How can I synchronise void update with void keypress/keyrelease

neanderground

here are the variables in the main tab

public float bellyXloc, bellyYloc;
public float bellyWidth, bellyHeight;
public float accelerationX,accelerationY;
public float decelerationX, decelerationY;
public PVector location, acceleration, deceleration;
public float max_speedx,max_speedy ;
public float gravity;
public color characterColor;
public Boolean   isLeft=false ,  isRight=false , isUp= false ;

constructor

 bellyXloc=width/2;
  bellyYloc=height/2; //-(1.6*bellyHeight);
  bellyWidth=width/20;
  bellyHeight= height*0.1;
  characterColor = color(152,223,234);
  location = new PVector(bellyXloc,bellyYloc);
  accelerationX=1.3;
  accelerationY=0;
  max_speedx = 5;
  max_speedy = 3;
  acceleration = new PVector(accelerationX,accelerationY);
  decerelationX = 0.75;
  decerelationY = 0.75;
  deceleration = new PVector(decelerationX, decelerationY);
  gravity = .3;


  a = new AlienCharacter(location,bellyWidth,bellyHeight, color(152,223,234),
                        acceleration, max_speedx, max_speedy, decerelation ,gravity);

in the class void update

void update() {
if ( isRight ) {
  location.add(acceleration);
  if ( acceleration.x > max_speedx ) {
    max_speedx = acceleration.x;
  }
}
else if ( isLeft ) {
  location.sub(acceleration);
  if ( acceleration.x < -max_speedx ) {
    max_speedx = acceleration.x;
  }
}
else { //neither right or left pressed, decelerate
  if ( acceleration.x > 0 ) {
    acceleration.x -= deceleration.x;
    if ( acceleration.x < 0 ) {
      acceleration.x = 0;
    }
  }
  else if ( acceleration.x < 0 ) {
    acceleration.x += deceleration.x;
    if ( acceleration.x > 0 ) {
      acceleration.x = 0;
    }
  }
  }

  if ( isUp ) {
  location.sub(acceleration);
    if ( acceleration.y-0.5 < -max_speedy ) {
    max_speedy = acceleration.y*deceleration.y;
  }
  }

and in the main tab

  void keyPressed() {
  switch(keyCode) {
  case RIGHT: isRight  = true; break;
  case LEFT: isLeft = true; break;
  case UP: isUp = true; break;
  }
  }
  void keyReleased() {
  switch(keyCode) {
  case RIGHT: isRight = false; break;
  case LEFT: isLeft = false; break;
  case UP: isUp = false; break;

  }
  }

The problem that character doesn't react to keyboard I don't where might be the problem

TfGuy44

Here's some basic movement.

boolean isRight, isLeft, isUp;

float x, y;

void setup(){
  size(400,400);
  x = 200;
  y = 200;
}

void draw(){
  if( isRight ){
    x++;
  }
 if( isLeft ){
   x--;
 }
 if( isUp ){
   y--;
 } else if (y<200){
   y++;
 }
 background(0);
 fill(255,0,0);
 rect(x-5,y-5,10,10);
}

void keyPressed() {
  switch(keyCode) {
  case RIGHT: 
    isRight  = true; 
    break;
  case LEFT: 
    isLeft = true; 
    break;
  case UP: 
    isUp = true; 
    break;
  }
}
void keyReleased() {
  switch(keyCode) {
  case RIGHT: 
    isRight = false; 
    break;
  case LEFT: 
    isLeft = false; 
    break;
  case UP: 
    isUp = false; 
    break;
  }
}

It is hard to say what's wrong with your object not moving unless you post a ready-to-go snippet of code that we can copy, paste, and run to see you issue.

neanderground

Here is the full one

int gameScreen = 0;
final int displayWidth = 800;
final int displayHeight = 600;

Alien a;

int FPS = 30;

