API Reference — tdm/Ang

ang

A strongly-typed angle value tagged with its unit (degrees or radians) at compile time.

Why this exists

ang exists so that angle values carry their unit as part of the type, preventing the common bug of mixing degrees and radians in the same expression. Converting between ang<T, impl::degrees> and ang<T, impl::radians> is done through an explicit converting constructor, so unit conversion becomes visible in code rather than an implicit, easy-to-miss detail.

Fields

Name Type Description
value value_type (alias for T) required — the raw numeric angle value in the unit denoted by TUnit

Construction

tdm::ang<double, tdm::impl::degrees> heading{45.0};
tdm::ang<double, tdm::impl::radians> headingRad{heading};  // converts degrees -> radians

Relationships

  • pi — used internally to convert between the degrees and radians unit tags
  • degrees / radians — free-function equivalents for converting raw (untyped) values

Constraints

  • Supports +=, -=, *= value_type, /= value_type, unary -, ==, !=.

template<typename T> T degrees(T radians)

Convert an angle expressed in radians to degrees.

When to use this

Use this when you have a raw floating-point radian value (not wrapped in an ang<T, TUnit>) and need it in degrees for display, logging, or interop with APIs that expect degrees. For strongly-typed angle values, prefer converting via the ang constructor instead, which tracks units at compile time.

Example

double deg = tdm::degrees(1.5707963267948966);
// deg is approximately 90.0

Parameters

Name Type Description
radians T required — angle value in radians; T must be a floating-point type

Returns

T — the equivalent angle expressed in degrees.

Watch out for

  • Passing an integer literal (e.g., tdm::degrees(3)) triggers a SFINAE substitution failure at compile time. Cast to float or double first.

constexpr double pi()

Get the value of π as a compile-time constant for use in angle conversions and trigonometric calculations.

When to use this

Use this instead of hardcoding a π literal so that all angle-unit conversions in the codebase (degrees, radians) stay consistent with a single source of truth.

Example

constexpr double circumference = 2.0 * tdm::pi() * radius;
// circumference computed using the library's canonical pi value

Returns

double — the mathematical constant π (3.14159265358979323846).

Constraints

  • constexpr — always evaluated at compile time; zero runtime overhead.

template<typename T> T radians(T degrees)

Convert an angle expressed in degrees to radians.

When to use this

Use this when you have a raw floating-point degree value and need it in radians for trigonometric functions (std::sin, std::cos, etc.), which expect radians. For strongly-typed angle values, prefer the ang constructor instead.

Example

double rad = tdm::radians(90.0);
// rad is approximately 1.5707963267948966

Parameters

Name Type Description
degrees T required — angle value in degrees; T must be a floating-point type

Returns

T — the equivalent angle expressed in radians.

Watch out for

  • Like degrees(), integer inputs cause a compile-time SFINAE failure. Cast to a floating-point type before calling.