diff --git a/index.html b/index.html
index fcac4de..d44c520 100644
--- a/index.html
+++ b/index.html
@@ -13,6 +13,13 @@ async function run() {
let game = new Game("game-canvas");
let last = performance.now();
+ window.addEventListener("keydown", e => {
+ game.key_down(e.key);
+ });
+ window.addEventListener("keyup", e => {
+ game.key_up(e.key);
+ });
+
function loop(now) {
const dt = (now - last);
last = now;
diff --git a/src/lib.rs b/src/lib.rs
index 3d5072f..6ec05d7 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,4 +1,5 @@
use std::f64;
+use std::collections::HashSet;
use wasm_bindgen::prelude::*;
use wasm_bindgen::JsCast;
@@ -10,7 +11,7 @@ use cga::CGA;
const PI: f64 = f64::consts::PI;
const TWO_PI: f64 = 2.*PI;
-const ERROR: f64 = 0.0001;
+const ERROR: f64 = 0.000001;
const WIDTH: f64 = 600.;
const HEIGHT: f64 = 600.;
@@ -21,7 +22,7 @@ const RADIUS: f64 = 250.;
const BACKGROUND: &str = "#ffffff";
const BLACK: &str = "#000000";
const RED: &str = "#ff0000";
-const GREEN: &str = "#00ff00";
+const _GREEN: &str = "#00ff00";
const _BLUE: &str = "#0000ff";
const SCALAR: usize = 0;
@@ -30,16 +31,16 @@ const E2: usize = 2;
//const E3: usize = 3;
//const E4: usize = 4;
//const E5: usize = 5;
-//const E12: usize = 6;
-//const E13: usize = 7;
-//const E14: usize = 8;
-//const E15: usize = 9;
-//const E23: usize = 10;
-//const E24: usize = 11;
-//const E25: usize = 12;
-//const E34: usize = 13;
-//const E35: usize = 14;
-//const E45: usize = 15;
+const E12: usize = 6;
+const E13: usize = 7;
+const E14: usize = 8;
+const E15: usize = 9;
+const E23: usize = 10;
+const E24: usize = 11;
+const E25: usize = 12;
+const E34: usize = 13;
+const E35: usize = 14;
+const E45: usize = 15;
//const E123: usize = 16;
//const E124: usize = 17;
//const E125: usize = 18;
@@ -57,18 +58,23 @@ const E2: usize = 2;
//const E2345: usize = 30;
//const E12345: usize = 31;
+const DRAG: f64 = 1.;
+const ACCEL_STR: f64 = 1.;
+
struct Ship {
- pos: CGA,
- //_vel: CGA,
- //_orientation: CGA,
+ com: CGA,
+ verts: (CGA, CGA, CGA),
+ vel: CGA,
+ orientation: CGA,
}
-enum Geometry {
+enum _Geometry {
Circle(f64, f64, f64), //x,y,r
Line(f64, f64, f64) //x,r,theta
}
-fn point_to_cga(x: f64, y: f64) -> CGA {
+/* Translation of a Euclidean Point. Need to use hyperbolic*/
+fn _point_to_cga(x: f64, y: f64) -> CGA {
let x_vec = CGA::e1();
let y_vec = CGA::e2();
let _z_vec =CGA::e3(); //This game assumes everything takes place in the plane.
