Reflection

[Gekigengar]

Hi, I wanted to simulate a reflection,
in my missile system.

http://en.wikipedia.org/wiki/File:Corner-reflector.svg
http://en.wikipedia.org/wiki/File:Fényvisszaverődés.jpg
http://en.wikipedia.org/wiki/File:Reflection_angles.svg

Assuming you know the position of the shooter,
direction to which its shot to,
Position on where it hits a wall (how do we find the normal of the wall? )
Direction of the bullet.

how do i do this?

i saw maps like Elimination tournament are able to do this.

anyone give me a hint or idea?

 

[Gekigengar]

:/ Bump

 

[Gekigengar]

After further research, i found that there is a way on how to find the normal of a terrain using Vector system created by Anitarf

http://www.wc3c.net/showthread.php?t=87027

could anybody explain me how it work? and what to do?

can it be used to find the normal of pathing blockers?

 

[-Kobas-]

Hmm it depends on your map, if you use cliffs you can detect projectile Z coordinate and if it's value higher than some constant you set you can then handle reflection.

If you don't use cliffs you can use dummy units for example and check is projectile in range of dummy each time when you move it, and so on.

You can use recs as well.

Well it depend on map really, decide will you code this to work for your map or to be public resource.

 

[Gekigengar]

What i want to achieve is, how does it detects the terrain's normal?
i know very little of jass, and its very limited.

and i wanted to create one for pathing blockers (assuming they count as infinite height).
since my map mostly contains doodads, and there is no "Cliffs" around.

I hear from someone in chat, that is familiar with the system, that its possible to do with pathing blockers, but its a "bit" more complex.

3 equations or so i hear. i forgot what he said xD

 

[Garfield1337]

When using vectors for unit or projectile movement, you add vector's coordinates to unit's.
So you start off by finding the vector with which the projectile should move.
To get vector between 2 locations, you subtract coordinates of location towards which vector should point to with coordinates of location from which vector should point (which is projectile's starting location). The resulting coordinates are coordinates of your vector. This vector has proper direction, but length of distance between those locations.
Now you set vector's length using setLength function from Antiarf's library to the speed of the projectile (the speed per tick, which is usually how much the projectile moves each 0.03 secs).
In the looping trigger, assuming v is your vector and p projectile, do this:

SetUnitX(p) = GetUnitX(p) + v.x //vector's X
SetUnitY(p) = GetUnitY(p) + v.y //Y
SetUnitZ(p) = GetUnitZ(p) + v.z //Z

Z functions

library Z
    globals
        private location l = Location(0.00,0.00)
    endglobals  

    function GetUnitZ takes unit u returns real
        call MoveLocation(l, GetUnitX(u), GetUnitY(u))
        return GetUnitFlyHeight(u) + GetLocationZ(l)
    endfunction

    function SetUnitZ takes unit u, real z returns nothing
        call MoveLocation(l, GetUnitX(u), GetUnitY(u))
        return SetUnitFlyHeight(u, z - GetLocationZ(l), 0)
    endfunction

endlibrary

When hitting terrain or cliffs (when projectile's height is 0), use createTerrainNormal function to make a terrain normal vector, project movement vector on terrain normal one and add the projection to the movement vector.

For pathing blockers, it depends how you place them :X
If they form straight lines on map edges, for example, you can, when projectile flies over them, enumerate nearby pathing blockers to find angle between them. Then create a vector perpendicular to this line and add it to the movement vector.