loadPixel()+updatePixels() issue with P3D

lubimaer

Hi,

I have an app showing 2 windows with exactly the same images (taken from a Video stream)

I would like to make one of those images brighter than the other

I've created a simple method to increase the brightness of each pixel in the image

Because I've seen the method was returning images inverted in x and y I've commented out the part that change brightness on the pixels so the following code should not do anything else other than loadPixels() and updatePixels()

class ImgProcess {
  ImgProcess () {
  }

  void setBrightness (PImage pi, int brightness_level_percent) {
    int ba = (int) ((float) brightness_level_percent * 2.55); 

    pi.loadPixels();

    //for (int iii = 0; iii < pi.pixels.length; iii++) {
    //  int r = (int) constrain(red(pi.pixels[iii]) + ba , 0, 255);
    //  int g = (int) constrain(green(pi.pixels[iii]) + ba, 0, 255);
    //  int b = (int) constrain(blue(pi.pixels[iii]) + ba, 0, 255);
    //  pi.pixels[iii] = color(r, g, b);
    //}
    pi.updatePixels();
  }
}

This code is still inverting axis for the image

I have the feeling this is a trivial mistake I'm doing here!!!

Any idea why calling this method swap x and y of my image?

Thanks, Marco

lubimaer

I've narrowed down the weird behavior to a simple example

In my case the following code draw a line from the top-left to the bottom right

PGraphics offscreen;

void setup() {
  size(300,300,P3D);

  offscreen = createGraphics(300, 300,P3D);
}

void draw() {
  offscreen.beginDraw();
  offscreen.background(255, 0);
  offscreen.line(0, 0, offscreen.width, offscreen.height);
  offscreen.endDraw();

  // add back this two lines to see the issue
  //offscreen.loadPixels();
  //offscreen.updatePixels();

  image(offscreen,0,0);
}

But if I'm adding back the two lines:

      //offscreen.loadPixels();
      //offscreen.updatePixels();

I'm actually getting a line from top-right to bottom-left

I've also found how to solve the issue: remove the P3D renderer from size() and createGraphics()

Can somebody confirm this is a real problem or is just an issue with my machine?

Thanks, Marco

kfrajer

Hey

I have the same problem. I solved it by using updatePixels() instead of offscreen.updatePixels()

I do find it odd. For this case I will stick to what I have seen in examples: they call updatePixels() by itself.

Kf

lubimaer

Hi Kf,

Thank for confirming that.

(Unfortunately I can't use just updatePixels(); my final code is more complex than my example here.)

I've opened a issue ticket in GitHub

https://github.com/processing/processing/issues/4637

Marco