glEdgeFlagPointer
[New
- Windows 95, OEM Service Release 2]
The glEdgeFlagPointer
function defines an array of edge flags.
void glEdgeFlagPointer(
|
GLsizei stride, |
|
|
GLsizei count, |
|
|
const GLboolean * pointer |
|
|
); |
|
Parameters
stride
The byte
offset between consecutive edge flags. When stride is zero, the edge
flags are tightly packed in the array.
count
The number of
edge flags, counting from the first, that are static.
pointer
A pointer to
the first edge flag in the array.
Remarks
The glEdgeFlagPointer
function specifies the location and data of an array of Boolean edge flags to
use when rendering. The stride parameter determines the byte offset from
one edge flag to the next, which enables the packing of vertices and attributes
in a single array or storage in separate arrays. In some implementations,
storing the vertices and attributes in a single array can be more efficient
than using separate arrays.
Starting from
the first edge-flag array element, count indicates the total number of
static elements. Your application can modify static elements, but once the
elements are modified, the application must explicitly specify the array again
before using it for any rendering. Nonstatic array elements are not accessed
until you call glDrawArrays
or glArrayElement.
Static array
data can be read at any time. If any static array elements are modified and the
array is not specified again, the results of any subsequent calls to glEdgeFlagPointer
are undefined.
An edge-flag
array is enabled when you specify the GL_EDGE_FLAG_ARRAY constant with glEnableClientState. When enabled, glDrawArrays or glArrayElement uses the edge-flag array.
By default the edge-flag array is disabled.
You cannot
include glEdgeFlagPointer in display lists.
When you
specify an edge-flag array using glEdgeFlagPointer, the values of all
the function s edge-flag array parameters are saved in a client-side state and
static array elements can be cached. Because the edge-flag array parameters are
in a client-side state, glPushAttrib and glPopAttrib do not save or restore
their values.
Although
calling glEdgeFlagPointer within a glBegin/glEnd pair does not generate an
error, the results are undefined.
The following
functions retrieve information related to the glEdgeFlagPointer function:
glIsEnabled
with argument GL_EDGE_FLAG_ARRAY
glGet with
argument GL_EDGE_FLAG_ARRAY_STRIDE
glGet with
argument GL_EDGE_FLAG_ARRAY_COUNT
glGetPointerv
with argument GL_EDGE_FLAG_ARRAY_POINTER
Error Codes
The following
are the error codes generated and their conditions.
|
Error
Code |
Condition |
|
GL_INVALID_ENUM
|
stride or count was negative. |
See Also