2010
Khronos Group.
glBeginQueryIndexed, glEndQueryIndexed
3G
glBeginQueryIndexed, glEndQueryIndexed
delimit the boundaries of a query object on an indexed target
C Specification
void glBeginQueryIndexed
GLenum target
GLuint index
GLuint id
Parameters
target
Specifies the target type of query object established between
glBeginQueryIndexed and the subsequent glEndQueryIndexed.
The symbolic constant must be one of GL_SAMPLES_PASSED, GL_ANY_SAMPLES_PASSED,
GL_PRIMITIVES_GENERATED, GL_TRANSFORM_FEEDBACK_PRIMITIVES_WRITTEN, or
GL_TIME_ELAPSED.
index
Specifies the index of the query target upon which to begin the query.
id
Specifies the name of a query object.
C Specification
void glEndQueryIndexed
GLenum target
GLuint index
Parameters
target
Specifies the target type of query object to be concluded.
The symbolic constant must be one of GL_SAMPLES_PASSED, GL_ANY_SAMPLES_PASSED,
GL_PRIMITIVES_GENERATED, GL_TRANSFORM_FEEDBACK_PRIMITIVES_WRITTEN, or
GL_TIME_ELAPSED.
index
Specifies the index of the query target upon which to end the query.
Description
glBeginQueryIndexed and glEndQueryIndexed delimit the
boundaries of a query object. query must be a name previously returned from a call to
glGenQueries. If a query object with name id
does not yet exist it is created with the type determined by target. target must
be one of GL_SAMPLES_PASSED, GL_ANY_SAMPLES_PASSED, GL_PRIMITIVES_GENERATED,
GL_TRANSFORM_FEEDBACK_PRIMITIVES_WRITTEN, or GL_TIME_ELAPSED. The behavior of the query
object depends on its type and is as follows.
index specifies the index of the query target and must be between a target-specific
maximum.
If target is GL_SAMPLES_PASSED, target must be an unused name,
or the name of an existing occlusion query object.
When glBeginQueryIndexed is executed, the query object's samples-passed counter is reset to 0. Subsequent
rendering will increment the counter for every sample that passes the depth test. If the value of GL_SAMPLE_BUFFERS
is 0, then the samples-passed count is incremented by 1 for each fragment. If the value of GL_SAMPLE_BUFFERS
is 1, then the samples-passed count is incremented by the number of samples whose coverage bit is set. However, implementations, at their
discression may instead increase the samples-passed count by the value of GL_SAMPLES if any sample in the fragment
is covered. When glEndQueryIndexed
is executed, the samples-passed counter is assigned to the query object's result value. This value can be queried by
calling glGetQueryObject with pname
GL_QUERY_RESULT.
When target is GL_SAMPLES_PASSED, index must be zero.
If target is GL_ANY_SAMPLES_PASSED, target must be an unused name,
or the name of an existing boolean occlusion query object.
When glBeginQueryIndexed is executed, the query object's samples-passed flag is reset to GL_FALSE.
Subsequent rendering causes the flag to be set to GL_TRUE if any sample passes the depth test. When
glEndQueryIndexed is executed, the samples-passed flag is assigned to the query object's result value. This value can
be queried by calling glGetQueryObject with pname
GL_QUERY_RESULT.
When target is GL_ANY_SAMPLES_PASSED, index must be zero.
If target is GL_PRIMITIVES_GENERATED, target must be an unused
name, or the name of an existing primitive query object previously bound to the GL_PRIMITIVES_GENERATED query binding.
When glBeginQueryIndexed is executed, the query object's primitives-generated counter is reset to 0. Subsequent
rendering will increment the counter once for every vertex that is emitted from the geometry shader to the stream given by index,
or from the vertex shader if index is zero and no geometry shader is present.
When glEndQueryIndexed is executed, the primitives-generated counter for stream index is assigned to
the query object's result value. This value can be queried by calling glGetQueryObject
with pname GL_QUERY_RESULT.
When target is GL_PRIMITIVES_GENERATED, index must be
less than the value of GL_MAX_VERTEX_STREAMS.
If target is GL_TRANSFORM_FEEDBACK_PRIMITIVES_WRITTEN, target must be
an unused name, or the name of an existing primitive query object previously bound to the GL_TRANSFORM_FEEDBACK_PRIMITIVES_WRITTEN
query binding. When glBeginQueryIndexed is executed, the query object's primitives-written counter for the stream specified by
index is reset to 0. Subsequent rendering will increment the counter once for every vertex that is written into the bound
transform feedback buffer(s) for stream index. If transform feedback
mode is not activated between the call to glBeginQueryIndexed and glEndQueryIndexed, the counter will not be
incremented. When glEndQueryIndexed is executed, the primitives-written counter for stream index is assigned to
the query object's result value. This value can be queried by calling glGetQueryObject with pname
GL_QUERY_RESULT.
When target is GL_TRANSFORM_FEEDBACK_PRIMITIVES_WRITTEN, index must be
less than the value of GL_MAX_VERTEX_STREAMS.
If target is GL_TIME_ELAPSED, target must be
an unused name, or the name of an existing timer query object previously bound to the GL_TIME_ELAPSED
query binding. When glBeginQueryIndexed is executed, the query object's time counter is reset to 0. When glEndQueryIndexed
is executed, the elapsed server time that has passed since the call to glBeginQueryIndexed is written into the query object's
time counter. This value can be queried by calling glGetQueryObject with pname
GL_QUERY_RESULT.
When target is GL_TIME_ELAPSED, index must be zero.
Querying the GL_QUERY_RESULT implicitly flushes the GL pipeline until the rendering delimited by the
query object has completed and the result is available. GL_QUERY_RESULT_AVAILABLE can be queried to
determine if the result is immediately available or if the rendering is not yet complete.
Notes
If the query target's count exceeds the maximum value representable in the number of available bits, as reported by
glGetQueryiv with target set to the
appropriate query target and pname
GL_QUERY_COUNTER_BITS, the count becomes undefined.
An implementation may support 0 bits in its counter, in which case query results are always undefined
and essentially useless.
When GL_SAMPLE_BUFFERS is 0, the samples-passed counter of an occlusion query will increment once for each
fragment that passes the depth test. When GL_SAMPLE_BUFFERS is 1, an implementation may either increment
the samples-passed counter individually for each sample of a fragment that passes the depth test, or it may choose to increment
the counter for all samples of a fragment if any one of them passes the depth test.
Calling glBeginQuery or
glEndQuery is equivalent to
calling glBeginQueryIndexed or
glEndQueryIndexed with
index set to zero, respectively.
Errors
GL_INVALID_ENUM is generated if target is not one of the accepted tokens.
GL_INVALID_VALUE is generated if index is greater than the
query target-specific maximum.
GL_INVALID_OPERATION is generated if glBeginQueryIndexed is executed while
a query object of the same target is already active.
GL_INVALID_OPERATION is generated if glEndQueryIndexed
is executed when a query object of the same target is not active.
GL_INVALID_OPERATION is generated if id is 0.
GL_INVALID_OPERATION is generated if id is the name of an already active query object.
GL_INVALID_OPERATION is generated if id refers to an existing query object whose type
does not does not match target.
See Also
glDeleteQueries,
glBeginQuery,
glEndQuery,
glGenQueries,
glGetQueryiv,
glGetQueryObject,
glIsQuery
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/.