feat(omath): Add NDC to screen position coordinate diagram

Increments the project version number in CMakeLists.txt
from 3.0.4.1 to 3.2.1, indicating a release or significant
changes in the project.

CMakeLists.txt

@@ -1,6 +1,6 @@
 cmake_minimum_required(VERSION 3.26)
 
-project(omath VERSION 3.0.4.1 LANGUAGES CXX)
+project(omath VERSION 3.2.1 LANGUAGES CXX)
 
 include(CMakePackageConfigHelpers)
 

include/omath/projectile_prediction/proj_pred_engine_legacy.hpp

@@ -13,7 +13,32 @@
 
 namespace omath::projectile_prediction
 {
+    template<class T>
+    concept PredEngineConcept =
+            requires(const Projectile& projectile, const Target& target, const Vector3<float>& vec_a,
+                     const Vector3<float>& vec_b,
+                     Vector3<float> v3, // by-value for calc_viewpoint_from_angles
+                     float pitch, float yaw, float time, float gravity, std::optional<float> maybe_pitch) {
+                // Presence + return types
+                { T::predict_projectile_position(projectile, pitch, yaw, time, gravity) } -> std::same_as<Vec3>;
+                { T::predict_target_position(target, time, gravity) } -> std::same_as<Vec3>;
+                { T::calc_vector_2d_distance(vec_a) } -> std::same_as<float>;
+                { T::get_vector_height_coordinate(vec_b) } -> std::same_as<float>;
+                { T::calc_viewpoint_from_angles(projectile, v3, maybe_pitch) } -> std::same_as<Vec3>;
+                { T::calc_direct_pitch_angle(vec_a, vec_b) } -> std::same_as<float>;
+                { T::calc_direct_yaw_angle(vec_a, vec_b) } -> std::same_as<float>;
+
+                // Enforce noexcept as in PredEngineTrait
+                requires noexcept(T::predict_projectile_position(projectile, pitch, yaw, time, gravity));
+                requires noexcept(T::predict_target_position(target, time, gravity));
+                requires noexcept(T::calc_vector_2d_distance(vec_a));
+                requires noexcept(T::get_vector_height_coordinate(vec_b));
+                requires noexcept(T::calc_viewpoint_from_angles(projectile, v3, maybe_pitch));
+                requires noexcept(T::calc_direct_pitch_angle(vec_a, vec_b));
+                requires noexcept(T::calc_direct_yaw_angle(vec_a, vec_b));
+            };
     template<class EngineTrait = source_engine::PredEngineTrait>
+    requires PredEngineConcept<EngineTrait>
     class ProjPredEngineLegacy final : public ProjPredEngineInterface
     {
     public:

include/omath/projection/camera.hpp

@@ -26,7 +26,23 @@ namespace omath::projection
     };
     using FieldOfView = Angle<float, 0.f, 180.f, AngleFlags::Clamped>;
 
+    template<class T, class MatType, class ViewAnglesType>
+    concept CameraEngineConcept =
+            requires(const Vector3<float>& cam_origin, const Vector3<float>& look_at, const ViewAnglesType& angles,
+                     const FieldOfView& fov, const ViewPort& viewport, float znear, float zfar) {
+                // Presence + return types
+                { T::calc_look_at_angle(cam_origin, look_at) } -> std::same_as<ViewAnglesType>;
+                { T::calc_view_matrix(angles, cam_origin) } -> std::same_as<MatType>;
+                { T::calc_projection_matrix(fov, viewport, znear, zfar) } -> std::same_as<MatType>;
+
+                // Enforce noexcept as in the trait declaration
+                requires noexcept(T::calc_look_at_angle(cam_origin, look_at));
+                requires noexcept(T::calc_view_matrix(angles, cam_origin));
+                requires noexcept(T::calc_projection_matrix(fov, viewport, znear, zfar));
+            };
+
     template<class Mat4X4Type, class ViewAnglesType, class TraitClass>
+    requires CameraEngineConcept<TraitClass, Mat4X4Type, ViewAnglesType>
     class Camera final
     {
     public:
@@ -170,6 +186,18 @@ namespace omath::projection
 
         [[nodiscard]] Vector3<float> ndc_to_screen_position(const Vector3<float>& ndc) const noexcept
         {
+/*
+                    ^
+                    |        y
+                1   |
+                    |
+                    |
+        -1 ---------0--------- 1  --> x
+                    |
+                    |
+               -1   |
+                    v
+*/
             return {(ndc.x + 1.f) / 2.f * m_view_port.m_width, (1.f - ndc.y) / 2.f * m_view_port.m_height, ndc.z};
         }
     };