XMFLOAT3PK Structure

Describes a 3D vector with X and Y components stored as 11-bit floating point number, and Z component stored as a 10-bit floating-point value.

If you are programming in C++, you can use the constructors and operator methods of this structure.

Syntax

struct XMFLOAT3PK  

Remarks

The fields in the XMFLOAT3PK structure are declared as follows:

struct XMFLOAT3PK
{
    union
    {
        struct
        {
            uint32_t xm : 6; // The 6-bit mantissa for the x component. 
            uint32_t xe : 5; // The 5-bit biased exponent for the x component.
            uint32_t ym : 6; // The 6-bit mantissa for the y component.
            uint32_t ye : 5; // The 5-bit biased exponent for the y component.
            uint32_t zm : 5; // The 5-bit mantissa for the z component.
            uint32_t ze : 5; // The 5-bit biased exponent for the z component.
        };
        uint32_t v; // Unsigned 32-bit integer representing the 3D vector.
    };  

There are no sign bits. This means all partial-precision numbers are positive. The z component is stored in the most significant bits, and the x component is stored in the least significant bits like this:

        (Z10Y11X11): [31] ZZZZZzzz zzYYYYYy yyyyyXXX XXxxxxxx [0]  

Or in detail:

• Bits 0-5 of v are the 6-bit mantissa of the x component’s floating point value: the xm member of the structure.
• Bits 6-10 of v are the 5-bit exponent of the x component’s floating point value the xe member of the structure.
• Bits 11-16 of v are the 6-bit mantissa of the y component’s floating point value: the ym member of the structure.
• Bits 17-21 of v are the 5-bit exponent of the y component’s floating point value: the ye member of the structure.
• Bits 22-26 of v are the 5-bit mantissa of the z component’s floating point value: the zm member of the structure.
• Bits 27-31 of v are the 5-bit exponent of the z component’s floating point value: the ze member of the structure.

XMFLOAT3PK can be loaded into instances of XMVECTOR by using XMLoadFloat3PK.

Instances of XMVECTOR can be stored into an instance of XMFLOAT3PK with XMStoreFloat3PK.

Note the following limits:

MIN_F10 = MIN_F11 = 6.10352e-5  

MAX_F10 = 64512  

MAX_F11 = 65024  

Namespace: Use DirectX::PackedVector

Requirements

Header: Declared in directxpackedvector.h.