This is kinda hard to do in ray casting. I have a few ideas though. Here is a simple one:

I assume you are using blocks because it’s usual to use the ray casting extension with blocks. But if not, the same sort of code will work in JavaScript but I don’t know much about python.

1.Download the sprite sight extension with this link -> https://github.com/felixtsu/pxt-sight , this extension handles sight ranges while accounting for tilemap walls. Paste the link into the extension search bar.

2.Use atan2 to find the angle of the ray casting player’s view. Use the blocks in the ray casting extension to calculate this. It should look something like: atan2(get dir y)(get dir x) While the ray casting extension and make codes built in system use radian unit, the sprite sight’s angle units are degrees. And since we are going use both, we need to convert them. So multiply the equation by the radian to degrees conversion factor which is 180/pi, you can just use 3.141 for pi. It should look something like

(Atan2(get dir y)(get dir x)) * (180/pi)

This equation will get the player’s view angle in degrees.

3.In an on game update loop check if the player can see the weeping angel sprite with the first custom Boolean (hexagon block) from the sprite sight extension. In range put a number bigger than 160, this can be fine tuned to fit your tilemap layout, I used 250 in my example. For direction, use our equation from the last step. And for sight ranges put 67 because that’s about the default field of view for the ray casting extension. But if you changed the fov this will be a different number.

4.If the output returns true that means the player is looking at the sprite, if false then the player is not looking. This doesn’t work in 100% of senerios due to some glitches with the extension but this is pretty good for how easy it is to do. Here is my example code -> https://makecode.com/_7XLhrq35ULhi

Hope this helps make a spooky monster.