Blitz3D+ Command Reference

ScaleMesh mesh,x_scale#,y_scale#,z_scale#

Parameters

mesh - mesh handle
x_scale# - scale factor along x
y_scale# - scale factor along y
z_scale# - scale factor along z

Description

Scales every vertex of a mesh by the given factors, relative to the entity's pivot.

Unlike ScaleEntity, this permanently modifies the geometry: MeshWidth-style measurements, collisions and picking all see the new size. It is the usual way to normalise a loaded model's size once at load time (or use FitMesh to hit an exact box), keeping ScaleEntity free for gameplay effects.

Two things to watch: after a non-uniform scale, call UpdateNormals so lighting stays correct; and a negative factor mirrors the mesh, which reverses the triangle winding and makes it look inside-out - follow up with FlipMesh to fix the visible side.

See also: FitMesh, ScaleEntity, PositionMesh, RotateMesh, UpdateNormals, FlipMesh.

Example

; ScaleMesh Example
; -----------------

; ScaleMesh rescales the mesh's VERTICES, and it is cumulative: every
; call multiplies on top of the last. ScaleEntity, by contrast, sets
; an absolute display scale and leaves the mesh data alone - which is
; why MeshWidth below tracks ScaleMesh but would ignore ScaleEntity.

Graphics3D 640,480
SetBuffer BackBuffer()

camera=CreateCamera()
PositionEntity camera,0,0,-4

light=CreateLight()
RotateEntity light,30,40,0

; Load a drum and fit it into a 2-unit box to start from a known size
drum=LoadMesh("media/oil-drum/oildrum.3ds")
FitMesh drum,-1,-1,-1,2,2,2,1

While Not KeyDown(1)

    ; Hold [ / ] to shrink / grow the mesh 2% per frame - the
    ; documented command, applied cumulatively
    If KeyDown(26) Then ScaleMesh drum,0.98,0.98,0.98
    If KeyDown(27) Then ScaleMesh drum,1.02,1.02,1.02

    TurnEntity drum,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,"Hold [ / ] : shrink / grow the mesh   Arrow keys: move camera   Esc: exit"
    Text 0,20,"MeshWidth after ScaleMesh: "+MeshWidth(drum)

    Flip

Wend

End

Index