# glDrawElementsInstancedBaseVertex

## Name

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

## C Specification

 void glDrawElementsInstancedBaseVertex( GLenum mode, GLsizei count, GLenum type, GLvoid *indices, GLsizei primcount, GLint basevertex);

## 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, and GL_TRIANGLES 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.

## Description

glDrawElementsInstancedBaseVertex 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.

## 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.