MathUtils: Add exponential interpolation

Change-Id: I58bb26a6e921cbd1f5532bddcd6a6700ff80b94f
Reviewed-by: Eike Ziller <eike.ziller@qt.io>

1 files changed, 27 insertions, 0 deletions

diff --git a/tests/auto/utils/mathutils/tst_mathutils.cpp b/tests/auto/utils/mathutils/tst_mathutils.cpp
index 30d2d8d6c59..a585868d994 100644
--- a/tests/auto/utils/mathutils/tst_mathutils.cpp
+++ b/tests/auto/utils/mathutils/tst_mathutils.cpp
@@ -16,6 +16,8 @@ private slots:
     void interpolateLinear();
     void interpolateTangential_data();
     void interpolateTangential();
+    void interpolateExponential_data();
+    void interpolateExponential();
 };
 
 void tst_MathUtils::interpolateLinear_data()
@@ -72,6 +74,31 @@ void tst_MathUtils::interpolateTangential()
     QCOMPARE(y, result);
 }
 
+void tst_MathUtils::interpolateExponential_data()
+{
+    QTest::addColumn<int>("x");
+    QTest::addColumn<int>("xHalfLife");
+    QTest::addColumn<int>("y1");
+    QTest::addColumn<int>("y2");
+    QTest::addColumn<int>("result");
+
+    QTest::newRow("zero") << 0 << 8 << 10 << 20 << 10;
+    QTest::newRow("halfLife") << 8 << 8 << 10 << 20 << 15;
+    QTest::newRow("approxInfinity") << 1000 << 8 << 10 << 20 << 20;
+}
+
+void tst_MathUtils::interpolateExponential()
+{
+    QFETCH(int, x);
+    QFETCH(int, xHalfLife);
+    QFETCH(int, y1);
+    QFETCH(int, y2);
+    QFETCH(int, result);
+
+    const int y = MathUtils::interpolateExponential(x, xHalfLife, y1, y2);
+    QCOMPARE(y, result);
+}
+
 QTEST_GUILESS_MAIN(tst_MathUtils)
 
 #include "tst_mathutils.moc"