GLARRAYELEMENT() MachTen Programmer’s Manual GLARRAYELEMENT()

NAME
glArrayElement - render a vertex using the specified ver-
tex array element

C SPECIFICATION
void glArrayElement( GLint i )

delim $$

PARAMETERS
i Specifies an index into the enabled vertex data arrays.

DESCRIPTION
glArrayElement commands are used within glBegin/glEnd
pairs to specify vertex and attribute data for point,
line, and polygon primitives. If GL_VERTEX_ARRAY is
enabled when glArrayElement is called, a single vertex is
drawn, using vertex and attribute data taken from location
i of the enabled arrays. If GL_VERTEX_ARRAY is not
enabled, no drawing occurs but the attributes correspond-
ing to the enabled arrays are modified.

Use glArrayElement to construct primitives by indexing
vertex data, rather than by streaming through arrays of
data in first-to-last order. Because each call specifies
only a single vertex, it is possible to explicitly specify
per-primitive attributes such as a single normal per indi-
vidual triangle.

Changes made to array data between the execution of glBe-
gin and the corresponding execution of glEnd may affect
calls to glArrayElement that are made within the same
glBegin/glEnd period in non-sequential ways. That is, a
call to
glArrayElement that precedes a change to array data may
access the changed data, and a call that follows a change
to array data may access original data.

NOTES
glArrayElement is available only if the GL version is 1.1
or greater.

glArrayElement is included in display lists. If glAr-
rayElement is entered into a display list, the necessary
array data (determined by the array pointers and enables)
is also entered into the display list. Because the array
pointers and enables are client-side state, their values
affect display lists when the lists are created, not when
the lists are executed.

SEE ALSO
glColorPointer, glDrawArrays, glEdgeFlagPointer, glGet-
Pointerv,
glIndexPointer, glInterleavedArrays, glNormalPointer,
glTexCoordPointer, glVertexPointer

MachTen 1