Collision Detection in 2D Squares

Programming Questions

harrison...

Collision Detection in 2D Squares

in Programming Questions • 3 years ago

Hey all,

Just wondering if anyone can guide with my code I've sort of got it working but it's not perfect I'm trying to make it so the smaller Square is detected as soon as any part of it enters the area of the bigger one but I have no clue how to do that.

any ideas?

thanks so much,

Harrison

code

float blockX = random(500);
float blockY = random(500);
void setup(){
size(500,500);
smooth();
noStroke();
}
void draw()
{
collide();
background(200);
fill(0);
rect(mouseX,mouseY,20,20);
fill(0,0,255);
rect(blockX,blockY,5,5);
}
void collide(){
if(((mouseX + 10 >= blockX)&&(mouseX <= blockX )&&(mouseY + 10 >= blockY)&&(mouseY <= blockY))
||((mouseX - 10 >= blockX)&&(mouseX <= blockX )&&(mouseY - 10 >= blockY)&&(mouseY <= blockY))){
blockX = random(500);
blockY = random(500);
}
}

Replies(2)

blindfish

Re: Collision Detection in 2D Squares

3 years ago

First off you might want to look at using rectMode(CENTER), then the dragged rectangle will appear at the centre of the mouse location rather than the corner. As for the collision detection, assuming you're using rectMode(CENTER) on all rectangles then the x/y coordinates represent the centres of the rectangles and you need to determine when an edge of one rectangle crosses the edge of another. You were actually on the right track with mouseX + 10.... So:

// where 'rect1' is at the mouse location and rect2 is the target
if(mouseX + rect1HalfSide > blockX - rect2HalfSide
&& mouseX - rect1HalfSide < blockX + rect2HalfSide
&& mouseY + rect1HalfSide > blockY - rect2HalfSide
&& mouseY - rect1HalfSide < blockY + rect2HalfSide
) {
//do stuff...
}

Notice that separating things out onto lines makes it a bit more readable and there's no || (OR) being used...

harrison...

Re: Re: Collision Detection in 2D Squares

3 years ago

Ah, that's a neat little function rectMODE thanks! I like this format too

Thank you!

Top Reply