TransformComponent.hpp

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#ifndef _TRANSFORM_COMPONENT_H_
#define _TRANSFORM_COMPONENT_H_
 
#include <ECS/Component.hpp>
#include "Math/Vector.hpp"
#include "Math/Quaternion.hpp"
#include "Math/Matrix.hpp"
#include <Memory/RefPtr.hpp>
 
namespace Sleak {
 
    using namespace Sleak::Math;
 
    namespace RenderEngine { class BufferBase; };
 
    /**
     * @class TransformComponent
     * @brief Represents the position, rotation, and scale of an entity in 3D space.
     *
     * This component is essential for positioning and orienting entities
     * within the game world. It provides functionalities for setting and
     * retrieving the transform properties, as well as calculating transformation
     * matrices for rendering and physics calculations.
     * @ingroup scene
     */
    class ENGINE_API TransformComponent : public Component {
    public:
            // Constructors
         TransformComponent(GameObject* object, const Vector3D& position);
            TransformComponent(GameObject* object, const Vector3D& position,
                               const Quaternion& rotation);
         TransformComponent(GameObject* object, const Vector3D& position,
                            const Quaternion& rotation, const Vector3D& scale);
        ~TransformComponent() override;
 
        /// Allocates the transform's GPU constant buffer.
        bool Initialize() override;
        /// Refreshes and rebinds the transform constant buffer for this frame.
        void Update(float DeltaTime) override;
 
        // Transformation matrix calculation
        Matrix4 GetTransformMatrix();
 
        // Transformations
        /// Adds translation to position and refreshes the cached matrix.
        void Translate(const Vector3D& translation);
        void Translate(float x, float y, float z);
        /// Composes rotation onto the current orientation.
        void Rotate(const Quaternion& rotation);
        /// Uniformly scales by amount along all axes.
        void Scale(float amount);
        /// Multiplies the current scale componentwise by scale.
        void Scale(const Vector3D& scale);
 
        // Setters
        void SetPosition(const Vector3D& position);
        void SetRotation(const Quaternion& rotation);
        void SetScale(const Vector3D& scale);
 
        // Direction vectors
        Vector3D Forward() const;
        Vector3D Right() const;
        Vector3D Up() const;
 
        // Rotation utilities
        /// Rotates by angle around axis in world space.
        void RotateAround(const Vector3D& axis, float angle);
        /// Rotates by angle around axis expressed in the object's local space.
        void RotateAroundLocal(const Vector3D& axis, float angle);
        /// Orients the transform to face target, using world up as reference.
        void LookAt(const Vector3D& target);
 
        // Getters
        Vector3D GetWorldPosition() const;
        Quaternion GetWorldRotation() const;
        Vector3D GetWorldScale() const;
 
        /// Cached translation/rotation/scale matrices combined into the final transform matrix.
        struct TransformMatrix {
 
            TransformMatrix() : Translation(Matrix4::Identity()), Rotation(Matrix4::Identity()), Scaling(Matrix4::Identity()) {}
 
            Math::Matrix4 CalculateTransformMatrix() const {
                return (Scaling * Rotation) * Translation ;
            }
 
            Math::Matrix4 Translation;
            Math::Matrix4 Rotation;
            Math::Matrix4 Scaling;
 
        };
 
    protected:
        Vector3D position = Vector3D(0.0f, 0.0f, 0.0f);
        Quaternion rotation = Quaternion();
        Vector3D scale = Vector3D(1.0f, 1.0f, 1.0f);
        TransformMatrix* Transform = nullptr;
 
       private:
        RefPtr<RenderEngine::BufferBase> ConstantBuffer;
 
        /// Rebuilds the transform matrix and pushes it to the GPU constant buffer.
        void UpdateConstantBuffer();
        /// Recomputes the cached Translation/Rotation/Scaling matrices from position/rotation/scale.
        void UpdateTransform();
        /// Combines the transform with the main camera's view and projection matrices.
        Math::Matrix4 GetMVP();
    };
 
} // namespace Sleak
 
#endif // _TRANSFORM_COMPONENT_H_