use rust_num::{Zero, One};
use rust_num::traits::cast;
use angle::{Angle, Rad, tan, cot};
use frustum::Frustum;
use matrix::Matrix4;
use num::BaseFloat;
use plane::Plane;
pub fn perspective<S: BaseFloat + 'static, A: Angle<S>>(fovy: A, aspect: S, near: S, far: S) -> Matrix4<S> {
PerspectiveFov {
fovy: fovy,
aspect: aspect,
near: near,
far: far,
}.into()
}
pub fn frustum<S: BaseFloat + 'static>(left: S, right: S, bottom: S, top: S, near: S, far: S) -> Matrix4<S> {
Perspective {
left: left,
right: right,
bottom: bottom,
top: top,
near: near,
far: far,
}.into()
}
pub fn ortho<S: BaseFloat + 'static>(left: S, right: S, bottom: S, top: S, near: S, far: S) -> Matrix4<S> {
Ortho {
left: left,
right: right,
bottom: bottom,
top: top,
near: near,
far: far,
}.into()
}
pub trait Projection<S: BaseFloat>: Into<Matrix4<S>> {
fn to_frustum(&self) -> Frustum<S>;
}
#[derive(Copy, Clone, PartialEq, RustcEncodable, RustcDecodable)]
pub struct PerspectiveFov<S, A> {
pub fovy: A,
pub aspect: S,
pub near: S,
pub far: S,
}
impl<S: BaseFloat, A: Angle<S>> PerspectiveFov<S, A> {
pub fn to_perspective(&self) -> Perspective<S> {
let angle = self.fovy.div_s(cast(2i8).unwrap());
let angle: Rad<_> = angle.into();
let ymax = self.near * tan(angle);
let xmax = ymax * self.aspect;
Perspective {
left: -xmax,
right: xmax,
bottom: -ymax,
top: ymax,
near: self.near.clone(),
far: self.far.clone(),
}
}
}
impl<S: BaseFloat + 'static, A: Angle<S>> Projection<S> for PerspectiveFov<S, A> {
fn to_frustum(&self) -> Frustum<S> {
Frustum::from_matrix4(self.clone().into()).unwrap()
}
}
impl<S: BaseFloat, A: Angle<S>> From<PerspectiveFov<S, A>> for Matrix4<S> {
fn from(persp: PerspectiveFov<S, A>) -> Matrix4<S> {
let half_turn: A = Angle::turn_div_2();
assert!(persp.fovy > A::zero(), "The vertical field of view cannot be below zero, found: {:?}", persp.fovy);
assert!(persp.fovy < half_turn, "The vertical field of view cannot be greater than a half turn, found: {:?}", persp.fovy);
assert!(persp.aspect > S::zero(), "The aspect ratio cannot be below zero, found: {:?}", persp.aspect);
assert!(persp.near > S::zero(), "The near plane distance cannot be below zero, found: {:?}", persp.near);
assert!(persp.far > S::zero(), "The far plane distance cannot be below zero, found: {:?}", persp.far);
assert!(persp.far > persp.near, "The far plane cannot be closer than the near plane, found: far: {:?}, near: {:?}", persp.far, persp.near);
let f: Rad<_> = persp.fovy.div_s(cast(2i8).unwrap()).into();
let f = cot(f);
let two: S = cast(2i8).unwrap();
let c0r0 = f / persp.aspect;
let c0r1 = S::zero();
let c0r2 = S::zero();
let c0r3 = S::zero();
let c1r0 = S::zero();
let c1r1 = f;
let c1r2 = S::zero();
let c1r3 = S::zero();
let c2r0 = S::zero();
let c2r1 = S::zero();
let c2r2 = (persp.far + persp.near) / (persp.near - persp.far);
let c2r3 = -S::one();
let c3r0 = S::zero();
let c3r1 = S::zero();
let c3r2 = (two * persp.far * persp.near) / (persp.near - persp.far);
let c3r3 = S::zero();
Matrix4::new(c0r0, c0r1, c0r2, c0r3,
c1r0, c1r1, c1r2, c1r3,
c2r0, c2r1, c2r2, c2r3,
c3r0, c3r1, c3r2, c3r3)
}
}
