eglfs: Introduce way of filtering out unwanted EGL configs.

Some times a platform might want to exclude certain configs, for example
based on EGL_NATIVE_VISUAL_ID. This patch introduces a new
QEglConfigChooser class which has a virtual filterConfig() function
which can be re-implemented in a sub-class to give finer control of how
configs are chosen.

Change-Id: I8b684f01be95a47307b1e429857f01337a9a38d8
Reviewed-by: Eskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@digia.com>
Reviewed-by: Gunnar Sletta <gunnar.sletta@digia.com>

src/platformsupport/eglconvenience/qeglconvenience.cpp

@@ -210,75 +210,106 @@ bool q_reduceConfigAttributes(QVector<EGLint> *configAttributes)
     return false;
 }
 
-EGLConfig q_configFromGLFormat(EGLDisplay display, const QSurfaceFormat &format, bool highestPixelFormat, int surfaceType)
+QEglConfigChooser::QEglConfigChooser(EGLDisplay display)
+    : m_display(display)
+    , m_surfaceType(EGL_WINDOW_BIT)
+    , m_ignore(false)
+    , m_confAttrRed(0)
+    , m_confAttrGreen(0)
+    , m_confAttrBlue(0)
+    , m_confAttrAlpha(0)
 {
-    EGLConfig cfg = 0;
+}
-    QVector<EGLint> configureAttributes = q_createConfigAttributesFromFormat(format);
+
+QEglConfigChooser::~QEglConfigChooser()
+{
+}
+
+EGLConfig QEglConfigChooser::chooseConfig()
+{
+    QVector<EGLint> configureAttributes = q_createConfigAttributesFromFormat(m_format);
     configureAttributes.append(EGL_SURFACE_TYPE);
-    configureAttributes.append(surfaceType);
+    configureAttributes.append(surfaceType());
 
     configureAttributes.append(EGL_RENDERABLE_TYPE);
-    if (format.renderableType() == QSurfaceFormat::OpenVG)
+    if (m_format.renderableType() == QSurfaceFormat::OpenVG)
         configureAttributes.append(EGL_OPENVG_BIT);
 #ifdef EGL_VERSION_1_4
-    else if (format.renderableType() == QSurfaceFormat::OpenGL)
+    else if (m_format.renderableType() == QSurfaceFormat::OpenGL)
         configureAttributes.append(EGL_OPENGL_BIT);
 #endif
-    else if (format.majorVersion() == 1)
+    else if (m_format.majorVersion() == 1)
         configureAttributes.append(EGL_OPENGL_ES_BIT);
     else
         configureAttributes.append(EGL_OPENGL_ES2_BIT);
 
     configureAttributes.append(EGL_NONE);
 
+    EGLConfig cfg;
     do {
         // Get the number of matching configurations for this set of properties.
         EGLint matching = 0;
-        if (!eglChooseConfig(display, configureAttributes.constData(), 0, 0, &matching) || !matching)
+        if (!eglChooseConfig(display(), configureAttributes.constData(), 0, 0, &matching) || !matching)
             continue;
 
-        // If we want the best pixel format, then return the first
-        // matching configuration.
-        if (highestPixelFormat) {
-            eglChooseConfig(display, configureAttributes.constData(), &cfg, 1, &matching);
-            if (matching < 1)
-                continue;
-            return cfg;
-        }
-
         // Fetch all of the matching configurations and find the
         // first that matches the pixel format we wanted.
         int i = configureAttributes.indexOf(EGL_RED_SIZE);
-        int confAttrRed = configureAttributes.at(i+1);
+        m_confAttrRed = configureAttributes.at(i+1);
         i = configureAttributes.indexOf(EGL_GREEN_SIZE);
-        int confAttrGreen = configureAttributes.at(i+1);
+        m_confAttrGreen = configureAttributes.at(i+1);
         i = configureAttributes.indexOf(EGL_BLUE_SIZE);
-        int confAttrBlue = configureAttributes.at(i+1);
+        m_confAttrBlue = configureAttributes.at(i+1);
         i = configureAttributes.indexOf(EGL_ALPHA_SIZE);
-        int confAttrAlpha = i == -1 ? 0 : configureAttributes.at(i+1);
+        m_confAttrAlpha = i == -1 ? 0 : configureAttributes.at(i+1);
 
