NAME

       glDrawArraysInstancedBaseInstance - draw multiple instances of a range of elements with
       offset applied to instanced attributes

C SPECIFICATION

       void glDrawArraysInstancedBaseInstance(GLenum mode, GLint first, GLsizei count,
                                              GLsizei primcount, 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.

       first
           Specifies the starting index in the enabled arrays.

       count
           Specifies the number of indices to be rendered.

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

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

DESCRIPTION

       glDrawArraysInstancedBaseInstance behaves identically to glDrawArrays() except that
       primcount instances of the range 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.

       glDrawArraysInstancedBaseInstance has the same effect as:

               if ( mode or count is invalid )
                   generate appropriate error
               else {
                   for (int i = 0; i < primcount ; i++) {
                       instanceID = i;
                       glDrawArrays(mode, first, count);
                   }
                   instanceID = 0;
               }

       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.

ERRORS

       GL_INVALID_ENUM is generated if mode is not one of the accepted values.

       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_VALUE is generated if count or primcount are negative.

       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.

VERSION SUPPORT

       ┌──────────────────────────────────┬───────────────────────────────────────────────────────────────────────┐
       │                                  │                OpenGL Version                                         │
       ├──────────────────────────────────┼─────┬─────┬─────┬─────┬─────┬─────┬─────┬─────┬─────┬─────┬─────┬─────┤
       │Function                          │ 2.0 │ 2.1 │ 3.0 │ 3.1 │ 3.2 │ 3.3 │ 4.0 │ 4.1 │ 4.2 │ 4.3 │ 4.4 │ 4.5 │
       │/                                 │     │     │     │     │     │     │     │     │     │     │     │     │
       │Feature                           │     │     │     │     │     │     │     │     │     │     │     │     │
       │Name                              │     │     │     │     │     │     │     │     │     │     │     │     │
       ├──────────────────────────────────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┤
       │glDrawArraysInstancedBaseInstance │  -  │  -  │  -  │  -  │  -  │  -  │  -  │  -  │  ✔  │  ✔  │  ✔  │  ✔  │
       └──────────────────────────────────┴─────┴─────┴─────┴─────┴─────┴─────┴─────┴─────┴─────┴─────┴─────┴─────┘

SEE ALSO

       glDrawArrays(), glDrawElementsInstanced()

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/.

COPYRIGHT

       Copyright © 2011-2014 Khronos Group

[FIXME: source]                             01/03/2018                   GLDRAWARRAYSINSTANCE(3G)