Introduce Vector2

docs/api/vector2.md

@@ -0,0 +1,55 @@
+# Vector2
+
+A vector in 2D space.
+
+*Since:* 0.4.0
+
+## Properties
+
+### x
+
+`vector.x: number`
+
+The x coordinate of the vector.
+
+### y
+
+`vector.y: number`
+
+The y coordinate of the vector.
+
+## Methods
+
+### length
+
+`vector.length(): number`
+
+Compute the length of the vector: `sqrt(x^2 + y^2)`.
+
+**Returns**
+
+The length of the vector.
+
+### equals
+
+`vector.equals(v: Vector2): boolean`
+
+Check if `this` and `v` have the same coordinates.
+
+**Arguments**
+
+* `v: Vector2`. A vector.
+
+**Returns**
+
+`true` if `this` and `v` have the same coordinates.
+
+### toString
+
+`vector.toString(): string`
+
+Generate a string representation of the vector.
+
+**Returns**
+
+A string representation of the vector.

mkdocs.yml

@@ -97,6 +97,7 @@ nav:
       - 'Transform': 'api/transform.md'
       - 'Quaternion': 'api/quaternion.md'
       - 'Vector3': 'api/vector3.md'
+      - 'Vector2': 'api/vector2.md'
     - 'Visualization':
       - 'Viewport': 'api/viewport.md'
       - 'HUD': 'api/hud.md'

src/geometry/vector2.ts

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+/*
+ * encantar.js
+ * GPU-accelerated Augmented Reality for the web
+ * Copyright (C) 2022-2024 Alexandre Martins <alemartf(at)gmail.com>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published
+ * by the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ * vector2.ts
+ * 2D vectors
+ */
+
+/** Small number */
+const EPSILON = 1e-6;
+
+// public / non-internal methods do not change the contents of the vector
+
+
+
+/**
+ * A vector in 2D space
+ */
+export class Vector2
+{
+    /** x coordinate */
+    public x: number;
+
+    /** y coordinate */
+    public y: number;
+
+
+
+
+    /**
+     * Constructor
+     */
+    constructor(x: number = 0, y: number = 0)
+    {
+        this.x = +x;
+        this.y = +y;
+    }
+
+    /**
+     * Instantiate a zero vector
+     * @returns a new zero vector
+     */
+    static Zero(): Vector2
+    {
+        return new Vector2(0, 0);
+    }
+
+    /**
+     * The length of this vector
+     * @returns sqrt(x^2 + y^2)
+     */
+    length(): number
+    {
+        const x = this.x;
+        const y = this.y;
+
+        return Math.sqrt(x*x + y*y);
+    }
+
+    /**
+     * Check if this and v have the same coordinates
+     * @param v a vector
+     * @returns true if this and v have the same coordinates
+     */
+    equals(v: Vector2): boolean
+    {
+        return this.x === v.x && this.y === v.y;
+    }
+
+    /**
+     * Convert to string
+     * @returns a string
+     */
+    toString(): string
+    {
+        const x = this.x.toFixed(5);
+        const y = this.y.toFixed(5);
+
+        return `Vector2(${x},${y})`;
+    }
+
+    /**
+     * Normalize this vector
+     * @returns this vector, normalized
+     * @internal
+     */
+    _normalize(): Vector2
+    {
+        const length = this.length();
+
+        if(length < EPSILON) // zero?
+            return this;
+
+        this.x /= length;
+        this.y /= length;
+
+        return this;
+    }
+
+    /**
+     * Copy v to this
+     * @param v a vector
+     * @returns this vector
+     * @internal
+     */
+    _copyFrom(v: Vector2): Vector2
+    {
+        this.x = v.x;
+        this.y = v.y;
+
+        return this;
+    }
+
+    /**
+     * Set the coordinates of this vector
+     * @param x x-coordinate
+     * @param y y-coordinate
+     * @returns this vector
+     * @internal
+     */
+    _set(x: number, y: number): Vector2
+    {
+        this.x = +x;
+        this.y = +y;
+
+        return this;
+    }
+}