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glextensions - WGL_ARB_pbuffer.wiki

Contents

  • Dependencies
  • Overview
  • New Procedures and Functions
  • New Tokens
  • New State
  • New Implementation Dependent State

Dependencies

WGL_ARB_extensions_string is required.

WGL_ARB_pixel_format is required.

WGL_ARB_make_current_read affects the definition of this extension.

Overview

This extension defines pixel buffers (pbuffer for short). Pbuffers are additional non-visible rendering buffers for an OpenGL renderer. Pbuffers are equivalent to a window that has the same pixel format descriptor with the following exceptions:

  1. There is no rendering to a pbuffer by GDI.

  2. The pixel format descriptors used for a pbuffer can only be those that are supported by the ICD. Generic formats are not valid.

  3. The allocation of a pbuffer can fail if there are insufficient resources (i.e., all the pbuffer memory has been allocated).

  4. The pixel buffer might be lost if a display mode change occurs. A query is provided that can be called after a display mode change to determine the state of the pixel buffer.

The intent of the pbuffer semantics is to enable implementations to allocate pbuffers in non-visible frame buffer memory. These pbuffers are intended to be "static" resources in that a program will typically allocate them only once rather than as a part of its rendering loop. (Pbuffers should be deallocated when the program is no longer using them -- for example, if the program is iconified.)

The frame buffer resources that are associated with a pbuffer are also static and are deallocated when the pbuffer is destroyed or possibly when a display mode change occurs.

New Procedures and Functions

``` DECLARE_HANDLE(HPBUFFERARB);

HPBUFFERARB wglCreatePbufferARB(HDC hDC, int iPixelFormat, int iWidth, int iHeight, const int *piAttribList);

HDC wglGetPbufferDCARB(HPBUFFERARB hPbuffer);

int wglReleasePbufferDCARB(HPBUFFERARB hPbuffer, HDC hDC);

BOOL wglDestroyPbufferARB(HPBUFFERARB hPbuffer);

BOOL wglQueryPbufferARB(HPBUFFERARB hPbuffer, int iAttribute, int *piValue); ```

New Tokens

Accepted by the

<attribute>

parameter of wglChoosePixelFormatEXT:

| WGL_DRAW_TO_PBUFFER_ARB | 0x202D| |:---------------------------------|:-------------|

Accepted by the

<attribute>

parameter of wglGetPixelFormatAttribivEXT, and wglGetPixelFormatAttribfvEXT:

|WGL_DRAW_TO_PBUFFER_ARB | 0x202D| |:-----------------------------------|:----------| |WGL_MAX_PBUFFER_PIXELS_ARB | 0x202E| |WGL_MAX_PBUFFER_WIDTH_ARB | 0x202F| |WGL_MAX_PBUFFER_HEIGHT_ARB | 0x2030|

Accepted by the

<piAttribList>

parameter of wglCreatePbufferARB:

|WGL_PBUFFER_LARGEST_ARB | 0x2033| |:---------------------------------|:-----------|

Accepted by the

<iAttribute>

parameter of wglQueryPbufferARB:

|WGL_PBUFFER_WIDTH_ARB | 0x2034| |:--------------------------------|:------------| |WGL_PBUFFER_HEIGHT_ARB | 0x2035| |WGL_PBUFFER_LOST_ARB | 0x2036|

New State

None

New Implementation Dependent State

None