perspective.rs - source
Description: Source of the Rust file `/Users/erlendbasso/.cargo/registry/src/github.com-1ecc6299db9ec823/nalgebra-0.32.1/src/geometry/perspective.rs`.
Keywords: rust, rustlang, rust-lang

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    #[cfg(feature = "arbitrary")]
    use quickcheck::{Arbitrary, Gen};
    #[cfg(feature = "rand-no-std")]
    use rand::{
        distributions::{Distribution, Standard},
        Rng,
    };

    #[cfg(feature = "serde-serialize-no-std")]
    use serde::{Deserialize, Deserializer, Serialize, Serializer};
    use std::fmt;

    use simba::scalar::RealField;

    use crate::base::dimension::U3;
    use crate::base::storage::Storage;
    use crate::base::{Matrix4, Vector, Vector3};

    use crate::geometry::{Point3, Projective3};

    /// A 3D perspective projection stored as a homogeneous 4x4 matrix.
    #[repr(C)]
    #[cfg_attr(
        feature = "rkyv-serialize-no-std",
        derive(rkyv::Archive, rkyv::Serialize, rkyv::Deserialize),
        archive(
            as = "Perspective3<T::Archived>",
            bound(archive = "
            T: rkyv::Archive,
            Matrix4<T>: rkyv::Archive<Archived = Matrix4<T::Archived>>
        ")
        )
    )]
    #[cfg_attr(feature = "rkyv-serialize", derive(bytecheck::CheckBytes))]
    #[cfg_attr(feature = "cuda", derive(cust_core::DeviceCopy))]
    #[derive(Copy, Clone)]
    pub struct Perspective3<T> {
        matrix: Matrix4<T>,
    }

    impl<T: RealField> fmt::Debug for Perspective3<T> {
        fn fmt(&self, f: &mut fmt::Formatter<'_>) -> Result<(), fmt::Error> {
            self.matrix.fmt(f)
        }
    }

    impl<T: RealField> PartialEq for Perspective3<T> {
        #[inline]
        fn eq(&self, right: &Self) -> bool {
            self.matrix == right.matrix
        }
    }

    #[cfg(feature = "bytemuck")]
    unsafe impl<T> bytemuck::Zeroable for Perspective3<T>
    where
        T: RealField + bytemuck::Zeroable,
        Matrix4<T>: bytemuck::Zeroable,
    {
    }

    #[cfg(feature = "bytemuck")]
    unsafe impl<T> bytemuck::Pod for Perspective3<T>
    where
        T: RealField + bytemuck::Pod,
        Matrix4<T>: bytemuck::Pod,
    {
    }

    #[cfg(feature = "serde-serialize-no-std")]
    impl<T: RealField + Serialize> Serialize for Perspective3<T> {
        fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
        where
            S: Serializer,
        {
            self.matrix.serialize(serializer)
        }
    }

    #[cfg(feature = "serde-serialize-no-std")]
    impl<'a, T: RealField + Deserialize<'a>> Deserialize<'a> for Perspective3<T> {
        fn deserialize<Des>(deserializer: Des) -> Result<Self, Des::Error>
        where
            Des: Deserializer<'a>,
        {
            let matrix = Matrix4::<T>::deserialize(deserializer)?;

            Ok(Self::from_matrix_unchecked(matrix))
        }
    }

    impl<T> Perspective3<T> {
        /// Wraps the given matrix to interpret it as a 3D perspective matrix.
        ///
        /// It is not checked whether or not the given matrix actually represents a perspective
        /// projection.
        #[inline]
        pub const fn from_matrix_unchecked(matrix: Matrix4<T>) -> Self {
            Self { matrix }
        }
    }

    impl<T: RealField> Perspective3<T> {
        /// Creates a new perspective matrix from the aspect ratio, y field of view, and near/far planes.
        pub fn new(aspect: T, fovy: T, znear: T, zfar: T) -> Self {
            assert!(
                relative_ne!(zfar, znear),
                "The near-plane and far-plane must not be superimposed."
            );
            assert!(
                !relative_eq!(aspect, T::zero()),
                "The aspect ratio must not be zero."
            );

            let matrix = Matrix4::identity();
            let mut res = Self::from_matrix_unchecked(matrix);

            res.set_fovy(fovy);
            res.set_aspect(aspect);
            res.set_znear_and_zfar(znear, zfar);

