GLDRAWELEMENTS() MachTen Programmer’s Manual GLDRAWELEMENTS()

NAME
glDrawElements - render primitives from array data

C SPECIFICATION
void glDrawElements( GLenum mode,
GLsizei count,
GLenum type,
const GLvoid *indices )

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PARAMETERS
mode Specifies what kind of primitives to render.
Symbolic constants GL_POINTS, GL_LINE_STRIP,
GL_LINE_LOOP, GL_LINES, GL_TRIANGLE_STRIP,
GL_TRIANGLE_FAN, GL_TRIANGLES, GL_QUAD_STRIP,
GL_QUADS, and GL_POLYGON are accepted.

count Specifies the number of elements to be rendered.

type Specifies the type of the values in indices. Must
be one of GL_UNSIGNED_BYTE, GL_UNSIGNED_SHORT, or
GL_UNSIGNED_INT.

indices Specifies a pointer to the location where the
indices are stored.

DESCRIPTION
glDrawElements specifies multiple geometric primitives
with very few subroutine calls. Instead of calling a GL
function to pass each individual vertex, normal, texture
coordinate, edge flag, or color, you can prespecify sepa-
rate arrays of vertexes, normals, and so on and use them
to construct a sequence of primitives with a single call
to glDrawElements.

When glDrawElements is called, it uses count sequential
elements from an enabled array, starting at indices to
construct a sequence of geometric primitives. mode speci-
fies what kind of primitives are constructed, and how the
array elements construct these primitives. If more than
one array is enabled, each is used. If GL_VERTEX_ARRAY is
not enabled, no geometric primitives are constructed.

Vertex attributes that are modified by glDrawElements have
an unspecified value after glDrawElements returns. For
example, if GL_COLOR_ARRAY is enabled, the value of the
current color is undefined after glDrawElements executes.
Attributes that aren’t modified remain well defined.

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

glDrawElements is included in display lists. If glDrawEle-
ments 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.

ERRORS
GL_INVALID_ENUM is generated if mode is not an accepted
value.

GL_INVALID_VALUE is generated if count is negative.

GL_INVALID_OPERATION is generated if glDrawElements is
executed between the execution of glBegin and the corre-
sponding glEnd.

SEE ALSO
glArrayElement, glColorPointer, glDrawArrays, glEdgeFlag-
Pointer,
glGetPointerv, glIndexPointer, glInterleavedArrays, glNor-
malPointer,
glTexCoordPointer, glVertexPointer

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