yukijoou/kwin
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

kwineffects: Fix destruction of s_fbo with shared GLTexture objects

Browse source 
The WindowThumbnail item uses the GLTexture class. In order to destroy
the thumbnail texture, the item will schedule a destroy job.

This means that the GLTexture can be alive during or after graphics
reset.

On the other hand, as an implementation detail, GLTexture::clear() may
allocate a framebuffer object, which is going to be destroyed together
with the last texture.

Given that window thumbnail textures can be still alive after a graphics
reset and the fact that GLTexturePrivate::s_fbo gets destroyed when the
last texture is destroyed, kwin can end up trying to clear a decoration
texture with now defunct s_fbo.

Since the old old s_fbo is inert, the glBindFramebuffer() function will
fail and the glClear() operation will affect the default framebuffer,
thus leading to black flickering visual artifacts.

In order to fix that issue, this change makes GLTexture destroy s_fbo
unconditionally in GLTexturePrivate::cleanup() which is called whenever
OpenGL stuff is about to tear down, e.g. due to graphics reset, etc.

BUG: 443951
This commit is contained in:
Vlad Zahorodnii 2021-10-25 12:39:05 +03:00
parent bd3d275293
commit fda7e150df
2 changed files with 4 additions and 8 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

11
src/libkwineffects/kwingltexture.cpp
View file

@ -36,7 +36,6 @@ bool GLTexturePrivate::s_supportsUnpack = false;
bool GLTexturePrivate::s_supportsTextureStorage = false;
bool GLTexturePrivate::s_supportsTextureSwizzle = false;
bool GLTexturePrivate::s_supportsTextureFormatRG = false;
uint GLTexturePrivate::s_textureObjectCounter = 0;
uint GLTexturePrivate::s_fbo = 0;
// Table of GL formats/types associated with different values of QImage::Format.
@ -287,7 +286,6 @@ GLTexturePrivate::GLTexturePrivate()
, m_normalizeActive(0)
, m_vbo(nullptr)
{
++s_textureObjectCounter;
}
GLTexturePrivate::~GLTexturePrivate()
@ -296,11 +294,6 @@ GLTexturePrivate::~GLTexturePrivate()
if (m_texture != 0 && !m_foreign) {
glDeleteTextures(1, &m_texture);
}
// Delete the FBO if this is the last Texture
if (--s_textureObjectCounter == 0 && s_fbo) {
glDeleteFramebuffers(1, &s_fbo);
s_fbo = 0;
}
}
void GLTexturePrivate::initStatic()
@ -334,6 +327,10 @@ void GLTexturePrivate::cleanup()
{
s_supportsFramebufferObjects = false;
s_supportsARGB32 = false;
if (s_fbo) {
glDeleteFramebuffers(1, &s_fbo);
s_fbo = 0;
}
}
bool GLTexture::isNull() const

1
src/libkwineffects/kwingltexture_p.h
View file

@ -69,7 +69,6 @@ public:
static bool s_supportsTextureSwizzle;
static bool s_supportsTextureFormatRG;
static GLuint s_fbo;
static uint s_textureObjectCounter;
private:
friend void KWin::cleanupGL();
static void cleanup();