OpenGL pixel format-pixelformatdescriptor

The pixel format defines the characteristics of OpenGL to draw a plane, such as whether the pixel buffer is a single buffer or dual buffer, whether the data is rgba or color index.

Each OpenGL display device generally uses a structure named pixelformatdescriptor to represent a pixel format. This structure contains 26 attribute information. Win32 defines pixelformatdescriptor as follows:

typedef struct tagPIXELFORMATDESCRIPTOR 

{// pfd 

WORD nSize; 

WORD nVersion; 

DWORD dwFlags; 

BYTE iPixelType; 

BYTE cColorBits; 

BYTE cRedBits; 

BYTE cRedShift; 

BYTE cGreenBits; 

BYTE cGreenShift; 

BYTE cBlueBits; 

BYTE cBlueShift; 

BYTE cAlphaBits; 

BYTE cAlphaShift; 

BYTE cAccumBits; 

BYTE cAccumRedBits; 

BYTE cAccumGreenBits; 

BYTE cAccumBlueBits; 

BYTE cAccumAlphaBits; 

BYTE cDepthBits; 

BYTE cStencilBits; 

BYTE cAuxBuffers; 

BYTE iLayerType; 

BYTE bReserved; 

DWORD dwLayerMask; 

DWORD dwVisibleMask; 

DWORD dwDamageMask; } PIXELFORMATDESCRIPTOR; 

Nsize indicates the sub-structure size in pixel format, and sizeof (pixelformatdescriptor) sets its value;

Nversion is the version of the pixelformatdescriptor structure, which is generally set to 1;

Dwflags is a set of flags that indicate the buffer properties of pixels, such as whether the buffer supports GDI or OpenGL;

Ipixeltype indicates whether the pixel data type is rgba or color index;

Ccolorbits the number of color Bit Planes in each color buffer. The color index method is the buffer size;

The number of red Bit Planes in each rgba color buffer;

Credshift the offset of the red bit plane in each rgba color buffer;

The number of green Bit Planes in each rgba color buffer;

Cgreenshift the number of green bit plane offsets in each rgba color buffer;

Cbluebits the number of blue Bit Planes in each rgba color buffer;

Cblueshift the offset of the Blue bit plane in each rgba color buffer;

The number of Alpha planes in each rgba color buffer in calphabits (retained, not supported currently );

The offset of the Alpha plane in each rgba color buffer of calphashift (retained, not supported currently );

Caccumbits accumulates the number of planes in all parts of the buffer zone;

Number of red bit planes in the caccumredbits accumulation buffer;

Number of green bit planes in the caccumgreenbits accumulation buffer;

The number of blue bit planes in the caccumbluebits accumulation buffer;

The number of Alpha planes in the caccumalphabits accumulation buffer;

Cdepthbits Z (depth) buffer depth;

Depth of the cstencilbits template buffer;

Number of axial buffers in cauxbuffers (not supported in general in version 1.0 );

Ilayertype is ignored and included for consistency;

Number of breserved surfaces and underlying planes: a maximum of 15 surface planes can be created in Table 0-3 and a minimum of table 4-7;

Dwlayermask is ignored and included for consistency;

Dwvisiblemask is a transparent color value (rgba mode) or an index on the underlying plane );

Dwdamagemask is ignored and included for consistency.