; FindSurface Example
; -------------------

; FindSurface retrieves the surface of a mesh that was created with a
; given brush - handy for picking one material group out of a mesh.
; It returns the surface handle, or 0 if no surface matches.

Graphics3D 640,480
SetBuffer BackBuffer()

camera=CreateCamera()
PositionEntity camera,0,0,-5

; Two brushes: grey stone and glowing lava
stone=CreateBrush()
BrushColor stone,130,130,140
lava=CreateBrush()
BrushColor lava,255,120,0

; One mesh with two surfaces, one per brush
mesh=CreateMesh()

; Left quad: created with the stone brush
s1=CreateSurface(mesh,stone)
v0=AddVertex(s1,-2.1,1,0)
v1=AddVertex(s1,-0.1,1,0)
v2=AddVertex(s1,-0.1,-1,0)
v3=AddVertex(s1,-2.1,-1,0)
AddTriangle s1,v0,v1,v2
AddTriangle s1,v0,v2,v3

; Right quad: created with the lava brush
s2=CreateSurface(mesh,lava)
v0=AddVertex(s2,0.1,1,0)
v1=AddVertex(s2,2.1,1,0)
v2=AddVertex(s2,2.1,-1,0)
v3=AddVertex(s2,0.1,-1,0)
AddTriangle s2,v0,v1,v2
AddTriangle s2,v0,v2,v3

; Fullbright so the brush colours show without lighting setup
EntityFX mesh,1

; The documented command: fetch whichever surface used the lava brush
found=FindSurface(mesh,lava)

While Not KeyDown(1)

    ; Bob the FOUND surface's vertices up and down to prove we
    ; grabbed the right one - the stone quad is untouched
    wob#=Sin(MilliSecs()*0.3)*0.2
    VertexCoords found,0,0.1,1+wob,0
    VertexCoords found,1,2.1,1+wob,0
    VertexCoords found,2,2.1,-1+wob,0
    VertexCoords found,3,0.1,-1+wob,0

    ; Arrow keys move the camera
    If KeyDown(200) Then MoveEntity camera,0,0,0.1
    If KeyDown(208) Then MoveEntity camera,0,0,-0.1
    If KeyDown(203) Then TurnEntity camera,0,1,0
    If KeyDown(205) Then TurnEntity camera,0,-1,0

    RenderWorld

    Text 0,0,"Arrow keys: move camera   Esc: exit"
    Text 0,20,"FindSurface(mesh,lava) = "+found+" (0 would mean not found)"
    Text 0,40,"Only the found (orange) surface is animated"

    Flip

Wend

End