A list of attribute/value
pairs. The last attribute in the list must be None.
The following is a list of valid attributes:
PGL_BUFFER_SIZE
Must be followed by a nonnegative
integer that indicates the desired color index buffer size. The smallest
index buffer of at least the specified size is preferred. Ignored if PGL_RGBA
is asserted.
PGL_LEVEL
Must
be followed by an integer buffer-level specification. This specification
is honored exactly. Buffer level zero corresponds to the default frame buffer
of the display. Buffer level one is the first overlay frame buffer, level
two the second overlay frame buffer, and so on. Negative buffer levels correspond
to underlay frame buffers.
PGL_RGBA
If
present, only RGBA visual configs are considered. Otherwise, Color Index
visual configs are considered.
PGL_DOUBLEBUFFER
If present, only double bufferered visual configs
are considered. Otherwise both single buffered and double buffered visual
configs may be considered.
PGL_SINGLEBUFFER
If
present, only single buffered visual configs are considered. Otherwise both
single buffered and double buffered visual config may be considered.
PGL_STEREO
If present, only stereo visual configs are considered.
Otherwise, both monoscopic and stereoscopic visual configs are considered.
PGL_AUX_BUFFERS
Must be
followed by a nonnegative integer that indicates the desired number of auxiliary
buffers. Visual configs with the smallest number of auxiliary buffers that
meets or exceeds the specified number are preferred.
PGL_RED_SIZE
Must be followed by a nonnegative minimum size
specification. If this value is zero, the smallest available red buffer
is preferred. Otherwise, the largest available red buffer of at least the
minimum size is preferred.
PGL_GREEN_SIZE
Must
be followed by a nonnegative minimum size specification. If this value is
zero, the smallest available green buffer is preferred. Otherwise, the largest
available green buffer of at least the minimum size is preferred.
PGL_BLUE_SIZE
Must be followed by a nonnegative minimum size
specification. If this value is zero, the smallest available blue buffer
is preferred. Otherwise, the largest available blue buffer of at least the
minimum size is preferred.
PGL_ALPHA_SIZE
Must
be followed by a nonnegative minimum size specification. If this value is
zero, the smallest available alpha buffer is preferred. Otherwise, the largest
available alpha buffer of at least the minimum size is preferred.
PGL_DEPTH_SIZE
Must be followed by a nonnegative minimum size
specification. If this value is zero, visual configs with no depth buffer
are preferred. Otherwise, the largest available depth buffer of at least
the minimum size is preferred.
PGL_STENCIL_SIZE
Must be followed by a nonnegative integer that
indicates the desired number of stencil bitplanes. The smallest stencil
buffer of at least the specified size is preferred. If the desired value
is zero, visual configs with no stencil buffer are preferred.
PGL_ACCUM_RED_SIZE
Must be followed by a nonnegative minimum size
specification. If this value is zero, visual configs with no red accumulation
buffer are preferred. Otherwise, the largest possible red accumulation buffer
of at least the minimum size is preferred.
PGL_ACCUM_GREEN_SIZE
Must be followed by a nonnegative minimum size
specification. If this value is zero, visual configs with no green accumulation
buffer are preferred. Otherwise, the largest possible green accumulation
buffer of at least the minimum size is preferred.
PGL_ACCUM_BLUE_SIZE
Must be followed by a nonnegative minimum size
specification. If this value is zero, visual configs with no blue accumulation
buffer are preferred. Otherwise, the largest possible blue accumulation
buffer of at least the minimum size is preferred.
PGL_ACCUM_ALPHA_SIZE
Must be followed by a nonnegative minimum size
specification. If this value is zero, visual configs with no alpha accumulation
buffer are preferred. Otherwise, the largest possible alpha accumulation
buffer of at least the minimum size is preferred.