QMatrix4x4::mapVector() to transform by top-left 3x3

It is useful to be able to map direction vectors by the top-left
3x3 component of a 4x4 matrix, ignoring the translation and
projection components.

Reviewed-by: Sarah Smith

1 files changed, 61 insertions, 0 deletions

diff --git a/tests/auto/qmatrixnxn/tst_qmatrixnxn.cpp b/tests/auto/qmatrixnxn/tst_qmatrixnxn.cpp
index 90db496a90..ff5e00f084 100644
--- a/tests/auto/qmatrixnxn/tst_qmatrixnxn.cpp
+++ b/tests/auto/qmatrixnxn/tst_qmatrixnxn.cpp
@@ -170,6 +170,9 @@ private slots:
     void mapRect_data();
     void mapRect();
 
+    void mapVector_data();
+    void mapVector();
+
     void properties();
     void metaTypes();
 
@@ -3317,6 +3320,64 @@ void tst_QMatrixNxN::mapRect()
     QVERIFY(mri == tri);
 }
 
+void tst_QMatrixNxN::mapVector_data()
+{
+    QTest::addColumn<void *>("mValues");
+
+    QTest::newRow("null")
+        << (void *)nullValues4;
+
+    QTest::newRow("identity")
+        << (void *)identityValues4;
+
+    QTest::newRow("unique")
+        << (void *)uniqueValues4;
+
+    static const qreal scale[] =
+        {2.0f, 0.0f, 0.0f, 0.0f,
+         0.0f, 11.0f, 0.0f, 0.0f,
+         0.0f, 0.0f, -6.5f, 0.0f,
+         0.0f, 0.0f, 0.0f, 1.0f};
+    QTest::newRow("scale")
+        << (void *)scale;
+
+    static const qreal scaleTranslate[] =
+        {2.0f, 0.0f, 0.0f, 1.0f,
+         0.0f, 11.0f, 0.0f, 2.0f,
+         0.0f, 0.0f, -6.5f, 3.0f,
+         0.0f, 0.0f, 0.0f, 1.0f};
+    QTest::newRow("scaleTranslate")
+        << (void *)scaleTranslate;
+
+    static const qreal translate[] =
+        {1.0f, 0.0f, 0.0f, 1.0f,
+         0.0f, 1.0f, 0.0f, 2.0f,
+         0.0f, 0.0f, 1.0f, 3.0f,
+         0.0f, 0.0f, 0.0f, 1.0f};
+    QTest::newRow("translate")
+        << (void *)translate;
+}
+void tst_QMatrixNxN::mapVector()
+{
+    QFETCH(void *, mValues);
+
+    QMatrix4x4 m1((const qreal *)mValues);
+    m1.inferSpecialType();
+
+    QVector3D v(3.5f, -1.0f, 2.5f);
+
+    QVector3D expected
+        (v.x() * m1(0, 0) + v.y() * m1(0, 1) + v.z() * m1(0, 2),
+         v.x() * m1(1, 0) + v.y() * m1(1, 1) + v.z() * m1(1, 2),
+         v.x() * m1(2, 0) + v.y() * m1(2, 1) + v.z() * m1(2, 2));
+
+    QVector3D actual = m1.mapVector(v);
+
+    QVERIFY(fuzzyCompare(actual.x(), expected.x()));
+    QVERIFY(fuzzyCompare(actual.y(), expected.y()));
+    QVERIFY(fuzzyCompare(actual.z(), expected.z()));
+}
+
 class tst_QMatrixNxN4x4Properties : public QObject
 {
     Q_OBJECT