@@ -87,7 +93,7 @@ fn point_to_cga(x: f64, y: f64) -> CGA {
}
0.5*mag_sqr*n_vec + ux*x_vec + uy*y_vec - 0.5*n_bar //F(x) = 1/2(x^2 n + 2x - nbar) = -1/2(x-e)n(x-e)
-}
+}
fn point_to_screen_space(x: f64, y: f64) -> (f64, f64) {
let screen_x = x*RADIUS + CENTER_X;
@@ -97,7 +103,7 @@ fn point_to_screen_space(x: f64, y: f64) -> (f64, f64) {
fn draw_point(context: &CanvasRenderingContext2d, point: &CGA) {
//Naively assume we are given a valid point
- let (x,y) = get_point(point);
+ let (x,y) = get_hyperbolic_point(point);
let (x,y) = point_to_screen_space(x, y);
context.begin_path();
@@ -107,18 +113,35 @@ fn draw_point(context: &CanvasRenderingContext2d, point: &CGA) {
}
//TODO Integrate into get geometry
-fn get_point(point: &CGA) -> (f64, f64) {
- let e_vec = CGA::e4();
- let e_bar = CGA::e5();
- let n_vec = &e_vec + &e_bar; //Null vector for the point at infinity.
+fn get_hyperbolic_point(point: &CGA) -> (f64, f64) {
+ let n_bar = CGA::e4() - CGA::e5();
- let normalization = -(point | &n_vec)[SCALAR];
- let x = point[E1] / normalization;
- let y = point[E2] / normalization;
- (x,y)
+ //Construct r hat dir for the point.
+ let mut x = point[E1];
+ let mut y = point[E2];
+ let mag_sqr = x*x + y*y;
+ if mag_sqr > ERROR {
+ x /= mag_sqr.sqrt();
+ y /= mag_sqr.sqrt();
+ //(x,y) is a unit vector pointing in the direction of our point
+ } else {
+ //mag_sqr is too small to be confident in our vector.
+ //Assume vector is at the origin.
+ return (0., 0.);
+ }
+
+ //A normalized hyperbolic point in the full CGA satisfies p dot e4 = -1,
+ //where e4 is the positive squaring conformal vector.
+ let norm = -(point | CGA::e4())[SCALAR];
+ //Get the normalize component of the n term. Note n dot n = 0 and n dot n_bar = 2
+ let n_term = (0.5/norm) * (point | &n_bar)[SCALAR];
+ //Solve for r^2
+ let r_sqr = n_term/(1.+n_term);
+ let r = r_sqr.sqrt();
+ (r*x,r*y)
}
-fn get_geometry(circle: &CGA) -> Geometry {
+fn _get_geometry(circle: &CGA) -> _Geometry {
//Naively assume we are given a valid line/circle
let n_bar = CGA::e4() - CGA::e5();
let n_vec = CGA::e4() + CGA::e5();
@@ -137,34 +160,34 @@ fn get_geometry(circle: &CGA) -> Geometry {
}
let x = a*c/norm_sqr/2.;
let y = b*c/norm_sqr/2.;
- return Geometry::Line(x,y,theta);
+ return _Geometry::Line(x,y,theta);
} else {
//Circle
let c_x = a/l;
let c_y = b/l;
let r_sqr = c_x*c_x + c_y*c_y + c/l;
let r = r_sqr.sqrt();
- return Geometry::Circle(-c_x, -c_y, r);
+ return _Geometry::Circle(-c_x, -c_y, r);
}
}
-fn draw_line(context: &CanvasRenderingContext2d, line: &CGA) {
+fn _draw_line(context: &CanvasRenderingContext2d, line: &CGA) {
context.begin_path();
- context.set_stroke_style_str(GREEN);
+ context.set_stroke_style_str(_GREEN);
- let geometry = get_geometry(line);
+ let geometry = _get_geometry(line);
match geometry {
- Geometry::Circle(x,y,r) => {
+ _Geometry::Circle(x,y,r) => {
