Merge pull request #445 from xndcn/patch-1
Fix code sample in EXT_disjoint_timer_query
diff --git a/extensions/EXT/EXT_disjoint_timer_query.txt b/extensions/EXT/EXT_disjoint_timer_query.txt
index 9c30452..d31619a 100644
--- a/extensions/EXT/EXT_disjoint_timer_query.txt
+++ b/extensions/EXT/EXT_disjoint_timer_query.txt
@@ -33,7 +33,7 @@
Version
- Version 8, December 11, 2019
+ Version 9, November 20, 2020
Number
@@ -477,7 +477,7 @@
(2) This example uses QueryCounter.
- GLint queries[1];
+ GLint queries[2];
GLint available = 0;
GLint disjointOccurred = 0;
/* Timer queries can contain more than 32 bits of data, so always
@@ -485,20 +485,24 @@
GLuint64 timeStart, timeEnd, timeElapsed = 0;
/* Create a query object. */
- glGenQueries(1, queries);
+ glGenQueries(2, queries);
/* Clear disjoint error */
glGetIntegerv(GL_GPU_DISJOINT_EXT, &disjointOccurred);
+ /* Query current timestamp before drawing */
+ glQueryCounterEXT(queries[0], GL_TIMESTAMP_EXT);
+
/* Draw full rendertarget of objects */
- glQueryCounterEXT(queries[0], GL_TIMESTAMP_EXT);
+ /* Query current timestamp after drawing */
+ glQueryCounterEXT(queries[1], GL_TIMESTAMP_EXT);
/* Do some other work so you don't stall waiting for available */
/* Wait for the query result to become available */
while (!available) {
- glGetQueryObjectiv(queries[0], GL_QUERY_RESULT_AVAILABLE, &available);
+ glGetQueryObjectiv(queries[1], GL_QUERY_RESULT_AVAILABLE, &available);
}
/* Check for disjoint operation. */
@@ -507,15 +511,18 @@
/* If a disjoint operation occurred, continue without reading the the
values */
if (!disjointOccurred) {
+ /* Get timestamp for when rendertarget started. */
+ glGetQueryObjectui64vEXT(queries[0], GL_QUERY_RESULT, &timeStart);
/* Get timestamp for when rendertarget finished. */
- glGetQueryObjectui64vEXT(queries[0], GL_QUERY_RESULT, &timeElapsed);
+ glGetQueryObjectui64vEXT(queries[1], GL_QUERY_RESULT, &timeEnd);
+ /* See how much time the rendering took in nanoseconds. */
+ timeElapsed = timeEnd - timeStart;
/* Do something useful with the time if a disjoint operation did
not occur. Note that care should be taken to use all
significant bits of the result, not just the least significant
32 bits. */
-
- AdjustObjectLODBasedOnDrawTime(i, timeElapsed);
+ AdjustObjectLODBasedOnDrawTime(timeElapsed);
}
(3) This example demonstrates how to measure the latency between GL
@@ -538,7 +545,7 @@
glGetIntegerv(GL_GPU_DISJOINT_EXT, &disjointOccurred);
/* Queue a query to find out when the frame finishes on the GL */
- glQueryCounterEXT(GL_TIMESTAMP_EXT, endFrameQuery);
+ glQueryCounterEXT(endFrameQuery, GL_TIMESTAMP_EXT);
/* Get the current GL time without stalling the GL */
glGetIntegerv(GL_TIMESTAMP_EXT, &flushTime);
@@ -754,6 +761,8 @@
will not be set.
Revision History
+ Revision 9, 2020/11/20 (xndcn)
+ - Minor fix of code sample
Revision 8, 2019/12/11 (Jon Leech)
- Add actual spec language defining GetInteger64vEXT (github
OpenGL-Registry issue 326)
