; CreateMesh Example
; ------------------

; CreateMesh creates an empty mesh with no geometry at all.
; We then add a surface, add vertices, and connect them with
; triangles to build a ramp entirely by hand.

Graphics3D 640,480
SetBuffer BackBuffer()

camera=CreateCamera()
PositionEntity camera,0,1,-6

light=CreateLight()
RotateEntity light,45,30,0

; Create the blank mesh - the documented command
ramp=CreateMesh()

; Surfaces hold the actual triangles (a surface must belong to a mesh)
surf=CreateSurface(ramp)

; Six vertices, one per corner of a wedge shape
v0=AddVertex(surf,-2,0,-1) ; bottom front left
v1=AddVertex(surf,-2,0,1)  ; bottom back left
v2=AddVertex(surf,2,0,1)   ; bottom back right
v3=AddVertex(surf,2,0,-1)  ; bottom front right
v4=AddVertex(surf,-2,2,-1) ; top front left
v5=AddVertex(surf,-2,2,1)  ; top back left

; Triangles are one-sided: list each triangle's vertices in clockwise
; order as seen from OUTSIDE the ramp, or that face will be invisible
AddTriangle surf,v0,v3,v2 ; bottom half 1
AddTriangle surf,v0,v2,v1 ; bottom half 2
AddTriangle surf,v0,v4,v3 ; front face
AddTriangle surf,v1,v2,v5 ; back face
AddTriangle surf,v0,v1,v5 ; left side half 1
AddTriangle surf,v0,v5,v4 ; left side half 2
AddTriangle surf,v2,v4,v5 ; slope half 1
AddTriangle surf,v2,v3,v4 ; slope half 2

; Point the normals outwards so the light shades the ramp correctly
UpdateNormals ramp

EntityColor ramp,90,180,255

wire=0

While Not KeyDown(1)

    ; Space toggles wireframe so you can see the triangle structure
    If KeyHit(57) Then wire=1-wire : WireFrame wire

    ; Keep the ramp slowly turning
    TurnEntity ramp,0,1,0

    ; 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,"Space: toggle wireframe   Arrow keys: move camera   Esc: exit"
    Text 0,20,"CreateMesh ramp: 6 vertices, 8 triangles built by hand"

    Flip

Wend

End