1 files changed, 119 insertions, 0 deletions
diff --git a/source/blender/blenlib/tests/BLI_float3x3_test.cc b/source/blender/blenlib/tests/BLI_float3x3_test.cc
new file mode 100644
index 00000000000..d22993ee69e
--- /dev/null
+++ b/source/blender/blenlib/tests/BLI_float3x3_test.cc
@@ -0,0 +1,119 @@
+/* SPDX-License-Identifier: Apache-2.0 */
+
+#include "testing/testing.h"
+
+#include "BLI_float3x3.hh"
+#include "BLI_math_base.h"
+#include "BLI_math_vec_types.hh"
+
+namespace blender::tests {
+
+TEST(float3x3, Identity)
+{
+  float2 point(1.0f, 2.0f);
+  float3x3 transformation = float3x3::identity();
+  float2 result = transformation * point;
+  EXPECT_EQ(result, point);
+}
+
+TEST(float3x3, Translation)
+{
+  float2 point(1.0f, 2.0f);
+  float3x3 transformation = float3x3::from_translation(float2(5.0f, 3.0f));
+  float2 result = transformation * point;
+  EXPECT_FLOAT_EQ(result[0], 6.0f);
+  EXPECT_FLOAT_EQ(result[1], 5.0f);
+}
+
+TEST(float3x3, Rotation)
+{
+  float2 point(1.0f, 2.0f);
+  float3x3 transformation = float3x3::from_rotation(M_PI_2);
+  float2 result = transformation * point;
+  EXPECT_FLOAT_EQ(result[0], -2.0f);
+  EXPECT_FLOAT_EQ(result[1], 1.0f);
+}
+
+TEST(float3x3, TranslationRotationScale)
+{
+  float2 point(1.0f, 2.0f);
+  float3x3 transformation = float3x3::from_translation_rotation_scale(
+      float2(1.0f, 3.0f), M_PI_2, float2(2.0f, 3.0f));
+  float2 result = transformation * point;
+  EXPECT_FLOAT_EQ(result[0], -5.0f);
+  EXPECT_FLOAT_EQ(result[1], 5.0f);
+}
+
+TEST(float3x3, NormalizedAxes)
+{
+  float2 point(1.0f, 2.0f);
+
+  /* The horizontal is aligned with (1, 1) and vertical is aligned with (-1, 1), in other words, a
+   * Pi / 4 rotation. */
+  float value = std::sqrt(2.0f) / 2.0f;
+  float3x3 transformation = float3x3::from_normalized_axes(
+      float2(1.0f, 3.0f), float2(value), float2(-value, value));
+  float2 result = transformation * point;
+
+  float3x3 expected_transformation = float3x3::from_translation_rotation_scale(
+      float2(1.0f, 3.0f), M_PI_4, float2(1.0f));
+  float2 expected = expected_transformation * point;
+
+  EXPECT_FLOAT_EQ(result[0], expected[0]);
+  EXPECT_FLOAT_EQ(result[1], expected[1]);
+}
+
+TEST(float3x3, PostTransformationMultiplication)
+{
+  float2 point(1.0f, 2.0f);
+  float3x3 translation = float3x3::from_translation(float2(5.0f, 3.0f));
+  float3x3 rotation = float3x3::from_rotation(M_PI_2);
+  float3x3 transformation = translation * rotation;
+  float2 result = transformation * point;
+  EXPECT_FLOAT_EQ(result[0], 3.0f);
+  EXPECT_FLOAT_EQ(result[1], 4.0f);
+}
+
+TEST(float3x3, PreTransformationMultiplication)
+{
+  float2 point(1.0f, 2.0f);
+  float3x3 translation = float3x3::from_translation(float2(5.0f, 3.0f));
+  float3x3 rotation = float3x3::from_rotation(M_PI_2);
+  float3x3 transformation = rotation * translation;
+  float2 result = transformation * point;
+  EXPECT_FLOAT_EQ(result[0], -5.0f);
+  EXPECT_FLOAT_EQ(result[1], 6.0f);
+}
+
+TEST(float3x3, TransformationMultiplicationAssignment)
+{
+  float2 point(1.0f, 2.0f);
+  float3x3 transformation = float3x3::from_translation(float2(5.0f, 3.0f));
+  transformation *= float3x3::from_rotation(M_PI_2);
+  float2 result = transformation * point;
+  EXPECT_FLOAT_EQ(result[0], 3.0f);
+  EXPECT_FLOAT_EQ(result[1], 4.0f);
+}
+
+TEST(float3x3, Inverted)
+{
+  float2 point(1.0f, 2.0f);
+  float3x3 transformation = float3x3::from_translation_rotation_scale(
+      float2(1.0f, 3.0f), M_PI_4, float2(1.0f));
+  transformation *= transformation.inverted();
+  float2 result = transformation * point;
+  EXPECT_FLOAT_EQ(result[0], 1.0f);
+  EXPECT_FLOAT_EQ(result[1], 2.0f);
+}
+
+TEST(float3x3, Origin)
+{
+  float2 point(1.0f, 2.0f);
+  float3x3 rotation = float3x3::from_rotation(M_PI_2);
+  float3x3 transformation = float3x3::from_origin_transformation(rotation, float2(0.0f, 2.0f));
+  float2 result = transformation * point;
+  EXPECT_FLOAT_EQ(result[0], 0.0f);
+  EXPECT_FLOAT_EQ(result[1], 3.0f);
+}
+
+}  // namespace blender::tests