Initial commit.

physics/vector.cpp

@@ -0,0 +1,52 @@
+// -*- C++ -*-
+
+#include <algorithm>
+#include <stdlib.h>
+
+#include "vector.h"
+
+using namespace mbostock;
+
+const Vector& Vector::ZERO() {
+  static const Vector v;
+  return v;
+}
+
+const Vector& Vector::X() {
+  static const Vector v(1.f, 0.f, 0.f);
+  return v;
+}
+
+const Vector& Vector::Y() {
+  static const Vector v(0.f, 1.f, 0.f);
+  return v;
+}
+
+const Vector& Vector::Z() {
+  static const Vector v(0.f, 0.f, 1.f);
+  return v;
+}
+
+const Vector& Vector::INF() {
+  static const Vector v(INFINITY, INFINITY, INFINITY);
+  return v;
+}
+
+static float randomf() {
+  return random() / (float) RAND_MAX;
+}
+
+Vector Vector::min(const Vector& a, const Vector& b) {
+  return Vector(std::min(a.x, b.x), std::min(a.y, b.y), std::min(a.z, b.z));
+}
+
+Vector Vector::max(const Vector& a, const Vector& b) {
+  return Vector(std::max(a.x, b.x), std::max(a.y, b.y), std::max(a.z, b.z));
+}
+
+Vector Vector::randomVector(float k) {
+  Vector v(randomf() - .5f, randomf() - .5f, randomf() - .5f);
+  return ((v.x == 0.f) && (v.y == 0.f) && (v.z == 0.f))
+    ? Vector(k, 0.f, 0.f) // very unlikely, but still...
+    : v.normalize() * k;
+}