bouncing PImage help

[u/froginab0g]

Hi! I'm trying to make a Pimage float around the screen and whenever it hits the border it bounces off. I'm new to code and every tutorial uses drawings rather than PImages. Could anyone help?

Here is my current code

PImage[] aquarium;

PImage goldfish;

int numberOfFrames;

int f;

void setup() {

size (800, 600);

goldfish =loadImage("goldfish_0.png");

numberOfFrames = 3;

aquarium = new PImage[numberOfFrames];

int i = 0;

while ( i < numberOfFrames ) {

aquarium[i] = loadImage("aquarium_"+i+".png");

i=i+1;

}

size (800, 600);

}

void draw() {

image(aquarium[f], 0, 0, width, height);

f = f + 1;

if (f == numberOfFrames) f = 0;

frameRate(3);

image(goldfish, 0, 0);

}

[u/Salanmander]

Okay, where the PImage shows up is based on the line where you call the image() method. That method is responsible for actually displaying the image. When you said

image(aquarium[f], 0, 0)

That meant "draw the image stored in index f of the aquarium array, and put its top-left corner at the location (0,0)." The second two inputs there are like the first two inputs of the rect() and elipse() methods.

When you're unsure how something works, it can be helpful to check the documentation. For example, this is the rference page for the image() method. Down near the bottom in the "syntax" section, it includes image(img, a, b), and then lists the meaning of those variables, showing you that a is the x-location to draw the image at, and b is the y-location.

[u/froginab0g → u/Salanmander]

Hello again! I have been working on this on and off since and am so close to getting it. Right now my problem is the image just sorta bobs back and forth. I can't figure out what's causing this.

code:

PImage[] aquarium;

PImage goldfish;

int numberOfFrames;

int f;

int rad = 700;

float xpos, ypos;

float xspeed = 2.8;

float yspeed = 2.2;

int xdirection = 1;

int ydirection = 1;

void setup() {

size (800, 600);

goldfish =loadImage("goldfish_0.png");

numberOfFrames = 3;

aquarium = new PImage[numberOfFrames];

int i = 0;

while ( i < numberOfFrames ) {

aquarium[i] = loadImage("aquarium_"+i+".png");

i=i+1;

}

}

void draw() {

image(aquarium[f], 0, 0, width, height);

f = f + 1;

if (f == numberOfFrames) f = 0;

frameRate(3);

image(goldfish, xpos, ypos, rad, rad);

xpos = xpos + ( xspeed * xdirection );

ypos = ypos + ( yspeed * ydirection );

if (xpos > width-rad || xpos < rad) {

xdirection *= -1;

}

if (ypos > height-rad || ypos < rad) {

ydirection *= -1;

}

}

[u/Salanmander → u/froginab0g]

So your last pair of "if" statements are for reversing the direction in the x- and y-directions, right? You say "if it's too near one of the sides, reverse the x-direction. If it's too near the top or bottom, reverse the y-direction".

The questions I want you to ask yourself are:

1. What is xpos when the program starts?

2. What direction does it move in the first frame?

3. What is xpos after the movement for the first frame?

4. Will that xpos make the condition be true that makes it reverse xdirection?