[Galaxy] Finding Terrain Direction/Angle

[Juxtapoz]

I have a unit colliding with terrain and need help finding the direction the terrain hit was facing.
My unit is a flying unit that ignores terrain height, and collision is detected by the Z of the unit being lower than the Z of the world height.
Terrain can be facing 8 possible ways, the standard 4, and the 4 diagonals.
I attempted to find it through checking point(x+1,y) and point(x-1, y) (then vise versa for the y's), to find which side of the terrain had a higher Z point, but it doesn't have 100% accuracy. I don't need the exact angle of the wall, just if it is closer to 0, 45, 90, etc.
Anyone know a solution? thanks for any help!

 

[Dr Super Good]

The terrain is made up of a node mesh which is used to create triangles. Simply find the height of the 3 nearest nodes (terrain is made of triangles) and then work out the normal vector.

Using the normal vector, you can do terrain deflections or anything needing the angle of the terrain.

 

[Juxtapoz]

How would I find the height of the nearest 3 nodes? and thanks, triangles explains why I'm getting the numbers I'm getting.

 

[Dr Super Good]

by getting the position of the nodes and then measuring their height. It will always be 2 from a diagonal (as the mesh I think faces all 1 direction) and then 1 from the nearest other side.

 

[Juxtapoz]

i'm not really getting how to find these nodes lol.
I have collision point c, which is somewhere on the side of a terrain cliff. I don't get what diagonal you're talking about either. sorry, i've never heard of any of this before...

 

[Dr Super Good]

Each square in SC2 is 1*1 unit with diagonals running from origan (lower left) to maximum (upper right).

Thus the 3 nodes which form the triangle are found via.
1. Rounding both X and Y fixed value down to whole unit.
2. Rounding both X and Y fixed values up to nearest unit.
3. Checking if the gradient from node 1 to position is greater than 1 meaning upper left or less than 1 meaning lower right.

This will give you a triangle (3 points of X,Y,Z) from which you can compute the normal to it.

 

[Juxtapoz]

Oh I see now haha. Thanks!