QtPlatformSupport: A helper library for platform plugins

QtPlatformSupport is a static library. Platform plugins are meant to
link against this library to pull in dependencies such as fontengines
and convenience functions for finding the right GL configs. The linker
will only pull in the symbols used, so the size of the library doesn't
really matter

1 files changed, 184 insertions, 0 deletions

diff --git a/src/platformsupport/eglconvenience/qxlibeglintegration.cpp b/src/platformsupport/eglconvenience/qxlibeglintegration.cpp
new file mode 100644
index 0000000000..aeebd35d21
--- /dev/null
+++ b/src/platformsupport/eglconvenience/qxlibeglintegration.cpp
@@ -0,0 +1,184 @@
+/****************************************************************************
+**
+** Copyright (C) 2011 Nokia Corporation and/or its subsidiary(-ies).
+** All rights reserved.
+** Contact: Nokia Corporation (qt-info@nokia.com)
+**
+** This file is part of the plugins of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** GNU Lesser General Public License Usage
+** This file may be used under the terms of the GNU Lesser General Public
+** License version 2.1 as published by the Free Software Foundation and
+** appearing in the file LICENSE.LGPL included in the packaging of this
+** file. Please review the following information to ensure the GNU Lesser
+** General Public License version 2.1 requirements will be met:
+** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Nokia gives you certain additional
+** rights. These rights are described in the Nokia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU General
+** Public License version 3.0 as published by the Free Software Foundation
+** and appearing in the file LICENSE.GPL included in the packaging of this
+** file. Please review the following information to ensure the GNU General
+** Public License version 3.0 requirements will be met:
+** http://www.gnu.org/copyleft/gpl.html.
+**
+** Other Usage
+** Alternatively, this file may be used in accordance with the terms and
+** conditions contained in a signed written agreement between you and Nokia.
+**
+**
+**
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "qxlibeglintegration_p.h"
+
+static int countBits(unsigned long mask)
+{
+    int count = 0;
+    while (mask != 0) {
+        if (mask & 1)
+            ++count;
+        mask >>= 1;
+    }
+    return count;
+}
+
+VisualID QXlibEglIntegration::getCompatibleVisualId(Display *display, EGLDisplay eglDisplay, EGLConfig config)
+{
+    VisualID    visualId = 0;
+    EGLint      eglValue = 0;
+
+    EGLint configRedSize = 0;
+    eglGetConfigAttrib(eglDisplay, config, EGL_RED_SIZE, &configRedSize);
+
+    EGLint configGreenSize = 0;
+    eglGetConfigAttrib(eglDisplay, config, EGL_GREEN_SIZE, &configGreenSize);
+
+    EGLint configBlueSize = 0;
+    eglGetConfigAttrib(eglDisplay, config, EGL_BLUE_SIZE, &configBlueSize);
+
+    EGLint configAlphaSize = 0;
+    eglGetConfigAttrib(eglDisplay, config, EGL_ALPHA_SIZE, &configAlphaSize);
+
+    eglGetConfigAttrib(eglDisplay, config, EGL_CONFIG_ID, &eglValue);
+    int configId = eglValue;
+
+    // See if EGL provided a valid VisualID:
+    eglGetConfigAttrib(eglDisplay, config, EGL_NATIVE_VISUAL_ID, &eglValue);
+    visualId = (VisualID)eglValue;
+    if (visualId) {
+        // EGL has suggested a visual id, so get the rest of the visual info for that id:
+        XVisualInfo visualInfoTemplate;
+        memset(&visualInfoTemplate, 0, sizeof(XVisualInfo));
+        visualInfoTemplate.visualid = visualId;
+
+        XVisualInfo *chosenVisualInfo;
+        int matchingCount = 0;
+        chosenVisualInfo = XGetVisualInfo(display, VisualIDMask, &visualInfoTemplate, &matchingCount);
+        if (chosenVisualInfo) {
+            // Skip size checks if implementation supports non-matching visual
+            // and config (http://bugreports.qt.nokia.com/browse/QTBUG-9444).
+            if (q_hasEglExtension(eglDisplay,"EGL_NV_post_convert_rounding")) {
+                XFree(chosenVisualInfo);
+                return visualId;
+            }
+
