Signature
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.
Version Support
| glDrawArraysIndirect |
See Also
Copyright
Copyright
2010-2014 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/
.