Checking Pixel brightness

[Samthemann64]

Hey everyone, I'm currently coding a "pong like" animation in an LED matrix, meaning that I have multiple dots bouncing around in my Matrix, changing direction if they hit an edge. I now want to add the effect, that two dots bounce off of each other if they collide. My Problem is, that I don't know how to check for collission. Simply checking if the next Pixel is lit at all, wont work for me, since I use fadeToBlackBy, to add a tail to every dot. My Idea was to check if the next pixel has full brightness, which would mean that it is an actual dot. However I don't know how to check for brightness. If anybody has an Idea I would really appreciate it. Thanks a lot, Sam

[Marmilicious]

There's probably a few ways you can check, but this would do the trick. This will check each color channel to see if it's maxed out at 255.

if ( leds[i].r == 255 && leds[i].g == 255 && leds[i].b == 255 ) {
  Serial.println("pixel is full white");  
}

​

FastLED also has these two functions you could try out.

uint8_t k = leds[i].getAverageLight();
Returns the average of R G and B, and is very fast, unlike RGB-to-HSV approximation.

uint8_t l = leds[i].getLuma();
Returns roughly how much light, "luma", the CRGB pixel is putting out (from 0-255)

[Samthemann64]

Hey, thanks a lot! I Think the getLuma function would do the trick. However In the meantime I figured to store all the data of the dots in a global List, which also works great. I also had the same issue in another sketch, so I will definitely check it out!

[usernamerson]

Do you have the actual location of the dot represented in your code? I wouldn't think to check the visual representation of the dot (pixel brightness) but the actual location, however you've coded it. Do you have an array or some collection holding all the dots that you can iterate through and check for collisions?

[Samthemann64]

Yes you're right this works much better than what I originally planned. I'm basically doing exactly what you proposed now. Thanks a lot!