//Player
public float bellyXloc, bellyYloc;
public float bellyWidth, bellyHeight;
public float accelerationX,accelerationY;
public float decelerationX, decelerationY;  
public PVector location, acceleration, deceleration;
public float max_speedx,max_speedy ;
public float gravity;
public color characterColor;
public Boolean   isLeft=false ,  isRight=false , isUp= false ;

void setup() {

size(800, 600, JAVA2D);
smooth(4);
frameRate(FPS); 
bellyXloc=width/2;
bellyYloc=height/2; //-(1.6*bellyHeight)
bellyWidth=width/20;
bellyHeight= height*0.1;
characterColor = color(152,223,234);
location = new PVector(bellyXloc,bellyYloc);
accelerationX=1.3;
accelerationY=0;
max_speedx = 5;
max_speedy = 3;
acceleration = new PVector(accelerationX,accelerationY);
decelerationX = 0.75;
decelerationY = 0.75;
deceleration = new PVector(decelerationX, decelerationY);
gravity = .3;

//Constructor
a = new Alien(location,bellyWidth,bellyHeight, color(152,223,234),
acceleration, max_speedx, max_speedy, deceleration ,gravity);

}

/********* SCREEN CONTENTS *********/
void initScreen() {
background(0);
textAlign(CENTER);
text("Click to start", width/2, height/2);
}

//initialize game screen
void gameScreen() {
background(255);
}

void gameOverScreen() {
background(0);
textAlign(CENTER);
fill(255);
textSize(30);
text("Game Over", height/2, width/2 - 20);
textSize(15);
text("Click to Restart", height/2, width/2 + 10); 
}

void draw() {
// Display the contents of the current screen
if (gameScreen == 0) {
initScreen();
} else if (gameScreen == 1) {
gameScreen();
a.update();
background(0);
fill(characterColor);
a.displayAlien();


} else if (gameScreen == 2) {
gameOverScreen();
}
}


/********* INPUTS *********/

public void mousePressed() {
// PUBLIC provide other classes access the fields and methods within a class. 
// The public keyword is used before a field or method that you want to make        
// if we are on the initial screen when clicked, start the game
if (gameScreen==0) {
startGame();
}
}

void keyPressed() {
switch(keyCode) {
case RIGHT: isRight  = true; break;
case LEFT: isLeft = true; break;
case UP: isUp = true; break; 
}
}

void keyReleased() {
switch(keyCode) {
case RIGHT: isRight = false; break;
case LEFT: isLeft = false; break;
case UP: isUp = false; break;

}
}


/********* OTHER FUNCTIONS *********/

// This method sets the necessery variables to start the game  
void startGame() {
gameScreen=1;
}

/*********CLASS TAB****************/
class Alien{

//chest
float lowerchestXloc;
float lowerchestYloc;
float lowerchestWidth;
float lowerchestHeight;
float upperchestXloc;
float upperchestYloc;
float upperchestWidth;
float upperchestHeight;

//hand 
float handfrontXloc;
float handfrontYloc;
float handfrontWidth;
float handfrontHeight;

//head
float headXloc;
float headYloc;
float headWidth;
float headHeight;

//feets
//front
float tightfrontXloc;
float tightfrontYloc;
float tightfrontWidth;
float thightfrontHeight;
float legfrontXloc;
float legfrontYloc;
float legfrontWidth;
float legfrontHeight;
float toefrontX1;
float toefrontY1;
float toefrontX2;
float toefrontY2;
float toefrontX3;
float toefrontY3;

//back feet
float tightbackXloc;
float tightbackYloc;
float tightbackWidth;
float tightbackHeight;
float legbackXloc;
float legbackYloc;
float legbackWidth;
float legbackHeight;
float toebackX1;
float toebackY1;
float toebackX2;
float toebackY2;
float toebackX3;
float toebackY3;

Alien (PVector L, float bWidth, float bHeight, color cColor, PVector A, float msx,     
float  msy, PVector D, float G ) { 

location = new PVector(bellyXloc, bellyYloc);
location = L;
bellyWidth = bWidth;
bellyHeight = bHeight;
characterColor = cColor;
acceleration = A;
max_speedx = msx;
max_speedy = msy;
deceleration = D;
gravity = G;
}

void displayAlien() {

bellyXloc=width/2;
bellyYloc=height-(1.6*bellyHeight);
bellyWidth=width/20;
bellyHeight= height*0.1;

background(255);
noStroke();
fill(152, 223, 234);
//BODY
//belly
ellipse(location.x, location.y, bellyWidth, bellyHeight);

