`omath::iw_engine::MeshTrait` — mesh transformation trait for IW Engine

Header: omath/engines/iw_engine/traits/mesh_trait.hpp Namespace: omath::iw_engine Purpose: provide IW Engine-specific rotation matrix computation for omath::primitives::Mesh

Summary

MeshTrait is a trait class that provides the rotation_matrix function for transforming meshes in IW Engine's (Infinity Ward) coordinate system. It serves as a template parameter to omath::primitives::Mesh, enabling engine-specific rotation behavior.

Coordinate System

IW Engine (Call of Duty) uses: * Up axis: +Z * Forward axis: +Y * Right axis: +X * Handedness: Right-handed * Rotation order: Pitch (X) → Yaw (Z) → Roll (Y)

API

namespace omath::iw_engine {

class MeshTrait final {
public:
    [[nodiscard]]
    static Mat4X4 rotation_matrix(const ViewAngles& rotation);
};

} // namespace omath::iw_engine

Method: `rotation_matrix`

static Mat4X4 rotation_matrix(const ViewAngles& rotation);

Computes a 4×4 rotation matrix from IW Engine-style Euler angles.

Parameters: * rotation — ViewAngles containing pitch, yaw, and roll angles

Returns: 4×4 rotation matrix suitable for mesh transformation

Implementation: Delegates to iw_engine::rotation_matrix(rotation) defined in formulas.hpp.

Usage

With Mesh

using namespace omath::iw_engine;

// Create mesh (MeshTrait is used automatically)
Mesh my_mesh(vertices, indices);

// Set rotation using ViewAngles
ViewAngles angles;
angles.pitch = PitchAngle::from_degrees(30.0f);
angles.yaw = YawAngle::from_degrees(45.0f);
angles.roll = RollAngle::from_degrees(0.0f);

my_mesh.set_rotation(angles);

// The rotation matrix is computed using MeshTrait::rotation_matrix
auto matrix = my_mesh.get_to_world_matrix();

Rotation Conventions

IW Engine uses a right-handed Z-up coordinate system (similar to Source Engine):

Pitch (rotation around X-axis / right axis)
Positive pitch looks upward (+Z direction)
Range: typically [-89°, 89°]
Yaw (rotation around Z-axis / up axis)
Positive yaw rotates counterclockwise when viewed from above
Range: [-180°, 180°]
Roll (rotation around Y-axis / forward axis)
Positive roll tilts right
Range: [-180°, 180°]

Type Alias

namespace omath::iw_engine {
    using Mesh = primitives::Mesh<Mat4X4, ViewAngles, MeshTrait, float>;
}

omath::iw_engine::MeshTrait — mesh transformation trait for IW Engine