Add distance field rendering to OpenGL runtime

The old text rendering remains in the background and is used to render
clipped text, since that feature is not yet implemented for distance
field fonts. Building the runtime with Qt version older than 5.12.2 also
causes a fallback to the old text rendering.

Depth pass rendering also needs to be redone in the future to avoid
another full render pass.

Task-number: QT3DS-3210
Change-Id: Ib7666c437d23ae25e1872682f010df3721476a14
Reviewed-by: Tomi Korpipää <tomi.korpipaa@qt.io>

1 files changed, 75 insertions, 0 deletions

diff --git a/src/Runtime/Source/runtimerender/Qt3DSDistanceFieldGlyphCacheManager.cpp b/src/Runtime/Source/runtimerender/Qt3DSDistanceFieldGlyphCacheManager.cpp
new file mode 100644
index 00000000..750301dc
--- /dev/null
+++ b/src/Runtime/Source/runtimerender/Qt3DSDistanceFieldGlyphCacheManager.cpp
@@ -0,0 +1,75 @@
+/****************************************************************************
+**
+** Copyright (C) 2019 The Qt Company Ltd.
+** Contact: http://www.qt.io/licensing/
+**
+** This file is part of Qt 3D Studio.
+**
+** $QT_BEGIN_LICENSE:GPL$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3 or (at your option) any later version
+** approved by the KDE Free Qt Foundation. The licenses are as published by
+** the Free Software Foundation and appearing in the file LICENSE.GPL3
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "Qt3DSDistanceFieldGlyphCacheManager_p.h"
+#include "Qt3DSDistanceFieldGlyphCache_p.h"
+
+#include <QtQuick/private/qsgdefaultrendercontext_p.h>
+
+#if QT_VERSION >= QT_VERSION_CHECK(5,12,2)
+
+QT_BEGIN_NAMESPACE
+
+namespace {
+    class FontKeyAccessor : public QSGDefaultRenderContext
+    {
+    public:
+        static QString fontKey(const QRawFont &font)
+        {
+            return QSGDefaultRenderContext::fontKey(font);
+        }
+    };
+}
+
+Q3DSDistanceFieldGlyphCacheManager::~Q3DSDistanceFieldGlyphCacheManager()
+{
+    for (auto &cache : qAsConst(m_glyphCaches))
+        delete cache;
+}
+
+Q3DSDistanceFieldGlyphCache *Q3DSDistanceFieldGlyphCacheManager::glyphCache(const QRawFont &font)
+{
+    QString key = FontKeyAccessor::fontKey(font);
+    Q3DSDistanceFieldGlyphCache *cache = m_glyphCaches.value(key);
+    if (cache == nullptr) {
+        cache = new Q3DSDistanceFieldGlyphCache(font, *m_context);
+        m_glyphCaches.insert(key, cache);
+    }
+
+    return cache;
+}
+
+void Q3DSDistanceFieldGlyphCacheManager::setContext(qt3ds::render::IQt3DSRenderContext &context)
+{
+    m_context = &context;
+}
+
+QT_END_NAMESPACE
+
+#endif // QT_VERSION >= QT_VERSION_CHECK(5,12,2)