GAM670/DPS905 Weekly Schedule 20121

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GAM670/DPS905 -- Weekly Schedule 20121

Week 1 - Jan 8

This Week

• Assignment Discussion
• Suggested Enhancements
• Review of the Base Code
  • Definition of a Framework
    • Modularity through stable interfaces
    • Re-usability through generic components
    • Extensibility through hook methods
    • Inversion of control - determines which application methods to invoke in response to external events
  • Framework Architecture
    • Modelling Layer
    • API Translation Layer
  • Notable Features of the Base Code
  • camera, sound, and light are also derived from the Frame class
  • textures attach at the object level
  • texture connection is uncoupled from drawing of the graphics primitives
  • reference frames are relative
  • very simple collision detection

To Do

1. add your name to the student list
2. create a team page that includes the semester number 20121
   • describe the game that you intend to develop
   • list the topics of interest to your team in developing its game
   • list the other topics of interest

Week 2 - Jan 16

This Week

• Relative Reference Frames
  • Recursive calls

    Vector Frame::position()

    Matrix Frame::rotation()

    Matrix Frame::world()

  • Detaching from and attaching to a parent frame

    Frame::attachTo()

• Geometry
  • Plane

    normal + constant - examples

    equation of a plane: dot(n, x) + D = 0

    positive side of a plane dot(n, x) + D > 0

• Collision Detection

  types of colliders

  spheres

  planes

  axis-aligned bounding boxes

  oriented bounding boxes

• Comprehensive Camerawork

  rotation about an axis

  order of rotation matters

  Euler angles

  gimble lock

  quaternions

  geometric algebra (more abstract)

To Do

• Research the feature that you are going to add and prepare a plan of action

Week 3 - Jan 23

Resources

• DirectX SDK June 2010

Week 4 - Jan 30

This Week

• Mathematics of Lighting
• Vertex Shaders
• Lighting in Vertex Shaders
  • Notation

    G_a - global ambient color

    C_a - material ambient color

    C_d - material diffuse color

    C_s - material specular color

    L_ai - ambient color of light i

    L_di - diffuse color of light i

    L_si - specular color of light i

    L_diri - direction vector of light i

    N - normal to the surface at the vertex

    • Attenuation and Spotlight Factors
      • Atten_i - attenuation of light i

      d_i - distance from light i

      d_i = |L_diri|

      a₀ - constant attenuation factor

      a₁ - linear attenuation factor

      a₂ - quadratic attenuation factor

      Atten_i = 1/(a₀ + a₁ d_i + a₂ d_i²)

      Atten_i = [0, 1]

      • Spot_i - spot factor of light i

      Spot_i = {[r_i - cos(phi_i/2)]/[cos(theta_i/2) - cos(phi_i/2)]}^f_i

      r_i - cosine of angle from axis of spotlight_i

      r_i = norm(- light direction in camera space) . norm(L_diri)

      phi_i - penumbra (exterior cone) angle of spotlight_i

      theta_i - umbra (interior cone) angle of spotlight_i

      f_i - falloff factor of spotlight_i

  • Blinn-Phong and Phong

    V - viewpoint vector

    V = norm(Camera_position - Vertex_position)

  • Phong - account accurately for position of viewer

    Specular reflectance = (R_i . V)^p_i

    R_i - reflection vector

    R_i = 2 * (N . L_diri) N - L_diri

    p_i - true specular power of light i

  • Blinn-Phong - use halfway vector instead of reflection vector - adjust power to compensate

    Specular reflectance = (N . H_i)^p'_i

    H_i - halfway vector

    H_i = norm(V + L_diri)

    H_i = norm([0,0,1] + L_diri) - less computationally intensive - assumes that camera is at infinity along z axis

    p'_i - adjusted specular power of light i

  • Ambient

    C_a * ( G_a + sum [L_ai * Atten_i * Spot_i] )

  • Diffuse

    C_d * sum [ L_di * (N . L_diri) * Atten_i * Spot_i ]

  • Specular

    C_s * sum [ L_si * (N . H_i)^p'_i * Atten_i * Spot_i ] - Blinn-Phong

    C_s * sum [ L_si * (R_i . V)^p_i * Atten_i * Spot_i ] - Phong

  • HLSL Intrinsic Functions
    • normalize() - normalize a vector
    • dot(,) - dot product of two vectors of any size
    • length() - length of a vector
    • saturate() - clamp scalar, vector, or matrix to [0, 1]

To Do

• reorganize framework code so that vertex shader receives product of world, view, and projection matrices
  • store viewProjection matrix as an instance variable in Display
  • add viewProjection query to Display to extract product of view and projection matrices
  • retrieve viewProjection in *::draw() method
  • pre-multiply viewProjection by world to obtain composite matrix to pass to vertex shader
  • add composite matrix to the constant table in the vertex shader
• reorganize framework code to minimize duplication of heading normalization
  • perform normalization of heading in Display::beginDraw()

Week 7 - Feb 20

Resources

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