            res.matrix[(3, 3)] = T::zero();
            res.matrix[(3, 2)] = -T::one();

            res
        }

        /// Retrieves the inverse of the underlying homogeneous matrix.
        #[inline]
        #[must_use]
        pub fn inverse(&self) -> Matrix4<T> {
            let mut res = self.clone().to_homogeneous();

            res[(0, 0)] = T::one() / self.matrix[(0, 0)].clone();
            res[(1, 1)] = T::one() / self.matrix[(1, 1)].clone();
            res[(2, 2)] = T::zero();

            let m23 = self.matrix[(2, 3)].clone();
            let m32 = self.matrix[(3, 2)].clone();

            res[(2, 3)] = T::one() / m32.clone();
            res[(3, 2)] = T::one() / m23.clone();
            res[(3, 3)] = -self.matrix[(2, 2)].clone() / (m23 * m32);

            res
        }

        /// Computes the corresponding homogeneous matrix.
        #[inline]
        #[must_use]
        pub fn to_homogeneous(self) -> Matrix4<T> {
            self.matrix.clone_owned()
        }

        /// A reference to the underlying homogeneous transformation matrix.
        #[inline]
        #[must_use]
        pub fn as_matrix(&self) -> &Matrix4<T> {
            &self.matrix
        }

        /// A reference to this transformation seen as a `Projective3`.
        #[inline]
        #[must_use]
        pub fn as_projective(&self) -> &Projective3<T> {
            unsafe { &*(self as *const Perspective3<T> as *const Projective3<T>) }
        }

        /// This transformation seen as a `Projective3`.
        #[inline]
        #[must_use]
        pub fn to_projective(self) -> Projective3<T> {
            Projective3::from_matrix_unchecked(self.matrix)
        }

        /// Retrieves the underlying homogeneous matrix.
        #[inline]
        pub fn into_inner(self) -> Matrix4<T> {
            self.matrix
        }

        /// Retrieves the underlying homogeneous matrix.
        /// Deprecated: Use [`Perspective3::into_inner`] instead.
        #[deprecated(note = "use `.into_inner()` instead")]
        #[inline]
        pub fn unwrap(self) -> Matrix4<T> {
            self.matrix
        }

        /// Gets the `width / height` aspect ratio of the view frustum.
        #[inline]
        #[must_use]
        pub fn aspect(&self) -> T {
            self.matrix[(1, 1)].clone() / self.matrix[(0, 0)].clone()
        }

        /// Gets the y field of view of the view frustum.
        #[inline]
        #[must_use]
        pub fn fovy(&self) -> T {
            (T::one() / self.matrix[(1, 1)].clone()).atan() * crate::convert(2.0)
        }

        /// Gets the near plane offset of the view frustum.
        #[inline]
        #[must_use]
        pub fn znear(&self) -> T {
            let ratio =
                (-self.matrix[(2, 2)].clone() + T::one()) / (-self.matrix[(2, 2)].clone() - T::one());

            self.matrix[(2, 3)].clone() / (ratio * crate::convert(2.0))
                - self.matrix[(2, 3)].clone() / crate::convert(2.0)
        }

        /// Gets the far plane offset of the view frustum.
        #[inline]
        #[must_use]
        pub fn zfar(&self) -> T {
            let ratio =
                (-self.matrix[(2, 2)].clone() + T::one()) / (-self.matrix[(2, 2)].clone() - T::one());

            (self.matrix[(2, 3)].clone() - ratio * self.matrix[(2, 3)].clone()) / crate::convert(2.0)
        }

        // TODO: add a method to retrieve znear and zfar simultaneously?

        // TODO: when we get specialization, specialize the Mul impl instead.
        /// Projects a point. Faster than matrix multiplication.
        #[inline]
        #[must_use]
        pub fn project_point(&self, p: &Point3<T>) -> Point3<T> {
            let inverse_denom = -T::one() / p[2].clone();
            Point3::new(
                self.matrix[(0, 0)].clone() * p[0].clone() * inverse_denom.clone(),
                self.matrix[(1, 1)].clone() * p[1].clone() * inverse_denom.clone(),
                (self.matrix[(2, 2)].clone() * p[2].clone() + self.matrix[(2, 3)].clone())
                    * inverse_denom,
            )
        }