//lowerchest
lowerchestXloc = location.x;
lowerchestYloc = location.y - (bellyHeight*0.2);
lowerchestWidth = bellyWidth*0.95;
lowerchestHeight = bellyHeight*0.85;
upperchestXloc = location.x;
upperchestYloc = lowerchestYloc - (lowerchestHeight*0.2);
upperchestWidth = lowerchestWidth * 0.98;
upperchestHeight = lowerchestHeight * 0.9;

ellipse(lowerchestXloc, lowerchestYloc, lowerchestWidth, lowerchestHeight);
ellipse(upperchestXloc, upperchestYloc, upperchestWidth, upperchestHeight);

//HEAD

headXloc = location.x;
headYloc = upperchestYloc - (upperchestHeight * 0.79);
headWidth = bellyWidth*1.1;
headHeight = headWidth;

ellipse(headXloc, headYloc, headWidth, headHeight);

//face


//feets
//front feet
tightfrontXloc = location.x - 7;
tightfrontYloc = location.y + ((bellyHeight/2)-5);
tightfrontWidth = 0.2*bellyWidth;
thightfrontHeight = 0.65*bellyHeight;
legfrontXloc = tightfrontXloc;
legfrontYloc = tightfrontYloc+(thightfrontHeight-3);
legfrontWidth = tightfrontWidth;
legfrontHeight = 0.45*bellyHeight;
toefrontX1 = legfrontXloc+legfrontWidth/2;
toefrontY1 = legfrontYloc+(legfrontHeight-5);
toefrontX2 = toefrontX1-8;
toefrontY2 = toefrontY1+14;
toefrontX3 = toefrontX1+8;
toefrontY3 = toefrontY2;

if(toefrontY2 > height){
     toefrontY2 = height;
}
//left feet
rect(tightfrontXloc, tightfrontYloc, tightfrontWidth, thightfrontHeight);
rect(legfrontXloc, legfrontYloc, legfrontWidth, legfrontHeight);
triangle(toefrontX1, toefrontY1, toefrontX2, toefrontY2, toefrontX3,     
toefrontY3);
//back feet

tightbackXloc = location.x - 4;
tightbackYloc = tightfrontYloc;
tightbackWidth = tightfrontWidth;
tightbackHeight = thightfrontHeight;
legbackXloc = tightbackXloc;
legbackYloc = legfrontYloc;
legbackWidth = legfrontWidth;
legbackHeight = legfrontHeight;
toebackX1 = legbackXloc+legbackWidth/2;
toebackY1 = toefrontY1;
toebackX2 = toebackX1-8;
toebackY2 = toefrontY2;
toebackX3 = toebackX1+8;
toebackY3 = toefrontY3;

rect(tightbackXloc, tightbackYloc, tightbackWidth, tightbackHeight);
rect(legbackXloc, legbackYloc, legbackWidth, legbackHeight);
triangle(toebackX1, toebackY1, toebackX2, toebackY2, toebackX3, toebackY3);

//hands

handfrontXloc = tightbackXloc;
handfrontYloc = upperchestYloc-(upperchestHeight*0.25);
handfrontWidth = tightfrontWidth;
handfrontHeight = bellyHeight/2+lowerchestHeight/2;
stroke(255);
rect(handfrontXloc, handfrontYloc, handfrontWidth, handfrontHeight);

}//end display


void update() {
if ( isRight ) {
location.add(acceleration);
if ( acceleration.x > max_speedx ) {
max_speedx = acceleration.x;
}
}
else if ( isLeft ) {
location.sub(acceleration);
if ( acceleration.x < -max_speedx ) {
max_speedx = acceleration.x;
}
}
else { //neither right or left pressed, decelerate
if ( acceleration.x > 0 ) {
acceleration.x -= deceleration.x;
if ( acceleration.x < 0 ) {
acceleration.x = 0;
}
}
else if ( acceleration.x < 0 ) {
acceleration.x += deceleration.x;
if ( acceleration.x > 0 ) {
acceleration.x = 0;
}
}
}

if ( isUp ) {
location.sub(acceleration);
if ( acceleration.y-0.5 < -max_speedy ) {
max_speedy = acceleration.y*deceleration.y;
}
}

}// end update


 }//end class

koogs

ctrl-t in the pde editor will indent the code for you, which aids readability.

