cgmath/src/transform.rs
2016-05-16 15:22:37 +02:00

309 lines
10 KiB
Rust

// Copyright 2014 The CGMath Developers. For a full listing of the authors,
// refer to the Cargo.toml file at the top-level directory of this distribution.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
use structure::*;
use approx::ApproxEq;
use matrix::{Matrix2, Matrix3, Matrix4};
use num::{BaseFloat, BaseNum};
use point::{Point2, Point3};
use rotation::*;
use vector::{Vector2, Vector3};
/// A trait representing an [affine
/// transformation](https://en.wikipedia.org/wiki/Affine_transformation) that
/// can be applied to points or vectors. An affine transformation is one which
pub trait Transform<P: EuclideanSpace>: Sized {
/// Create an identity transformation. That is, a transformation which
/// does nothing.
fn one() -> Self;
/// Create a transformation that rotates a vector to look at `center` from
/// `eye`, using `up` for orientation.
fn look_at(eye: P, center: P, up: P::Diff) -> Self;
/// Transform a vector using this transform.
fn transform_vector(&self, vec: P::Diff) -> P::Diff;
/// Transform a point using this transform.
fn transform_point(&self, point: P) -> P;
/// Combine this transform with another, yielding a new transformation
/// which has the effects of both.
fn concat(&self, other: &Self) -> Self;
/// Create a transform that "un-does" this one.
fn inverse_transform(&self) -> Option<Self>;
/// Combine this transform with another, in-place.
#[inline]
fn concat_self(&mut self, other: &Self) {
*self = Self::concat(self, other);
}
}
/// A generic transformation consisting of a rotation,
/// displacement vector and scale amount.
#[derive(Copy, Clone, Debug)]
#[cfg_attr(feature = "rustc-serialize", derive(RustcEncodable, RustcDecodable))]
pub struct Decomposed<V: VectorSpace, R> {
pub scale: V::Scalar,
pub rot: R,
pub disp: V,
}
impl<P: EuclideanSpace, R: Rotation<P>> Transform<P> for Decomposed<P::Diff, R> where
// FIXME: Ugly type signatures - blocked by rust-lang/rust#24092
<P as EuclideanSpace>::Scalar: BaseFloat,
// FIXME: Investigate why this is needed!
<P as EuclideanSpace>::Diff: VectorSpace,
{
#[inline]
fn one() -> Decomposed<P::Diff, R> {
Decomposed {
scale: P::Scalar::one(),
rot: R::one(),
disp: P::Diff::zero(),
}
}
#[inline]
fn look_at(eye: P, center: P, up: P::Diff) -> Decomposed<P::Diff, R> {
let rot = R::look_at(center - eye, up);
let disp = rot.rotate_vector(P::origin() - eye);
Decomposed {
scale: P::Scalar::one(),
rot: rot,
disp: disp,
}
}
#[inline]
fn transform_vector(&self, vec: P::Diff) -> P::Diff {
self.rot.rotate_vector(vec * self.scale)
}
#[inline]
fn transform_point(&self, point: P) -> P {
self.rot.rotate_point(point * self.scale) + self.disp
}
fn concat(&self, other: &Decomposed<P::Diff, R>) -> Decomposed<P::Diff, R> {
Decomposed {
scale: self.scale * other.scale,
rot: self.rot * other.rot,
disp: self.disp + other.disp,
}
}
fn inverse_transform(&self) -> Option<Decomposed<P::Diff, R>> {
if self.scale.approx_eq(&P::Scalar::zero()) {
None
} else {
let s = P::Scalar::one() / self.scale;
let r = self.rot.invert();
let d = r.rotate_vector(self.disp.clone()) * -s;
Some(Decomposed {
scale: s,
rot: r,
disp: d,
})
}
}
}
pub trait Transform2<S: BaseNum>: Transform<Point2<S>> + Into<Matrix3<S>> {}
pub trait Transform3<S: BaseNum>: Transform<Point3<S>> + Into<Matrix4<S>> {}
impl<S: BaseFloat, R: Rotation2<S>> From<Decomposed<Vector2<S>, R>> for Matrix3<S> {
fn from(dec: Decomposed<Vector2<S>, R>) -> Matrix3<S> {
let m: Matrix2<_> = dec.rot.into();
let mut m: Matrix3<_> = (&m * dec.scale).into();
m.z = dec.disp.extend(S::one());
m
}
}
impl<S: BaseFloat, R: Rotation3<S>> From<Decomposed<Vector3<S>, R>> for Matrix4<S> {
fn from(dec: Decomposed<Vector3<S>, R>) -> Matrix4<S> {
let m: Matrix3<_> = dec.rot.into();
let mut m: Matrix4<_> = (&m * dec.scale).into();
m.w = dec.disp.extend(S::one());
m
}
}
impl<S: BaseFloat, R: Rotation2<S>> Transform2<S> for Decomposed<Vector2<S>, R> {}
