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-rw-r--r--src/Geometry.js121
-rw-r--r--src/MapView.js5
-rw-r--r--src/Terrain.js139
-rw-r--r--src/main.js24
4 files changed, 268 insertions, 21 deletions
diff --git a/src/Geometry.js b/src/Geometry.js
index 23ef480..05c22e0 100644
--- a/src/Geometry.js
+++ b/src/Geometry.js
@@ -117,6 +117,31 @@ export class Vec3 {
return new Point(latitude, longitude)
}
+ copy() {
+ return new Vec3(this.x, this.y, this.z);
+ }
+
+ add(vec) {
+ this.x = this.x + vec.x;
+ this.y = this.y + vec.y;
+ this.z = this.z + vec.z;
+ return this
+ }
+
+ sub(vec) {
+ this.x = this.x - vec.x;
+ this.y = this.y - vec.y;
+ this.z = this.z - vec.z;
+ return this;
+ }
+
+ scale(a) {
+ this.x = this.x * a;
+ this.y = this.y * a;
+ this.z = this.z * a;
+ return this;
+ }
+
dot(vec) {
return (this.x * vec.x) + (this.y * vec.y) + (this.z * vec.z);
}
@@ -143,25 +168,17 @@ export class Vec3 {
}
+export function RandomNormal() {
+ const theta = 2*Math.PI*Math.random();
+ const z = 2*Math.random() - 1;
+ const s = Math.sqrt(1-(z*z));
+ return new Vec3(s*Math.cos(theta), s*Math.sin(theta), z).normalize();
+}
+
+
export class Shape {
constructor(normals) {
this.normals = normals;
- let avgx = 0;
- let avgy = 0;
- let avgz = 0;
- for (let normal of normals) {
- avgx += normal.x;
- avgy += normal.y;
- avgz += normal.z;
- }
- avgx /= normals.length;
- avgy /= normals.length;
- avgz /= normals.length;
- this.center = new Vec3(avgx, avgy, avgz).normalize();
- this.extent = 0
- for (let normal of normals) {
- this.extent = Math.max(this.extent, normal.dot(this.center));
- }
}
translate(circle, angle) {
@@ -169,7 +186,6 @@ export class Shape {
for (let i=0; i<this.normals.length; i++) {
this.normals[i] = transform.mulv(this.normals[i]);
}
- this.center = transform.mulv(this.normals[i]);
}
getNextRenderPoint(ct, start, view) {
@@ -198,12 +214,81 @@ export class Shape {
return;
}
-
ct.moveTo(v.x, v.y);
+ let count = 0;
while(v != null) {
+ count += 1;
ct.lineTo(v.x, v.y);
[ i, v ] = this.getNextRenderPoint(ct, i, view);
}
+ if (count == this.normals.length) {
+ ct.closePath();
+ }
ct.stroke();
}
}
+
+
+export function ConvexHull(points) {
+ const hull = [];
+
+ console.log("compute center");
+ // compute the average of the group of points
+ let center = new Vec3(0, 0, 0);
+ for (let point of points) {
+ center.add(point);
+ }
+ center.scale(1/points.length).normalize;
+
+ console.log("find furthest");
+ // find the furthest point from the center
+ let furthest = null;
+ let mindot = 1;
+ for (let point of points) {
+ const d = center.dot(point);
+ if (d < mindot) {
+ mindot = d;
+ furthest = point;
+ }
+ }
+
+ const t0 = furthest.copy().sub(center).cross(furthest).normalize();
+
+ function getNextHullPoint(p, tangent) {
+ let next = null;
+ let max = -1;
+ for (let point of points) {
+ const v = point.copy().sub(p).normalize();
+ const d = v.dot(tangent);
+ if (d > max) {
+ max = d;
+ next = point;
+ }
+ }
+ return next;
+ }
+
+ function tangent(p, prev) {
+ return p.copy().sub(prev).normalize();
+ }
+
+ hull.push[furthest];
+ let p = getNextHullPoint(furthest, t0);
+ let tan = tangent(p, furthest);
+
+ // begin loop
+ console.log("loop");
+ let count = 0;
+ while (p != null) {
+ count += 1;
+ hull.push(p);
+ p = getNextHullPoint(p, tan);
+ tan = tangent(p, hull[hull.length-1]);
+ if (p == furthest || count > 50) {
+ console.log(count);
+ p = null;
+ }
+ }
+
+ return new Shape(hull);
+}
diff --git a/src/MapView.js b/src/MapView.js
index 8f41480..0afa713 100644
--- a/src/MapView.js
+++ b/src/MapView.js
@@ -105,11 +105,12 @@ export class MapView {
zoom(delta) {
let scale;
+ const zoom = 1.1;
if (delta < 0) {
- scale = 2;
+ scale = zoom;
}
else {
- scale = 1/2;
+ scale = 1/zoom;
}
this.scale *= scale;
diff --git a/src/Terrain.js b/src/Terrain.js
new file mode 100644
index 0000000..a51c0a3
--- /dev/null
+++ b/src/Terrain.js
@@ -0,0 +1,139 @@
+import { Mat3, Vec3, Point, RandomNormal, Shape, ConvexHull } from './Geometry.js';
+
+
+export function RandomPoints(n) {
+ const points = [];
+ for (let i=0; i<n; i++) {
