FOSS gamedev and creative worlds

Posted: **Mon Feb 20, 2017 21:30**

Someone that know how to calculate / or know where to find code, to check if an object is in field of view?

I think it could be something to sneak behind mobs without to be detected.

Posted: **Mon Feb 20, 2017 23:01**

VanessaE in IRC wrote:there's a line-of-sight call or two in the API I think
https://github.com/minetest/minetest/blob/master/doc/lua_api.txt#L2323

I decided not to wait for someone to see this and asked there too :P

Posted: **Tue Feb 21, 2017 03:16**

See if this can help. I think it's mostly on a two plane but it might work.

http://blog.wolfire.com/2009/07/linear- ... rs-part-2/

Posted: **Tue Feb 21, 2017 15:37**

line-of-sight checks if something is blocking the view.

the tutorial at blog.wolfire.com works as long the bot is looking at same direction (weird), but was usefull.

Posted: **Tue Feb 21, 2017 21:43**

AiTechEye wrote:Someone that know how to calculate / or know where to find code, to check if an object is in field of view?

I think it could be something to sneak behind mobs without to be detected.

It would be almost impossible to determine the exact FOV of any client/view mode. You could possibly make a reasonable approximation but that wouldn't help without a lot of complicated trigonometry. `minetest.line_of_sight` is about the best we've got right now, though I believe there is a PR for better ray-casting support.

If the mob checks the LOS towards you and if that is not blocked by a node then it can 'see' you.

Posted: **Tue Feb 21, 2017 21:49**

After a few hours of googling and testing, i got this idea, and its a lot easier:
if the object is nearer then the position front of it

so its just to check if the player is front of the mob

so you gets a viewfield that looks like this

Your phone or window isn't wide enough to display the code box. If it's a phone, try rotating it to landscape mode.

Code: Select all: function is_front_of(pos1,pos2) local pos1=self.object:getpos() local pos2=ob:getpos() local l1=distance(pos1,pos2) local l2=distance(aliveai.pointat(self,1),pos2) return l1>l2 end function distance(pos1,pos2) return math.sqrt((pos1.x-pos2.x)*(pos1.x-pos2.x) + (pos1.y-pos2.y)*(pos1.y-pos2.y)+(pos1.z-pos2.z)*(pos1.z-pos2.z)) end function pointat(self,d)-- get position front of object local pos=self.object:getpos() local yaw=self.object:getyaw() d=d or 1 local x =math.sin(yaw) * -d local z =math.cos(yaw) * d return {x=pos.x+x,y=pos.y,z=pos.z+z} end

Posted: **Tue Feb 21, 2017 22:09**

You really should use the built-in vector helpers, for distance especially. It still looks to me like a rather inefficient way to accomplish this, though I do not fully understand your requirements.

Posted: **Tue Feb 21, 2017 22:39**

i need them to this mod, but this easy version works too :-)

in my case its too late to use the helpers, because i had no idea there was such features in minetest when i started this mod project a few months ago.

https://forum.minetest.net/viewtopic.php?f=11&t=16083

minetest.line_of_sight checks if you are behind something, so you can hide behind flowers...
(im using a more useful function for that)

FOSS gamedev and creative worlds

[≈ solved] Check if an object is in field of view?

[≈ solved] Check if an object is in field of view?

Re: Check if an object is in field of view?

Re: Check if an object is in field of view?

Re: Check if an object is in field of view?

Re: Check if an object is in field of view?

Re: Check if an object is in field of view?

Re: Check if an object is in field of view?

Re: [≈ solved] Check if an object is in field of view?