Camera3D requires CNA link

Easy3D / Cameras / Camera3D

Easy3D::Camera3D is a small, explicit perspective camera. It stores a position/target/up and the usual perspective parameters, and produces CNA (Microsoft::Xna::Framework::Matrix) view and projection matrices. CNA types are used directly and on purpose: Easy3D does not hide CNA.

#include <Easy3D/Camera3D.hpp>

namespace Easy3D { class Camera3D; }

GetViewMatrix() / GetProjectionMatrix() call into CNA's compiled math (Matrix::CreateLookAt, Matrix::CreatePerspectiveFieldOfView), so executables that call them must link the CNA library. See Building & CMake.

Type aliases

Alias	Refers to
`Camera3D::Vector3`	`Microsoft::Xna::Framework::Vector3`
`Camera3D::Matrix`	`Microsoft::Xna::Framework::Matrix`

Defaults

A default-constructed Camera3D is immediately usable — it looks at the origin from slightly above and behind:

Property	Default	Notes
Position	`(0, 2, 5)`
Target	`(0, 0, 0)`	`Vector3::Zero`
Up	`(0, 1, 0)`	`Vector3::Up`
Field of view	`0.785398163` rad	45°, vertical
Aspect ratio	`16/9`
Near plane	`0.1`
Far plane	`1000`

Eye / target / up

[[nodiscard]] const Vector3& GetPosition() const noexcept
void SetPosition(const Vector3& value) noexcept

The eye position of the camera in world space.

[[nodiscard]] const Vector3& GetTarget() const noexcept
void SetTarget(const Vector3& value) noexcept

The world-space point the camera looks at.

[[nodiscard]] const Vector3& GetUp() const noexcept
void SetUp(const Vector3& value) noexcept

The camera's up vector (default Vector3::Up).

Perspective parameters

[[nodiscard]] float GetFieldOfView() const noexcept
void SetFieldOfView(float radians) noexcept

Vertical field of view, in radians.

[[nodiscard]] float GetAspectRatio() const noexcept
void SetAspectRatio(float aspect) noexcept

Viewport width divided by height. Update this when the window resizes.

[[nodiscard]] float GetNearPlane() const noexcept
void SetNearPlane(float value) noexcept

Distance to the near clipping plane.

[[nodiscard]] float GetFarPlane() const noexcept
void SetFarPlane(float value) noexcept

Distance to the far clipping plane.

Derived matrices requires CNA link

[[nodiscard]] Matrix GetViewMatrix() const

Returns Matrix::CreateLookAt(position, target, up) — a right-handed CNA look-at view matrix.

[[nodiscard]] Matrix GetProjectionMatrix() const

Returns Matrix::CreatePerspectiveFieldOfView(fieldOfView, aspectRatio, nearPlane, farPlane) — a CNA perspective projection matrix.

Example

#include <Easy3D/Camera3D.hpp>

using Vector3 = Easy3D::Camera3D::Vector3;

Easy3D::Camera3D camera;
camera.SetPosition(Vector3(0.0f, 3.0f, 8.0f));
camera.SetTarget(Vector3::Zero);
camera.SetAspectRatio(static_cast<float>(viewportWidth) / viewportHeight);

// Hand the CNA matrices straight to your CNA rendering code.
const auto view       = camera.GetViewMatrix();
const auto projection = camera.GetProjectionMatrix();

Working with the other cameras

Camera3D is the single "real" camera; OrbitCamera and FollowCamera are positioning helpers that do not own one. Both provide an ApplyTo() that pushes their computed position/target into a Camera3D:

Easy3D::OrbitCamera orbit;
orbit.SetDistance(12.0f);
orbit.SetYaw(0.6f);
orbit.ApplyTo(camera);      // sets camera position + target

Keep one Camera3D as the source of truth for view/projection, and drive it from whichever rig (orbit, follow, or your own code) fits the current game state.