+ points.push(RandomNormal());
+ }
+ return points;
+}
+
+
+export class Plate {
+ constructor(points) {
+ this.color = `hsl(${360*Math.random()}, 100%, 50%)`
+ this.points = points;
+ this.hull = ConvexHull(points);
+ let [avgX, avgY, avgZ] = [0, 0, 0];
+ for (let point of points) {
+ avgX += point.x;
+ avgY += point.y;
+ avgZ += point.z;
+ }
+ avgX /= points.length;
+ avgY /= points.length;
+ avgZ /= points.length;
+ this.center = new Vec3(avgX, avgY, avgZ).normalize();
+ this.extent = 0;
+ for (let point of points) {
+ this.extent = Math.max(this.extent, this.center.dot(point));
+ }
+
+ this.speed = Math.random();
+ this.axis = RandomNormal().cross(this.center).normalize();
+ }
+
+ filterColliding(plate) {
+ const extent = Math.max(this.extent, plate.extent);
+ return this.center.dot(plate.center) < extent;
+ }
+
+ checkColliding(plate) {
+ if (!this.filterColliding(plate)) {
+ return false;
+ }
+
+ console.log("check", this, plate);
+
+ const threshold = 0.00001;
+ let collisionTotal = 0;
+ for (let pa of this.points) {
+ for (let pb of plate.points) {
+ collisionTotal += pa.dot(pb);
+ }
+ }
+ collisionTotal /= this.points.length * plate.points.length;
+ console.log(this, plate, collisionTotal);
+ if (collisionTotal > threshold) {
+ return true;
+ }
+ return false;
+ }
+
+ move() {
+ const matrix = new Mat3().rotation(this.axis, this.speed * 0.01 * Math.PI);
+ for (let i=0; i<this.points.length; i++) {
+ this.points[i] = matrix.mulv(this.points[i]);
+ }
+ this.hull.translate(this.axis, this.speed * 0.01 * Math.PI);
+ this.center = matrix.mulv(this.center);
+ }
+
+ render(ct, view) {
+ ct.fillStyle = this.color;
+ for (let point of this.points) {
+ point.render(ct, view);
+ }
+ this.hull.render(ct, view);
+ }
+}
+
+
+function randomChoice(array) {
+ const index = Math.floor(array.length * Math.random());
+ return array[index];
+}
+
+
+export class PlateManager {
+ constructor(points, plateCount) {
+ this.points = points;
+ this.plates = this.buildPlates(plateCount);
+ }
+
+
+ buildPlates(plateCount) {
+ const seedPoints = [];
+ const points = [];
+ for (let i=0; i<plateCount; i++) {
+ seedPoints.push(randomChoice(this.points));
+ points.push([]);
+ }
+
+ for (let point of this.points) {
+ let maxDot = -1;
+ let index = -1;
+ for (let i=0; i<plateCount; i++) {
+ const seed = seedPoints[i];
+ const d = seed.dot(point);
+ if (d > maxDot) {
+ maxDot = d;
+ index = i;
+ }
+ }
+ if (index == -1) {
+ console.error("no closest point", point);
+ }
+ points[index].push(point);
+ }
+
+ const plates = [];
+ for (let p of points) {
+ plates.push(new Plate(p));
+ }
+ return plates;
+ }
+
+ update() {
+ for (let plate of this.plates) {
+ plate.move();
+ }
+ }
+
+ render(ct, view) {
+ for (let plate of this.plates) {
+ plate.render(ct, view);
+ }
+ }
+}
diff --git a/src/main.js b/src/main.js
index db8963d..8ed95d1 100644
--- a/src/main.js
+++ b/src/main.js
@@ -1,6 +1,7 @@
import Canvas from './Canvas.js';
-import { Mat3, Vec3, Point, Shape } from './Geometry.js';
+import { Mat3, Vec3, Point, Shape, RandomNormal } from './Geometry.js';
import { MapGrid, MapView } from './MapView.js';
+import { RandomPoints, Plate, PlateManager } from './Terrain.js';
const $ = id => document.getElementById(id)
@@ -14,6 +15,17 @@ window.onload = () => {
const grid = new MapGrid(30, 30);
const map = new MapView(canvas);
+ const points = [];
+ for (let i=0; i<100; i++) {
+ points.push(
+ new Point(Math.random() * 0.2 * Math.PI, Math.random() * 0.2 * Math.PI).normal()
+ );
+ }
+ const plate = new Plate(points);
+
+// const points = RandomPoints(100);
+// const mgr = new PlateManager(points, 10);
+
map.onDraw = (ct, view) => {
ct.fillStyle = "#01162B"
ct.fillRect(-10,-10, 100, 100);
@@ -22,6 +34,16 @@ window.onload = () => {
ct.fillStyle = "blue";
grid.render(ct, view);
+
+ //mgr.render(ct, view);
+ plate.render(ct, view);
+ ct.fillStyle = "blue";
+ plate.hull.normals[0].render(ct, view);
};
canvas.draw();
+
+// setInterval(() => {
+// mgr.update();
+// canvas.draw();
+// }, 100);
}
generated by cgit v1.2.1 (git 2.18.0) at 2024-12-23 12:07:06 +0000