From 7d8aad2b14a8b519e624ab44aed24e0b7e4a0ac7 Mon Sep 17 00:00:00 2001
From: aozhiwei <aozhiwe@kingsome.cn>
Date: Tue, 25 Jun 2019 11:08:12 +0800
Subject: [PATCH] add vec2

---
 a8/vec2.cc | 139 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 a8/vec2.h  |  35 ++++++++++++++
 2 files changed, 174 insertions(+)
 create mode 100644 a8/vec2.cc
 create mode 100644 a8/vec2.h

diff --git a/a8/vec2.cc b/a8/vec2.cc
new file mode 100644
index 0000000..a8c755e
--- /dev/null
+++ b/a8/vec2.cc
@@ -0,0 +1,139 @@
+#include <math.h>
+#include <a8/a8.h>
+
+#include <glm/glm.hpp>
+#include <glm/gtc/matrix_transform.hpp>
+#include <glm/vec2.hpp>
+#include <Eigen/Core>
+#include <Eigen/Dense>
+
+#include <a8/vec2.h>
+
+namespace a8
+{
+    const Vec2 Vec2::UP = Vec2(0.0f, 1.0f);
+    const Vec2 Vec2::RIGHT = Vec2(1.0f, 0.0f);
+    const Vec2 Vec2::DOWN = Vec2(0.0f, -1.0f);
+    const Vec2 Vec2::LEFT = Vec2(-1.0f, 0.0f);
+
+    void Vec2::Normalize()
+    {
+#if 1
+        glm::vec2 v = glm::normalize(glm::vec2(x, y));
+        assert(!isnan(v[0]));
+        assert(!isnan(v[1]));
+        x = v[0];
+        y = v[1];
+#else
+        Eigen::Vector2f v(x, y);
+        v.normalize();
+        x = v[0];
+        y = v[1];
+#endif
+    }
+
+    bool Vec2::operator == (const Vec2& b) const
+    {
+        return std::abs(x - b.x) < 0.01f && std::abs(y - b.y) < 0.01f;
+    }
+
+    Vec2 Vec2::operator + (const Vec2& b) const
+    {
+#if 1
+        glm::vec2 v = glm::vec2(x, y) + glm::vec2(b.x, b.y);
+        return Vec2(v[0], v[1]);
+#else
+        Eigen::Vector2f v = Eigen::Vector2f(x, y) + Eigen::Vector2f(b.x, b.y);
+        return Vec2(v[0], v[1]);
+#endif
+    }
+
+    Vec2 Vec2::operator - (const Vec2& b) const
+    {
+#if 1
+        glm::vec2 v = glm::vec2(x, y) - glm::vec2(b.x, b.y);
+        return Vec2(v[0], v[1]);
+#else
+        Eigen::Vector2f v = Eigen::Vector2f(x, y) - Eigen::Vector2f(b.x, b.y);
+        return Vec2(v[0], v[1]);
+#endif
+    }
+
+    Vec2 Vec2::operator * (float scale) const
+    {
+#if 1
+        glm::vec2 v = glm::vec2(x, y) * scale;
+        return Vec2(v[0], v[1]);
+#else
+        Eigen::Vector2f v = Eigen::Vector2f(x, y) * scale;
+        return Vec2(v[0], v[1]);
+#endif
+    }
+
+    Vec2 Vec2::operator / (float scale) const
+    {
+#if 1
+        glm::vec2 v = glm::vec2(x, y) / scale;
+        return Vec2(v[0], v[1]);
+#else
+        Eigen::Vector2f v = Eigen::Vector2f(x, y) * (1.0 / scale);
+        return Vec2(v[0], v[1]);
+#endif
+    }
+
+    void Vec2::Rotate(float angle)
+    {
+        Eigen::Vector3f v(x, y, 0);
+        v = Eigen::AngleAxisf(angle * 3.1415926f, Eigen::Vector3f::UnitZ()) * v;
+        x = v[0];
+        y = v[1];
+    }
+
+    float Vec2::CalcAngle(const Vec2& b)
+    {
+        float a1 = acos(Dot(b) / Norm() / b.Norm());
+        float a2 = atan2(y, x);
+        float a3 = atan2(y, x) / 0.017 - 90.0f;
+#if 0
+        return a2;
+#else
+        bool at_right_side = Vec2::RIGHT.Dot(*this) > 0.0001f;
+        if (at_right_side) {
+            a1 = -a1;
+        }
+        return a1 / 3.1415926f;
+        //    return a3 / 360.0f;
+#endif
+    }
+
+    Vec2 Vec2::FromAngle(float angle)
+    {
+        Vec2 vec2;
+        float hu = angle * 3.1415926f / 180.0f;
+        vec2.x = cos(hu);
+        vec2.y = sin(hu);
+        vec2.Normalize();
+        return vec2;
+    }
+
+    float Vec2::Distance(const Vec2& b)
+    {
+        Vec2 v = b - *this;
+        return v.Norm();
+    }
+
+    Vec2 Vec2::Perp()
+    {
+        return Vec2(y, -x);
+    }
+
+    float Vec2::Dot(const Vec2& v) const
+    {
+        return x*v.x + y*v.y;
+    }
+
+    float Vec2::Norm() const
+    {
+        return fabs(sqrt(x*x + y*y));
+    }
+}
diff --git a/a8/vec2.h b/a8/vec2.h
new file mode 100644
index 0000000..3357e7e
--- /dev/null
+++ b/a8/vec2.h
@@ -0,0 +1,35 @@
+#ifndef A8_VEC2_H
+#define A8_VEC2_H
+
+namespace a8
+{
+    struct Vec2
+    {
+        float x = 0.0f;
+        float y = 0.0f;
+
+        Vec2(float _x = 0.0f, float _y = 0.0f):x(_x), y(_y) {};
+
+        void Normalize();
+        void Rotate(float angle);
+        float CalcAngle(const Vec2& b);
+        static Vec2 FromAngle(float angle);
+        float Distance(const Vec2& b);
+
+        bool operator == (const Vec2& b) const;
+        Vec2 operator + (const Vec2& b) const;
+        Vec2 operator - (const Vec2& b) const;
+        Vec2 operator * (float scale) const;
+        Vec2 operator / (float scale) const;
+        Vec2 Perp();
+        float Dot(const Vec2& v) const;
+        float Norm() const;
+
+        static const Vec2 UP;
+        static const Vec2 DOWN;
+        static const Vec2 LEFT;
+        static const Vec2 RIGHT;
+    };
+}
+
+#endif