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_LINE_STRIP_ADJACENCY,
GL_LINES_ADJACENCY, GL_TRIANGLE_STRIP, GL_TRIANGLE_FAN,
GL_TRIANGLES, GL_TRIANGLE_STRIP_ADJACENCY,
GL_TRIANGLES_ADJACENCY and GL_PATCHES 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 vertices, 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.
Vertex attributes that are modified by
glDrawElements have an unspecified
value after
glDrawElements returns. Attributes that aren't modified
maintain their previous values.
NOTES¶
GL_LINE_STRIP_ADJACENCY,
GL_LINES_ADJACENCY,
GL_TRIANGLE_STRIP_ADJACENCY and
GL_TRIANGLES_ADJACENCY are
available only if the GL version is 3.2 or greater.
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 a geometry shader is active and
mode is incompatible with the input primitive type of the geometry
shader in the currently installed program object.
GL_INVALID_OPERATION is generated if a non-zero buffer object name is
bound to an enabled array or the element array and the buffer object's data
store is currently mapped.
SEE ALSO¶
glDrawArrays(),
glDrawElementsInstanced(),
glDrawElementsBaseVertex(),
glDrawRangeElements()
COPYRIGHT¶
Copyright © 1991-2006 Silicon Graphics, Inc. This document is licensed
under the SGI Free Software B License. For details, see
http://oss.sgi.com/projects/FreeB/.