From 695a8035b5ff54e750f0aca4002384f34cba1fd8 Mon Sep 17 00:00:00 2001
From: Orange <orange-cpp@yandex.ru>
Date: Wed, 6 Aug 2025 05:45:37 +0300
Subject: [PATCH] Adds engine traits for projectile prediction

Implements engine-specific traits for projectile and target position prediction.
Each trait encapsulates logic tailored to a specific game engine (IW, OpenGL, Unity),
accounting for engine-specific coordinate systems and calculations.
This allows for accurate projectile prediction across different game environments.
---
 .../engine_traits/iw_engine_trait.hpp         | 80 +++++++++++++++++++
 .../engine_traits/opengl_engine_trait.hpp     | 79 ++++++++++++++++++
 .../engine_traits/unity_engine_trait.hpp      | 79 ++++++++++++++++++
 3 files changed, 238 insertions(+)
 create mode 100644 include/omath/projectile_prediction/engine_traits/iw_engine_trait.hpp
 create mode 100644 include/omath/projectile_prediction/engine_traits/opengl_engine_trait.hpp
 create mode 100644 include/omath/projectile_prediction/engine_traits/unity_engine_trait.hpp

diff --git a/include/omath/projectile_prediction/engine_traits/iw_engine_trait.hpp b/include/omath/projectile_prediction/engine_traits/iw_engine_trait.hpp
new file mode 100644
index 0000000..0361e3b
--- /dev/null
+++ b/include/omath/projectile_prediction/engine_traits/iw_engine_trait.hpp
@@ -0,0 +1,80 @@
+//
+// Created by Vlad on 8/6/2025.
+//
+#pragma once
+
+#include "omath/engines/iw_engine/formulas.hpp"
+#include "omath/projectile_prediction/projectile.hpp"
+#include "omath/projectile_prediction/target.hpp"
+#include <optional>
+
+namespace omath::projectile_prediction::traits
+{
+    class IwEngineTrait final
+    {
+    public:
+        constexpr static Vector3<float> predict_projectile_position(const Projectile& projectile, const float pitch,
+                                                                    const float yaw, const float time,
+                                                                    const float gravity) noexcept
+        {
+            auto current_pos = projectile.m_origin
+                               + iw_engine::forward_vector({iw_engine::PitchAngle::from_degrees(-pitch),
+                                                            iw_engine::YawAngle::from_degrees(yaw),
+                                                            iw_engine::RollAngle::from_degrees(0)})
+                                         * projectile.m_launch_speed * time;
+            current_pos.z -= (gravity * projectile.m_gravity_scale) * (time * time) * 0.5f;
+
+            return current_pos;
+        }
+        [[nodiscard]]
+        static constexpr Vector3<float> predict_target_position(const Target& target, const float time,
+                                                                const float gravity) noexcept
+        {
+            auto predicted = target.m_origin + target.m_velocity * time;
+
+            if (target.m_is_airborne)
+                predicted.z -= gravity * (time * time) * 0.5f;
+
+            return predicted;
+        }
+        [[nodiscard]]
+        static float calc_vector_2d_distance(const Vector3<float>& delta) noexcept
+        {
+            return std::sqrt(delta.x * delta.x + delta.y * delta.y);
+        }
+
+        [[nodiscard]]
+        constexpr static float get_vector_height_coordinate(const Vector3<float>& vec) noexcept
+        {
+            return vec.z;
+        }
+
+        [[nodiscard]]
+        static Vector3<float> calc_viewpoint_from_angles(const Projectile& projectile,
+                                                         Vector3<float> predicted_target_position,
+                                                         const std::optional<float> projectile_pitch) noexcept
+        {
+            const auto delta2d = calc_vector_2d_distance(predicted_target_position - projectile.m_origin);
+            const auto height = delta2d * std::tan(angles::degrees_to_radians(projectile_pitch.value()));
+
+            return {predicted_target_position.x, predicted_target_position.y, projectile.m_origin.z + height};
+        }
+        // Due to specification of maybe_calculate_projectile_launch_pitch_angle, pitch angle must be:
+        // 89 look up, -89 look down
+        [[nodiscard]]
+        static float calc_direct_pitch_angle(const Vector3<float>& origin, const Vector3<float>& view_to) noexcept
+        {
+            const auto distance = origin.distance_to(view_to);
+            const auto delta = view_to - origin;
+
+            return angles::radians_to_degrees(std::asin(delta.z / distance));
+        }
+        [[nodiscard]]
