glDrawElementsInstancedBaseVertexBaseInstance - OpenGL 4 Reference Pages

## Name

glDrawElementsInstancedBaseVertexBaseInstance — render multiple instances of a set of primitives from array data with a per-element offset

## C Specification

`void glDrawElementsInstancedBaseVertexBaseInstance(` | GLenum mode,
| GLsizei count,
| GLenum type,
| GLvoid *indices,
| GLsizei primcount,
| GLint basevertex,
| GLuint baseinstance`)`;

## 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_LINES_ADJACENCY`, `GL_LINE_STRIP_ADJACENCY`, `GL_TRIANGLES_ADJACENCY`, `GL_TRIANGLE_STRIP_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 indexed geometry that should be drawn.

`basevertex`

  Specifies a constant that should be added to each element of `indices` when chosing elements from the enabled vertex arrays.

`baseinstance`

  Specifies the base instance for use in fetching instanced vertex attributes.

## Description

`glDrawElementsInstancedBaseVertexBaseInstance` behaves identically to glDrawElementsInstanced except that the ith element transferred by the corresponding draw call will be taken from element `indices`[i] + `basevertex` of each enabled array. If the resulting value is larger than the maximum value representable by `type`, it is as if the calculation were upconverted to 32-bit unsigned integers (with wrapping on overflow conditions). The operation is undefined if the sum would be negative.

Specific vertex attributes may be classified as instanced through the use of glVertexAttribDivisor. Instanced vertex attributes supply per-instance vertex data to the vertex shader. The index of the vertex fetched from the enabled instanced vertex attribute arrays is calculated as gl _ InstanceID divisor + baseInstance . Note that `baseinstance` does not affect the shader-visible value of `gl_InstanceID`.

## Notes

`glDrawElementsInstancedBaseVertex` is only supported 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` or `primcount` 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.

## Version Support

| OpenGL Version
--- | ---
Function / Feature Name | 2.0 | 2.1 | 3.0 | 3.1 | 3.2 | 3.3 | 4.0 | 4.1 | 4.2 | 4.3 | 4.4 | 4.5
`glDrawElementsInstancedBaseVertexBaseInstance` | - | - | - | - | - | - | - | - | ✔ | ✔ | ✔ | ✔

## See Also

glDrawElements, glDrawRangeElements, glDrawRangeElementsBaseVertex, glDrawElementsInstanced, glDrawElementsInstancedBaseVertex

## Copyright

Copyright © 2011-2014 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/.