let (canvas_x, canvas_y) = point_to_screen_space(x, y);
let canvas_r = r*RADIUS;
context.arc(canvas_x, canvas_y, canvas_r, 0., TWO_PI).unwrap();
},
- Geometry::Line(x,y,theta) => {
+ _Geometry::Line(x,y,theta) => {
let (p1x, p1y) = (x - theta.cos(), y - theta.sin());
let (p2x, p2y) = (x + theta.cos(), y + theta.sin());
let (canvas_x1, canvas_y1) = point_to_screen_space(p1x, p1y);
let (canvas_x2, canvas_y2) = point_to_screen_space(p2x, p2y);
- draw_point(&context, &point_to_cga(x,y));
+ //draw_point(&context, &point_to_cga(x,y));
context.move_to(canvas_x1, canvas_y1);
context.line_to(canvas_x2, canvas_y2);
},
@@ -172,18 +195,16 @@ fn draw_line(context: &CanvasRenderingContext2d, line: &CGA) {
context.stroke();
}
-fn get_hyperbolic_translation(vec: &CGA) -> CGA {
+fn _get_hyperbolic_translation(vec: &CGA) -> CGA {
let vec_sqr = (vec * vec)[SCALAR];
if vec_sqr >= 1. {
panic!("Translation Vector Out of Bounds");
}
- let message = format!("Get TX\nvec {} \nvecvec {}\nvec_sqr {}", vec, vec*vec, vec_sqr);
- console::log_1(&message.into());
let t = 1.0 / ( 1. - vec_sqr).sqrt() * ( CGA::new(1., SCALAR) + CGA::e5()*vec);
t
}
-fn get_hyperbolic_point(vec: &CGA) -> CGA {
+fn gen_hyperbolic_point(vec: &CGA) -> CGA {
let vec_sqr = (vec * vec)[SCALAR];
if vec_sqr >= 1. {
panic!("Vector out of bounds");
@@ -193,7 +214,36 @@ fn get_hyperbolic_point(vec: &CGA) -> CGA {
p
}
-struct Asteroid {
+fn bivector_exponential(bivector: &CGA) -> CGA {
+ //Explicitly take only the bivector part.
+ //The library doesn't provide a grade 2 selection.
+ let a = bivector[E12];
+ let b = bivector[E13];
+ let c = bivector[E14];
+ let d = bivector[E15];
+ let e = bivector[E23];
+ let f = bivector[E24];
+ let g = bivector[E25];
+ let h = bivector[E34];
+ let i = bivector[E35];
+ let j = bivector[E45];
+
+ let bivector = a*CGA::e12() + b*CGA::e13() + c*CGA::e14()
+ + d*CGA::e15() + e*CGA::e23() + f*CGA::e24() + g*CGA::e25()
+ + h*CGA::e34() + i *CGA::e35() + j*CGA::e45();
+ let sqr = (&bivector*&bivector)[SCALAR];
+ if sqr.abs() < ERROR {
+ CGA::new(1., SCALAR) + bivector
+ } else if sqr < 0. {
+ let theta = sqr.abs().sqrt();
+ CGA::new(theta.cos(), SCALAR) + theta.sin()/theta*bivector //Division by theta to normalize bivector
+ } else {
+ let t = sqr.sqrt();
+ CGA::new(t.cosh(), SCALAR) + t.sinh()/t*bivector //Division by t to normalize the bivector
+ }
+}
+
+struct _Asteroid {
}
#[wasm_bindgen]
@@ -201,8 +251,7 @@ pub struct Game {
context: CanvasRenderingContext2d,
ship: Ship,
//asteroids: Vec::,
- point: (f64, f64),
- //keys: HashSet,
+ keys: HashSet,
}
#[wasm_bindgen]
@@ -222,8 +271,21 @@ impl Game {
.ok_or_else( || JsValue::from_str("Failed to get context")).unwrap()
.dyn_into::().unwrap();
- let ship = Ship { pos: get_hyperbolic_point(&CGA::zero()) };
- Game { context: context, point: (0.,0.), ship }
+ let tx_gen = CGA::e15();
+ let ty_gen = CGA::e25();
+
+ let ship = Ship {
