Spawning Trees and Boulders on Texture2d

Anyone want to explain how I do this? my planet generates out with different textures around, would I spawn my trees and boulders on the vertices? I seen a tutorial on doing pools on youtube but I'm not sure how I'd make it so they spawn on locations, so I want trees/grass to be on my ground texture, boulders and rocks on mountain texture.

 

Definitely want to go back to here (Learn) and take a look at a few of the tutorials to see how this sort of thing is commonly done.

 

Wouldn't I just use the texture height of my terrain? to spawn trees out and about and then use identity for the rotation?

 

If your terrain is 2D sideview (like one giant sprite) then you need to write code to find the pixel edges of the ground going across. Or you can put custom polygon colliders on them and use that to test.

If instead your texture is a 2D heightmap representation of a Unity3D terrain object (for a 3D game), then it is a completely different problem to find the height at a given point.