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UIKit: Don't reallocate renderbuffer on QIOSContext::swapBuffers()

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During device rotation, the backing CEAGLLayer of our custom UIView is
resized by the system. Normally this is the time where we would then
reconfigure the corresponding renderbuffer that we render to, which
shares memory with the CEAGLLayer, but we chose a lazy approach where
we'd defer the reconfigure until client code actually called makeCurrent.

This caused problems because not only did we implement the lazy reconfig
in makeCurrent, but in every QIOSContext function that operated on the
default FBO, including swapBuffers(). When using threaded rendering,
such as in Qt Quick, the render thread may be half way in rendering a
new frame when the system resizes the CEAGLLayer, and we pick up that
resize on the swapBuffer call and allocate a new renderbuffer, before
flushing the queued up GL commands that were operating on another
renderbuffer of a different size. This resulted in the following crash:

  0 - gpus_ReturnObjectErrorKillClient()
  1 - gpusSubmitDataBuffers()
  2 - glrFlushContextToken()
  3 - flush(__GLIContextRec*)()
  4 - QIOSContext::swapBuffers(QPlatformSurface*)
  ...

We solve this by still being lazy in how we reconfigure, but limit the
reconfigure to makeCurrent(). If the CEAGLLayer is resized in between
two frames, we skip the half-drawn frame. The old frame will then be
scaled to match the new size by the system, but this is preferable to
flushing a new frame that may have been drawn with two conflicting
window geometries.

Task-number: QTBUG-50017
Change-Id: Ie229f26d156dfbfc7ed8d9efd0eb5e992eee73f1
Reviewed-by: Richard Moe Gustavsen <richard.gustavsen@qt.io>
This commit is contained in:
Tor Arne Vestbø 2016-06-01 13:29:24 +02:00 committed by Tor Arne Vestbø
parent 0b6adbcd23
commit 655687d84d
4 changed files with 100 additions and 67 deletions
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5
src/plugins/platforms/ios/qioscontext.h
View File

@ -34,6 +34,7 @@
#ifndef QIOSCONTEXT_H
#define QIOSCONTEXT_H
#include <QtCore/qloggingcategory.h>
#include <qpa/qplatformopenglcontext.h>
@class EAGLContext;
@ -83,7 +84,9 @@ private:
static void deleteBuffers(const FramebufferObject &framebufferObject);
FramebufferObject &backingFramebufferObjectFor(QPlatformSurface *) const;
mutable QHash<QIOSWindow *, FramebufferObject> m_framebufferObjects;
mutable QHash<QPlatformSurface *, FramebufferObject> m_framebufferObjects;
bool needsRenderbufferResize(QPlatformSurface *) const;
};
QT_END_NAMESPACE

