kwin/eglonxbackend.cpp
Martin Gräßlin c2aacca735 Ensure that our compositing context is current when starting to render
With QtQuick2 KWin is no longer the only one having an OpenGL context
thus we need to ensure that our context is current. If not it results in
highly interesting crashes when our code is executed on the QtQuick
context.

The context is made current before we swap and before we start to render
a frame. During rendering a frame it's not made current again based on
the assumption that while we render there is no interference. If this
assumption doesn't hold, we need a more sophisticated solution at the
moment it seems to fix the crashes.
2013-09-26 11:13:40 +02:00

430 lines
14 KiB
C++

/********************************************************************
KWin - the KDE window manager
This file is part of the KDE project.
Copyright (C) 2010, 2012 Martin Gräßlin <mgraesslin@kde.org>
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*********************************************************************/
#include "eglonxbackend.h"
// kwin
#include "options.h"
#include "overlaywindow.h"
#include "xcbutils.h"
// kwin libs
#include <kwinglplatform.h>
// Qt
#include <QDebug>
// system
#include <unistd.h>
namespace KWin
{
EglOnXBackend::EglOnXBackend()
: OpenGLBackend()
, ctx(EGL_NO_CONTEXT)
, surfaceHasSubPost(0)
{
init();
// Egl is always direct rendering
setIsDirectRendering(true);
}
EglOnXBackend::~EglOnXBackend()
{
cleanupGL();
eglMakeCurrent(dpy, EGL_NO_SURFACE, EGL_NO_SURFACE, EGL_NO_CONTEXT);
eglDestroyContext(dpy, ctx);
eglDestroySurface(dpy, surface);
eglTerminate(dpy);
eglReleaseThread();
if (overlayWindow()->window()) {
overlayWindow()->destroy();
}
}
static bool gs_tripleBufferUndetected = true;
static bool gs_tripleBufferNeedsDetection = false;
void EglOnXBackend::init()
{
if (!initRenderingContext()) {
setFailed(QStringLiteral("Could not initialize rendering context"));
return;
}
initEGL();
if (!hasGLExtension(QStringLiteral("EGL_KHR_image")) &&
(!hasGLExtension(QStringLiteral("EGL_KHR_image_base")) ||
!hasGLExtension(QStringLiteral("EGL_KHR_image_pixmap")))) {
setFailed(QStringLiteral("Required support for binding pixmaps to EGLImages not found, disabling compositing"));
return;
}
GLPlatform *glPlatform = GLPlatform::instance();
glPlatform->detect(EglPlatformInterface);
if (GLPlatform::instance()->driver() == Driver_Intel)
options->setUnredirectFullscreen(false); // bug #252817
options->setGlPreferBufferSwap(options->glPreferBufferSwap()); // resolve autosetting
if (options->glPreferBufferSwap() == Options::AutoSwapStrategy)
options->setGlPreferBufferSwap('e'); // for unknown drivers - should not happen
glPlatform->printResults();
initGL(EglPlatformInterface);
if (!hasGLExtension(QStringLiteral("GL_OES_EGL_image"))) {
setFailed(QStringLiteral("Required extension GL_OES_EGL_image not found, disabling compositing"));
return;
}
// check for EGL_NV_post_sub_buffer and whether it can be used on the surface
if (eglPostSubBufferNV) {
if (eglQuerySurface(dpy, surface, EGL_POST_SUB_BUFFER_SUPPORTED_NV, &surfaceHasSubPost) == EGL_FALSE) {
EGLint error = eglGetError();
if (error != EGL_SUCCESS && error != EGL_BAD_ATTRIBUTE) {
setFailed(QStringLiteral("query surface failed"));
return;
} else {
surfaceHasSubPost = EGL_FALSE;
}
}
}
setSyncsToVBlank(false);
setBlocksForRetrace(false);
gs_tripleBufferNeedsDetection = false;
m_swapProfiler.init();
if (surfaceHasSubPost) {
qDebug() << "EGL implementation and surface support eglPostSubBufferNV, let's use it";
if (options->glPreferBufferSwap() != Options::NoSwapEncourage) {
// check if swap interval 1 is supported
EGLint val;
eglGetConfigAttrib(dpy, config, EGL_MAX_SWAP_INTERVAL, &val);
if (val >= 1) {
if (eglSwapInterval(dpy, 1)) {
qDebug() << "Enabled v-sync";
setSyncsToVBlank(true);
const QByteArray tripleBuffer = qgetenv("KWIN_TRIPLE_BUFFER");
if (!tripleBuffer.isEmpty()) {
setBlocksForRetrace(qstrcmp(tripleBuffer, "0") == 0);
gs_tripleBufferUndetected = false;
}
gs_tripleBufferNeedsDetection = gs_tripleBufferUndetected;
}
} else {
qWarning() << "Cannot enable v-sync as max. swap interval is" << val;
}
} else {
// disable v-sync
eglSwapInterval(dpy, 0);
}
} else {
/* In the GLX backend, we fall back to using glCopyPixels if we have no extension providing support for partial screen updates.