-        EGLint size = matching;
+        QVector<EGLConfig> configs(matching);
-        EGLConfig *configs = new EGLConfig [size];
+        eglChooseConfig(display(), configureAttributes.constData(), configs.data(), configs.size(), &matching);
-        eglChooseConfig(display, configureAttributes.constData(), configs, size, &matching);
+        if (!cfg && matching > 0)
-        for (EGLint index = 0; index < size; ++index) {
+            cfg = configs.first();
-            EGLint red, green, blue, alpha;
+
-            eglGetConfigAttrib(display, configs[index], EGL_RED_SIZE, &red);
+        for (int i = 0; i < configs.size(); ++i) {
-            eglGetConfigAttrib(display, configs[index], EGL_GREEN_SIZE, &green);
+            if (filterConfig(configs[i]))
-            eglGetConfigAttrib(display, configs[index], EGL_BLUE_SIZE, &blue);
+                return configs.at(i);
-            eglGetConfigAttrib(display, configs[index], EGL_ALPHA_SIZE, &alpha);
-            if ((confAttrRed == 0 || red == confAttrRed) &&
-                (confAttrGreen == 0 || green == confAttrGreen) &&
-                (confAttrBlue == 0 || blue == confAttrBlue) &&
-                (confAttrAlpha == 0 || alpha == confAttrAlpha)) {
-                cfg = configs[index];
-                delete [] configs;
-                return cfg;
-            }
         }
-        delete [] configs;
     } while (q_reduceConfigAttributes(&configureAttributes));
-    qWarning("Cant find EGLConfig, returning null config");
+
-    return 0;
+    if (!cfg)
+        qWarning("Cant find EGLConfig, returning null config");
+    return cfg;
+}
+
+bool QEglConfigChooser::filterConfig(EGLConfig config) const
+{
+    if (m_ignore)
+        return true;
+
+    EGLint red = 0;
+    EGLint green = 0;
+    EGLint blue = 0;
+    EGLint alpha = 0;
+
+    if (m_confAttrRed)
+        eglGetConfigAttrib(display(), config, EGL_RED_SIZE, &red);
+    if (m_confAttrGreen)
+        eglGetConfigAttrib(display(), config, EGL_GREEN_SIZE, &green);
+    if (m_confAttrBlue)
+        eglGetConfigAttrib(display(), config, EGL_BLUE_SIZE, &blue);
+    if (m_confAttrAlpha)
+        eglGetConfigAttrib(display(), config, EGL_ALPHA_SIZE, &alpha);
+
+    return red == m_confAttrRed && green == m_confAttrGreen
+           && blue == m_confAttrBlue && alpha == m_confAttrAlpha;
+}
+
+EGLConfig q_configFromGLFormat(EGLDisplay display, const QSurfaceFormat &format, bool highestPixelFormat, int surfaceType)
+{
+    QEglConfigChooser chooser(display);
+    chooser.setSurfaceFormat(format);
+    chooser.setSurfaceType(surfaceType);
+    chooser.setIgnoreColorChannels(highestPixelFormat);
+
+    return chooser.chooseConfig();
 }
 
 QSurfaceFormat q_glFormatFromConfig(EGLDisplay display, const EGLConfig config, const QSurfaceFormat &referenceFormat)

src/platformsupport/eglconvenience/qeglconvenience_p.h

@@ -56,6 +56,41 @@ QSurfaceFormat q_glFormatFromConfig(EGLDisplay display, const EGLConfig config,
 bool q_hasEglExtension(EGLDisplay display,const char* extensionName);
 void q_printEglConfig(EGLDisplay display, EGLConfig config);
 
