1 files changed, 64 insertions, 0 deletions
diff --git a/_shared/math/vec2.js b/_shared/math/vec2.js
new file mode 100644
index 0000000..11e71cd
--- /dev/null
+++ b/_shared/math/vec2.js
@@ -0,0 +1,64 @@
+function vec2(x = 0, y = 0) {
+    return { x: x, y: y};
+}
+
+function addVec2(v1, v2) {
+    return {
+        x: v1.x + v2.x,
+        y: v1.y + v2.y
+    };
+}
+
+function subVec2(v1, v2) {
+    return {
+        x: v1.x - v2.x,
+        y: v1.y - v2.y
+    };
+}
+
+function scaleVec2(v, s) {
+    return {
+        x: v.x * s,
+        y: v.y * s
+    };
+}
+
+function dot2(v1, v2) {
+    return v1.x * v2.x + v1.y * v2.y;
+}
+
+function length2(v) {
+    return Math.sqrt(v.x * v.x + v.y * v.y);
+}
+
+function normalize2(v) {
+    const lLength = length2(v);
+    const lInverseLength = lLength === 0 ? 1.0 : 1.0 / length2(v);
+    return { x: v.x * lInverseLength, y: v.y * lInverseLength };
+}
+
+function vec2str(v) {
+    return `(${v.x.toFixed(2)}, ${v.y.toFixed(2)})`;
+}
+
+function getPerp2(v) {
+    return {
+        x: -v.y,
+        y: v.x
+    };
+}
+
+function negate2(v) {
+    return {
+        x: -v.x,
+        y: -v.y
+    };
+}
+
+// Algorithm plucked from: https://matthew-brett.github.io/teaching/rotation_2d.html
+function rotateAboutOrigin2(v, angle) {
+    return {
+        x: v.x * Math.cos(angle) - v.y * Math.sin(angle),
+        y: v.x * Math.sin(angle) + v.y * Math.cos(angle),
+    };
+}
+\ No newline at end of file