Fixes Unreal Engine view angle matrix order

The view angle rotation matrix order in Unreal Engine was incorrect, leading to incorrect camera orientation.

This commit fixes the order of rotation matrices to roll, pitch, yaw
to correctly implement Unreal Engine camera rotations.

Adds comprehensive unit tests for Unreal Engine formulas, camera and constants.

Marks Unreal Engine as supported in README.md.

.idea/codeStyles/Project.xml

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.idea/codeStyles/codeStyleConfig.xml

@@ -1,5 +1,6 @@
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   <state>
     <option name="USE_PER_PROJECT_SETTINGS" value="true" />
+    <option name="PREFERRED_PROJECT_CODE_STYLE" value="Default" />
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README.md

@@ -42,7 +42,8 @@ Oranges's Math Library (omath) is a comprehensive, open-source library aimed at
 | Source   | ✅YES    |
 | Unity    | ✅YES    |
 | IWEngine | ✅YES    |
-| Unreal   | ❌NO     |
+| OpenGL   | ✅YES    |
+| Unreal   | ✅YES    |
 
 ## Supported Operating Systems
 

source/engines/unreal_engine/formulas.cpp

@@ -30,9 +30,9 @@ namespace omath::unreal_engine
     }
     Mat4X4 rotation_matrix(const ViewAngles& angles) noexcept
     {
-        return mat_rotation_axis_x<float, MatStoreType::ROW_MAJOR>(angles.pitch)
+        return mat_rotation_axis_x<float, MatStoreType::ROW_MAJOR>(angles.roll)
-               * mat_rotation_axis_y<float, MatStoreType::ROW_MAJOR>(angles.yaw)
+               * mat_rotation_axis_y<float, MatStoreType::ROW_MAJOR>(angles.pitch)
-               * mat_rotation_axis_z<float, MatStoreType::ROW_MAJOR>(angles.roll);
+               * mat_rotation_axis_z<float, MatStoreType::ROW_MAJOR>(angles.yaw);
     }
     Mat4X4 calc_perspective_projection_matrix(const float field_of_view, const float aspect_ratio, const float near,
                                               const float far) noexcept

tests/engines/unit_test_unreal_engine.cpp

@@ -1,3 +1,108 @@
 //
 // Created by Vlad on 8/25/2025.
 //
+//
+// Created by Orange on 11/27/2024.
+//
+#include <gtest/gtest.h>
+#include <omath/engines/unreal_engine/camera.hpp>
+#include <omath/engines/unreal_engine/constants.hpp>
+#include <omath/engines/unreal_engine/formulas.hpp>
+#include <print>
+
+TEST(unit_test_unreal_engine, ForwardVector)
+{
+    const auto forward = omath::unreal_engine::forward_vector({});
+
+    EXPECT_EQ(forward, omath::unreal_engine::k_abs_forward);
+}
+
+TEST(unit_test_unreal_engine, ForwardVectorRotationYaw)
+{
+    omath::unreal_engine::ViewAngles angles;
+
+    angles.yaw = omath::unreal_engine::YawAngle::from_degrees(90.f);
+
+    const auto forward = omath::unreal_engine::forward_vector(angles);
+    EXPECT_NEAR(forward.x, omath::unreal_engine::k_abs_right.x, 0.00001f);
+    EXPECT_NEAR(forward.y, omath::unreal_engine::k_abs_right.y, 0.00001f);
+    EXPECT_NEAR(forward.z, omath::unreal_engine::k_abs_right.z, 0.00001f);
+}
+
+TEST(unit_test_unreal_engine, ForwardVectorRotationPitch)
+{
+    omath::unreal_engine::ViewAngles angles;
+
+    angles.pitch = omath::unreal_engine::PitchAngle::from_degrees(-90.f);
+
+    const auto forward = omath::unreal_engine::forward_vector(angles);
+    EXPECT_NEAR(forward.x, omath::unreal_engine::k_abs_up.x, 0.00001f);
+    EXPECT_NEAR(forward.y, omath::unreal_engine::k_abs_up.y, 0.00001f);
+    EXPECT_NEAR(forward.z, omath::unreal_engine::k_abs_up.z, 0.00001f);
+}
+
+TEST(unit_test_unreal_engine, ForwardVectorRotationRoll)
+{
+    omath::unreal_engine::ViewAngles angles;
+
+    angles.roll = omath::unreal_engine::RollAngle::from_degrees(-90.f);
+
+    const auto forward = omath::unreal_engine::up_vector(angles);
+    EXPECT_NEAR(forward.x, omath::unreal_engine::k_abs_right.x, 0.00001f);
+    EXPECT_NEAR(forward.y, omath::unreal_engine::k_abs_right.y, 0.00001f);
+    EXPECT_NEAR(forward.z, omath::unreal_engine::k_abs_right.z, 0.00001f);
+}
+
+TEST(unit_test_unreal_engine, RightVector)
+{
+    const auto right = omath::unreal_engine::right_vector({});
+
+    EXPECT_EQ(right, omath::unreal_engine::k_abs_right);
+}
+
+TEST(unit_test_unreal_engine, UpVector)
+{
+    const auto up = omath::unreal_engine::up_vector({});
+    EXPECT_EQ(up, omath::unreal_engine::k_abs_up);
+}
+
+TEST(unit_test_unreal_engine, ProjectTargetMovedFromCamera)
+{
+    constexpr auto fov = omath::projection::FieldOfView::from_degrees(60.f);
+    const auto cam = omath::unreal_engine::Camera({0, 0, 0}, {}, {1280.f, 720.f}, fov, 0.01f, 1000.f);
+
+
+    for (float distance = 0.02f; distance < 100.f; distance += 0.01f)
+    {
+        const auto projected = cam.world_to_screen({distance, 0, 0});
+
+        EXPECT_TRUE(projected.has_value());
+
+        if (!projected.has_value())
+            continue;
+
+        EXPECT_NEAR(projected->x, 640, 0.00001f);
+        EXPECT_NEAR(projected->y, 360, 0.00001f);
+    }
+}
+
+TEST(unit_test_unreal_engine, CameraSetAndGetFov)
+{
+    constexpr auto fov = omath::projection::FieldOfView::from_degrees(90.f);
+    auto cam = omath::unreal_engine::Camera({0, 0, 0}, {}, {1920.f, 1080.f}, fov, 0.01f, 1000.f);
+
+    EXPECT_EQ(cam.get_field_of_view().as_degrees(), 90.f);
+    cam.set_field_of_view(omath::projection::FieldOfView::from_degrees(50.f));
+
+    EXPECT_EQ(cam.get_field_of_view().as_degrees(), 50.f);
+}
+
+TEST(unit_test_unreal_engine, CameraSetAndGetOrigin)
+{
+    auto cam = omath::unreal_engine::Camera({0, 0, 0}, {}, {1920.f, 1080.f}, {}, 0.01f, 1000.f);
+
+    EXPECT_EQ(cam.get_origin(), omath::Vector3<float>{});
+    cam.set_field_of_view(omath::projection::FieldOfView::from_degrees(50.f));
+
+    EXPECT_EQ(cam.get_field_of_view().as_degrees(), 50.f);
+}