blitz3d/_release/help/commands/3d_examples/CreateMesh.bb

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

; In this example, we will create a custom mesh. This custom mesh will be in the shape of a ramp.

Graphics3D 640,480
SetBuffer BackBuffer()

camera=CreateCamera()

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

; Create blank mesh
ramp=CreateMesh()

; Create blank surface which is attached to mesh (surfaces must always be attached to a mesh)
surf=CreateSurface(ramp)

; Now we have our blank mesh and surface, we can start adding vertices to it, to form the shape of our
; ramp.
; Vertices are invisible 'points' in a 3D object that we can attach triangles too later.
; To create a single triangle, you need three vertices, one for each corner.
; However, you can share vertices between triangles, so you do not always need 3 new vertices per
; triangle.
; In the case of our ramp mesh, we will require 6 vertices, one for each corner

v0=AddVertex(surf,0,0,0) ; bottom corner 1
v1=AddVertex(surf,0,0,1) ; bottom corner 2
v2=AddVertex(surf,4,0,1) ; bottom corner 3
v3=AddVertex(surf,4,0,0) ; bottom corner 4
v4=AddVertex(surf,0,2,0) ; top corner 1
v5=AddVertex(surf,0,2,1) ; top corner 2 

; Having created our blank mesh and surface, and added our vertices to form the shape of the mesh, we
; now need to add triangles to it in order to make it solid and visible to the user. We create
; triangles simply by connecting vertices up, very much like a 3D dot-to-dot.

; When adding triangles, we need to remember that they are only one sided, and the side they are
; visible from is determined by the order in which we specify the vertices when using AddTriangle.
; If the vertices, in the order that they are specified, are aligned in a clockwise fashion relative 
; to the camera then they will appear visible, otherwise they won't. 
; So, to make our ramp visible from the outside, we will be connecting all vertices in a clockwise
; fashion, relative to the camera.

t0=AddTriangle(surf,v0,v3,v2) ; bottom triangle 1
t1=AddTriangle(surf,v0,v2,v1) ; bottom triangle 2
t2=AddTriangle(surf,v0,v4,v3) ; front triangle
t3=AddTriangle(surf,v1,v2,v5) ; back triangle
t4=AddTriangle(surf,v0,v1,v5) ; side triangle 1
t5=AddTriangle(surf,v0,v5,v4) ; side triangle 2
t6=AddTriangle(surf,v2,v4,v5) ; top triangle 1
t7=AddTriangle(surf,v2,v3,v4) ; top triangle 2

; Now we will position our ramp in front of the camera so we can see it!
PositionEntity ramp,0,-4,10

; Enable wireframe mode so we can see structure of model more clearly
WireFrame True

; And a quick loop that renders the scene and displays the contents on the screen until we press esc
While Not KeyDown(1)

; Constantly turn our ramp entity to show it off a bit
TurnEntity ramp,0,1,0

RenderWorld
Flip

Wend

; The end! 
End