TfGuy44

Lines 307-318 are the problem. If neither key is pressed, acceleration.x rapidly becomes 0 because of the logic there. And then what value added/subtracted from the location? Yep, acceleration!

Removing the offending lines causes your figure to move.

neanderground

thanks I got it, it solved now, i add two new global variable speedX=0 speedY=0 PVector speed(speedX,speedY) however than again my question would if I jump and due to the gravity I fall back how can I stop my character to stay on the ground?

int gameScreen = 0;
final int displayWidth = 800;
final int displayHeight = 600;

Alien a;

int FPS = 30;

//Player
public float bellyXloc, bellyYloc;
public float bellyWidth, bellyHeight;
public float speedX, speedY;
public float accelerationX,accelerationY;
public float decelerationX, decelerationY;  
public PVector location, speed, acceleration, deceleration;
public float max_speedx,max_speedy ;
public float gravity;
public color characterColor;
public Boolean   isLeft=false ,  isRight=false , isUp= false ;

void setup() {

size(800, 600, JAVA2D);
smooth(4);
frameRate(FPS); 
bellyXloc=width/2;
bellyYloc=height/2; //-(1.6*bellyHeight)
bellyWidth=width/20;
bellyHeight= height*0.1;
characterColor = color(152,223,234);
location = new PVector(bellyXloc,bellyYloc);
speedX = 0;
speedY = 0;
speed = new PVector(speedX,speedY);
accelerationX=1.3;
accelerationY=0;
max_speedx = 5;
max_speedy = 3;
acceleration = new PVector(accelerationX,accelerationY);
decelerationX = 0.75;
decelerationY = 0.75;
deceleration = new PVector(decelerationX, decelerationY);
gravity = 1.1;

//Constructor
a = new Alien(location,bellyWidth,bellyHeight, color(152,223,234),speed,
acceleration, max_speedx, max_speedy, deceleration ,gravity);

}

/********* SCREEN CONTENTS *********/
void initScreen() {
background(0);
textAlign(CENTER);
text("Click to start", width/2, height/2);
}

//initialize game screen
void gameScreen() {
background(255);
}

void gameOverScreen() {
background(0);
textAlign(CENTER);
fill(255);
textSize(30);
text("Game Over", height/2, width/2 - 20);
textSize(15);
text("Click to Restart", height/2, width/2 + 10); 
}

void draw() {
// Display the contents of the current screen
if (gameScreen == 0) {
initScreen();
} else if (gameScreen == 1) {
gameScreen();
a.update();
background(0);
fill(characterColor);
a.displayAlien();


} else if (gameScreen == 2) {
gameOverScreen();
}
}


/********* INPUTS *********/

public void mousePressed() {
// PUBLIC provide other classes access the fields and methods within a class. 
// The public keyword is used before a field or method that you want to make        
// if we are on the initial screen when clicked, start the game
if (gameScreen==0) {
startGame();
}
}

void keyPressed() {
switch(keyCode) {
case RIGHT: isRight  = true; break;
case LEFT: isLeft = true; break;
case UP: isUp = true; break; 
}
}

void keyReleased() {
switch(keyCode) {
case RIGHT: isRight = false; break;
case LEFT: isLeft = false; break;
case UP: isUp = false; break;

}
}


/********* OTHER FUNCTIONS *********/

// This method sets the necessery variables to start the game  
void startGame() {
gameScreen=1;
}

/*********CLASS TAB****************/
class Alien{

//chest
float lowerchestXloc;
float lowerchestYloc;
float lowerchestWidth;
float lowerchestHeight;
float upperchestXloc;
float upperchestYloc;
float upperchestWidth;
float upperchestHeight;

