ExRatatui.ThreeD.Transform (ExRatatui v0.11.0)

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Position, rotation, and scale of a 3D object.

The model matrix is composed scale, then rotate, then translate.

Fields

  • :position - {x, y, z} translation (floats), defaults to the origin
  • :rotation - one of the rotation forms below, defaults to identity
  • :scale - {x, y, z} scale factors, defaults to {1.0, 1.0, 1.0}

Rotation forms

  • {:euler_xyz, {rx, ry, rz}} - intrinsic X then Y then Z, in radians
  • {:axis_angle, {ax, ay, az}, angle} - rotation of angle radians about the (non-zero) axis
  • {:quat, {x, y, z, w}} - a raw quaternion

Examples

iex> %ExRatatui.ThreeD.Transform{}
%ExRatatui.ThreeD.Transform{
  position: {0.0, 0.0, 0.0},
  rotation: {:quat, {0.0, 0.0, 0.0, 1.0}},
  scale: {1.0, 1.0, 1.0}
}

iex> %ExRatatui.ThreeD.Transform{
...>   position: {1.0, 0.0, 0.0},
...>   rotation: {:axis_angle, {0.0, 1.0, 0.0}, 0.7}
...> }.rotation
{:axis_angle, {0.0, 1.0, 0.0}, 0.7}

Summary

Types

rotation()
t()
vec3()

Functions

compose(parent, child)

Compose two transforms: compose(parent, child) is the single transform equal to the matrix product M_parent · M_child (parent applied outermost).

to_quat(arg)

Normalize any rotation form to a unit quaternion {x, y, z, w}.

Types

rotation()

@type rotation() ::
  {:euler_xyz, vec3()}
  | {:axis_angle, vec3(), number()}
  | {:quat, {number(), number(), number(), number()}}

t()

@type t() :: %ExRatatui.ThreeD.Transform{
  position: vec3(),
  rotation: rotation(),
  scale: vec3()
}

vec3()

@type vec3() :: {number(), number(), number()}

Functions

compose(parent, child)

@spec compose(t(), t()) :: t()

Compose two transforms: compose(parent, child) is the single transform equal to the matrix product M_parent · M_child (parent applied outermost).

Exact when parent.scale == {1.0, 1.0, 1.0} (the rigid-frame contract used by ExRatatui.ThreeD.Node); for a non-uniform parent scale with a rotated child the result is approximate. The result rotation is always {:quat, _}.

Examples

iex> alias ExRatatui.ThreeD.Transform
iex> parent = %Transform{position: {1.0, 0.0, 0.0}}
iex> child = %Transform{position: {0.0, 2.0, 0.0}}
iex> Transform.compose(parent, child).position
{1.0, 2.0, 0.0}

to_quat(arg)

@spec to_quat(rotation()) :: {float(), float(), float(), float()}

Normalize any rotation form to a unit quaternion {x, y, z, w}.