+        static float calc_direct_yaw_angle(const Vector3<float>& origin, const Vector3<float>& view_to) noexcept
+        {
+            const auto delta = view_to - origin;
+
+            return angles::radians_to_degrees(std::atan2(delta.y, delta.x));
+        };
+    };
+} // namespace omath::projectile_prediction::traits
\ No newline at end of file
diff --git a/include/omath/projectile_prediction/engine_traits/opengl_engine_trait.hpp b/include/omath/projectile_prediction/engine_traits/opengl_engine_trait.hpp
new file mode 100644
index 0000000..3241842
--- /dev/null
+++ b/include/omath/projectile_prediction/engine_traits/opengl_engine_trait.hpp
@@ -0,0 +1,79 @@
+//
+// Created by Vlad on 8/6/2025.
+//
+#pragma once
+#include "omath/engines/opengl_engine/formulas.hpp"
+#include "omath/projectile_prediction/projectile.hpp"
+#include "omath/projectile_prediction/target.hpp"
+#include <optional>
+
+namespace omath::projectile_prediction::traits
+{
+    class OpenGlEngineTrait final
+    {
+    public:
+        constexpr static Vector3<float> predict_projectile_position(const Projectile& projectile, const float pitch,
+                                                                    const float yaw, const float time,
+                                                                    const float gravity) noexcept
+        {
+            auto current_pos = projectile.m_origin
+                               + opengl_engine::forward_vector({opengl_engine::PitchAngle::from_degrees(-pitch),
+                                                                opengl_engine::YawAngle::from_degrees(yaw),
+                                                                opengl_engine::RollAngle::from_degrees(0)})
+                                         * projectile.m_launch_speed * time;
+            current_pos.y -= (gravity * projectile.m_gravity_scale) * (time * time) * 0.5f;
+
+            return current_pos;
+        }
+        [[nodiscard]]
+        static constexpr Vector3<float> predict_target_position(const Target& target, const float time,
+                                                                const float gravity) noexcept
+        {
+            auto predicted = target.m_origin + target.m_velocity * time;
+
+            if (target.m_is_airborne)
+                predicted.y -= gravity * (time * time) * 0.5f;
+
+            return predicted;
+        }
+        [[nodiscard]]
+        static float calc_vector_2d_distance(const Vector3<float>& delta) noexcept
+        {
+            return std::sqrt(delta.x * delta.x + delta.z * delta.z);
+        }
+
+        [[nodiscard]]
+        constexpr static float get_vector_height_coordinate(const Vector3<float>& vec) noexcept
+        {
+            return vec.z;
+        }
+
+        [[nodiscard]]
+        static Vector3<float> calc_viewpoint_from_angles(const Projectile& projectile,
+                                                         Vector3<float> predicted_target_position,
+                                                         const std::optional<float> projectile_pitch) noexcept
+        {
+            const auto delta2d = calc_vector_2d_distance(predicted_target_position - projectile.m_origin);
+            const auto height = delta2d * std::tan(angles::degrees_to_radians(projectile_pitch.value()));
+
+            return {predicted_target_position.x, predicted_target_position.y + height, projectile.m_origin.z};
+        }
+        // Due to specification of maybe_calculate_projectile_launch_pitch_angle, pitch angle must be:
+        // 89 look up, -89 look down
+        [[nodiscard]]
+        static float calc_direct_pitch_angle(const Vector3<float>& origin, const Vector3<float>& view_to) noexcept
+        {
+            const auto distance = origin.distance_to(view_to);
+            const auto delta = view_to - origin;
+
+            return angles::radians_to_degrees(std::asin(delta.y / distance));
+        }
+        [[nodiscard]]
+        static float calc_direct_yaw_angle(const Vector3<float>& origin, const Vector3<float>& view_to) noexcept
+        {
+            const auto delta = view_to - origin;
+
+            return angles::radians_to_degrees(std::atan2(delta.z, delta.x));
+        };
+    };
+} // namespace omath::projectile_prediction::traits
diff --git a/include/omath/projectile_prediction/engine_traits/unity_engine_trait.hpp b/include/omath/projectile_prediction/engine_traits/unity_engine_trait.hpp
new file mode 100644
index 0000000..4246ba0
--- /dev/null
+++ b/include/omath/projectile_prediction/engine_traits/unity_engine_trait.hpp
@@ -0,0 +1,79 @@
+//
+// Created by Vlad on 8/6/2025.
