ColladaFX

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(No Transcript)
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ColladaFX
Presented by Christian Laforte,
President www.feelingsoftware.com
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Agenda

• ColladaFX overview
• Common-profile materials
• Effects and shaders
• Complementary Collada features
• Demos
• Feeling Softwares ColladaFX plug-in for Maya
• nVidias FX Composer 2.0
• Feeling Softwares Feeling Viewer

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ColladaFX overview

• Pros
• Data-driven Easy to author and modify
• Empower the artists
• Open-format with contributions from HW vendors,
  DCCs, application and game developers
• Designed for cross-platform, cross-API
• Cons
• Somewhat complex specification
• Chances are youll still need to write special
  rendering code for some algorithms

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Comparison with other effects representations
CgFX, .fx

• nVidia CgFX and Microsoft .fx focus exclusively
  on materials and shaders
• In contrast, ColladaFX augments Collada itself,
  to store geometry, animations, effects in a
  unified format.
• Extensible, cross-API, cross-platform, vendor
  agnostic standard ? perfect for OpenGL ES as well
  as other profiles.
• ColladaFX can still refer to lower-level concepts
  like existing CgFX assets.

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Agenda

• ColladaFX overview
• Common-profile materials
• Effects and shaders
• Complementary Collada features
• Demos
• Feeling Softwares ColladaFX plug-in for Maya
• nVidias FX Composer 2.0
• Feeling Softwares Feeling Viewer

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Common-profile shaders - Overview

• Shading models supported Lambert, Blinn, Phong
• Supported by all DCCs
• Encapsulates values and declarations for
  platform-independent fixed-function shader

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Common-profile shadersFloppy disk example
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Collada document
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Document asset tag
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Image library
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Effects library 1
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Effects library 2
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Effects library 3
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Materials library
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Geometry library 1
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Geometry library 2
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Polygons
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Visual scenes library
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Instancing geometry, multiple-material assignment
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Usefulness of common-profile materials

• Wide support in DCCs
• Fall-back when no other profile is supported
• Orthogonal with lighting
• Supports some advanced concepts
• Multi-texturing
• higher-level shading trees
• Bump
• Limitations
• Limited to simple effects

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Agenda

• ColladaFX overview
• Common-profile materials
• Effects and shaders
• Complementary Collada features
• Demos
• Feeling Softwares ColladaFX plug-in for Maya
• nVidias FX Composer 2.0
• Feeling Softwares Feeling Viewer

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Effects and shaders

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ColladaFX profiles

• Concepts
• Supported
• Common (profile_COMMON)
• Cg (profile_CG)
• OpenGL (profile_GLSL)
• OpenGL ES 1.x (profile_GLES)
• In progress
• OpenGL ES 2.0
• HLSL

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Pass

• Declaration of render states, shaders, and
  settings for one rendering pipeline
• Applied by FX runtime before submitting geometry

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Render states

• paramparam_reference/
• Fully-define render states for each profile
• Details in Collada 1.4 spec and schema

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• Exposes some of the shaders parameters to the
  compiler and runtime
• Specifies type and initial value

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Semantics

• Meta information that describes the purpose of a
  parameter declaration
• Three common uses
• Hardware resource allocated to a parameter, e.g.
  TEXCOORD2, NORMAL
• Value extracted from scene graph or API, e.g.
  MODELVIEWMATRIX, CAMERAPOS, VIEWPORTSIZE
• User-defined value set by the application at
  run-time, e.g. DAMAGE_PERCENT, MAGIC_LEVEL

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Annotations

• Annotations communicate meta-information from DCC
  to effect runtime

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Bind

• Binds value to uniform inputs of a shader or
  binds values to effect parameters upon
  instantiation
• Also used to map predefined parameters

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• Supported types
• 1D, 2D, Rect, 3D and Cube texture samplers

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3 ways to specify shader source

• Can be included from external file
• Can be inlined
• Can be pre-compiled

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Texture pipeline (specific to fixed pipeline
GLES)

• Defines a set of texturing commands that will be
  converted into multitexturing operations using
  glTexEnv
• Commands are assigned to texture units in a late
  binding step based on name
• See next slide

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Texture pipeline(specific to fixed pipeline GLES)
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Agenda

• ColladaFX overview
• Common-profile materials
• Effects and shaders
• Complementary Collada features
• Demos
• Feeling Softwares ColladaFX plug-in for Maya
• nVidias FX Composer 2.0
• Feeling Softwares Feeling Viewer

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• A trap-door for extensibility
• Applications are free to define their own extra
  data
• Similar to GL extensions, can evolve into
  core feature.
• Examples from ColladaMaya
• layered textures, using to encode texture
  blending mode.
• wrap, mirror modes for each texture (next slide)

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example
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Animation

• Pretty much everything can be animated,
  targetting through id/sid (scope id).

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So much to say, so little time

• 1.4 has support for
• Flexible multiple render targets (MRT)
• Procedural surface generators

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Current Limitations forColladaFX for OpenGL ES

• No standard binding runtime yet
• No DCC support for OpenGL ES fixed pipeline
• Work-around use other profiles (e.g. Cg or
  common) or ask Feeling Software.
• GL extensions require manual code

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Agenda

• ColladaFX overview
• Common-profile materials
• Effects and shaders
• Complementary Collada features
• Demos
• Feeling Softwares ColladaFX plug-in for Maya
• nVidias FX Composer 2.0
• Feeling Softwares Feeling Viewer

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Demonstrations

• From Feeling Software
• ColladaFX plug-in for Maya
• Feeling Viewer
• From nVidia
• FX Composer

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Conclusion

• Collada and ColladaFX
• Are flexible enough for next-gen games
• Simplify assets authoring and conditioning
• Expose entire OpenGL ES state
• Continue to evolve at fast pace

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Thanks

• ColladaFX working group, especiallyRobin Green,
  SCEA (chair for 1.4)Daniel Horowitz, nVidia
  (present chair)Stephen Wilkinson, Nokia (GLES)
• Feeling Software Collada teamGuillaume Laforte,
  Zhang Jian, Antoine Azar, Alfred Leung, Misako
  Matsumoto

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Questions?

• claforte_at_feelingsoftware.com
• http//www.feelingsoftware.com
• Free tools include ColladaMaya, Feeling Viewer,
  ColladaFX plug-in for Maya, including Japanese
  documentation.
• http//www.nvidia.com
• FX Composer