+class QEglConfigChooser
+{
+public:
+    QEglConfigChooser(EGLDisplay display);
+    virtual ~QEglConfigChooser();
+
+    EGLDisplay display() const { return m_display; }
+
+    void setSurfaceType(EGLint surfaceType) { m_surfaceType = surfaceType; }
+    EGLint surfaceType() const { return m_surfaceType; }
+
+    void setSurfaceFormat(const QSurfaceFormat &format) { m_format = format; }
+    QSurfaceFormat surfaceFormat() const { return m_format; }
+
+    void setIgnoreColorChannels(bool ignore) { m_ignore = ignore; }
+    bool ignoreColorChannels() const { return m_ignore; }
+
+    EGLConfig chooseConfig();
+
+protected:
+    virtual bool filterConfig(EGLConfig config) const;
+
+private:
+    QSurfaceFormat m_format;
+    EGLDisplay m_display;
+    EGLint m_surfaceType;
+    bool m_ignore;
+
+    int m_confAttrRed;
+    int m_confAttrGreen;
+    int m_confAttrBlue;
+    int m_confAttrAlpha;
+};
+
+
 QT_END_NAMESPACE
 
 #endif //QEGLCONVENIENCE_H

src/platformsupport/eglconvenience/qeglplatformcontext.cpp

@@ -64,8 +64,22 @@ QEGLPlatformContext::QEGLPlatformContext(const QSurfaceFormat &format, QPlatform
     : m_eglDisplay(display)
     , m_eglApi(eglApi)
     , m_eglConfig(q_configFromGLFormat(display, format, true))
-    , m_format(q_glFormatFromConfig(display, m_eglConfig))
 {
+    init(format, share);
+}
+
+QEGLPlatformContext::QEGLPlatformContext(const QSurfaceFormat &format, QPlatformOpenGLContext *share, EGLDisplay display,
+                                         EGLConfig config, EGLenum eglApi)
+    : m_eglDisplay(display)
+    , m_eglApi(eglApi)
+    , m_eglConfig(config)
+{
+    init(format, share);
+}
+
+void QEGLPlatformContext::init(const QSurfaceFormat &format, QPlatformOpenGLContext *share)
+{
+    m_format = q_glFormatFromConfig(m_eglDisplay, m_eglConfig);
     m_shareContext = share ? static_cast<QEGLPlatformContext *>(share)->m_eglContext : 0;
 
     QVector<EGLint> contextAttrs;

src/platformsupport/eglconvenience/qeglplatformcontext_p.h

@@ -51,6 +51,8 @@ class QEGLPlatformContext : public QPlatformOpenGLContext
 public:
     QEGLPlatformContext(const QSurfaceFormat &format, QPlatformOpenGLContext *share, EGLDisplay display,
                         EGLenum eglApi = EGL_OPENGL_ES_API);
+    QEGLPlatformContext(const QSurfaceFormat &format, QPlatformOpenGLContext *share, EGLDisplay display,
+                        EGLConfig config, EGLenum eglApi = EGL_OPENGL_ES_API);
     ~QEGLPlatformContext();
 
     bool makeCurrent(QPlatformSurface *surface);
@@ -70,12 +72,14 @@ protected:
     virtual EGLSurface eglSurfaceForPlatformSurface(QPlatformSurface *surface) = 0;
 
 private:
+    void init(const QSurfaceFormat &format, QPlatformOpenGLContext *share);
+
     EGLContext m_eglContext;
     EGLContext m_shareContext;
     EGLDisplay m_eglDisplay;
     EGLenum m_eglApi;
     EGLConfig m_eglConfig;
-    const QSurfaceFormat m_format;
+    QSurfaceFormat m_format;
 };
 
 #endif //QEGLPLATFORMCONTEXT_H

src/plugins/platforms/eglfs/qeglfscontext.cpp

@@ -43,6 +43,7 @@
 #include "qeglfswindow.h"
 #include "qeglfscursor.h"
 #include "qeglfshooks.h"
+#include "qeglfsintegration.h"
 
 #include <QtDebug>
 
@@ -50,7 +51,7 @@ QT_BEGIN_NAMESPACE
 
 QEglFSContext::QEglFSContext(const QSurfaceFormat &format, QPlatformOpenGLContext *share,
                              EGLDisplay display, EGLenum eglApi)
-    : QEGLPlatformContext(hooks->surfaceFormatFor(format), share, display, eglApi)
+    : QEGLPlatformContext(format, share, display, QEglFSIntegration::chooseConfig(display, format), eglApi)
 {
 }
 

src/plugins/platforms/eglfs/qeglfshooks.h

@@ -67,6 +67,7 @@ public:
     virtual void destroyNativeWindow(EGLNativeWindowType window);
     virtual bool hasCapability(QPlatformIntegration::Capability cap) const;
     virtual QEglFSCursor *createCursor(QEglFSScreen *screen) const;
+    virtual bool filterConfig(EGLDisplay display, EGLConfig config) const;
 };
 
