[core] Privatize math.hpp and vec.hpp

3 files changed, 244 insertions, 1 deletions

diff --git a/src/mbgl/util/geo.cpp b/src/mbgl/util/geo.cpp
index 7d9db65c4c..2cb5d09806 100644
--- a/src/mbgl/util/geo.cpp
+++ b/src/mbgl/util/geo.cpp
@@ -1,4 +1,4 @@
-#include <mbgl/util/math.hpp>
+#include <mbgl/math/clamp.hpp>
 #include <mbgl/util/geo.hpp>
 #include <mbgl/util/constants.hpp>
 #include <mbgl/map/tile_id.hpp>
diff --git a/src/mbgl/util/math.hpp b/src/mbgl/util/math.hpp
new file mode 100644
index 0000000000..6c6b02d126
--- /dev/null
+++ b/src/mbgl/util/math.hpp
@@ -0,0 +1,117 @@
+#ifndef MBGL_UTIL_MATH
+#define MBGL_UTIL_MATH
+
+#include <cmath>
+#include <array>
+#include <limits>
+
+#include <mbgl/util/vec.hpp>
+
+namespace mbgl {
+namespace util {
+
+// TODO: split this file up into individual headers, following mbgl/math/*.hpp.
+
+// Find the angle of the two vectors, solving the formula for the cross product
+// a x b = |a||b|sin(θ) for θ.
+template <typename T = double, typename S>
+inline T angle_between(S ax, S ay, S bx, S by) {
+    return std::atan2((ax * by - ay * bx), ax * bx + ay * by);
+}
+
+template <typename T = double, typename S>
+inline T angle_between(const vec2<S>& a, const vec2<S>& b) {
+    return angle_between(a.x, a.y, b.x, b.y);
+}
+
+template <typename T = double, typename S>
+inline T angle_to(const vec2<S>& a, const vec2<S>& b) {
+    return std::atan2(a.y - b.y, a.x - b.x);
+}
+
+// Reflect an angle around 0 degrees
+template <typename T>
+inline std::array<T, 2> flip(const std::array<T, 2>& c) {
+    return {{
+        static_cast<T>(2 * M_PI - c[0]),
+        static_cast<T>(2 * M_PI - c[1])
+    }};
+}
+
+template <typename T, typename S1, typename S2>
+inline vec2<T> normal(const S1& a, const S2& b) {
+    T dx = b.x - a.x;
+    T dy = b.y - a.y;
+    T c = std::sqrt(dx * dx + dy * dy);
+    return { dx / c, dy / c };
+}
+
+template <typename T>
+inline T perp(const T& a) {
+    return T(-a.y, a.x);
+}
+
+template <typename T, typename S1, typename S2>
+inline T dist(const S1& a, const S2& b) {
+    T dx = b.x - a.x;
+    T dy = b.y - a.y;
+    T c = std::sqrt(dx * dx + dy * dy);
+    return c;
+}
+
+template <typename T, typename S1, typename S2>
+inline T distSqr(const S1& a, const S2& b) {
+    T dx = b.x - a.x;
+    T dy = b.y - a.y;
+    T c = dx * dx + dy * dy;
+    return c;
+}
+
+template <typename T>
+inline T round(const T& a) {
+    return T(::round(a.x), ::round(a.y));
+}
+
+template <typename T>
+inline T length(T a, T b) {
+    return std::sqrt(a * a + b * b);
+}
+
+// Take the magnitude of vector a.
+template <typename T = double, typename S>
+inline T mag(const S& a) {
+    return std::sqrt(a.x * a.x + a.y * a.y);
+}
+
+template <typename S>
+inline S unit(const S& a) {
+    auto magnitude = mag(a);
+    if (magnitude == 0) {
+        return a;
+    }
+    return a * (1 / magnitude);
+}
+
+template <typename T, typename S = double>
+inline T rotate(const T& a, S angle) {
+    S cos = std::cos(angle);
+    S sin = std::sin(angle);
+    S x = cos * a.x - sin * a.y;
+    S y = sin * a.x + cos * a.y;
+    return T(x, y);
+}
+
+template <typename T>
+T smoothstep(T edge0, T edge1, T x) {
+    T t = clamp((x - edge0) / (edge1 - edge0), T(0), T(1));
+    return t * t * (T(3) - T(2) * t);
+}
+
+// Computes the log2(x) rounded up to the next integer.
