I just want to make a 2D rpg games with the background of the game can change in different stages of the game. Please send help:((
Hello,
Resources here:
https://processing.org/tutorials/interactivity
https://processing.org/reference/mouseClicked_.html < You should be able to adapt this to change the background.
:)
1 Like
Hi @steven,
Sorry, but if you’re wondering how to set the proper background, the path to programming an RPG is a pretty demanding challenge…
However, and as so often said, one grows with its tasks. 
As it is always fun to do some coding…
I just made a simple example for a game and how it could be structured and maybe you can get some ideas from it.
(Doesn’t make much more than a movable player and sets the background of the room if the player is inside …)
Cheers
— mnse
// Main Sketch
KeyHandler keyhandler;
World world;
void setup() {
size(1000, 1000);
keyhandler = new KeyHandler();
world=new World();
}
void keyPressed() {
keyhandler.update(key, true);
}
void keyReleased() {
keyhandler.update(key, false);
}
void draw() {
background(0);
world.update();
world.display();
}
// -----------------------------------------------------
public class KeyHandler {
public final static int KEY_UP = 0;
public final static int KEY_DN = 1;
public final static int KEY_LEFT = 2;
public final static int KEY_RIGHT = 3;
public final static int KEY_FIRE = 4;
private final boolean[] keyStates = new boolean[] {false, false, false, false,false};
public void update(char k, boolean state) {
switch(k) {
case 'w':
keyStates[KEY_UP]=state;
break;
case 's':
keyStates[KEY_DN]=state;
break;
case 'a':
keyStates[KEY_LEFT]=state;
break;
case 'd':
keyStates[KEY_RIGHT]=state;
break;
case ' ':
keyStates[KEY_FIRE]=state;
break;
default:
}
}
public boolean isKeyOn(int k) {
switch(k) {
case KEY_UP:
case KEY_DN:
case KEY_LEFT:
case KEY_RIGHT:
case KEY_FIRE:
return keyStates[k];
default:
return false;
}
}
}
// -----------------------------------------------------
public class Room {
int id;
PVector pos, size;
color bg;
boolean isPlayerInside;
int playerspeed;
public Room(int i, PVector p, PVector s) {
id = i;
playerspeed = i;
pos=p;
isPlayerInside=false;
size=s;
pushStyle();
colorMode(HSB, 360, 100, 100);
bg=color(random(360), 100, 100);
popStyle();
}
public void update(Player p) {
isPlayerInside = p.pos.x > pos.x && p.pos.x < pos.x+size.x && p.pos.y > pos.y && p.pos.y < pos.y+size.y;
if (isPlayerInside)
p.speed=playerspeed;
}
public void display() {
pushStyle();
stroke(255);
noFill();
if (isPlayerInside) fill(bg);
rect(pos.x, pos.y, size.x, size.y);
popStyle();
}
}
// -----------------------------------------------------
public class Player {
PVector pos, vel;
float size = 40, speed = 5, rot=0;
Cannon cannon;
PVector firepos;
public Player(PVector p) {
pos = p;
vel = new PVector();
cannon=new Cannon();
}
public void update() {
vel.mult(0);
if (keyhandler.isKeyOn(KeyHandler.KEY_UP))
vel.y=-speed;
else if (keyhandler.isKeyOn(KeyHandler.KEY_DN))
vel.y=speed;
if (keyhandler.isKeyOn(KeyHandler.KEY_LEFT))
vel.x=-speed;
else if (keyhandler.isKeyOn(KeyHandler.KEY_RIGHT))
vel.x=speed;
// move
pos.add(vel);
if (vel.x != 0 || vel.y != 0)
rot= vel.heading();
//check boundary
if (pos.x < 0) {
pos.x+=width;
} else if (pos.x > width ) {
pos.x-=width;
}
if (pos.y < 0) {
pos.y+=height;
} else if (pos.y > height ) {
pos.y-=height;
}
