find distance to edge

Programming Questions

clankill3r

in Programming Questions • 1 year ago

How can i find the distance to the edge pointing from the center in the direction of the mouse?

or... check bottom post

PVector center;
void setup() {
size(400, 400);
smooth();
center = new PVector(width/2, height/2);
}
// . . . . . . . . . . . . . . . . . . .
void draw() {
background(255);
ellipse(center.x, center.y, 5, 5);
line(mouseX, mouseY, center.x, center.y);
float d1 = dist(mouseX, 0, center.x, center.y);
float d2 = dist(0, mouseY, center.x, center.y);
float d = (d1+d2)/2;
translate(center.x, center.y);
float a = atan2(mouseY - center.y, mouseX - center.x );
rotate(a);
line(d, 0, 0, 0);
}
// . . . . . . . . . . . . . . . . . . .

if i have a grid float[][]

[][][][][][][][][][][][]

then i want to know the distance between the center and any other index to the edge.

For example:

c = center of 2d array

i = index

p = what i'm interested in since it's the edge in the direction c i.

[][][p][][][][][][][][][]

[][][][][][][][][][][][]

[][][][][i][][][][][][][]

[][][][][][][c][][][][][]

[][][][][][][][][][][][]

Replies(6)

cedrickie..

Re: find distance to edge

1 year ago

Still working, good good :)

PVector center;
void setup() {
size(400, 400);
smooth();
center = new PVector(width/2, height/2);
}
// . . . . . . . . . . . . . . . . . . .
void draw() {
background(255);
rectMode(CENTER);
int rectS = 250;
rect(center.x, center.y, rectS, rectS);
ellipse(center.x, center.y, 5, 5);
float d1 = dist(mouseX, 0, center.x, center.y);
float d2 = dist(0, mouseY, center.x, center.y);
float d = (d1+d2)/2;
translate(center.x, center.y);
float a = atan2(mouseY - center.y, mouseX - center.x );
rotate(a);
float magnitude;
float cos_angle= abs(cos(a));
float sin_angle= abs(sin(a));
if (rectS/2/ cos_angle <= rectS/2/ sin_angle)
magnitude= abs(rectS/2/ cos_angle);
else
magnitude= rectS/2/ sin_angle;
line(magnitude, 0, 0, 0);
}

edit: you added the grid example,sounds like another question to me...

clankill3r

Re: find distance to edge

1 year ago

haha didn't expect a reply from you :)

Well i want to apply the same idea for a grid, i explain later :)

need some sleep.

clankill3r

Re: find distance to edge

1 year ago

how can i let the circle follow the ellipse on the position of the line?

(Run the sketch and you know what i mean)

PVector center;
void setup() {
size(400, 400);
smooth();
center = new PVector(width/2, height/2);
}
// . . . . . . . . . . . . . . . . . . .
void draw() {
background(255);
pushMatrix();
rectMode(CENTER);
int rectW = 250;
int rectH = 100;
float maxXDist = rectW/2;
float maxYDist = rectH/2;
rect(center.x, center.y, rectW, rectH);
ellipse(center.x, center.y, 5, 5);
translate(center.x, center.y);
// it should follow something like this
ellipseMode(CENTER);
ellipse(0, 0, rectW, rectH);
float a = atan2(mouseY - center.y, mouseX - center.x );
rotate(a);
float magnitude;
float targetMagnitude;
float cos_angle = abs(cos(a));
float sin_angle = abs(sin(a));
if (rectW/2/ cos_angle <= rectH/2/ sin_angle) {
magnitude = abs(rectW/2/ cos_angle);
}
else {
magnitude= rectH/2/ sin_angle;
}
line(magnitude, 0, 0, 0);
popMatrix();
fill(255, 0, 0);
float x = (cos(a)) * maxXDist;
float y = (sin(a)) * maxYDist;
ellipse(x+center.x, y+center.y, 9, 9);
noFill();
text(degrees(a), 20, 20);
}

clankill3r

Re: find distance to edge

1 year ago

someone?

Here you can see what i mean, the big white ellipse is the mouse position.

From the center the line goes in the good direction and stops at the edge.

The red ellipse however is not at the good position.

benja

Re: find distance to edge

1 year ago

I think don't like ellipses, the formulas do not look pretty.
Try this in line 57ff:

float x = (rectW/2 * rectH/2) / sqrt(sq(rectH/2) + sq(rectW/2)* sq(tan(a)));
if(abs(a) > PI/2){
x *= -1;
}
float y = tan(a)*x;

clankill3r

Re: find distance to edge

1 year ago

works, thanks :)

Top Reply