Getting color from an image in the buffer ... ? Is that possible or how could I do sth similar?

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xeronimo

Getting color from an image in the buffer ... ? Is that possible or how could I do sth similar?

in General Discussion • Other • 24 days ago

Hi,

I'd like to copy my original image in a buffer or something similar and then have a walker reference the x and y of that 'copied' image for its color instead of it's own x and y. I tried to load an image to (width,0) but then all I get is black when I use something like 'x+width'. I guess because it's offscreen?

The thing is that I want the original image not to be changed so that the referenced color information won't be changed either.

So how would I do that?

Thanks a lot!

Replies(2)

Mushussu

Re: Getting color from an image in the buffer ... ? Is that possible or how could I do sth similar?

24 days ago

Hello,

You have to look to the pixels[], loadPixels() and updatePixels() :

PImage source, buffer;
boolean visible;
void setup() {
size(800, 400);
source = loadImage("http://mushussu.net/spirale.png");
// Copy the source image in the buffer image
buffer = createImage(source.width, source.height, RGB);
buffer.loadPixels();
for (int i = 0; i < buffer.pixels.length; i++) {
buffer.pixels[i] = source.pixels[i];
}
buffer.updatePixels();
visible = false;
}
void draw() {
background(255);
if (mouseX < 400) {
source.loadPixels();
for (int i = 0; i < 10; i++) {
for (int j = 0; j < 10; j++) {
source.pixels[(mouseY + j) * source.width + mouseX + i] = color(0);
}
}
source.updatePixels();
}
image(source, 0, 0);
if (visible) {
image(buffer, source.width, 0);
}
}
void keyPressed() {
if (key == ' ') {
visible = !visible;
}
if (key == 'r') {
// Restore the buffer image in the source image
source.loadPixels();
for (int i = 0; i < source.pixels.length; i++) {
source.pixels[i] = buffer.pixels[i];
}
source.updatePixels();
}
}

xeronimo

Re: Getting color from an image in the buffer ... ? Is that possible or how could I do sth similar?

24 days ago

Thank you! loadPixels was the solution indeed :)

I'm using a loadImage and loadPixels in the setup and then I have my walkers pick the color of the pixel 'beneath' them with c = myImage.pixels[int(py)*width+int(px)];

This is the result: http://p5art.tumblr.com/post/62058360012/john-malkovich-ive-used-80-small-walkers-for-a :)