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 glDrawArraysInstanced,
except that the parameters to glDrawArraysInstanced
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 reserved; } DrawArraysIndirectCommand; const DrawArraysIndirectCommand *cmd = (const DrawArraysIndirectCommand *)indirect; glDrawArraysInstanced(mode, cmd->first, cmd->count, cmd->primCount);
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 glDrawArraysInstanced,
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 reserved
member of the DrawArraysIndirectCommand
structure should be set to zero. Behavior is undefined if it is non-zero.
GL_LINE_STRIP_ADJACENCY
,
GL_LINES_ADJACENCY
,
GL_TRIANGLE_STRIP_ADJACENCY
,
GL_TRIANGLES_ADJACENCY
and
GL_PATCHES
are available only if the GL ES version is 3.2 or greater.
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.
OpenGL ES API Version | ||||
---|---|---|---|---|
Function Name | 2.0 | 3.0 | 3.1 | 3.2 |
glDrawArraysIndirect
|
- | - | ✔ | ✔ |
Copyright © 2010-2015 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. https://opencontent.org/openpub/.