* However, that does not work in EGL - glCopyPixels with glDrawBuffer(GL_FRONT); does nothing.
* Hence we need EGL to preserve the backbuffer for us, so that we can draw the partial updates on it and call
* eglSwapBuffers() for each frame. eglSwapBuffers() then does the copy (no page flip possible in this mode),
* which means it is slow and not synced to the v-blank. */
qWarning() << "eglPostSubBufferNV not supported, have to enable buffer preservation - which breaks v-sync and performance";
eglSurfaceAttrib(dpy, surface, EGL_SWAP_BEHAVIOR, EGL_BUFFER_PRESERVED);
}
}
bool EglOnXBackend::initRenderingContext()
{
dpy = eglGetDisplay(display());
if (dpy == EGL_NO_DISPLAY)
return false;
EGLint major, minor;
if (eglInitialize(dpy, &major, &minor) == EGL_FALSE)
return false;
#ifdef KWIN_HAVE_OPENGLES
eglBindAPI(EGL_OPENGL_ES_API);
#else
if (eglBindAPI(EGL_OPENGL_API) == EGL_FALSE) {
qCritical() << "bind OpenGL API failed";
return false;
}
#endif
initBufferConfigs();
if (!overlayWindow()->create()) {
qCritical() << "Could not get overlay window";
return false;
} else {
overlayWindow()->setup(None);
}
surface = eglCreateWindowSurface(dpy, config, overlayWindow()->window(), 0);
#ifdef KWIN_HAVE_OPENGLES
const EGLint context_attribs[] = {
EGL_CONTEXT_CLIENT_VERSION, 2,
EGL_NONE
};
ctx = eglCreateContext(dpy, config, EGL_NO_CONTEXT, context_attribs);
#else
const EGLint context_attribs_31_core[] = {
EGL_CONTEXT_MAJOR_VERSION_KHR, 3,
EGL_CONTEXT_MINOR_VERSION_KHR, 1,
EGL_NONE
};
const EGLint context_attribs_legacy[] = {
EGL_NONE
};
const QByteArray eglExtensions = eglQueryString(dpy, EGL_EXTENSIONS);
const QList<QByteArray> extensions = eglExtensions.split(' ');
// Try to create a 3.1 core context
if (options->glCoreProfile() && extensions.contains("EGL_KHR_create_context"))
ctx = eglCreateContext(dpy, config, EGL_NO_CONTEXT, context_attribs_31_core);
if (ctx == EGL_NO_CONTEXT)
ctx = eglCreateContext(dpy, config, EGL_NO_CONTEXT, context_attribs_legacy);
#endif
if (ctx == EGL_NO_CONTEXT) {
qCritical() << "Create Context failed";
return false;
}
if (eglMakeCurrent(dpy, surface, surface, ctx) == EGL_FALSE) {
qCritical() << "Make Context Current failed";
return false;
}
qDebug() << "EGL version: " << major << "." << minor;
EGLint error = eglGetError();
if (error != EGL_SUCCESS) {
qWarning() << "Error occurred while creating context " << error;
return false;
}
return true;
}
bool EglOnXBackend::initBufferConfigs()
{
const EGLint config_attribs[] = {
EGL_SURFACE_TYPE, EGL_WINDOW_BIT|EGL_SWAP_BEHAVIOR_PRESERVED_BIT,
EGL_RED_SIZE, 1,
EGL_GREEN_SIZE, 1,
EGL_BLUE_SIZE, 1,
EGL_ALPHA_SIZE, 0,
#ifdef KWIN_HAVE_OPENGLES
EGL_RENDERABLE_TYPE, EGL_OPENGL_ES2_BIT,
#else
EGL_RENDERABLE_TYPE, EGL_OPENGL_BIT,
#endif
EGL_CONFIG_CAVEAT, EGL_NONE,
EGL_NONE,
};
EGLint count;
EGLConfig configs[1024];
if (eglChooseConfig(dpy, config_attribs, configs, 1024, &count) == EGL_FALSE) {
qCritical() << "choose config failed";
return false;
}
Xcb::WindowAttributes attribs(rootWindow());
if (!attribs) {
qCritical() << "Failed to get window attributes of root window";
return false;
}
config = configs[0];
for (int i = 0; i < count; i++) {
EGLint val;
if (eglGetConfigAttrib(dpy, configs[i], EGL_NATIVE_VISUAL_ID, &val) == EGL_FALSE) {
qCritical() << "egl get config attrib failed";
}
if (uint32_t(val) == attribs->visual) {
config = configs[i];
break;
}
}
return true;
}
void EglOnXBackend::present()
{
if (lastDamage().isEmpty())
return;
// a different context might have been current
eglMakeCurrent(dpy, surface, surface, ctx);
const QRegion displayRegion(0, 0, displayWidth(), displayHeight());
const bool fullRepaint = (lastDamage() == displayRegion);
if (fullRepaint || !surfaceHasSubPost) {
if (gs_tripleBufferNeedsDetection) {
eglWaitGL();
m_swapProfiler.begin();
}
// the entire screen changed, or we cannot do partial updates (which implies we enabled surface preservation)
eglSwapBuffers(dpy, surface);
if (gs_tripleBufferNeedsDetection) {
eglWaitGL();
if (char result = m_swapProfiler.end()) {
