glDrawArraysIndirect — render primitives from array data, taking parameters from memory
void glDrawArraysIndirect(
|
GLenum mode, |
const void *indirect); |
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.
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.
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.
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.
| 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 |
glDrawArraysIndirect
|
- | - | - | - | - | - | ✔ | ✔ | ✔ | ✔ | ✔ | ✔ |
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/.