trouble reading images.

Programming Questions

theguyiso..

in Programming Questions • 1 year ago

I am trying to modify this DLA script to respond to an image loaded in the background.

I can't get it to work for some reason. It seems to be responding to parts of the image and not others.

What should be happening is the points should become more dense in the areas where the red value is 58 and less dense where it is 256. This is modulated with the sticking probability parameter.

This is the image I am using.

Can someone help? This is the code am using.

//list of current circles
ArrayList circles;
//radius of the circle
public float diameter = 4;
float diameter_sq = sq(diameter);
//where to add new circles
int w = 1000;
int h = 500;
float rr = 0;
float gg = 255;
float bb = 0;
float max_distance = w;
//maximum move in x or y direction at each step
float max_move = 1;
//tie this variable into an image value
public float sticking_probability = 1;
float max_x, max_y, min_x, min_y;
PVector dla_center;
float dla_radius;
float bounds_addition = 50;
float bounds_scalar = 1.5;
//use bucking for quick interestion
HashMap buckets = new HashMap();
// FORREST ADDED TWO FUNCTIONS, fillArea and addCell
// fill an area with random green
void fillArea() {
fill(rr,gg,bb);
}
//int[][] cp = new int[w][h];
public float[] allc = new float[h+w*w];
// addCell takes the x,y position and plots a random sized dot.
void addCell(float xPosition, float yPosition) {
// for right now, we use center mode. It may be better to use corner mode.
ellipseMode(CENTER);
ellipse(xPosition, yPosition, diameter/2, diameter/2);
}
void setup() {
size(w,h);
background(255);
fill(rr,gg,bb);
loadPixels();
// Since we are going to access the image's pixels too
PImage img = loadImage("aw.png");
image(img, 0, 0);
img.loadPixels();
for (int y = 0; y < height; y++) {
for (int x = 0; x < width; x++) {
int loc = x + y*width;
// The functions red(), green(), and blue() pull out the 3 color components from a pixel.
float r = red(img.pixels[loc]);
//println(r);
allc[loc] = r;
// Image Processing would go here
// If we were to change the RGB values, we would do it here, before setting the pixel in the display window.
// Set the display pixel to the image pixel
//pixels[loc] = color(r,g,b);
}
}
smooth();
noStroke();
circles = new ArrayList();
//seed it with an initial circle in the middle
PVector first_circle = new PVector(width/2.0,height/2.0);
//draw circle
//ellipse(first_circle.x, first_circle.y, diameter, diameter);
// FORREST ADDED TO FUNCTION CALLS
fillArea();
addCell(first_circle.x, first_circle.y);
dla_center = new PVector();
max_x = min_x = dla_center.x = first_circle.x;
max_y = min_y = dla_center.y = first_circle.y;
dla_radius = 1;
circles.add(first_circle);
//add first_circle to the bucket
int x_index = int(first_circle.x/diameter);
int y_index = int(first_circle.y/diameter);
Integer index = new Integer(((x_index <<16) >>> 16) | (y_index << 16));
if(buckets.containsKey(index)) ((ArrayList) buckets.get(index)).add(first_circle);
else {
ArrayList new_bucket = new ArrayList();
new_bucket.add(first_circle);
buckets.put(index, new_bucket);
}
}
void draw() {
addCircle();
}
void addCircle() {
//computer lower and upper bounds of space
float bound_radius = dla_radius*bounds_scalar+bounds_addition;
float bound_radius_sq = sq(bound_radius);
//rect(lower_bound_x,lower_bound_y,upper_bound_x-lower_bound_x, upper_bound_y-lower_bound_y);
fill(rr,gg,bb);
//make a new circle on the bounds at a random angle
float angle = random(0,TWO_PI);
PVector current_circle = new PVector(cos(angle)*bound_radius+dla_center.x,sin(angle)*bound_radius+dla_center.y);
//move the circle randomly until it hits the an existing circle
while(true) {
if(intersect(current_circle)) {
int loc = int(current_circle.x) + int(current_circle.y)*width;
// if(xPosition<height && yPosition<width){
// sticking_probability = allc[loc]/1000;
// }
if(current_circle.x>height && current_circle.y<width && current_circle.y>0){
//println("uuu");
//println(allc[loc]);
if(allc[loc] == 58.0){
//sticking_probability = allc[loc]/1000;
sticking_probability = 0.01;
}
if(allc[loc] == 255.0){
sticking_probability = 1;
//println("zzzz");
}
//println("shit2");
//fill(allc[loc]);
//println(sticking_probability);
//println("zzz2");
}
if(random(1.0) < sticking_probability) {
gg -= 0.2;
bb += 0.2;
//println(allc[loc]);
break;
}
else {
//move away
}
}
current_circle.add(random(-max_move, max_move),random(-max_move, max_move),0);
//wrap around so it cannot get too far away
//get the vector from dla_center to current_circle
PVector center_to_circle = PVector.sub(current_circle,dla_center);
float sq_dist = sq(center_to_circle.x)+sq(center_to_circle.y);
if(sq_dist > bound_radius_sq) {
float prev_dist = sqrt(sq_dist);
float new_dist = 2*bound_radius-prev_dist;
center_to_circle.mult(-new_dist/prev_dist);
current_circle.x = center_to_circle.x+dla_center.x;
current_circle.y = center_to_circle.y+dla_center.y;
}
}
// ellipse(current_circle.x, current_circle.y, diameter, diameter);
fillArea();
//int loc = int(current_circle.x) + int(current_circle.y)*width;
//println(height);
//println(current_circle.x);
//println(width);
//println(current_circle.y);
//println("l");
//if(current_circle.x>height && current_circle.y<width && current_circle.y>0){
//sticking_probability = allc[loc]/1000+0.00001;
//println("shit");
//println(sticking_probability);
//println("zzz");
//}
//else{
//sticking_probability = 0.25;
//println("yo");
//}
addCell(current_circle.x, current_circle.y);
//update bounds
PVector center_to_circle = PVector.sub(current_circle,dla_center);
float sq_dist = sq(center_to_circle.x)+sq(center_to_circle.y);
if(sq_dist > sq(dla_radius)) {
float curr_dist = sqrt(sq_dist);
float to_move = (curr_dist-dla_radius)/2;
dla_radius+=to_move;
center_to_circle.mult(to_move/curr_dist);
dla_center.add(center_to_circle);
}
circles.add(current_circle);
//add circle to the buckets
int x_index = int(current_circle.x/diameter);
int y_index = int(current_circle.y/diameter);
Integer index = new Integer(((x_index <<16) >>> 16) | (y_index << 16));
if(buckets.containsKey(index)) ((ArrayList) buckets.get(index)).add(current_circle);
else {
ArrayList new_bucket = new ArrayList();
new_bucket.add(current_circle);
buckets.put(index, new_bucket);
}
}
boolean intersect(PVector circle) {
ArrayList near_circles = new ArrayList();
int x_index = int(circle.x/diameter);
int y_index = int(circle.y/diameter);
//get nearby points
Integer index = new Integer(((x_index <<16) >>> 16) | (y_index << 16));
if(buckets.containsKey(index)) near_circles.addAll((ArrayList) buckets.get(index));
index = new Integer((((x_index-1) <<16) >>> 16) | (y_index << 16));
if(buckets.containsKey(index)) near_circles.addAll((ArrayList) buckets.get(index));
index = new Integer((((x_index+1) <<16) >>> 16) | (y_index << 16));
if(buckets.containsKey(index)) near_circles.addAll((ArrayList) buckets.get(index));
index = new Integer(((x_index <<16) >>> 16) | ((y_index-1) << 16));
if(buckets.containsKey(index)) near_circles.addAll((ArrayList) buckets.get(index));
index = new Integer((((x_index-1) <<16) >>> 16) | ((y_index-1) << 16));
if(buckets.containsKey(index)) near_circles.addAll((ArrayList) buckets.get(index));
index = new Integer((((x_index+1) <<16) >>> 16) | ((y_index-1) << 16));
if(buckets.containsKey(index)) near_circles.addAll((ArrayList) buckets.get(index));
index = new Integer(((x_index <<16) >>> 16) | ((y_index+1) << 16));
if(buckets.containsKey(index)) near_circles.addAll((ArrayList) buckets.get(index));
index = new Integer((((x_index-1) <<16) >>> 16) | ((y_index+1) << 16));
if(buckets.containsKey(index)) near_circles.addAll((ArrayList) buckets.get(index));
index = new Integer((((x_index+1) <<16) >>> 16) | ((y_index+1) << 16));
if(buckets.containsKey(index)) near_circles.addAll((ArrayList) buckets.get(index));
//find intersection with nearby points
for(Iterator it = near_circles.iterator();it.hasNext();) {
PVector circle2 = (PVector) it.next();
float dist_sq = sq(circle2.x-circle.x)+sq(circle2.y-circle.y);
if(dist_sq < diameter_sq) return true;
}
return false;
}
void mouseClicked() {
println(mouseX);
println(mouseY);
println(allc[mouseX + mouseY* width]);
}