if (keyhandler.isKeyOn(KeyHandler.KEY_FIRE) && cannon.isReadyToShoot()) {
PVector tmp = PVector.add(pos, new PVector(size,0));
firepos=new PVector(cos(rot) * (tmp.x-pos.x) - sin(rot) * (tmp.y-pos.y) + pos.x
,sin(rot) * (tmp.x-pos.x) + cos(rot) * (tmp.y-pos.y) + pos.y);
cannon.fire(firepos,PVector.fromAngle(rot).mult(10));
}
cannon.update();
}
public void display() {
pushMatrix();
pushStyle();
fill(255);
stroke(128);
strokeWeight(3);
translate(pos.x, pos.y);
rotate(rot);
ellipse(0, 0, size, size);
line(0, 0, size, 0);
popStyle();
popMatrix();
cannon.display();
}
}
// -----------------------------------------------------
class CannonBall {
PVector pos;
PVector vel;
public CannonBall(PVector p, PVector v) {
pos=p;
vel=v;
}
public void update() {
pos.add(vel);
}
public boolean isDead() {
return (pos.x < 0 || pos.x > width || pos.y < 0 || pos.y >height);
}
public void display() {
pushStyle();
pushMatrix();
translate(pos.x,pos.y);
rotate(frameCount / 10.);
stroke(255);
fill(255,0,0);
beginShape();
for (int i=0;i<10;i++) {
float r = i%2==0 ? 10 : 5;
vertex(r*cos(radians(36*i)),r*sin(radians(36*i)));
}
endShape();
popMatrix();
popStyle();
}
}
// -----------------------------------------------------
class Cannon {
ArrayList<CannonBall> cannonballs;
int nextShot;
int cannonDelay = 250;
public Cannon() {
cannonballs = new ArrayList<CannonBall>();
nextShot = 0;
}
public boolean isReadyToShoot() {
return millis() > nextShot;
}
public void fire(PVector p, PVector v) {
if (isReadyToShoot()) {
cannonballs.add(new CannonBall(p,v));
nextShot = millis() + cannonDelay;
}
}
public void update() {
for (int i=cannonballs.size()-1;i>=0;i--) {
CannonBall c=cannonballs.get(i);
c.update();
if (c.isDead()) {
cannonballs.remove(i);
}
}
}
public void display() {
for (CannonBall b: cannonballs)
b.display();
}
}
// -----------------------------------------------------
public class World {
Room[] rooms;
Player player;
public World() {
rooms = new Room[] { new Room(2,new PVector(0, 0), new PVector(width/2, height/2)),
new Room(4,new PVector(width/2, 0), new PVector(width/2, height/2)),
new Room(6,new PVector(width/2, height/2), new PVector(width/2, height/2)),
new Room(8,new PVector(0, height/2), new PVector(width/2, height/2))};
player = new Player(new PVector(rooms[0].pos.x+rooms[0].size.x/2, rooms[0].pos.y+rooms[0].size.y/2));
}
public void update() {
player.update();
for (Room r : rooms)
r.update(player);
}
public void display() {
for (Room r : rooms)
r.display();
player.display();
}
}
EDIT1: For fun fact the player changes its walking speed depending on the room
EDIT2: As it was so much fun I’ve also added a little Cannon (Certainly for demonstration purposes only, so no targets … say no to weapons! …)
2 Likes
Can i ask something about blinking text?
1 Like
Can you give me and example on how to blink text? Please
Hi @steven,
you can use the same approch as from your other topic…
but instead of changing the background, switch on and off the text output …
Cheers
— mnse
PS:
final String myMessage="Hello World!";
int nextOne = 0;
boolean showText = false;
void setup() {
size(500, 500);
textSize(50);
fill(255);
textAlign(CENTER, CENTER);
}
void draw() {
background(0);
if (millis() > nextOne) {
showText = !showText;
nextOne = millis() + floor(map(mouseX, 0, width, 500, 50));
}
if (showText)
text(myMessage, width/2, height/2);
}