glDrawElementsInstanced — draw multiple instances of a set of elements
void glDrawElementsInstanced( | GLenum mode, |
GLsizei count, | |
GLenum type, | |
const void * indices, | |
GLsizei primcount) ; |
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.
primcount
Specifies the number of instances of the specified range of indices to be rendered.
glDrawElementsInstanced
behaves identically to glDrawElements
except that primcount
instances of the set of elements are executed and the value of the internal counter
instanceID
advances for each iteration. instanceID
is an internal 32-bit integer counter
that may be read by a vertex shader as gl_InstanceID
.
glDrawElementsInstanced
has the same effect as:
if (mode, count, or type is invalid ) generate appropriate error else { for (int i = 0; i < primcount ; i++) { instanceID = i; glDrawElements(mode, count, type, indices); } instanceID = 0; }
glDrawElementsInstanced
is available only if the GL version is 3.1 or greater.
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.
GL_INVALID_ENUM
is generated if mode
is not one of GL_POINTS
,
GL_LINE_STRIP
, GL_LINE_LOOP
, GL_LINES
,
GL_TRIANGLE_STRIP
, GL_TRIANGLE_FAN
, or GL_TRIANGLES
.
GL_INVALID_VALUE
is generated if count
or primcount
are 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 and the buffer object's data store is currently mapped.
Copyright © 2010 Khronos Group. This material may be distributed subject to the terms and conditions set forth in the Open Publication License, v 1.0, 8 June 1999. http://opencontent.org/openpub/.