Use Windows compositor for vsync when appropriate. #33127

TerminalJack · 2019-10-28T01:57:06Z

Some users are reporting bad jitter when running in windowed mode on the
Windows OS. This change will cause the OS's compositor to be used for
vsync when it is appropriate. This is a strategy that is used by other
projects such as Chromium and glfw.

fixes #19783
fixes #27211

clayjohn · 2019-10-28T05:01:29Z

You'll also want to squash your three commits together. :)

If you don't know how, there is a great reference in the docs http://docs.godotengine.org/en/latest/community/contributing/pr_workflow.html#mastering-the-pr-workflow-the-rebase

akien-mga · 2019-10-28T08:38:49Z

To test this PR, I reworked the test project from #19783 (comment) to allow toggling various export variables on the main script to control things which can influence stuttering.

StutterTest.zip

You can also toggle Fullscreen with the Return key.

To avoid interference from the remote debugger, I suggest running the project directly (not from the editor). Also best tested with a target=release template or at least target=release_debug editor build.

akien-mga · 2019-10-28T09:54:37Z

TL;DR: No impact from this PR on my system that I can notice.
Still get no stutter on Intel, and stutter at irregular intervals on Radeon.

I ran some tests on my system using the above project. So far I don't see much difference before/after the PR, but I'm probably one of the users who is not too affected by the stutter issue (which seems mostly to affect NVidia users).

Windows 10 Build 18362, laptop HP Spectre x360.
4K display but configured as 1080p, 125% scaling including Windows' "Fix scaling for apps" option.
Monitor refresh rate: unsure, Windows says 59 Hz in one settings window and 60 Hz in the more advanced one shrug.

Builds of commit 5014baf, respectiely without (Before PR) and with (After PR) the current https://github.com/godotengine/godot/pull/33127.patch
scons p=windows tools=yes target=release_debug

Applications running: explorer.exe, Firefox Beta, git-bash.exe, Notepad++

Intel HD Graphics 630, drivers 26.20.100.6912.

Before PR:

VSync ON
- Process
  - Windowed: No stutter
  - Fullscreen: No stutter
- Physics Process
  - Windowed: No stutter
  - Fullscreen: No stutter
VSync OFF
- Process
  - Windowed: No stutter
  - Fullscreen: No stutter
- Physics Process
  - Windowed: No stutter
  - Fullscreen: No stutter

After PR:

VSync ON
- Process
  - Windowed: No stutter
  - Fullscreen: No stutter
- Physics Process
  - Windowed: No stutter
  - Fullscreen: No stutter
VSync OFF
- Process
  - Windowed: No stutter
  - Fullscreen: No stutter
- Physics Process
  - Windowed: No stutter
  - Fullscreen: No stutter

Radeon RX Vega M GL, drivers 25.20.15002.58.

Before PR:

VSync ON
- Process
  - Windowed: Occasional stutter (irregular, every 3-15 sec)
  - Fullscreen: Occasional stutter (irregular, every 3-15 sec)
- Physics Process
  - Windowed: Occasional stutter (irregular, every 3-15 sec)
  - Fullscreen: Occasional stutter (irregular, every 3-15 sec)
VSync OFF
- Process
  - Windowed: Occasional micro stutter
  - Fullscreen: Occasional micro stutter
- Physics Process
  - Windowed: Occasional stutter (irregular, every 3-15 sec)
  - Fullscreen: Occasional stutter (irregular, every 3-15 sec)

After PR:

VSync ON
- Process
  - Windowed: Occasional stutter (irregular, every 3-15 sec)
  - Fullscreen: Occasional stutter (irregular, every 3-15 sec)
- Physics Process
  - Windowed: Occasional stutter (irregular, every 3-15 sec)
  - Fullscreen: Occasional stutter (irregular, every 3-15 sec)
VSync OFF
- Process
  - Windowed: Occasional micro stutter
  - Fullscreen: Occasional micro stutter
- Physics Process
  - Windowed: Occasional stutter (irregular, every 3-15 sec)
  - Fullscreen: Occasional stutter (irregular, every 3-15 sec)

starry-abyss · 2019-10-28T10:17:46Z

To avoid interference from the remote debugger, I suggest running the project directly (not from the editor)

Note that the compositor issue is more likely to happen when there are other windows on the screen with activity in them (e.g. the editor).

akien-mga · 2019-10-28T12:45:47Z

platform/windows/context_gl_windows.cpp

@@ -33,6 +33,9 @@
 // Author: Juan Linietsky <reduzio@gmail.com>, (C) 2008

 #include "context_gl_windows.h"
+#include <dwmapi.h>
+
+#pragma comment(lib, "dwmapi.lib")


What does this do? If you want to link dwmapi.lib, it should be added to the LIBS array in platform/windows/detect.py.

This has been fixed.

akien-mga · 2019-10-28T12:46:06Z

platform/windows/context_gl_windows.cpp

@@ -33,6 +33,9 @@
 // Author: Juan Linietsky <reduzio@gmail.com>, (C) 2008

 #include "context_gl_windows.h"
+#include <dwmapi.h>


Style wise, there should be an empty line before this one. See http://docs.godotengine.org/en/latest/community/contributing/code_style_guidelines.html#header-includes

This has been fixed.

akien-mga · 2019-10-28T12:46:38Z

platform/windows/context_gl_windows.cpp

+
+	if (OS::get_singleton()->is_window_fullscreen()) {
+		return false;
+	} else {


No need for the else and extra indentation since we're just returning in the previous branch.

This has been fixed.

akien-mga · 2019-10-28T12:52:13Z

platform/windows/context_gl_windows.cpp

 	SwapBuffers(hDC);
 }

 void ContextGL_Windows::set_use_vsync(bool p_use) {

+	if (p_use && should_vsync_via_compositor()) {
+		swap_interval = 0; // vsync will be done via DwmFlush().


It seems hacky to rely on the swap interval to define whether vsync should be handled by the compositor. I'd use a boolean like vsync_via_compositor to make things explicit. When swapping buffers you can then check if the value for the cached bool would change, and do logic appropriately.

I reworked it as you suggested.

…in windowed mode.

TerminalJack · 2019-10-28T18:53:32Z

I screwed things up during a rebase so I'm going to close this PR and try submitting it again later today.

clayjohn added bug platform:windows labels Oct 28, 2019

akien-mga added the topic:porting label Oct 28, 2019

akien-mga added this to the 3.2 milestone Oct 28, 2019

akien-mga requested a review from reduz October 28, 2019 07:14

akien-mga added the needs testing label Oct 28, 2019

akien-mga reviewed Oct 28, 2019

View reviewed changes

volzhs and others added 3 commits October 28, 2019 13:34

Update libwebp to 1.0.3

fd63729

Fix error when opening or closing scene with camera preview on

c6e99a7

V-sync via the Windows compositor when it is enabled and the game is …

14db27b

…in windowed mode.

TerminalJack closed this Oct 28, 2019

akien-mga added the archived label Oct 28, 2019

TerminalJack mentioned this pull request Oct 28, 2019

Vsync via the Windows compositor when appropriate. #33145

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Use Windows compositor for vsync when appropriate. #33127

Use Windows compositor for vsync when appropriate. #33127

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TerminalJack commented Oct 28, 2019

Use Windows compositor for vsync when appropriate. #33127

Use Windows compositor for vsync when appropriate. #33127

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TerminalJack commented Oct 28, 2019

clayjohn commented Oct 28, 2019

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Intel HD Graphics 630, drivers 26.20.100.6912.

Before PR:

After PR:

Radeon RX Vega M GL, drivers 25.20.15002.58.

Before PR:

After PR:

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