From NVIDIA's side, I don't think it would be that big of a problem to just
keep running our tests with PIGLIT_FORCE_WINDOW=1 or -fbo. However, my
reasoning is that Piglit should default to the 'correct' behavior according to
the OpenGL spec. While the NVIDIA driver is the only one I know of that
actually enforces pixel ownership, any driver theoretically could do so while
still adhering to the spec.
I agree that having a window pop up for every test is annoying, but using the
default framebuffer without mapping it is undefined behavior. The 'correct' way
to do offscreen rendering would be using FBOs which Piglit supports with the
-fbo argument. Is there a reason why this can't/shouldn't be used for running
Piglit offscreen? I originally removed the ability to render offscreen with the
default framebuffer altogether, but I figured some users might still desire
this behavior so instead decided to leave it in as a non-default option.
Thanks,
Alex
-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of Ilia Mirkin
Sent: Friday, August 14, 2015 8:07 AM
To: Alexander Goins
Cc: [email protected]
Subject: Re: [Piglit] [PATCH] winsys-framework Default to showing window
Interesting. PIGLIT_FORCE_WINDOW was introduced in this change:
commit b797406fb850c5e3c9fdaaebae36127b5e5f8954
Author: Paul Berry <[email protected]>
Date: Tue Jun 11 16:34:32 2013 -0700
Add PIGLIT_FORCE_WINDOW environment variable.
Setting PIGLIT_FORCE_WINDOW=1 causes all piglit windowsystem tests
(those that weren't invoked with the "-fbo" flag) to show the window
prior to calling piglit_display(). Setting PIGLIT_FORCE_WINDOW=0 (the
default) preserves piglit's existing behaviour, which is to only show
the window when the test is run in "manual" mode (with no "-auto"
argument supplied).
Setting PIGLIT_FORCE_WINDOW=1 slows down the piglit run, and produces
more annoying windows on the screen, but it has been observed to
produce more repeatable results when testing with the nVidia
proprietary driver for Linux.
Reviewed-by: Chad Versace <[email protected]>
Which explicitly mentions the nvidia blob driver thing. Having more windows
popping up during piglit runs is going to be annoying... and slowing things
down will also be unwelcome. Is there anything else that can be done here?
-ilia
On Thu, Aug 13, 2015 at 1:49 PM, agoins <[email protected]> wrote:
winsys-framework incorrectly assumed that it will always have
ownership of the pixels in its own buffers. If using the default
framebuffer (i.e., when Piglit is not running in FBO mode,) ownership
will not be acquired unless the window is mapped.
While this is not typically a problem because buffers are separate,
NVIDIA's Unified Back Buffer feature makes all windows share a back
buffer while still conforming to the OpenGL spec. If Piglit does not
establish pixel ownership, its output will be clobbered by other windows.
While this problem could be easily fixed by specifying
PIGLIT_FORCE_WINDOW=1 or -fbo, the current default takes advantage of
undefined behavior in the OpenGL spec. A better solution would be to
replace PIGLIT_FORCE_WINDOW with PIGLIT_NO_WINDOW, a flag that allows
tests to be run without mapping a window or using an FBO. The default
behavior, the, would be to map a window. Really, though, if users want
to test with offscreen rendering, they should use FBOs with flag -fbo.
More information on pixel ownership here:
https://www.opengl.org/documentation/specs/version1.1/glspec1.1/node94
.html
---
.../piglit-framework-gl/piglit_winsys_framework.c | 20 ++++++++++----------
1 file changed, 10 insertions(+), 10 deletions(-)
diff --git a/tests/util/piglit-framework-gl/piglit_winsys_framework.c
b/tests/util/piglit-framework-gl/piglit_winsys_framework.c
index c80e972..fcba91e 100644
--- a/tests/util/piglit-framework-gl/piglit_winsys_framework.c
+++ b/tests/util/piglit-framework-gl/piglit_winsys_framework.c
@@ -53,18 +53,18 @@ run_test(struct piglit_gl_framework *gl_fw,
int argc, char *argv[])
{
struct piglit_winsys_framework *winsys_fw =
piglit_winsys_framework(gl_fw);
- bool force_window = false;
- const char *env_force_window = getenv("PIGLIT_FORCE_WINDOW");
+ bool no_window = false;
+ const char *env_no_window = getenv("PIGLIT_NO_WINDOW");
- if (env_force_window != NULL) {
- if (strcmp(env_force_window, "0") == 0) {
- force_window = false;
- } else if (strcmp(env_force_window, "1") == 0) {
- force_window = true;
+ if (env_no_window != NULL) {
+ if (strcmp(env_no_window, "0") == 0) {
+ no_window = true;
+ } else if (strcmp(env_no_window, "1") == 0) {
+ no_window = true;
} else {
- fprintf(stderr, "PIGLIT_FORCE_WINDOW has invalid"
- " value: %s\n", env_force_window);
+ fprintf(stderr, "PIGLIT_NO_WINDOW has invalid"
+ " value: %s\n", env_no_window);
abort();
}
}
@@ -73,7 +73,7 @@ run_test(struct piglit_gl_framework *gl_fw,
gl_fw->test_config->init(argc, argv);
if (!gl_fw->test_config->requires_displayed_window &&
- piglit_automatic && !force_window) {
+ piglit_automatic && no_window) {
enum piglit_result result = PIGLIT_PASS;
if (gl_fw->test_config->display)
result = gl_fw->test_config->display();
--
1.9.1
New to the project - please commit for me.
_______________________________________________
Piglit mailing list
[email protected]
http://lists.freedesktop.org/mailman/listinfo/piglit
-----------------------------------------------------------------------------------
This email message is for the sole use of the intended recipient(s) and may
contain
confidential information. Any unauthorized review, use, disclosure or
distribution
is prohibited. If you are not the intended recipient, please contact the
sender by
reply email and destroy all copies of the original message.
-----------------------------------------------------------------------------------
