Terrain, Maths and hills

Heres a quick bit of code you can copy and paste to see for yourself:-

Graphics3D 640,480,16,2
SetBuffer BackBuffer()

TerraSize=128
x_scale=10
y_scale=50
z_scale=10 

radius# = 1

camera=CreateCamera()
PositionEntity camera,(TerraSize*x_scale)/2,50,-10
RotateEntity camera,30,0,0

light=CreateLight()
RotateEntity light,90,0,0

terra=CreateTerrain(TerraSize)
TerrainDetail terra,3000
ScaleEntity terra,x_scale,y_scale,z_scale
EntityPickMode terra,2

; Texture terrain
grass_tex=LoadTexture("tex.jpg")
EntityTexture terra,grass_tex

While Not KeyDown(1)

If KeyHit( 17 )=True Then enable=1-enable : WireFrame enable

If MouseDown(1)
	CameraPick(camera,MouseX(),MouseY())
	TFormPoint(PickedX(), PickedY(), PickedZ(), 0, Terra)
	x = TFormedX()
	z = TFormedZ()
	radius = 1
End If 

If KeyDown(30) 
	radius = radius + (TerrainHeight(terra,x,z));+0.3
		For xx=-radius*5 To radius*5
			For zz=-radius*5 To radius*5
 				x1=xx+x
 				z1=zz+z
 				e#=Sqr(xx*xx+zz*zz)
 			
				h#=(radius#/10)-(e/Sqr( (radius)*(radius) + (radius)*(radius) ) )
				If h# > TerrainHeight(terra,x1,z1)
 					h1#=-Cos(h*180.0)/2.0+0.5
					If h1<0.0 Then h1=0.0 
 			        If h1>1.0 Then h1=1.0 
	
 					ModifyTerrain terra,x1,z1,h1
				End If 
			Next
		Next
End If

RenderWorld 
Text 0,40,"Terrain Height: "+ TerrainHeight(terra,x,z)
Flip

Wend

End

First, click somewhere on the terrain in front of the camera, then hold down A to make it grow, and you'll see what I mean.

Its a poser, it really is!

Dabz