154
src/plugins/platforms/ios/qioscontext.mm
View File

@ -42,6 +42,8 @@
#import <OpenGLES/ES2/glext.h>
#import <QuartzCore/CAEAGLLayer.h>
Q_LOGGING_CATEGORY(lcQpaGLContext, "qt.qpa.glcontext");
QIOSContext::QIOSContext(QOpenGLContext *context)
: QPlatformOpenGLContext()
, m_sharedContext(static_cast<QIOSContext *>(context->shareHandle()))
@ -75,6 +77,8 @@ QIOSContext::QIOSContext(QOpenGLContext *context)
// could take advantage of the unchanged buffer, but this means clients (and Qt)
// will also assume that swapBufferes() is not needed, which is _not_ the case.
m_format.setSwapBehavior(QSurfaceFormat::DoubleBuffer);
qCDebug(lcQpaGLContext) << "created context with format" << m_format << "shared with" << m_sharedContext;
}
QIOSContext::~QIOSContext()
@ -117,10 +121,12 @@ static QString fboStatusString(GLenum status)
}
}
#define Q_ASSERT_IS_GL_SURFACE(surface) \
Q_ASSERT(surface && (surface->surface()->surfaceType() & (QSurface::OpenGLSurface | QSurface::RasterGLSurface)))
bool QIOSContext::makeCurrent(QPlatformSurface *surface)
{
Q_ASSERT(surface && (surface->surface()->surfaceType() == QSurface::OpenGLSurface
|| surface->surface()->surfaceType() == QSurface::RasterGLSurface));
Q_ASSERT_IS_GL_SURFACE(surface);
[EAGLContext setCurrentContext:m_eaglContext];
@ -128,54 +134,11 @@ bool QIOSContext::makeCurrent(QPlatformSurface *surface)
if (surface->surface()->surfaceClass() == QSurface::Offscreen)
return true;
Q_ASSERT(surface->surface()->surfaceClass() == QSurface::Window);
FramebufferObject &framebufferObject = backingFramebufferObjectFor(surface);
// We bind the default FBO even if it's incomplete, so that clients who
// call glCheckFramebufferStatus as a result of this function returning
// false will get a matching error code.
glBindFramebuffer(GL_FRAMEBUFFER, framebufferObject.handle);
return framebufferObject.isComplete;
}
void QIOSContext::doneCurrent()
{
[EAGLContext setCurrentContext:nil];
}
void QIOSContext::swapBuffers(QPlatformSurface *surface)
{
Q_ASSERT(surface && (surface->surface()->surfaceType() == QSurface::OpenGLSurface
|| surface->surface()->surfaceType() == QSurface::RasterGLSurface));
if (surface->surface()->surfaceClass() == QSurface::Offscreen)
return; // Nothing to do
FramebufferObject &framebufferObject = backingFramebufferObjectFor(surface);
[EAGLContext setCurrentContext:m_eaglContext];
glBindRenderbuffer(GL_RENDERBUFFER, framebufferObject.colorRenderbuffer);
[m_eaglContext presentRenderbuffer:GL_RENDERBUFFER];
}
QIOSContext::FramebufferObject &QIOSContext::backingFramebufferObjectFor(QPlatformSurface *surface) const
{
// We keep track of default-FBOs in the root context of a share-group. This assumes
// that the contexts form a tree, where leaf nodes are always destroyed before their
// parents. If that assumption (based on the current implementation) doesn't hold we
// should probably use QOpenGLMultiGroupSharedResource to track the shared default-FBOs.
if (m_sharedContext)
return m_sharedContext->backingFramebufferObjectFor(surface);
Q_ASSERT(surface && surface->surface()->surfaceClass() == QSurface::Window);
QIOSWindow *window = static_cast<QIOSWindow *>(surface);
FramebufferObject &framebufferObject = m_framebufferObjects[window];
// Set up an FBO for the window if it hasn't been created yet
if (!framebufferObject.handle) {
[EAGLContext setCurrentContext:m_eaglContext];
// Set up an FBO for the window if it hasn't been created yet
glGenFramebuffers(1, &framebufferObject.handle);
glBindFramebuffer(GL_FRAMEBUFFER, framebufferObject.handle);
@ -195,17 +158,17 @@ QIOSContext::FramebufferObject &QIOSContext::backingFramebufferObjectFor(QPlatfo
framebufferObject.depthRenderbuffer);
}
connect(window, SIGNAL(destroyed(QObject*)), this, SLOT(windowDestroyed(QObject*)));
connect(static_cast<QIOSWindow *>(surface), SIGNAL(destroyed(QObject*)), this, SLOT(windowDestroyed(QObject*)));
} else {
glBindFramebuffer(GL_FRAMEBUFFER, framebufferObject.handle);
}
// Ensure that the FBO's buffers match the size of the layer
UIView *view = reinterpret_cast<UIView *>(window->winId());
CAEAGLLayer *layer = static_cast<CAEAGLLayer *>(view.layer);
if (framebufferObject.renderbufferWidth != (layer.frame.size.width * layer.contentsScale) ||
framebufferObject.renderbufferHeight != (layer.frame.size.height * layer.contentsScale)) {
[EAGLContext setCurrentContext:m_eaglContext];
glBindFramebuffer(GL_FRAMEBUFFER, framebufferObject.handle);
if (needsRenderbufferResize(surface)) {
// Ensure that the FBO's buffers match the size of the layer
CAEAGLLayer *layer = static_cast<QIOSWindow *>(surface)->eaglLayer();
qCDebug(lcQpaGLContext, "Reallocating renderbuffer storage - current: %dx%d, layer: %gx%g",