+            int visualRedSize = countBits(chosenVisualInfo->red_mask);
+            int visualGreenSize = countBits(chosenVisualInfo->green_mask);
+            int visualBlueSize = countBits(chosenVisualInfo->blue_mask);
+            int visualAlphaSize = -1; // Need XRender to tell us the alpha channel size
+
+            bool visualMatchesConfig = false;
+            if ( visualRedSize == configRedSize &&
+                 visualGreenSize == configGreenSize &&
+                 visualBlueSize == configBlueSize )
+            {
+                // We need XRender to check the alpha channel size of the visual. If we don't have
+                // the alpha size, we don't check it against the EGL config's alpha size.
+                if (visualAlphaSize >= 0)
+                    visualMatchesConfig = visualAlphaSize == configAlphaSize;
+                else
+                    visualMatchesConfig = true;
+            }
+
+            if (!visualMatchesConfig) {
+                if (visualAlphaSize >= 0) {
+                    qWarning("Warning: EGL suggested using X Visual ID %d (ARGB%d%d%d%d) for EGL config %d (ARGB%d%d%d%d), but this is incompatable",
+                             (int)visualId, visualAlphaSize, visualRedSize, visualGreenSize, visualBlueSize,
+                             configId, configAlphaSize, configRedSize, configGreenSize, configBlueSize);
+                } else {
+                    qWarning("Warning: EGL suggested using X Visual ID %d (RGB%d%d%d) for EGL config %d (RGB%d%d%d), but this is incompatable",
+                             (int)visualId, visualRedSize, visualGreenSize, visualBlueSize,
+                             configId, configRedSize, configGreenSize, configBlueSize);
+                }
+                visualId = 0;
+            }
+        } else {
+            qWarning("Warning: EGL suggested using X Visual ID %d for EGL config %d, but that isn't a valid ID",
+                     (int)visualId, configId);
+            visualId = 0;
+        }
+        XFree(chosenVisualInfo);
+    }
+#ifdef QT_DEBUG_X11_VISUAL_SELECTION
+    else
+        qDebug("EGL did not suggest a VisualID (EGL_NATIVE_VISUAL_ID was zero) for EGLConfig %d", configId);
+#endif
+
+    if (visualId) {
+#ifdef QT_DEBUG_X11_VISUAL_SELECTION
+        if (configAlphaSize > 0)
+            qDebug("Using ARGB Visual ID %d provided by EGL for config %d", (int)visualId, configId);
+        else
+            qDebug("Using Opaque Visual ID %d provided by EGL for config %d", (int)visualId, configId);
+#endif
+        return visualId;
+    }
+
+    // Finally, try to
+    // use XGetVisualInfo and only use the bit depths to match on:
+    if (!visualId) {
+        XVisualInfo visualInfoTemplate;
+        memset(&visualInfoTemplate, 0, sizeof(XVisualInfo));
+        XVisualInfo *matchingVisuals;
+        int matchingCount = 0;
+
+        visualInfoTemplate.depth = configRedSize + configGreenSize + configBlueSize + configAlphaSize;
+        matchingVisuals = XGetVisualInfo(display,
+                                         VisualDepthMask,
+                                         &visualInfoTemplate,
+                                         &matchingCount);
+        if (!matchingVisuals) {
+            // Try again without taking the alpha channel into account:
+            visualInfoTemplate.depth = configRedSize + configGreenSize + configBlueSize;
+            matchingVisuals = XGetVisualInfo(display,
+                                             VisualDepthMask,
+                                             &visualInfoTemplate,
+                                             &matchingCount);
+        }
+
+        if (matchingVisuals) {
+            visualId = matchingVisuals[0].visualid;
+            XFree(matchingVisuals);
+        }
+    }
+
+    if (visualId) {
+#ifdef QT_DEBUG_X11_VISUAL_SELECTION
+        qDebug("Using Visual ID %d provided by XGetVisualInfo for EGL config %d", (int)visualId, configId);
+#endif
+        return visualId;
+    }
+
+    qWarning("Unable to find an X11 visual which matches EGL config %d", configId);
+    return (VisualID)0;
+}