        /// Un-projects a point. Faster than multiplication by the matrix inverse.
        #[inline]
        #[must_use]
        pub fn unproject_point(&self, p: &Point3<T>) -> Point3<T> {
            let inverse_denom =
                self.matrix[(2, 3)].clone() / (p[2].clone() + self.matrix[(2, 2)].clone());

            Point3::new(
                p[0].clone() * inverse_denom.clone() / self.matrix[(0, 0)].clone(),
                p[1].clone() * inverse_denom.clone() / self.matrix[(1, 1)].clone(),
                -inverse_denom,
            )
        }

        // TODO: when we get specialization, specialize the Mul impl instead.
        /// Projects a vector. Faster than matrix multiplication.
        #[inline]
        #[must_use]
        pub fn project_vector<SB>(&self, p: &Vector<T, U3, SB>) -> Vector3<T>
        where
            SB: Storage<T, U3>,
        {
            let inverse_denom = -T::one() / p[2].clone();
            Vector3::new(
                self.matrix[(0, 0)].clone() * p[0].clone() * inverse_denom.clone(),
                self.matrix[(1, 1)].clone() * p[1].clone() * inverse_denom,
                self.matrix[(2, 2)].clone(),
            )
        }

        /// Updates this perspective matrix with a new `width / height` aspect ratio of the view
        /// frustum.
        #[inline]
        pub fn set_aspect(&mut self, aspect: T) {
            assert!(
                !relative_eq!(aspect, T::zero()),
                "The aspect ratio must not be zero."
            );
            self.matrix[(0, 0)] = self.matrix[(1, 1)].clone() / aspect;
        }

        /// Updates this perspective with a new y field of view of the view frustum.
        #[inline]
        pub fn set_fovy(&mut self, fovy: T) {
            let old_m22 = self.matrix[(1, 1)].clone();
            let new_m22 = T::one() / (fovy / crate::convert(2.0)).tan();
            self.matrix[(1, 1)] = new_m22.clone();
            self.matrix[(0, 0)] *= new_m22 / old_m22;
        }

        /// Updates this perspective matrix with a new near plane offset of the view frustum.
        #[inline]
        pub fn set_znear(&mut self, znear: T) {
            let zfar = self.zfar();
            self.set_znear_and_zfar(znear, zfar);
        }

        /// Updates this perspective matrix with a new far plane offset of the view frustum.
        #[inline]
        pub fn set_zfar(&mut self, zfar: T) {
            let znear = self.znear();
            self.set_znear_and_zfar(znear, zfar);
        }

        /// Updates this perspective matrix with new near and far plane offsets of the view frustum.
        #[inline]
        pub fn set_znear_and_zfar(&mut self, znear: T, zfar: T) {
            self.matrix[(2, 2)] = (zfar.clone() + znear.clone()) / (znear.clone() - zfar.clone());
            self.matrix[(2, 3)] = zfar.clone() * znear.clone() * crate::convert(2.0) / (znear - zfar);
        }
    }

    #[cfg(feature = "rand-no-std")]
    impl<T: RealField> Distribution<Perspective3<T>> for Standard
    where
        Standard: Distribution<T>,
    {
        /// Generate an arbitrary random variate for testing purposes.
        fn sample<R: Rng + ?Sized>(&self, r: &mut R) -> Perspective3<T> {
            use crate::base::helper;
            let znear = r.gen();
            let zfar = helper::reject_rand(r, |x: &T| !(x.clone() - znear.clone()).is_zero());
            let aspect = helper::reject_rand(r, |x: &T| !x.is_zero());

            Perspective3::new(aspect, r.gen(), znear, zfar)
        }
    }

    #[cfg(feature = "arbitrary")]
    impl<T: RealField + Arbitrary> Arbitrary for Perspective3<T> {
        fn arbitrary(g: &mut Gen) -> Self {
            use crate::base::helper;
            let znear: T = Arbitrary::arbitrary(g);
            let zfar = helper::reject(g, |x: &T| !(x.clone() - znear.clone()).is_zero());
            let aspect = helper::reject(g, |x: &T| !x.is_zero());

            Self::new(aspect, Arbitrary::arbitrary(g), znear, zfar)
        }
    }

    impl<T: RealField> From<Perspective3<T>> for Matrix4<T> {
        #[inline]
        fn from(pers: Perspective3<T>) -> Self {
            pers.into_inner()
        }
    }