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use interface::i_shape::{ ShapeType, IShape };
use interface::i_bound::IBound;
use interface::i_vicinity::IVicinity;
use interface::i_comparable::IComparableError;
use implement::math::mat::Mat3x1;
use implement::math::bound::AxisAlignedBBox;
#[derive(Debug, Clone)]
pub struct Ray3 {
pub _ori: Mat3x1< f64 >,
pub _dir: Mat3x1< f64 >,
pub _bound: AxisAlignedBBox,
pub _vicinity: f64,
}
impl Ray3 {
pub fn init( origin: &[f64], dir: &[f64] ) -> Ray3 {
assert!( origin.len() == 3 );
assert!( dir.len() == 3 );
Ray3 {
_ori: Mat3x1 { _val: [ origin[0], origin[1], origin[2] ] },
_dir: Mat3x1 { _val: [ dir[0], dir[1], dir[2] ] }.normalize().unwrap(),
_bound: AxisAlignedBBox::init( ShapeType::RAY, &[ &origin[0..3], &dir[0..3] ].concat() ),
_vicinity: 0.000001f64,
}
}
}
impl IShape for Ray3 {
fn get_shape_data( & self ) -> Vec< f64 > {
vec![ self._ori[0], self._ori[1], self._ori[2],
self._dir[0], self._dir[1], self._dir[2] ]
}
fn get_type( & self ) -> ShapeType {
ShapeType::RAY
}
fn get_bound( & self ) -> &IBound {
&self._bound
}
// this shall test for intersection of bounding shapes first before procedding to test intersection using algorithms of higher complexity
fn get_intersect( & self, other: & IShape ) -> ( bool, Option< Mat3x1< f64 > > ){
if !self.get_bound().intersect( other.get_bound() ){
return ( false, None )
}else{
match other.get_type() {
ShapeType::RAY => {
let other_shape_data = other.get_shape_data();
let a_dir = self._dir;
let b_dir = Mat3x1 { _val: [ other_shape_data[3], other_shape_data[4], other_shape_data[5] ] };
let a_off = self._ori;
let b_off = Mat3x1 { _val: [ other_shape_data[0], other_shape_data[1], other_shape_data[2] ] };
let c = b_dir.minus( &a_dir ).unwrap();
let v = a_dir.cross( &b_dir ).unwrap();
let dot_v_c = v.dot( &c ).unwrap();
if !self.within_vicinity( dot_v_c, 0f64 ) {
//they are not in the same place, so no intersection occurs
return ( false, None )
}
//test for colinearity
let zero : Mat3x1< f64 > = Default::default();
let d = b_off.minus( &a_off ).unwrap();
if v.is_equal( &zero, 0.0001f64 ).unwrap() {
//lines are parallel
//check triangle area formed by points on ray a and b
let point1 = a_dir;
let point2 = b_off.minus( &a_off ).unwrap();
let triangle_area = point1.cross( &point2 ).unwrap().magnitude().unwrap();
// println!( "triangle area: {}", triangle_area );
if !self.within_vicinity( triangle_area, 0f64 ) {
//no overlap
// println!( "parallel but non-overlapping lines" );
return ( false, None )
} else {
//lines are colinear
let direction = if d.dot( &a_dir ).unwrap() < 0f64 { -1f64 } else { 1f64 };
let distance = direction * d.magnitude().unwrap() / a_dir.magnitude().unwrap();
// println!( "colinear lines, distance: {}", distance );
if distance < 0f64 {
//intersection at offset of ray a, so clamp t to 0
return ( true, Some( a_off ) )
} else {
//intersection at offset of ray b
return ( true, Some( self._dir.scale( distance ).unwrap().plus( &self._ori ).unwrap() ) )
}
}
} else {
//solvable intersection exists
let numerator = d.cross( & b_dir ).unwrap();
let t = numerator.magnitude().unwrap() / v.magnitude().unwrap();
if t < 0f64 {
return ( false, None )
} else {
return ( true, Some( self._dir.scale( t ).unwrap().plus( &self._ori ).unwrap() ) )
}