framebufferObject.renderbufferWidth, framebufferObject.renderbufferHeight,
layer.frame.size.width * layer.contentsScale, layer.frame.size.height * layer.contentsScale);
glBindRenderbuffer(GL_RENDERBUFFER, framebufferObject.colorRenderbuffer);
[m_eaglContext renderbufferStorage:GL_RENDERBUFFER fromDrawable:layer];
@ -228,12 +191,49 @@ QIOSContext::FramebufferObject &QIOSContext::backingFramebufferObjectFor(QPlatfo
framebufferObject.isComplete = glCheckFramebufferStatus(GL_FRAMEBUFFER) == GL_FRAMEBUFFER_COMPLETE;
if (!framebufferObject.isComplete) {
qWarning("QIOSContext failed to make complete framebuffer object (%s)",
qCWarning(lcQpaGLContext, "QIOSContext failed to make complete framebuffer object (%s)",
qPrintable(fboStatusString(glCheckFramebufferStatus(GL_FRAMEBUFFER))));
}
}
return framebufferObject;
return framebufferObject.isComplete;
}
void QIOSContext::doneCurrent()
{
[EAGLContext setCurrentContext:nil];
}
void QIOSContext::swapBuffers(QPlatformSurface *surface)
{
Q_ASSERT_IS_GL_SURFACE(surface);
if (surface->surface()->surfaceClass() == QSurface::Offscreen)
return; // Nothing to do
FramebufferObject &framebufferObject = backingFramebufferObjectFor(surface);
Q_ASSERT_X(framebufferObject.isComplete, "QIOSContext", "swapBuffers on incomplete FBO");
if (needsRenderbufferResize(surface)) {
qCWarning(lcQpaGLContext, "CAEAGLLayer was resized between makeCurrent and swapBuffers, skipping flush");
return;
}
[EAGLContext setCurrentContext:m_eaglContext];
glBindRenderbuffer(GL_RENDERBUFFER, framebufferObject.colorRenderbuffer);
[m_eaglContext presentRenderbuffer:GL_RENDERBUFFER];
}
QIOSContext::FramebufferObject &QIOSContext::backingFramebufferObjectFor(QPlatformSurface *surface) const
{
// We keep track of default-FBOs in the root context of a share-group. This assumes
// that the contexts form a tree, where leaf nodes are always destroyed before their
// parents. If that assumption (based on the current implementation) doesn't hold we
// should probably use QOpenGLMultiGroupSharedResource to track the shared default-FBOs.
if (m_sharedContext)
return m_sharedContext->backingFramebufferObjectFor(surface);
else
return m_framebufferObjects[surface];
}
GLuint QIOSContext::defaultFramebufferObject(QPlatformSurface *surface) const
@ -245,19 +245,41 @@ GLuint QIOSContext::defaultFramebufferObject(QPlatformSurface *surface) const
return 0;
}
return backingFramebufferObjectFor(surface).handle;
FramebufferObject &framebufferObject = backingFramebufferObjectFor(surface);
Q_ASSERT_X(framebufferObject.handle, "QIOSContext", "can't resolve default FBO before makeCurrent");
return framebufferObject.handle;
}
bool QIOSContext::needsRenderbufferResize(QPlatformSurface *surface) const
{
Q_ASSERT(surface->surface()->surfaceClass() == QSurface::Window);
FramebufferObject &framebufferObject = backingFramebufferObjectFor(surface);
CAEAGLLayer *layer = static_cast<QIOSWindow *>(surface)->eaglLayer();
if (framebufferObject.renderbufferWidth != (layer.frame.size.width * layer.contentsScale))
return true;
if (framebufferObject.renderbufferHeight != (layer.frame.size.height * layer.contentsScale))
return true;
return false;
}
void QIOSContext::windowDestroyed(QObject *object)
{
QIOSWindow *window = static_cast<QIOSWindow *>(object);
if (m_framebufferObjects.contains(window)) {
EAGLContext *originalContext = [EAGLContext currentContext];
[EAGLContext setCurrentContext:m_eaglContext];
deleteBuffers(m_framebufferObjects[window]);
m_framebufferObjects.remove(window);
[EAGLContext setCurrentContext:originalContext];
}
if (!m_framebufferObjects.contains(window))
return;
qCDebug(lcQpaGLContext) << object << "destroyed, deleting corresponding FBO";
EAGLContext *originalContext = [EAGLContext currentContext];
[EAGLContext setCurrentContext:m_eaglContext];
deleteBuffers(m_framebufferObjects[window]);
m_framebufferObjects.remove(window);
[EAGLContext setCurrentContext:originalContext];
}
QFunctionPointer QIOSContext::getProcAddress(const QByteArray& functionName)

2
src/plugins/platforms/ios/qioswindow.h
View File

@ -84,6 +84,8 @@ public:
void requestUpdate() Q_DECL_OVERRIDE;
CAEAGLLayer *eaglLayer() const;
private:
void applicationStateChanged(Qt::ApplicationState state);
void applyGeometry(const QRect &rect);

6
src/plugins/platforms/ios/qioswindow.mm
View File

@ -376,6 +376,12 @@ void QIOSWindow::requestUpdate()
static_cast<QIOSScreen *>(screen())->setUpdatesPaused(false);
}
CAEAGLLayer *QIOSWindow::eaglLayer() const
{
Q_ASSERT([m_view.layer isKindOfClass:[CAEAGLLayer class]]);
return static_cast<CAEAGLLayer *>(m_view.layer);
}
#include "moc_qioswindow.cpp"
QT_END_NAMESPACE