Misadventures in Shaderland: the jumping uniform array element

I work on OpenGL ES for an Android and iOS app, and from time to time a weird glitch shows up on a specific device (or a set of devices with the same GPU series). This was one of those times.

So, I was writing a new GLSL shader and all was going well. This shader has a uniform array as input, that is used to move the vertices dynamically along a polyline, without the need to reload geometry:
#define POLYLINE_SIZE 16 uniform highp vec2 u_polyline[POLYLINE_SIZE];
Then, the vertex shader is doing the following to interpolate a position between two points of the polyline:
vec2 pt1 = u_polyline[int(idx)]; vec2 pt2 = u_polyline[int(idx)+1]; vec2 pos = pt1 + (pt2 - pt1) * idx_diff;
That worked correctly, and the vertices were moving smoothly along the polyline, based on some data that is specific to each vertex. That was until I tested the app on a Nexus 7 (2nd Gen). On that device, which has an Adreno 320 GPU, vertex positions seemed to be a displaced. After checking every…

Home Assistant: Notify when a light was left on and no one is at home

I'm using Home Asisstant for about a year now, and this is one of those things that I wanted to add for a long time, but have been postponing it. Until a few days ago, when I've arrived home and found out that one of the lights was on all day. Actually, after checking the Home Assistant log, it was my cat that triggered a motion sensor, that turned the light on (more about cats and motion sensors in a future post).
The basic idea here is that if I'm not at home for more than 30 minutes and a light is on (or turns on), I get a notification on my phone. For sending notifications from Home Assistant to my phone, I'm using the Pushbullet component.
I already had a group were I list all the controllable lights in the house and I wanted to be able to use this group directly in the automation, so I don't have to define every light in two separate places. Also, I want to be able to exclude some lights from triggering a notification (but I don't want to remove them fro…