 #ifdef EGLFS_PLATFORM_HOOKS

src/plugins/platforms/eglfs/qeglfshooks_stub.cpp

@@ -134,6 +134,11 @@ QSurfaceFormat QEglFSHooks::surfaceFormatFor(const QSurfaceFormat &inputFormat)
     return inputFormat;
 }
 
+bool QEglFSHooks::filterConfig(EGLDisplay, EGLConfig) const
+{
+    return true;
+}
+
 EGLNativeWindowType QEglFSHooks::createNativeWindow(const QSize &size, const QSurfaceFormat &format)
 {
     Q_UNUSED(size);

src/plugins/platforms/eglfs/qeglfsintegration.cpp

@@ -49,6 +49,7 @@
 
 #include <QtPlatformSupport/private/qgenericunixfontdatabase_p.h>
 #include <QtPlatformSupport/private/qgenericunixeventdispatcher_p.h>
+#include <QtPlatformSupport/private/qeglconvenience_p.h>
 #include <QtPlatformSupport/private/qeglplatformcontext_p.h>
 
 #if !defined(QT_NO_EVDEV)
@@ -150,7 +151,7 @@ QPlatformBackingStore *QEglFSIntegration::createPlatformBackingStore(QWindow *wi
 
 QPlatformOpenGLContext *QEglFSIntegration::createPlatformOpenGLContext(QOpenGLContext *context) const
 {
-    return new QEglFSContext(context->format(), 0 /*share*/, mDisplay);
+    return new QEglFSContext(hooks->surfaceFormatFor(context->format()), 0 /*share*/, mDisplay);
 }
 
 QPlatformFontDatabase *QEglFSIntegration::fontDatabase() const
@@ -201,4 +202,29 @@ void *QEglFSIntegration::nativeResourceForContext(const QByteArray &resource, QO
     return 0;
 }
 
+EGLConfig QEglFSIntegration::chooseConfig(EGLDisplay display, const QSurfaceFormat &format)
+{
+    class Chooser : public QEglConfigChooser {
+    public:
+        Chooser(EGLDisplay display, QEglFSHooks *hooks)
+            : QEglConfigChooser(display)
+            , m_hooks(hooks)
+        {
+        }
+
+    protected:
+        bool filterConfig(EGLConfig config) const
+        {
+            return m_hooks->filterConfig(display(), config) && QEglConfigChooser::filterConfig(config);
+        }
+
+    private:
+        QEglFSHooks *m_hooks;
+    };
+
+    Chooser chooser(display, hooks);
+    chooser.setSurfaceFormat(format);
+    return chooser.chooseConfig();
+}
+
 QT_END_NAMESPACE

src/plugins/platforms/eglfs/qeglfsintegration.h

@@ -75,6 +75,8 @@ public:
     void *nativeResourceForIntegration(const QByteArray &resource);
     void *nativeResourceForContext(const QByteArray &resource, QOpenGLContext *context);
 
+    static EGLConfig chooseConfig(EGLDisplay display, const QSurfaceFormat &format);
+
 private:
     EGLDisplay mDisplay;
     QAbstractEventDispatcher *mEventDispatcher;

src/plugins/platforms/eglfs/qeglfswindow.cpp

@@ -84,7 +84,8 @@ void QEglFSWindow::create()
 
     EGLDisplay display = (static_cast<QEglFSScreen *>(window()->screen()->handle()))->display();
     QSurfaceFormat platformFormat = hooks->surfaceFormatFor(window()->requestedFormat());
-    EGLConfig config = q_configFromGLFormat(display, platformFormat);
+    EGLConfig config = QEglFSIntegration::chooseConfig(display, platformFormat);
+
     m_format = q_glFormatFromConfig(display, config);
     m_window = hooks->createNativeWindow(hooks->screenSize(), m_format);
     m_surface = eglCreateWindowSurface(display, config, m_window, NULL);