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glArrayElement

Chapter 1

glArrayElement

glArrayElement: render a vertex using the speciﬁed vertex array element.

C Speciﬁcation

void glArrayElement(

GLint i)

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 corresponding 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 individual triangle.

Changes made to array data between the execution of glBegin 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 glArrayElement 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.

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