CSG Animation Format Idea

CSG Animation Tool.
* Combine CSG with skeletal animation.
* The top level will exist as a list of objects.
* References from one object to another will be based on name.

CSG Solids
* CSG Solids will exist within Models.
* CSG Solids will be applied in-order.
* Solids may be either positive or negative.
** A negative solid will "cut a hole" in any preceding solids.
* Rounded solids will be approximated via polyhedra.
** The tessellation of the surface will be implicit.
* Solids with a transparent textures may only clip objects with the same texture.
** Likewise, they may only be clipped by the same texture.

Bones
* A given Model may contain Bones.
* CSG solids may be attached to bones.
** CSG solids assigned to different bones will not normally clip.


Model notation will be based on objects and lists.

Object:
 ObjType {
   ...
 }
 ObjType objName {
   ...
 }

Objects will contain key-value pairs:
* key: value
** Comma separators will be optional.
* Objects may contain other objects.
* Keys will be identifiers.

Identifier:
* Consists of 'A'..'Z', 'a'..'z', '0'..'9', '_', and '$'.
* Must start with a letter or underscore.


Value types will be one of several types:
* Integer literal
** 1234567
** 0x1234ABCD
** ...
* Floating point literal
** 3.14159
* String Literal
** "Foo"
** Adjacent string literals may merge without a separator.
** Escape sequences will be similar to those in C.
* Symbol
** #name
** May be used as an identifier for another object.
** Functionally similar to a string in most other regards.
* List / Array
** [ 1 2 3 ]
** Comma separators will be optional.
** Lists may contain arbitrary value types.
* Vector
** #[ x y ]
** #[ x y z ]
** #[ x y z w ]
** Consists of 2-4 floating point numbers.
* ...

Origins will be given with in a local or global XYZ space.
Rotations will be given as axis/angle, with the angle given in degrees.

The coordinate space will not be formally specified here, but for now will assume a unit size roughly comparable to an inch.


Objects:
* Model
** Top-level model object, contains Bones and solids
** Models may be instanced.
* Bone
** Defines part of a skeleton.
** Contains an origin and parent.
** Bones without a parent are relative to the model.
* Solids
** Will come in various forms.
** Box: Box, given as min/max or origin/size
*** May be given a rotation.
** Sphere: Spheroid, given as origin/radius.
*** Radius may be either a floating point number or a vector.
** Cylinder: Cylinder, Flat Ends, given as start/end and radius.
** CappedCylinder: Cylinder, Round Ends, given as start/end and radius.
** ...

Model model1 {
  Bone base          { origin: #[  0 0  0] }
  Bone leftArm       { origin: #[-10 0 10] parent: #base }
  Bone rightArm      { origin: #[ 10 0 10] parent: #base }
  Bone leftHand      { origin: #[-40 0 15] parent: #leftArm }
  Bone rightHand     { origin: #[ 40 0 15] parent: #rightArm }
  Bone head          { origin: #[  0 0 20] parent: #base }
  Sphere torsoSphere { origin: #[  0 0  0] radius: 20 bone: #base }
  Sphere headSphere  { origin: #[  0 0 25] radius: 10 bone: #head }
  Sphere lfHandSp    { origin: #[-40 0 15] radius: 20 bone: #leftHand }
  Sphere rtHandSp    { origin: #[ 40 0 15] radius: 20 bone: #rightHand }
}

If a Solid is not given a bone, it will exist at a fixed location within the model.

Textures will be applied to solids rather than to individual faces.
* Textures will contain of references to external texture images.
** One of several possible search paths may be used.
** File extension may be added implicitly.
* A texture object will define the projection strategy.
** Sphere: Spherical coordinates relative to a local space.
** Box: Nearest face on a 6-sided box within local space.
** Plane:

Texture tex1 {
  image: "textures/foo/bar"
  proj_type: #Sphere
  proj_x: #[1 0 0]
  proj_y: #[0 1 0]
  proj_z: #[0 0 1]
  proj_origin: #[0 0 0]
  transparent: 1
}

Polyhedra / Brush
* Will define an arbitrary solid in terms of planes.
* Each plane will contain a normal.
** The first three numbers will give the plane direction.
** The fourth number will give the distance.

Brush br1 {
  texture: tex1
  Plane { normal: #[-1  0  0 10] }
  Plane { normal: #[ 1  0  0 10] }
  Plane { normal: #[ 0 -1  0 10] }
  Plane { normal: #[ 0  1  0 10] }
  Plane { normal: #[ 0  0 -1 10] }
  Plane { normal: #[ 0  0  1 10] }
}


Animations:
* Animations exist within a model.
** Each animation will consist of frames.
** The frames will define the bone positions at that time.
*** These will either displace the origin or apply a rotation.
*** Translations will be relative to the base origin.
*** Rotations will be given in axis/angle.
** Each child bone will be relative to the position of the parent bone.
*** In effect, the transforms will be combined.
** If a bone position is absent in a given frame, it will be interpolated.

Anim jump1 {
  frametime: 0.1  //10 frames per second
  Frame {
    BonePos base { org: #[0 0 0] }
    BonePos leftArm { rot: #[0 1 0 0] }
    BonePos rightArm { rot: #[0 1 0 0] }
  }
  Frame {  }
  Frame {  }
  Frame {  }
  Frame {  }
  Frame {
    BonePos base { org: #[0 0 15] }
    BonePos leftArm { rot: #[0 1 0 30] }
    BonePos rightArm { rot: #[0 1 0 -30] }
  }
  Frame {  }
  Frame {  }
  Frame {  }
  Frame {  }
}


=== Scenes ===

Scene (If Relevant):
* A Scene will be composed of Entities.
** Each Entity will be an instance of a Model.
** Entities may be given an origin and rotation, and given an animation.
* Events will happen at time-codes.

Import { path: "models/model1" }

Entity ent1 {
  model: #model1
  origin: #[320 400 16]
  rotation: #[0 0 0]
}

Event ev0 {
  time: 0.0
  entity: ent1
  anim: idle1
}
Event ev1 {
  time: 16.0
  entity: ent1
  anim: jump1
}

If no events exist for an entity, it will exist as a static object.

Entities could also be assigned to scripts, in which case the script will manage any behaviors.