+//
+#pragma once
+#include "omath/engines/unity_engine/formulas.hpp"
+#include "omath/projectile_prediction/projectile.hpp"
+#include "omath/projectile_prediction/target.hpp"
+#include <optional>
+
+namespace omath::projectile_prediction::traits
+{
+    class UnityEngineTrait final
+    {
+    public:
+        constexpr static Vector3<float> predict_projectile_position(const Projectile& projectile, const float pitch,
+                                                                    const float yaw, const float time,
+                                                                    const float gravity) noexcept
+        {
+            auto current_pos = projectile.m_origin
+                               + unity_engine::forward_vector({unity_engine::PitchAngle::from_degrees(-pitch),
+                                                               unity_engine::YawAngle::from_degrees(yaw),
+                                                               unity_engine::RollAngle::from_degrees(0)})
+                                         * projectile.m_launch_speed * time;
+            current_pos.y -= (gravity * projectile.m_gravity_scale) * (time * time) * 0.5f;
+
+            return current_pos;
+        }
+        [[nodiscard]]
+        static constexpr Vector3<float> predict_target_position(const Target& target, const float time,
+                                                                const float gravity) noexcept
+        {
+            auto predicted = target.m_origin + target.m_velocity * time;
+
+            if (target.m_is_airborne)
+                predicted.y -= gravity * (time * time) * 0.5f;
+
+            return predicted;
+        }
+        [[nodiscard]]
+        static float calc_vector_2d_distance(const Vector3<float>& delta) noexcept
+        {
+            return std::sqrt(delta.x * delta.x + delta.z * delta.z);
+        }
+
+        [[nodiscard]]
+        constexpr static float get_vector_height_coordinate(const Vector3<float>& vec) noexcept
+        {
+            return vec.z;
+        }
+
+        [[nodiscard]]
+        static Vector3<float> calc_viewpoint_from_angles(const Projectile& projectile,
+                                                         Vector3<float> predicted_target_position,
+                                                         const std::optional<float> projectile_pitch) noexcept
+        {
+            const auto delta2d = calc_vector_2d_distance(predicted_target_position - projectile.m_origin);
+            const auto height = delta2d * std::tan(angles::degrees_to_radians(projectile_pitch.value()));
+
+            return {predicted_target_position.x, predicted_target_position.y + height, projectile.m_origin.z};
+        }
+        // Due to specification of maybe_calculate_projectile_launch_pitch_angle, pitch angle must be:
+        // 89 look up, -89 look down
+        [[nodiscard]]
+        static float calc_direct_pitch_angle(const Vector3<float>& origin, const Vector3<float>& view_to) noexcept
+        {
+            const auto distance = origin.distance_to(view_to);
+            const auto delta = view_to - origin;
+
+            return angles::radians_to_degrees(std::asin(delta.y / distance));
+        }
+        [[nodiscard]]
+        static float calc_direct_yaw_angle(const Vector3<float>& origin, const Vector3<float>& view_to) noexcept
+        {
+            const auto delta = view_to - origin;
+
+            return angles::radians_to_degrees(std::atan2(delta.z, delta.x));
+        };
+    };
+} // namespace omath::projectile_prediction::traits