Replies(2)

theguyiso..

Re: trouble reading images.

1 year ago

I think it might have something to do with the way I am indexing the values from the image. Does anyone have any ideas?

Any help at all would be amazing I am stuck on this...

jbum

Re: trouble reading images.

1 year ago

The problem. Well, the problem that's stumping you (there are many problems), is this line:

if(current_circle.x>height && current_circle.y<width && current_circle.y>0){

This condition is rarely true (because usually, x is going to be less than height, and x shouldn't be compared to height anyway), so the code that triggers your sticking_probability checks never happens. I think you probably intended to do a valid bounds check, more like this.

if(current_circle.x >= 0 && current_circle.x<width &&

current_circle.y >= 0 && current_cyrcle.y<height){

When I made this fix, your code worked as intended.

I should mention that this is really sloppy code and is full of mistakes. This is why you didn't get any help the

first time you posted it. It's just a train wreck, and it's hard to know where to begin. Many of the gaffes are somewhat harmless, but may bite you in the ass in the future. For example this line:

public float[] allc = new float[h+w*w];

I think what was intended was

new float[h*w];

If you change to a sketch that is taller than wide, you will start getting array out of bounds errors, as currently written.

That's lots more like this.

The section that begins

//get nearby points

Integer index = new Integer(((x_index <<16) >>> 16) | (y_index << 16));

if(buckets.containsKey(index)) near_circles.addAll((ArrayList) buckets.get(index));

Is bizarrely repetitive. It can probably be shortened to 4 lines.

Finally, the presence of all the commented out code makes this very hard to read. Remove that shit. If you're worried about losing that stuff, make a backup copy. Clean code is easier to debug.

So, to summarize, if you want help on this forum:

1) Remove old commented out code.

2) Carefully check every line before asking for help.

3) If a picture is needed, post a link to an archive of your project so we don't have to reconstruct it.

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