gs_tripleBufferUndetected = gs_tripleBufferNeedsDetection = false;
if (result == 'd' && GLPlatform::instance()->driver() == Driver_NVidia) {
// TODO this is a workaround, we should get __GL_YIELD set before libGL checks it
if (qstrcmp(qgetenv("__GL_YIELD"), "USLEEP")) {
options->setGlPreferBufferSwap(0);
eglSwapInterval(dpy, 0);
qWarning() << "\nIt seems you are using the nvidia driver without triple buffering\n"
"You must export __GL_YIELD=\"USLEEP\" to prevent large CPU overhead on synced swaps\n"
"Preferably, enable the TripleBuffer Option in the xorg.conf Device\n"
"For this reason, the tearing prevention has been disabled.\n"
"See https://bugs.kde.org/show_bug.cgi?id=322060\n";
}
}
setBlocksForRetrace(result == 'd');
}
}
} else {
// a part of the screen changed, and we can use eglPostSubBufferNV to copy the updated area
foreach (const QRect & r, lastDamage().rects()) {
eglPostSubBufferNV(dpy, surface, r.left(), displayHeight() - r.bottom() - 1, r.width(), r.height());
}
}
setLastDamage(QRegion());
eglWaitGL();
xcb_flush(connection());
}
void EglOnXBackend::screenGeometryChanged(const QSize &size)
{
Q_UNUSED(size)
// no backend specific code needed
// TODO: base implementation in OpenGLBackend
}
SceneOpenGL::TexturePrivate *EglOnXBackend::createBackendTexture(SceneOpenGL::Texture *texture)
{
return new EglTexture(texture, this);
}
void EglOnXBackend::prepareRenderingFrame()
{
if (gs_tripleBufferNeedsDetection) {
// the composite timer floors the repaint frequency. This can pollute our triple buffering
// detection because the glXSwapBuffers call for the new frame has to wait until the pending
// one scanned out.
// So we compensate for that by waiting an extra milisecond to give the driver the chance to
// fllush the buffer queue
usleep(1000);
}
present();
// different context might have been bound as present() can block
eglMakeCurrent(dpy, surface, surface, ctx);
startRenderTimer();
eglWaitNative(EGL_CORE_NATIVE_ENGINE);
}
void EglOnXBackend::endRenderingFrame(const QRegion &damage)
{
setLastDamage(damage);
glFlush();
if (!blocksForRetrace()) {
present(); // this sets lastDamage emtpy and prevents execution from prepareRenderingFrame()
}
if (overlayWindow()->window()) // show the window only after the first pass,
overlayWindow()->show(); // since that pass may take long
}
/************************************************
* EglTexture
************************************************/
EglTexture::EglTexture(KWin::SceneOpenGL::Texture *texture, KWin::EglOnXBackend *backend)
: SceneOpenGL::TexturePrivate()
, q(texture)
, m_backend(backend)
, m_image(EGL_NO_IMAGE_KHR)
{
m_target = GL_TEXTURE_2D;
}
EglTexture::~EglTexture()
{
if (m_image != EGL_NO_IMAGE_KHR) {
eglDestroyImageKHR(m_backend->dpy, m_image);
}
}
OpenGLBackend *EglTexture::backend()
{
return m_backend;
}
void EglTexture::findTarget()
{
if (m_target != GL_TEXTURE_2D) {
m_target = GL_TEXTURE_2D;
}
}
bool EglTexture::loadTexture(const Pixmap &pix, const QSize &size, int depth)
{
Q_UNUSED(depth)
if (pix == None)
return false;
glGenTextures(1, &m_texture);
q->setWrapMode(GL_CLAMP_TO_EDGE);
q->setFilter(GL_LINEAR);
q->bind();
const EGLint attribs[] = {
EGL_IMAGE_PRESERVED_KHR, EGL_TRUE,
EGL_NONE
};
m_image = eglCreateImageKHR(m_backend->dpy, EGL_NO_CONTEXT, EGL_NATIVE_PIXMAP_KHR,
(EGLClientBuffer)pix, attribs);
if (EGL_NO_IMAGE_KHR == m_image) {
qDebug() << "failed to create egl image";
q->unbind();
q->discard();
return false;
}
glEGLImageTargetTexture2DOES(GL_TEXTURE_2D, (GLeglImageOES)m_image);
q->unbind();
checkGLError("load texture");
q->setYInverted(true);
m_size = size;
updateMatrix();
return true;
}
void KWin::EglTexture::onDamage()
{
if (options->isGlStrictBinding()) {
// This is just implemented to be consistent with
// the example in mesa/demos/src/egl/opengles1/texture_from_pixmap.c
eglWaitNative(EGL_CORE_NATIVE_ENGINE);
glEGLImageTargetTexture2DOES(GL_TEXTURE_2D, (GLeglImageOES) m_image);
}
GLTexturePrivate::onDamage();
}
} // namespace