# Can you help me change the Speed of the ball?

Reset the velocity back to its initial value once the ball collides with an edge of the internal wall or the canvas
boundary. Note that the sign of the velocity will depend on the edge the ball hits. For example, after the ball
hits the right wall, the x-velocity will be reset to -3. Implement sensible behavior for the ball. The ball should
not be moving so fast that the graders cannot evaluate the behavior of your code.
<// Setup the value for the ball
float ballX;
float ballY;
float ballSpeedX = random(2, 8);
float ballSpeedY = random(1, 10);
float ballDia = 20.0;
float ballR = ballDia/2;

void setup() {
size(800, 600);
ballX= random(10, 370);
ballY= random(10, 570);
}

void draw() {
background(0);

// Draw the wall
fill(255);
noStroke();
rect(390, 300, 23, 300);

// Color of the ball changes gradually and continuously as it moves
if (ballSpeedX >=6) {
fill(255, 0, 0);
} else if (ballSpeedX>=3) {
fill(0, 255, 0);
} else fill(0, 0, 255);

// Draw the ball
ellipse(ballX, ballY, ballDia, ballDia);

// Update ball location
ballX=ballX+ballSpeedX;
ballY=ballY+ballSpeedY;

// If ball hit the right or left change direction of X
if (ballX> width- ballR ) {
ballX= width -ballR;
ballSpeedX=ballSpeedX*-1;
} else if (ballX<ballR) {
ballX=ballR;
ballSpeedX=ballSpeedX*-1;
}

// If ball hit top or bottom change direction of Y
if (ballY> height-ballR) {
ballY=height-ballR;
ballSpeedY=ballSpeedY*-1;
} else if (ballY<ballR) {
ballY=ballR;
ballSpeedY=ballSpeedY*-1;
}

// Setup variable to true if shapes are over lapping, false if not
boolean collision = hitWall(390, 300, 20, 300, ballX, ballY, ballR);

// Change ball direction when ball hit
//and bump it back

if (collision ==true) {
ballSpeedX=ballSpeedX*-1;
ballX=(ballX+ballSpeedX);
}
}
boolean hitWall(int rx, int ry, int rw, int rh, float cx, float cy, float cr) {
float circleDistanceX= abs(cx-rx-rw/2);
float circleDistanceY= abs(cy-ry-rh/2);

if (circleDistanceX >(rw/2+cr)) {
return false;
}
if (circleDistanceY >(rh/2+cr)) {
return false;
}
if (circleDistanceX<=rw/2) {
return true;
}
if (circleDistanceY<= rh/2) {
return true;
}

float cornerDistance = pow(circleDistanceX-rw/2, 2)+ pow(circleDistanceY-rh/2, 2);
if (cornerDistance <=pow(cr, 2)) {
return true;
} else {
return false;
}
}> homework policy

1 Like

You just copied the assignment

Where do you see a need for change in your code?

You wrote:

Can you help me change the Speed of the ball?

In what way?

``````// Setup the value for the ball
float ballX;
float ballY;
// speed gets modified in setup()
float ballSpeedX = random(1.5, 3.5);
float ballSpeedY = random(1.5, 3.5);
float ballDia = 20.0;
float ballR = ballDia/2;

void setup() {
size(800, 600);

ballX= random(10, 370);
ballY= random(10, 570);

// make it neg. in some cases
if (random(1) > 0.5)
ballSpeedX*=-1;
if (random(1) > 0.5)
ballSpeedY*=-1;
}

void draw() {
background(0);

// Draw the wall
fill(255);
noStroke();
rect(390, 300, 23, 300);

// Color of the ball changes gradually and continuously as it moves
if (ballSpeedX>=6) {
fill(255, 0, 0);
} else if (ballSpeedX>=3) {
fill(0, 255, 0);
} else fill(0, 0, 255);

// Draw the ball
ellipse(ballX, ballY, ballDia, ballDia);

// Update ball location
ballX=ballX+ballSpeedX;
ballY=ballY+ballSpeedY;

// If ball hit the right or left change direction of X
if (ballX > width-ballR ) {
ballX = width-ballR;
ballSpeedX=ballSpeedX*-1;
} else if (ballX<ballR) {
ballX=ballR;
ballSpeedX=ballSpeedX*-1;
}

// If ball hit top or bottom change direction of Y
if (ballY> height-ballR) {
ballY=height-ballR;
ballSpeedY=ballSpeedY*-1;
} else if (ballY<ballR) {
ballY=ballR;
ballSpeedY=ballSpeedY*-1;
}

// Setup variable to true if shapes are over lapping, false if not
boolean collision = hitWall(390, 300, 20, 300, ballX, ballY, ballR);

// Change ball direction when ball hit
//and bump it back
if (collision) {
ballSpeedX=ballSpeedX*-1;
ballX=(ballX+ballSpeedX);
}//if
} // draw

// -------------------------------------------------------------------------

boolean hitWall(int rx, int ry,
int rw, int rh,
float cx, float cy,
float cr) {
//
float circleDistanceX= abs(cx-rx-rw/2);
float circleDistanceY= abs(cy-ry-rh/2);

if (circleDistanceX >(rw/2+cr)) {
return false;
}
if (circleDistanceY >(rh/2+cr)) {
return false;
}
if (circleDistanceX<=rw/2) {
return true;
}
if (circleDistanceY<= rh/2) {
return true;
}

float cornerDistance = pow(circleDistanceX-rw/2, 2)+ pow(circleDistanceY-rh/2, 2);
if (cornerDistance <=pow(cr, 2)) {
return true;
} else {
return false;
}
}//func
// End of Sketch

``````

the color of the ball has to change when speed increases or decreases. Reset the velocity back to its initial value once the ball collides with an edge of the internal wall or the canvas boundary. Note that the sign of the velocity will depend on the edge the ball hits. For example, after the ball hits the right wall, the x-velocity will be reset to -3. It is like: when the ball hit the wall ball has the speed is 6 or more the ball will red color. After hit the size, the speed will reduce 2 and have green. The color will be changed when the speed change.

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In this code, the speed did not change. It just kept the pace when it started. It has only two values. However, I need the ball to have three different speeds and change three colors. Can you help me rewrite the code in the speed path?

Should the speed increase for every collisionâ€¦?

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Speed of the ball will increase when hitting the right, left, top, or bottom. it will decrease when hit the wall

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If I understand correctly, what you need to do is change the value of certain variables based on certain conditions. Can you think of any way to do that?

1 Like

This is wrong (what I wrote)

here a collision takes place. Since itâ€™s on the right side of the screen, ballSpeedX is posittive (you need to know if the value is currently pos or neg!),

so before ballSpeedX=ballSpeedX*-1; say ballSpeedX+=0.2; for example. Same for ballSpeedY (is it pos or neg?), here we want to add 0.2 or -0.2 as well (so that the direction stays the same)

Repeat for the other collisions accordingly, keep in mind whether itâ€™s neg or pos (if clause).

New attempt

first store the initial values globally.

YOU WROTE:

Assignment says:

I think you are wrong in saying, the ball will increase when hitting the right, left, top, or bottom.

I suggest the ball gets faster throughout and Reset the velocity back to its initial value once the ball collides with an edge of the internal wall or the canvas boundary.

1 Like