NAME
glDrawElements - render primitives from array data
C SPECIFICATION
void glDrawElements( GLenum mode,
GLsizei count,
GLenum type,
const GLvoid *indices )
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 separate 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 specifies
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
glDrawElements 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
corresponding glEnd.
SEE ALSO
glArrayElement, glColorPointer, glDrawArrays,
glEdgeFlagPointer,
glGetPointerv, glIndexPointer, glInterleavedArrays,
glNormalPointer,
glTexCoordPointer, glVertexPointer