//hand 
float handfrontXloc;
float handfrontYloc;
float handfrontWidth;
float handfrontHeight;

//head
float headXloc;
float headYloc;
float headWidth;
float headHeight;

//feets
//front
float tightfrontXloc;
float tightfrontYloc;
float tightfrontWidth;
float thightfrontHeight;
float legfrontXloc;
float legfrontYloc;
float legfrontWidth;
float legfrontHeight;
float toefrontX1;
float toefrontY1;
float toefrontX2;
float toefrontY2;
float toefrontX3;
float toefrontY3;

//back feet
float tightbackXloc;
float tightbackYloc;
float tightbackWidth;
float tightbackHeight;
float legbackXloc;
float legbackYloc;
float legbackWidth;
float legbackHeight;
float toebackX1;
float toebackY1;
float toebackX2;
float toebackY2;
float toebackX3;
float toebackY3;

Alien (PVector L, float bWidth, float bHeight, color cColor, PVector S,,PVector A, float msx,     
float  msy, PVector D, float G ) { 

location = new PVector(bellyXloc, bellyYloc);
location = L;
bellyWidth = bWidth;
bellyHeight = bHeight;
characterColor = colour;
speed = S;
acceleration = A;
max_speedx = msx;
max_speedy = msy;
deceleration = D;
gravity = G;
}

void displayAlien() {

bellyXloc=width/2;
bellyYloc=height-(1.6*bellyHeight);
bellyWidth=width/20;
bellyHeight= height*0.1;

background(255);
noStroke();
fill(152, 223, 234);
//BODY
//belly
ellipse(location.x, location.y, bellyWidth, bellyHeight);

//lowerchest
lowerchestXloc = location.x;
lowerchestYloc = location.y - (bellyHeight*0.2);
lowerchestWidth = bellyWidth*0.95;
lowerchestHeight = bellyHeight*0.85;
upperchestXloc = location.x;
upperchestYloc = lowerchestYloc - (lowerchestHeight*0.2);
upperchestWidth = lowerchestWidth * 0.98;
upperchestHeight = lowerchestHeight * 0.9;

ellipse(lowerchestXloc, lowerchestYloc, lowerchestWidth, lowerchestHeight);
ellipse(upperchestXloc, upperchestYloc, upperchestWidth, upperchestHeight);

//HEAD

headXloc = location.x;
headYloc = upperchestYloc - (upperchestHeight * 0.79);
headWidth = bellyWidth*1.1;
headHeight = headWidth;

ellipse(headXloc, headYloc, headWidth, headHeight);

//face


//feets
//front feet
tightfrontXloc = location.x - 7;
tightfrontYloc = location.y + ((bellyHeight/2)-5);
tightfrontWidth = 0.2*bellyWidth;
thightfrontHeight = 0.65*bellyHeight;
legfrontXloc = tightfrontXloc;
legfrontYloc = tightfrontYloc+(thightfrontHeight-3);
legfrontWidth = tightfrontWidth;
legfrontHeight = 0.45*bellyHeight;
toefrontX1 = legfrontXloc+legfrontWidth/2;
toefrontY1 = legfrontYloc+(legfrontHeight-5);
toefrontX2 = toefrontX1-8;
toefrontY2 = toefrontY1+14;
toefrontX3 = toefrontX1+8;
toefrontY3 = toefrontY2;

if(toefrontY2 > height){
     toefrontY2 = height;
}
//left feet
rect(tightfrontXloc, tightfrontYloc, tightfrontWidth, thightfrontHeight);
rect(legfrontXloc, legfrontYloc, legfrontWidth, legfrontHeight);
triangle(toefrontX1, toefrontY1, toefrontX2, toefrontY2, toefrontX3,     
toefrontY3);
//back feet

tightbackXloc = location.x - 4;
tightbackYloc = tightfrontYloc;
tightbackWidth = tightfrontWidth;
tightbackHeight = thightfrontHeight;
legbackXloc = tightbackXloc;
legbackYloc = legfrontYloc;
legbackWidth = legfrontWidth;
legbackHeight = legfrontHeight;
toebackX1 = legbackXloc+legbackWidth/2;
toebackY1 = toefrontY1;
toebackX2 = toebackX1-8;
toebackY2 = toefrontY2;
toebackX3 = toebackX1+8;
toebackY3 = toefrontY3;

rect(tightbackXloc, tightbackYloc, tightbackWidth, tightbackHeight);
rect(legbackXloc, legbackYloc, legbackWidth, legbackHeight);
triangle(toebackX1, toebackY1, toebackX2, toebackY2, toebackX3, toebackY3);

