glDrawElementsInstanced

3G

glDrawElementsInstanced

draw multiple instances of a set of elements

# C Specification

                    void glDrawElementsInstanced
                    GLenum mode
                    GLsizei count
                    GLenum type
                    const void * indices
                    GLsizei primcount

## 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.

`primcount`

- Specifies the number of instances of the specified range of indices to be rendered.

## Description

`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;
        }

## Notes

`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.

## Errors

`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.

## See Also

glDrawElements

,

glDrawArraysInstanced

## Copyright

Copyright 2010-2013 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/.