CameraProjMode camera,mode

Parameters

camera - camera handle

mode - projection mode
0: no projection - the camera is not rendered
1: perspective (default)
2: orthographic

Description

Sets a camera's projection mode.

Perspective (mode 1) is the normal 3D view: distant things shrink, parallel lines converge. Orthographic (mode 2) throws perspective away - an object is the same size on screen no matter how far from the camera it sits. That is the look for isometric strategy views, 2D-style games built from 3D models, map screens and level editors.

An orthographic camera starts extremely zoomed in, and distance no longer controls how big things appear - CameraZoom is your size control instead. The example drops the zoom to 0.2 the moment it switches to ortho; expect to tune that number for your scene.

Mode 0 switches the camera off: RenderWorld simply skips it, at no cost. This is the cheap way to disable a minimap, security-monitor or split-screen camera you are not showing this frame, without freeing and rebuilding it. Note that nothing clears the screen for a camera that is not rendered - old pixels stay - so Cls yourself if you leave mode 0 visible.

See also: CreateCamera, CameraZoom, CameraViewport, CameraRange.

Example

; CameraProjMode Example
; ----------------------

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

camera=CreateCamera()
PositionEntity camera,0,2,-8

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

; A corridor of columns - perspective makes the far ones shrink,
; orthographic draws every column the same size on screen
For i=0 To 5
    column=CreateCylinder()
    ScaleEntity column,0.5,2,0.5
    PositionEntity column,-2,1,i*3
    column=CreateCylinder()
    ScaleEntity column,0.5,2,0.5
    PositionEntity column,2,1,i*3
Next

mode=1
zoom#=1
CameraProjMode camera,mode

While Not KeyDown(1)

    ; 1: perspective   2: orthographic   0: camera off
    If KeyHit(2)
        mode=1
        CameraProjMode camera,mode
        zoom=1
        CameraZoom camera,zoom
    EndIf
    If KeyHit(3)
        mode=2
        CameraProjMode camera,mode
        ; Ortho views are very zoomed in - scale out with CameraZoom
        zoom=0.2
        CameraZoom camera,zoom
    EndIf
    If KeyHit(11)
        mode=0
        CameraProjMode camera,mode
    EndIf

    ; + / - adjust the zoom (best seen in orthographic mode)
    If KeyDown(13)
        zoom=zoom+0.005
        CameraZoom camera,zoom
    EndIf
    If KeyDown(12)
        If zoom>0.05
            zoom=zoom-0.005
            CameraZoom camera,zoom
        EndIf
    EndIf

    ; 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

    ; With the camera off nothing is rendered, so clear by hand
    If mode=0 Then Cls

    name$="perspective"
    If mode=2 Then name$="orthographic"
    If mode=0 Then name$="off - nothing is rendered"

    Text 0,0,"1/2: projection   0: camera off   +/-: zoom   Esc: exit"
    Text 0,20,"CameraProjMode camera,"+mode+" ("+name$+")   zoom "+zoom

    Flip

Wend

End

Index