//hands

handfrontXloc = tightbackXloc;
handfrontYloc = upperchestYloc-(upperchestHeight*0.25);
handfrontWidth = tightfrontWidth;
handfrontHeight = bellyHeight/2+lowerchestHeight/2;
stroke(255);
rect(handfrontXloc, handfrontYloc, handfrontWidth, handfrontHeight);

}//end display


void update() {
  if ( isRight ) {//if is going to right going to width direction
  speed.x+=acceleration.x;
  location.x+=speed.x;
  if ( acceleration.x > max_speedx ) {
  speed.x = max_speedx;
  }
  }
  else if ( isLeft ) {//if is going to left going to 0 direction

  speed.x+=acceleration.x;
  location.x-=speed.x;
  if ( acceleration.x < -max_speedx ) {
  speed.x = max_speedx;
  }
  }
  else { //neither right or left pressed, decelerate
  if ( speed.x > 0 ) {//if key is released 
  speed.x -= deceleration.x;// the acceleration decreasing with deceraltion
  if ( speed.x < 0 ) {// this stop that deceleration turn the character to opposite      
  direction
  speed.x = 0;
  }
  }
  else if ( speed.x < 0 ) {
  speed.x += deceleration.x;
  if ( speed.x > 0 ) {
  speed.x = 0;
  }
  }
  }

   if ( isUp ) {
  location.y -= speed.y;
  speed.y += max_speedy*deceleration.y;

  }
  else if(max_speedy>0){
  location.y+=speed.y;
  speed.y=((max_speedy*deceleration.y)*gravity);
  }

  }// end update

  }//end class

TfGuy44

You would need to add a conditional statement to check to see it your character is on the ground. Your character is on the ground when its y location reaches or exceeds a certain value. At that point, you will want to reassign that limit to the y position, and probably 0 out the y velocity.

neanderground

I added isOnGround as public boolean in class constructor I declared as false

int gameScreen = 0;
final int displayWidth = 800;
final int displayHeight = 600;

Alien a;

int FPS = 30;

//Player
public float bellyXloc, bellyYloc;
public float bellyWidth, bellyHeight;
public float accelerationX,accelerationY;
public float decelerationX, decelerationY;  
public PVector location, speed, acceleration, deceleration;
public float max_speedx,max_speedy ;
public float gravity;
public color characterColor;
public Boolean isOnGround;//added 
public Boolean   isLeft=false ,  isRight=false , isUp= false ;

void setup() {

size(800, 600, JAVA2D);
smooth(4);
frameRate(FPS); 
bellyXloc=width/2;
bellyYloc=height/2; //-(1.6*bellyHeight)
bellyWidth=width/20;
bellyHeight= height*0.1;
characterColor = color(152,223,234);
location = new PVector(bellyXloc,bellyYloc);
speed = new PVector();
accelerationX=1.3;
accelerationY=0;
max_speedx = 5;
max_speedy = 3;
acceleration = new PVector(accelerationX,accelerationY);
decelerationX = 0.75;
decelerationY = 0.75;
deceleration = new PVector(decelerationX, decelerationY);
gravity = 1.1;

//Constructor
a = new Alien(location,bellyWidth,bellyHeight, color(152,223,234),speed,
acceleration, max_speedx, max_speedy, deceleration ,gravity);

}

/********* SCREEN CONTENTS *********/
void initScreen() {
background(0);
textAlign(CENTER);
text("Click to start", width/2, height/2);
}