impl<S: BaseFloat, R: Rotation3<S>> Transform3<S> for Decomposed<Vector3<S>, R> {}
impl<S: VectorSpace, R, E: BaseFloat> ApproxEq for Decomposed<S, R>
where S: ApproxEq<Epsilon = E>, S::Scalar: ApproxEq<Epsilon = E>, R: ApproxEq<Epsilon = E>
{
type Epsilon = E;
fn approx_eq_eps(&self, other: &Self, epsilon: &Self::Epsilon) -> bool {
self.scale.approx_eq_eps(&other.scale, epsilon) &&
self.rot.approx_eq_eps(&other.rot, epsilon) &&
self.disp.approx_eq_eps(&other.disp, epsilon)
}
}
#[cfg(feature = "eders")]
#[doc(hidden)]
mod eders_ser {
use structure::VectorSpace;
use super::Decomposed;
use serde::{self, Serialize};
impl<V: VectorSpace, R> Serialize for Decomposed<V, R>
where V: Serialize, V::Scalar: Serialize, R: Serialize
{
fn serialize<S>(&self, serializer: &mut S) -> Result<(), S::Error>
where S: serde::Serializer
{
serializer.serialize_struct("Decomposed", DecomposedVisitor {
value: self,
state: 0,
})
}
}
struct DecomposedVisitor<'a, V: 'a + VectorSpace, R: 'a> {
value: &'a Decomposed<V, R>,
state: u8,
}
impl<'a, V: 'a + VectorSpace, R> serde::ser::MapVisitor for DecomposedVisitor<'a, V, R>
where V: Serialize, V::Scalar: Serialize, R: Serialize
{
fn visit<S>(&mut self, serializer: &mut S) -> Result<Option<()>, S::Error>
where S: serde::Serializer
{
match self.state {
0 => {
self.state += 1;
Ok(Some(try!(serializer.serialize_struct_elt("scale", &self.value.scale))))
},
1 => {
self.state += 1;
Ok(Some(try!(serializer.serialize_struct_elt("rot", &self.value.rot))))
},
2 => {
self.state += 1;
Ok(Some(try!(serializer.serialize_struct_elt("disp", &self.value.disp))))
},
_ => {
Ok(None)
},
}
}
}
}
#[cfg(feature = "eders")]
#[doc(hidden)]
mod eders_de {
use structure::VectorSpace;
use super::Decomposed;
use serde::{self, Deserialize};
use std::marker::PhantomData;
enum DecomposedField {
Scale,
Rot,
Disp,
}
impl Deserialize for DecomposedField {
fn deserialize<D>(deserializer: &mut D) -> Result<DecomposedField, D::Error>
where D: serde::Deserializer
{
struct DecomposedFieldVisitor;
impl serde::de::Visitor for DecomposedFieldVisitor {
type Value = DecomposedField;
fn visit_str<E>(&mut self, value: &str) -> Result<DecomposedField, E>
where E: serde::de::Error
{
match value {
"scale" => Ok(DecomposedField::Scale),
"rot" => Ok(DecomposedField::Rot),
"disp" => Ok(DecomposedField::Disp),
_ => Err(serde::de::Error::custom("expected scale, rot or disp")),
}
}
}
deserializer.deserialize(DecomposedFieldVisitor)
}
}
impl<S: VectorSpace, R> Deserialize for Decomposed<S, R>
where S: Deserialize, S::Scalar: Deserialize, R: Deserialize
{
fn deserialize<D>(deserializer: &mut D) -> Result<Decomposed<S, R>, D::Error>
where D: serde::de::Deserializer
{
const FIELDS: &'static [&'static str] = &["scale", "rot", "disp"];
deserializer.deserialize_struct("Decomposed", FIELDS, DecomposedVisitor(PhantomData))
}
}
struct DecomposedVisitor<S: VectorSpace, R>(PhantomData<(S, R)>);
impl<S: VectorSpace, R> serde::de::Visitor for DecomposedVisitor<S, R>
where S: Deserialize, S::Scalar: Deserialize, R: Deserialize
{
type Value = Decomposed<S, R>;
fn visit_map<V>(&mut self, mut visitor: V) -> Result<Decomposed<S, R>, V::Error>
where V: serde::de::MapVisitor
{
let mut scale = None;
let mut rot = None;
let mut disp = None;
loop {
match try!(visitor.visit_key()) {
Some(DecomposedField::Scale) => { scale = Some(try!(visitor.visit_value())); },
Some(DecomposedField::Rot) => { rot = Some(try!(visitor.visit_value())); },
Some(DecomposedField::Disp) => { disp = Some(try!(visitor.visit_value())); },
_ => { break; },
}
}
let scale = match scale {
Some(scale) => scale,
None => try!(visitor.missing_field("scale")),
};
let rot = match rot {
Some(rot) => rot,
None => try!(visitor.missing_field("rot")),
};
let disp = match disp {
Some(disp) => disp,
None => try!(visitor.missing_field("disp")),
};
try!(visitor.end());
Ok(Decomposed { scale: scale, rot: rot, disp: disp })
}
}
}