CS461561 Virtual Environments: Principles

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CS461/561Virtual Environments Principles
ApplicationsLights, Cameras, Action

• 1-24-2007
• Prof. Searleman
• SC375
• jets_at_clarkson.edu

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Overview

• Basic concepts in Virtools
• File types
• Using the life player
• Basic Block flags v, s
• Interaction response to keys
• Lights
• Cameras
• Virtools Exercise 4, due Monday 1/29/07
• Virtools Exercise 5, due Wednesday, 1/31/07

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CLASS on Monday, 1/29/07

• We will meet in the CEC at 400
• From 400 500, there is a talk by Xiaohua Sun
  on Digital Media
• From 500 515, we will work on Exercise 5

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File Types

• .cmo
• - full composition with both objects scripts
• - FileSave Composition
• .vmo
• - full composition without scripting
• - cannot be loaded by Dev
• - used by Web Player or standalone app
• - FileExport to Virtools Player

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File Types, cont.

• .nmo
• - 1 or more objects, with or without scripts
• - can be imported into the current composition
• - ResourcesImport File or Import File As
• - Useful for dynamic loading
• .nms
• - contain either a graph or a script
• - to save a script, select it, right click,
  select save as give directory name, in the
  Behavior Graph directory of your resources
  folder give description, version, author name to
  appear in the resource window

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Elements of a Composition (CMO)

• BeObject an object to which a behavior can be
  applied
• RenderObject visible in play mode
• Objects that may be visible, but usually are not
  Camera, Curve, Grid, Light
• Objects that are not visible Array, Group,
  Level, Material, Mesh, Place, Scene, Sound,
  Texture

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3D Entity

• A 3D Entity defines a position, an orientation,
  and a scale
• 3D Frame
• - null object
• - no geometry (invisible)
• - used to provide a referential
• 3D Object
• - have a geometry (i.e. mesh)
• - may have 1 mesh, but only 1 is active
• - cannot be created within Virtools

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Referential

• point of reference for a 3D transformation (e.g.
  scale, rotate, translate)
• used as a parameter input to a BB (pIn)
• referential value --NULL--
• means the world coordinate system
• referential value name of the entity
• means the local coordinate system

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Graphical Flags
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Construct

• v flag variable number of inputs/outputs
• To add a bIn/bOut or pIn/pOut, right-click in the
  BB and select Construct
• Example Switch On Key BB

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On/Off Details

• BB is inactive.
• The user presses the 1 key. On is activated, the
  BB performs an action and activates the Out On
  output (violet link). The BB is now active and
  will call itself every frame and perform an
  action until the Off input is activated.
• The user presses the 2 key. Off is activated, the
  BB performs an action and activates the Out Off
  output (pink link). The BB is now inactive. Go
  back to 1.

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Lights

• There are 3 types of lights in Virtools
• directional light point light spot
  light

directional complexity)
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Add Lighting

• Add a point light
• use the level manager to rename it
• use Setup to position it
• Add directional lighting
• use the level manager to rename it
• use Setup, select Directional
• Position it, say at (0,10,0)
• Change its orientation to (90,0,0)

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Cameras

• There are 2 types of cameras in Virtools
• Target camera
• - always looking at a target defined by a
  frame
• - cannot specify orientation
• Free camera
• - useful since you can change the
  orientation
• Create Camera button creates a camera

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Camera
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Rendering

• View Frustrum (view volume)
• defined by the current camera its near far
  clipping planes

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Add a Camera

• Click on create camera icon
• Use the Level Manager to rename it
• Use Setup to change its coordinates (or position
  it using the toolbar to the left of the 3D Layout
  window)

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Overview

• Exercise 4 Virtools Tutorial plus a new feature
  of your choice
• Exercise 5 cameras
• Surveillance cam
• First person cams
• Hierarchy camera is child of avatar
• Camera moves with avatar
• 3D Frame is child of avatar, camera mimics 3D
  Frame

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Example Exercise 5

• Composition Moving Teapot 4 cameras
• Surveillance Cam Looks at teapot from fixed
  point of view using BB Look At
• Hierarchy Cam Child of the Teapot
• Look at Cam not child, positions orients
  itself behind the teapot using BBs Set Position
  and Look At
• Mimic Cam uses a 3D Frame which is a child of
  the teapot uses BB Mimic to mimic the 3D
  position orientation of the 3D Frame
• Select cameras dynamically uses BB
• Set as active Camera in Camera

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ControllerMouse Waiter

• detects mouse actions
• note
• Mouse Position is
  in screen coords
• - delete unused
  pOuts, bOuts, 0

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Interface2DPicking

• returns the 3D entity, the normal and the exact
  position of the 2D mouse pick

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Parameters
Parameter shortcuts (copy paste as shortcut)

• Input parameters, in blue
• Output parameters, in green
• Local parameters, in red

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ParamOp

• ParamOp is part of the data flow (blue), not the
  behavior flow (red)

• Parameter operations are used to perform a
  computation
• ParamOps have 2 input parameters 1 output
  parameter (no target)

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Create ParamOp

• Right-click on script
• Select Add Parameter Operation

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Logics\CalculatorOp BB

• Encapsulates a ParamOp in a BB
• Use to perform an operation once at a given time

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Interface/Text 2D Text
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Logics/StreamingParameter Selector

• If In k is activated, selected parameter will
  be pIn k
• Variable number of inputs (v)

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ControllersKeyboard
Maps keys to Joystick messages, as followsNum 8
- Joy_UpNum 2 - Joy_DownNum 4 - Joy_LeftNum
6 - Joy_RightInsert - Button 1Home - Button
2Prior - Button 3Delete - Button 4End -
Button 5Next - Button 6

• Emulates a joystick