);
if (state>0) {
image(pacman[direction*2], x, y);
}
else {
image(pacman[(direction*2)+1], x, y);
}
if (x<100) {
x=526;
}//portal
if (x>540) {
x=110;
}//portal
}//display
void move (int pdirection) {
direction=pdirection;
state*=-1;
if (pdirection==0) {
x-=speed;
}
if (pdirection==1) {
x-=-speed;
}
if (pdirection==2) {
y-=speed;
}
if (pdirection==3) {
y-=-speed;
}
}//move
}//class end

Replies(1)

GoToLoop

Re: Pacman

4 months ago

I can't run your code. So the following is just a suggestion...

@ #59 You create a PShape[] eats to store only 2 elements.

But @ #60 - #63, you create 4 PShape instances, but store them all as 1st element of your eat Array!

It means only #63 gonna stay. The other instances go to Java's GC!

@ #79, you try to access the 3rd element of eats[]! But eats. length = 2!!!

Here's an attempt fix. But I also advise you to use camelCase naming convention for your variables!

class Collectables {
int xpos, ypos;
final int startx, starty;
static final int numofcirc = 5, spacing = 10;
static final int circsize = 5, circ2size = 15;
final PShape[] eats = new PShape[numofcirc];
Collectables (int x, int y) {
startx = x;
starty = y;
eats[0] = createShape (ELLIPSE, 118, 54, circ2size, circ2size);
eats[1] = createShape (ELLIPSE, 518, 54, circ2size, circ2size);
eats[2] = createShape (ELLIPSE, 118, 334, circ2size, circ2size);
eats[3] = createShape (ELLIPSE, 518, 334, circ2size, circ2size);
eats[4] = createShape (ELLIPSE, 100, 50, circsize, circsize);
}
// ...
}

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Pacman

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