Deflection

[Garfield1337]

I'm making a movement system and i can't solve a problem.
I'm trying to make an object deflect off edge of a rectangle. (Coordinates of vertices are known; rectangle isn't static and is, in most cases, rotated.)

Pic

The main problem is i can't get the angle of perpendicular on rectangle edge (The red line).
Each time i move the object, i check if the object's coordinates are within the rectangle, if they are, a collision occurs and i need to change the object's movement vector, but i need the perpendicular's angle for that. Anyone knows how to retrieve it?
+rep for help.

 

[Pharaoh_]

Are you trying to change the camera (and by extension the unit), when it comes along with destructibles?
Why do you need the rectangle?

 

[Garfield1337]

Well...the rectangle is the area covered by a unit (vehicle), so i use it as it's pathing and i need to deflect objects that hit it.

 

[Pharaoh_]

Since the perpendicular line will create a 90 degree angle, you can make a check of (1) 90 - (Angle between points), where points = Position of vehicle and Position of the moving object. Then, when the collision occurs (define offset limit), you will move the object in x1 + 500 * Cos (Facing of Vehicle - (1)) and y1 + 500 * Sin (Facing of Vehicle - (1)).
I am bored of making rad conversions to check the result, but it looks like it's a possible way.

 

[Garfield1337]

But that, as far as i know, wouldn't work for rotated rectangle. However, i've got an idea - i can loop through each side of rectangle and see if intersects the object's movement and since i'm looping through sides, i have their angles thus the perpendiculars too.
Thanks for efforts though.

 

[Pharaoh_]

The key in this case is the vehicle's facing. You can control pretty much everything if you have an accurate facing and you do have, since you are manipulating and simulating driving, so the rectangle's rotation is or should be (for easier handling) facing-dependent.

 

[Garfield1337]

The key in this case is the vehicle's facing. You can control pretty much everything if you have an accurate facing and you do have, since you are manipulating and simulating driving, so the rectangle's rotation is or should be (for easier handling) facing-dependent.

Lol...i'm so dumb D:
Should have thought of that; yeah, i'll do it like that, thanks ;D

 

[D4RK_G4ND4LF]

search for "reflection vector"
you will need the normal vector of the surface and the incoming vector v1
the reflection vector will be 2*(v1 dot normal)*normal-v1 (or the same *-1, not sure)
the surface normal should be normalized

if you want to do this with angles you can use "the angle of incidence equals the angle of reflection" (wikipedia article is nice)

and you probably asked that or something very similar before (or someone else)

your problem is solved already but I thought you could be interested in this