Triangle-Point Collision Detection Algorithm

Last edited by abhuva on Thu Oct 06, 2011 1:29 pm; edited 1 time in total

You may wonder what this shall be, so let me introduce first to my basic idea:

I wanted to be able to check what region a given party is into (for example if player is in snake land, or ashenborn etc..). Based on this i want to further improve my Unique Battlefields idea (region specific battlefields).
Now to implement this i wanted to put hidden partys at the regions border points and check if the player is inside the n-poly this forms.

The solution is to break this down further and make a check if the player is inside a given triangle.
Based on this article: http://www.blackpawn.com/texts/pointinpoly/default.html
i tried my own implementation into the module-system.
After some problems (ms dont let me use floating point variables) i finally have a working algorithm.

Now we could use this for a lot of stuff.
Basicly it just checks if a party A is inside the triangle formed from party B,C and D...
This can be either towns etc.. but also moving parties like lords.

Maybe this is usefull for other stuff too like AI-coding, rumors-coding (rumors based on the land you are in) etc...

Currently the code is still in development, but i wanted to share my first working version:

Spoiler:

You pass 4 party id´s .. the first is the party which shall get tested.
reg0 will be 0 if its failed and 1 if its inside the triangle.

Example:
(call_script,"script_point_triangle_collision","p_main_party","p_town_7","p_village_30","p_village_31"),
(try_begin),
(gt, reg0, 0),
(display_message, "@Test passed..."),
(else_try),
(display_message, "@Test failed..."),
(try_end),

Insidious Diety Posts : 2523 Join date : 2009-07-17

Impressive stuff Abhuva. We could also use this to create zones around Town (connect all the villages around it up) and then do a check to see what is inside that. This could then connect to the rumour system and be able to give out info.

Say Syla was inside the "Rachim Zone" then a rumour would say "X told me that Syla has been seen near Rachim"

Updated first post with the script and a example how to use.