; ModifyTerrain Example
; ---------------------

Graphics3D 640,480,0,2
SetBuffer BackBuffer()

; Terrain layout: 32 grid squares, scaled to 10 units per square
terra_size=32
x_scale=10
y_scale=50
z_scale=10

; Overlook the terrain from a fixed camera
camera=CreateCamera()
PositionEntity camera,(terra_size*x_scale)/2,120,-60
RotateEntity camera,35,0,0

light=CreateLight()
RotateEntity light,45,45,0

; Create a flat terrain to sculpt
terrain=CreateTerrain(terra_size)
ScaleEntity terrain,x_scale,y_scale,z_scale

; Texture the terrain
grass_tex=LoadTexture("media/MossyGround.BMP")
EntityTexture terrain,grass_tex

; A red marker showing which grid point we will sculpt
marker=CreateSphere(8)
EntityColor marker,255,60,60
EntityFX marker,1

marker_x=terra_size/2
marker_z=terra_size/2

While Not KeyDown(1)

    ; Cursor keys step the marker across the terrain grid
    If KeyHit(205) And marker_x<terra_size Then marker_x=marker_x+1
    If KeyHit(203) And marker_x>0 Then marker_x=marker_x-1
    If KeyHit(200) And marker_z<terra_size Then marker_z=marker_z+1
    If KeyHit(208) And marker_z>0 Then marker_z=marker_z-1

    ; Read the current height (0 to 1) at the marker's grid point
    height#=TerrainHeight(terrain,marker_x,marker_z)

    ; Hold Space to raise the ground, Z to lower it.
    ; ModifyTerrain sets the height of one grid point.
    If KeyDown(57) And height<1
        height=height+0.005
        ModifyTerrain terrain,marker_x,marker_z,height
    EndIf
    If KeyDown(44) And height>0
        height=height-0.005
        ModifyTerrain terrain,marker_x,marker_z,height
    EndIf

    ; Sit the marker on the sculpted ground
    PositionEntity marker,marker_x*x_scale,height*y_scale+2,marker_z*z_scale

    RenderWorld

    Text 0,0,"Cursor keys: move marker   Hold Space: raise   Hold Z: lower   Esc: exit"
    Text 0,20,"ModifyTerrain terrain,"+marker_x+","+marker_z+","+height

    Flip

Wend

End