Implement FCurve evaluation

Uses a couple of helper classes to do the tricky mathematics.

Change-Id: I3245c0e282a5eeede3d596ca99ac2c78e34f23ef
Reviewed-by: Sean Harmer <sean.harmer@kdab.com>

1 files changed, 83 insertions, 0 deletions

diff --git a/src/animation/backend/fcurve.cpp b/src/animation/backend/fcurve.cpp
new file mode 100644
index 000000000..95e3d1568
--- /dev/null
+++ b/src/animation/backend/fcurve.cpp
@@ -0,0 +1,83 @@
+/****************************************************************************
+**
+** Copyright (C) 2017 Klaralvdalens Datakonsult AB (KDAB).
+** Contact: http://www.qt-project.org/legal
+**
+** This file is part of the Qt3D module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL3$
+** Commercial License Usage
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+** and conditions see http://www.qt.io/terms-conditions. For further
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+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPLv3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or later 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 2.0 requirements will be
+** met: http://www.gnu.org/licenses/gpl-2.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "fcurve_p.h"
+#include <private/bezierevaluator_p.h>
+
+QT_BEGIN_NAMESPACE
+
+namespace Qt3DAnimation {
+namespace Animation {
+
+FCurve::FCurve()
+    : m_rangeFinder(m_localTimes)
+{
+}
+
+float FCurve::evaluateAtTime(float localTime) const
+{
+    // Find keyframes that sandwich the requested localTime
+    int keyframe0 = m_rangeFinder.findLowerBound(localTime);
+
+    BezierEvaluator evaluator(m_localTimes[keyframe0], m_keyframes[keyframe0],
+                              m_localTimes[keyframe0 + 1], m_keyframes[keyframe0 + 1]);
+    return evaluator.valueForTime(localTime);
+}
+
+float FCurve::startTime() const
+{
+    if (!m_localTimes.isEmpty())
+        return m_localTimes.first();
+    return 0.0f;
+}
+
+float FCurve::endTime() const
+{
+    if (!m_localTimes.isEmpty())
+        return m_localTimes.last();
+    return 0.0f;
+}
+
+void FCurve::appendKeyframe(float localTime, const Keyframe &keyframe)
+{
+    m_localTimes.append(localTime);
+    m_keyframes.append(keyframe);
+}
+
+} // namespace Animation
+} // namespace Qt3DAnimation
+
+QT_END_NAMESPACE