//initialize game screen
void gameScreen() {
background(255);
}

void gameOverScreen() {
background(0);
textAlign(CENTER);
fill(255);
textSize(30);
text("Game Over", height/2, width/2 - 20);
textSize(15);
text("Click to Restart", height/2, width/2 + 10); 
}

void draw() {
// Display the contents of the current screen
if (gameScreen == 0) {
initScreen();
} else if (gameScreen == 1) {
gameScreen();
a.update();
background(0);
fill(characterColor);
a.displayAlien();


} else if (gameScreen == 2) {
gameOverScreen();
}
}


/********* INPUTS *********/

public void mousePressed() {
// PUBLIC provide other classes access the fields and methods within a class. 
// The public keyword is used before a field or method that you want to make        
// if we are on the initial screen when clicked, start the game
if (gameScreen==0) {
startGame();
}
}

void keyPressed() {
switch(keyCode) {
case RIGHT: isRight  = true; break;
case LEFT: isLeft = true; break;
case UP: isUp = true; break; 
}
}

void keyReleased() {
switch(keyCode) {
case RIGHT: isRight = false; break;
case LEFT: isLeft = false; break;
case UP: isUp = false; break;

}
}


/********* OTHER FUNCTIONS *********/

// This method sets the necessery variables to start the game  
void startGame() {
gameScreen=1;
}

/*********CLASS TAB****************/
class Alien{

//chest
float lowerchestXloc;
float lowerchestYloc;
float lowerchestWidth;
float lowerchestHeight;
float upperchestXloc;
float upperchestYloc;
float upperchestWidth;
float upperchestHeight;

//hand 
float handfrontXloc;
float handfrontYloc;
float handfrontWidth;
float handfrontHeight;

//head
float headXloc;
float headYloc;
float headWidth;
float headHeight;

//feets
//front
float tightfrontXloc;
float tightfrontYloc;
float tightfrontWidth;
float thightfrontHeight;
float legfrontXloc;
float legfrontYloc;
float legfrontWidth;
float legfrontHeight;
float toefrontX1;
float toefrontY1;
float toefrontX2;
float toefrontY2;
float toefrontX3;
float toefrontY3;

//back feet
float tightbackXloc;
float tightbackYloc;
float tightbackWidth;
float tightbackHeight;
float legbackXloc;
float legbackYloc;
float legbackWidth;
float legbackHeight;
float toebackX1;
float toebackY1;
float toebackX2;
float toebackY2;
float toebackX3;
float toebackY3;

Alien (PVector L, float bWidth, float bHeight, color cColor, PVector S,,PVector A, float msx,     
float  msy, PVector D, float G ) { 

location = new PVector(bellyXloc, bellyYloc);
location = L;
bellyWidth = bWidth;
bellyHeight = bHeight;
characterColor = colour;
speed = S;
acceleration = A;
max_speedx = msx;
max_speedy = msy;
deceleration = D;
gravity = G;
isOnGround = false;
}

void displayAlien() {

bellyXloc=width/2;
bellyYloc=height-(1.6*bellyHeight);
bellyWidth=width/20;
bellyHeight= height*0.1;

background(255);
noStroke();
fill(152, 223, 234);
//BODY
//belly
ellipse(location.x, location.y, bellyWidth, bellyHeight);

//lowerchest
lowerchestXloc = location.x;
lowerchestYloc = location.y - (bellyHeight*0.2);
lowerchestWidth = bellyWidth*0.95;
lowerchestHeight = bellyHeight*0.85;
upperchestXloc = location.x;
upperchestYloc = lowerchestYloc - (lowerchestHeight*0.2);
upperchestWidth = lowerchestWidth * 0.98;
upperchestHeight = lowerchestHeight * 0.9;

ellipse(lowerchestXloc, lowerchestYloc, lowerchestWidth, lowerchestHeight);
ellipse(upperchestXloc, upperchestYloc, upperchestWidth, upperchestHeight);

//HEAD

headXloc = location.x;
headYloc = upperchestYloc - (upperchestHeight * 0.79);
headWidth = bellyWidth*1.1;
headHeight = headWidth;

ellipse(headXloc, headYloc, headWidth, headHeight);