+// (== number of bits required to store x)
+uint32_t ceil_log2(uint64_t x);
+
+} // namespace util
+} // namespace mbgl
+
+#endif
diff --git a/src/mbgl/util/vec.hpp b/src/mbgl/util/vec.hpp
new file mode 100644
index 0000000000..40d540fca4
--- /dev/null
+++ b/src/mbgl/util/vec.hpp
@@ -0,0 +1,126 @@
+#ifndef MBGL_UTIL_VEC
+#define MBGL_UTIL_VEC
+
+#include <limits>
+#include <type_traits>
+#include <cmath>
+#include <cstdint>
+#include <array>
+
+namespace mbgl {
+
+template <typename T = double>
+struct vec2 {
+    struct null {};
+    typedef T Type;
+
+    T x, y;
+
+    inline vec2() = default;
+
+    template<typename U = T, typename std::enable_if<std::numeric_limits<U>::has_quiet_NaN, int>::type = 0>
+    inline vec2(null) : x(std::numeric_limits<T>::quiet_NaN()), y(std::numeric_limits<T>::quiet_NaN()) {}
+
+    template<typename U = T, typename std::enable_if<!std::numeric_limits<U>::has_quiet_NaN, int>::type = 0>
+    inline vec2(null) : x(std::numeric_limits<T>::min()), y(std::numeric_limits<T>::min()) {}
+
+    inline vec2(const vec2& o) = default;
+
+    template<typename U>
+    inline vec2(const U& u) : x(u.x), y(u.y) {}
+
+    inline vec2(T x_, T y_) : x(x_), y(y_) {}
+
+    inline bool operator==(const vec2& rhs) const {
+        return x == rhs.x && y == rhs.y;
+    }
+
+    template <typename O>
+    inline typename std::enable_if<std::is_arithmetic<O>::value, vec2>::type
+    operator*(O o) const {
+        return {x * o, y * o};
+    }
+
+    inline void operator*=(T o) {
+        x *= o;
+        y *= o;
+    }
+
+    template <typename O>
+    inline typename std::enable_if<std::is_arithmetic<O>::value, vec2>::type
+    operator/(O o) const {
+        return {x / o, y / o};
+    }
+
+    inline void operator/=(T o) {
+        x /= o;
+        y /= o;
+    }
+
+    inline vec2<T> operator *(const std::array<float, 16>& matrix) {
+        return { x * matrix[0] + y * matrix[4] + matrix[12], x * matrix[1] + y * matrix[5] + matrix[13] };
+    }
+
+    template <typename O>
+    inline typename std::enable_if<std::is_arithmetic<O>::value, vec2>::type
+    operator-(O o) const {
+        return {x - o, y - o};
+    }
+
+    template <typename O>
+    inline typename std::enable_if<!std::is_arithmetic<O>::value, vec2>::type
+    operator-(const O &o) const {
+        return vec2<T>(x - o.x, y - o.y);
+    }
+
+    template <typename O>
+    inline typename std::enable_if<!std::is_arithmetic<O>::value, vec2>::type
+    operator+(const O &o) const {
+        return vec2<T>(x + o.x, y + o.y);
+    }
+
+    template <typename M>
+    inline vec2 matMul(const M &m) const {
+        return {m[0] * x + m[1] * y, m[2] * x + m[3] * y};
+    }
+
+    template<typename U = T, typename std::enable_if<std::numeric_limits<U>::has_quiet_NaN, int>::type = 0>
+    explicit operator bool() const {
+        return !std::isnan(x) && !std::isnan(y);
+    }
+
+    template<typename U = T, typename std::enable_if<!std::numeric_limits<U>::has_quiet_NaN, int>::type = 0>
+    explicit operator bool() const {
+        return x != std::numeric_limits<T>::min() && y != std::numeric_limits<T>::min();
+    }
+};
+
+template <typename T = double>
+struct vec4 {
+    T x, y, z, w;
+
+    inline vec4() = default;
+    inline vec4(const vec4& o) : x(o.x), y(o.y), z(o.z), w(o.w) {}
+    inline vec4(T x_, T y_, T z_, T w_) : x(x_), y(y_), z(z_), w(w_) {}
+    inline bool operator==(const vec4& rhs) const {
+        return x == rhs.x && y == rhs.y && z == rhs.z && w == rhs.w;
+    }
+
+    template<typename U = T, typename std::enable_if<std::numeric_limits<U>::has_quiet_NaN, int>::type = 0>
+    explicit operator bool() const {
+        return !std::isnan(x) && !std::isnan(y) && !std::isnan(z) && !std::isnan(w);
+    }
+
+    template<typename U = T, typename std::enable_if<!std::numeric_limits<U>::has_quiet_NaN, int>::type = 0>
+    explicit operator bool() const {
+        return x != std::numeric_limits<T>::min()
+            && y != std::numeric_limits<T>::min()
+            && z != std::numeric_limits<T>::min()
+            && w != std::numeric_limits<T>::min();
+    }
+};
+
+
+} // namespace mbgl
+
+#endif // MBGL_UTIL_VEC