}
},
ShapeType::POINT => {
let other_shape_data = other.get_shape_data();
let b_off = Mat3x1 { _val: [ other_shape_data[0], other_shape_data[1], other_shape_data[2] ] };
let a_dir = self._dir;
let a_off = self._ori;
//a_dir * t + a_off = b_off
//t = (b_off - a_off) / a_dir
let t = b_off.minus( &a_off ).unwrap().div( &a_dir ).unwrap();
if !self.within_vicinity( t[0], t[1] ) ||
!self.within_vicinity( t[1], t[2] ) {
return ( false, None )
} else {
if t[0] >= 0f64 {
return ( true, Some( a_dir.scale( t[0] ).unwrap().plus( &a_off ).unwrap() ) )
} else {
//the point is behind the ray origin and direction
return ( false, None )
}
}
},
ShapeType::SPHERE => {
let other_shape_data = other.get_shape_data();
let b_off = Mat3x1 { _val: [ other_shape_data[0], other_shape_data[1], other_shape_data[2] ] };
let b_r = other_shape_data[3];
let a_dir = self._dir;
let a_off = self._ori;
//sub in the ray equation into sphere equation
// b := projection of relative offset onto ray direction
// c := (minimal possible distance between sphere and ray origin )^2
let relative_offset = a_off.minus( &b_off ).unwrap();
let b = relative_offset.dot( &a_dir ).unwrap();
let c = relative_offset.dot( &relative_offset ).unwrap() - b_r * b_r;
if b > 0f64 && c > 0f64 {
//ray is outside of the sphere and points away from sphere
//thus no intersection occurs
return ( false, None )
}
let d = b * b - c;
if d < 0f64 {
//ray misses sphere
return ( false, None )
}
let t1 = -b - d.sqrt();
let t2 = -b + d.sqrt();
let t = if t1 < 0f64 {
t2
} else if t2 < 0f64 {
t1
} else if t1 < t2 {
t1
} else {
t2
};
return ( true, Some( a_dir.scale( t ).unwrap().plus( &a_off ).unwrap() ) )
},
ShapeType::PLANE => {
let other_shape_data = other.get_shape_data();
let b_off = Mat3x1 { _val: [ other_shape_data[0], other_shape_data[1], other_shape_data[2] ] };
let b_nor = Mat3x1 { _val: [ other_shape_data[3], other_shape_data[4], other_shape_data[5] ] };
//ray equation: r(t) = r.offset + r.dir * t
//plane: p(x) = dot(normal, x-p.offset) = 0
//p(x) = -dot(p.normal, p.offset) + dot(p.normal, x) = 0
//substitution:
// p(t) = -dot(p.fofset,p.normal) + dot(p.normal, r.offset + r.dir*t) = 0
// = -dot(p.fofset,p.normal) + dot(p.normal, r.offset) + t*dot(p.normal, r.dir) = 0
//t = ( dot(p.offset, p.normal) - dot(p.normal, r.offset) )/ dot(p.normal, r.dir )
let constant = b_off.dot( &b_nor ).unwrap();
let numerator = constant - b_nor.dot( &self._ori ).unwrap();
let denominator = b_nor.dot( &self._dir ).unwrap();
if denominator == 0f64 {
//ray direction is colplaner to the plane
if constant == self._ori.dot( &b_nor ).unwrap() {
return ( true, Some( self._ori ) )
} else {
return ( false, None )
}
} else if denominator > 0f64 {
//ray direction is not facing plane normal
return ( false, None )
}
let t = numerator / denominator;
if t < 0f64 {
return ( false, None )
}
return ( true, Some( self._dir.scale( t ).unwrap().plus( &self._ori ).unwrap() ) )
},
_ => { unimplemented!(); },
}
}
}
fn get_support( & self, v: & Mat3x1< f64 > ) -> Option< Mat3x1< f64 > > {
None
}
}
impl IVicinity< f64 > for Ray3 {
fn set_vicinity( & mut self, epsilon: f64 ) {
self._vicinity = epsilon.abs();
}
fn within_vicinity( & self, a: f64, b: f64 ) -> bool {
if a + self._vicinity >= b &&
a - self._vicinity <= b {
true
} else {
false
}
}
}