NAME

       glDrawArraysIndirect - render primitives from array data, taking parameters from memory

C SPECIFICATION

       void glDrawArraysIndirect(GLenum mode, const void *indirect);

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.

       indirect
           Specifies the address of a structure containing the draw parameters.

DESCRIPTION

       glDrawArraysIndirect specifies multiple geometric primitives with very few subroutine
       calls.  glDrawArraysIndirect behaves similarly to glDrawArraysInstancedBaseInstance(),
       execept that the parameters to glDrawArraysInstancedBaseInstance() are stored in memory at
       the address given by indirect.

       The parameters addressed by indirect are packed into a structure that takes the form (in
       C):

               typedef  struct {
                   uint  count;
                   uint  primCount;
                   uint  first;
                   uint  baseInstance;
               } DrawArraysIndirectCommand;

               const DrawArraysIndirectCommand  *cmd  = (const DrawArraysIndirectCommand  *)indirect;
               glDrawArraysInstancedBaseInstance(mode,  cmd->first,  cmd->count,  cmd->primCount, cmd->baseInstance);

       If a buffer is bound to the GL_DRAW_INDIRECT_BUFFER binding at the time of a call to
       glDrawArraysIndirect, indirect is interpreted as an offset, in basic machine units, into
       that buffer and the parameter data is read from the buffer rather than from client memory.

       In contrast to glDrawArraysInstancedBaseInstance(), the first member of the parameter
       structure is unsigned, and out-of-range indices do not generate an error.

       Vertex attributes that are modified by glDrawArraysIndirect have an unspecified value
       after glDrawArraysIndirect returns. Attributes that aren't modified remain well defined.

NOTES

       The baseInstance member of the DrawArraysIndirectCommand structure is defined only if the
       GL version is 4.2 or greater. For versions of the GL less than 4.2, this parameter is
       present but is reserved and should be set to zero. On earlier versions of the GL, behavior
       is undefined if it is non-zero.

ERRORS

       GL_INVALID_ENUM is generated if mode is not an accepted value.

       GL_INVALID_OPERATION is generated if a non-zero buffer object name is bound to an enabled
       array or to the GL_DRAW_INDIRECT_BUFFER binding and the buffer object's data store is
       currently mapped.

       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 mode is GL_PATCHES and no tessellation control shader
       is active.

SEE ALSO

       glDrawArrays(), glDrawArraysInstanced(), glDrawElements(), glDrawRangeElements(),

COPYRIGHT

       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/.

AUTHORS

       opengl.org