+ com: CGA::zero(),
+ verts: (-0.1*&tx_gen, 0.05*&tx_gen+0.02*&ty_gen, 0.05*&tx_gen-0.02*ty_gen),
+ vel: CGA::zero(),
+ orientation: CGA::zero()
+ };
+
+ Game {
+ context: context,
+ ship,
+ keys: HashSet::new()
+ }
}
pub fn draw(&self) {
@@ -235,9 +297,20 @@ impl Game {
self.context.arc(CENTER_X, CENTER_Y, RADIUS, 0., TWO_PI).unwrap();
self.context.stroke();
- let x = self.point.0;
- let y = self.point.1;
- draw_point(&self.context, &self.ship.pos);
+ let origin = gen_hyperbolic_point(&CGA::zero());
+ let com = bivector_exponential(&self.ship.com);
+ let orient_rotor = bivector_exponential(&(0.5 * &self.ship.orientation));
+ let v0_rotor = &com*&orient_rotor*bivector_exponential(&self.ship.verts.0);
+ let v1_rotor = &com*&orient_rotor*bivector_exponential(&self.ship.verts.1);
+ let v2_rotor = &com*&orient_rotor*bivector_exponential(&self.ship.verts.2);
+ let p0 = &v0_rotor*&origin*&v0_rotor.Reverse();
+ let p1 = &v1_rotor*&origin*&v1_rotor.Reverse();
+ let p2 = &v2_rotor*&origin*&v2_rotor.Reverse();
+
+ draw_point(&self.context, &(&com*&origin*&com.Reverse()));
+ draw_point(&self.context, &p0);
+ draw_point(&self.context, &p1);
+ draw_point(&self.context, &p2);
//self.context.begin_path();
//self.context.set_fill_style_str(GREEN);
@@ -246,18 +319,46 @@ impl Game {
}
- pub fn update(&mut self, dt: f64) { //dt in milliseconds
- let theta:f64 = 0.1;
- let vel:f64 = 1.*dt/1000.;
- let dir = theta.cos()*CGA::e1() + theta.sin()*CGA::e2();
- let vec = vel* &dir;
+ pub fn update(&mut self, dt_m: f64) {
+ let dt_s = if dt_m > 100. {
+ 0.1
+ } else {
+ dt_m / 1000.
+ };
+ let vel = self.ship.vel.clone();
+ let mut vel_2 = self.ship.vel.clone();
- let tx = get_hyperbolic_translation(&vec);
- let txr = tx.Reverse();
- self.ship.pos = &tx * &self.ship.pos * &txr;
+ let mut a_vec = - DRAG * &vel_2;
- let norm = (&self.ship.pos | CGA::e4() )[SCALAR];
- self.ship.pos = &self.ship.pos * (1.0 / norm);
+ if self.keys.contains("w") {
+ let orient = bivector_exponential(&(0.5*&self.ship.orientation));
+ let accel = &orient * ACCEL_STR * CGA::e15() * orient.Reverse();
+ a_vec = a_vec - accel;
+ }
+
+ if self.keys.contains("q") {
+ self.ship.orientation = &self.ship.orientation + 1. * dt_s * CGA::e12();
+ }
+
+ if self.keys.contains("e") {
+ self.ship.orientation = &self.ship.orientation - 1. * dt_s * CGA::e12();
+ }
+
+
+ vel_2 = vel_2 + a_vec*dt_s;
+ let vel_3 = 0.5*(vel+&vel_2);
+ let delta = vel_3 * dt_s;
+ let pos = &self.ship.com + delta;
+ self.ship.vel = vel_2;
+ self.ship.com = pos;
+ }
+
+ pub fn key_down(&mut self, key: String) {
+ self.keys.insert(key);
+ }
+
+ pub fn key_up(&mut self, key: String) {
+ self.keys.remove(&key);
}
}
@@ -278,7 +379,7 @@ pub fn start() -> Result<(), JsValue> {
.dyn_into::()?;
canvas.set_width(WIDTH as u32);
- canvas.set_height(HEIGHT as u32);
+canvas.set_height(HEIGHT as u32);
let context = canvas
.get_context("2d")?