#[derive(Copy, Clone, PartialEq, RustcEncodable, RustcDecodable)]
pub struct Perspective<S> {
pub left: S,
pub right: S,
pub bottom: S,
pub top: S,
pub near: S,
pub far: S,
}
impl<S: BaseFloat + 'static> Projection<S> for Perspective<S> {
fn to_frustum(&self) -> Frustum<S> {
Frustum::from_matrix4(self.clone().into()).unwrap()
}
}
impl<S: BaseFloat + 'static> From<Perspective<S>> for Matrix4<S> {
fn from(persp: Perspective<S>) -> Matrix4<S> {
assert!(persp.left <= persp.right, "`left` cannot be greater than `right`, found: left: {:?} right: {:?}", persp.left, persp.right);
assert!(persp.bottom <= persp.top, "`bottom` cannot be greater than `top`, found: bottom: {:?} top: {:?}", persp.bottom, persp.top);
assert!(persp.near <= persp.far, "`near` cannot be greater than `far`, found: near: {:?} far: {:?}", persp.near, persp.far);
let two: S = cast(2i8).unwrap();
let c0r0 = (two * persp.near) / (persp.right - persp.left);
let c0r1 = S::zero();
let c0r2 = S::zero();
let c0r3 = S::zero();
let c1r0 = S::zero();
let c1r1 = (two * persp.near) / (persp.top - persp.bottom);
let c1r2 = S::zero();
let c1r3 = S::zero();
let c2r0 = (persp.right + persp.left) / (persp.right - persp.left);
let c2r1 = (persp.top + persp.bottom) / (persp.top - persp.bottom);
let c2r2 = -(persp.far + persp.near) / (persp.far - persp.near);
let c2r3 = -S::one();
let c3r0 = S::zero();
let c3r1 = S::zero();
let c3r2 = -(two * persp.far * persp.near) / (persp.far - persp.near);
let c3r3 = S::zero();
Matrix4::new(c0r0, c0r1, c0r2, c0r3,
c1r0, c1r1, c1r2, c1r3,
c2r0, c2r1, c2r2, c2r3,
c3r0, c3r1, c3r2, c3r3)
}
}
#[derive(Copy, Clone, PartialEq, RustcEncodable, RustcDecodable)]
pub struct Ortho<S> {
pub left: S,
pub right: S,
pub bottom: S,
pub top: S,
pub near: S,
pub far: S,
}
impl<S: BaseFloat> Projection<S> for Ortho<S> {
fn to_frustum(&self) -> Frustum<S> {
Frustum {
left: Plane::from_abcd( S::one(), S::zero(), S::zero(), self.left.clone()),
right: Plane::from_abcd(-S::one(), S::zero(), S::zero(), self.right.clone()),
bottom: Plane::from_abcd(S::zero(), S::one(), S::zero(), self.bottom.clone()),
top: Plane::from_abcd(S::zero(), -S::one(), S::zero(), self.top.clone()),
near: Plane::from_abcd(S::zero(), S::zero(), -S::one(), self.near.clone()),
far: Plane::from_abcd(S::zero(), S::zero(), S::one(), self.far.clone()),
}
}
}
impl<S: BaseFloat> From<Ortho<S>> for Matrix4<S> {
fn from(ortho: Ortho<S>) -> Matrix4<S> {
let two: S = cast(2i8).unwrap();
let c0r0 = two / (ortho.right - ortho.left);
let c0r1 = S::zero();
let c0r2 = S::zero();
let c0r3 = S::zero();
let c1r0 = S::zero();
let c1r1 = two / (ortho.top - ortho.bottom);
let c1r2 = S::zero();
let c1r3 = S::zero();
let c2r0 = S::zero();
let c2r1 = S::zero();
let c2r2 = -two / (ortho.far - ortho.near);
let c2r3 = S::zero();
let c3r0 = -(ortho.right + ortho.left) / (ortho.right - ortho.left);
let c3r1 = -(ortho.top + ortho.bottom) / (ortho.top - ortho.bottom);
let c3r2 = -(ortho.far + ortho.near) / (ortho.far - ortho.near);
let c3r3 = S::one();
Matrix4::new(c0r0, c0r1, c0r2, c0r3,
c1r0, c1r1, c1r2, c1r3,
c2r0, c2r1, c2r2, c2r3,
c3r0, c3r1, c3r2, c3r3)
}
}