Boolean

oglplus/boolean.hpp

OGLplus defines a wrapper for boolean values represented in OpenGL, OpenAL, etc. by integer types with wider than one-bit range.

Instances of this type are implicitly constructible from and convertible to bool values and also explicitly constructible from values of the underlying type (like GLint, ALint, EGLBoolean, etc.) Instances of Boolean can be in three states: true, false and indeterminate, (i.e. both the operator bool and operator ! can return false for some instances).

Implementation

template <typename B, typename T, T TrueValue, T FalseValue>
struct WeakBoolImpl
{
public:
	operator bool (void) const
	noexcept; 

	bool operator ! (void) const;
	noexcept; 
};

template <typename B, typename T, T TrueValue, T FalseValue>
struct BoolImpl
{
public:
	BoolImpl(void)
	noexcept; 

	BoolImpl(bool bool_value)
	noexcept;

	BoolImpl(T value, std::nothrow_t);
	noexcept; 

	explicit
	BoolImpl(T value); 

	operator bool (void) const
	noexcept; 

	bool operator ! (void) const;
	noexcept; 

	WeakBoolImpl<T, TrueValue, FalseValue>
	operator ~ (void) const
	noexcept;
};

	Returns `true` if the wrapped value is not equal to `FalseValue`.
	Returns `true` if the wrapped value is not equal to `TrueValue`.
	Creates a false boolean value.
	Constructs a boolean from a value in the underlying type. This version does not throw if the `value` is neither `TrueValue` nor `FalseValue`, in such case the constructed instance is indeterminate.
	Constructs a boolean from a value in the underlying type. This constructor throws a `std::domain_error` if `value` is neither `TrueValue` not `FalseValue`.
	Returns `true` if the wrapped value is equal to `TrueValue`.
	Returns `true` if the wrapped value is equal to `FalseValue`.

Definition

typedef BoolImpl<GLboolean, GLint, GL_TRUE, GL_FALSE> Boolean;

Examples

Context gl;

if(gl.IsEnabled(Capability::DepthTest)) 
{
	/* ... */
}

if(!gl.IsEnabled(Capability::StencilTest)) 
{
	/* ... */
}

if(~gl.IsEnabled(Capability::DepthTest)) 
{
	/* ... */
}

if(!~gl.IsEnabled(Capability::StencilTest)) 
{
	/* ... */
}

	Equal to `GL_TRUE`.
	Equal to `GL_FALSE`.
	Not equal to `GL_FALSE`.
	Not equal to `GL_TRUE`.