//face


//feets
//front feet
tightfrontXloc = location.x - 7;
tightfrontYloc = location.y + ((bellyHeight/2)-5);
tightfrontWidth = 0.2*bellyWidth;
thightfrontHeight = 0.65*bellyHeight;
legfrontXloc = tightfrontXloc;
legfrontYloc = tightfrontYloc+(thightfrontHeight-3);
legfrontWidth = tightfrontWidth;
legfrontHeight = 0.45*bellyHeight;
toefrontX1 = legfrontXloc+legfrontWidth/2;
toefrontY1 = legfrontYloc+(legfrontHeight-5);
toefrontX2 = toefrontX1-8;
toefrontY2 = toefrontY1+14;
toefrontX3 = toefrontX1+8;
toefrontY3 = toefrontY2;

if(toefrontY2 > height){
     toefrontY2 = height;
}
//left feet
rect(tightfrontXloc, tightfrontYloc, tightfrontWidth, thightfrontHeight);
rect(legfrontXloc, legfrontYloc, legfrontWidth, legfrontHeight);
triangle(toefrontX1, toefrontY1, toefrontX2, toefrontY2, toefrontX3,     
toefrontY3);
//back feet

tightbackXloc = location.x - 4;
tightbackYloc = tightfrontYloc;
tightbackWidth = tightfrontWidth;
tightbackHeight = thightfrontHeight;
legbackXloc = tightbackXloc;
legbackYloc = legfrontYloc;
legbackWidth = legfrontWidth;
legbackHeight = legfrontHeight;
toebackX1 = legbackXloc+legbackWidth/2;
toebackY1 = toefrontY1;
toebackX2 = toebackX1-8;
toebackY2 = toefrontY2;
toebackX3 = toebackX1+8;
toebackY3 = toefrontY3;

rect(tightbackXloc, tightbackYloc, tightbackWidth, tightbackHeight);
rect(legbackXloc, legbackYloc, legbackWidth, legbackHeight);
triangle(toebackX1, toebackY1, toebackX2, toebackY2, toebackX3, toebackY3);

//hands

handfrontXloc = tightbackXloc;
handfrontYloc = upperchestYloc-(upperchestHeight*0.25);
handfrontWidth = tightfrontWidth;
handfrontHeight = bellyHeight/2+lowerchestHeight/2;
stroke(255);
rect(handfrontXloc, handfrontYloc, handfrontWidth, handfrontHeight);

}//end display


void update() {

 location.y += gravity;
// 

 if  (toefrontY2 >= (displayHeight-2)){
 location.y += speed.y; 

I try to stop the character to go above the screen but it doesn't work and neither the pervious statement above maybe because speed is PVector so speed.y is doesn't have a value or is it automatically 0?

 gravity=0;
 }

  if ( isRight ) {//if is going to right going to width direction
  speed.x+=acceleration.x;
  location.x+=speed.x;
  if ( acceleration.x > max_speedx ) {
  speed.x = max_speedx;
  }
  }
  else if ( isLeft ) {//if is going to left going to 0 direction

  speed.x+=acceleration.x;
  location.x-=speed.x;
  if ( acceleration.x < -max_speedx ) {
  speed.x = max_speedx;
  }
  }
  else { //neither right or left pressed, decelerate
  if ( speed.x > 0 ) {//if key is released 
  speed.x -= deceleration.x;// the acceleration decreasing with deceraltion
  if ( speed.x < 0 ) {// this stop that deceleration turn the character to opposite      
  direction
  speed.x = 0;
  }
  }
  else if ( speed.x < 0 ) {
  speed.x += deceleration.x;
  if ( speed.x > 0 ) {
  speed.x = 0;
  }
  }
  }
  if(isOnGround) { 
  if ( isUp ) {
  location.y -= speed.y;
  speed.y += (max_speedy*deceleration.y);
  isOnGround=false;

  }
  else if(max_speedy>0){
  location.y+=speed.y;
  speed.y=((max_speedy*deceleration.y)*gravity);
  }

  }// end update

  }//end class

How can fix first the this that the character will stop at the moment on the ground since at the moment i don't have a game grid, and 2nd how can I stop the character go above the screen ? Thanks