Implement Vector4, Vector4i, Projection

Implement built-in classes Vector4, Vector4i and Projection.

* Two versions of Vector4 (float and integer).
* A Projection class, which is a 4x4 matrix specialized in projection types.

These types have been requested for a long time, but given they were very corner case they were not added before.
Because in Godot 4, reimplementing parts of the rendering engine is now possible, access to these types (heavily used by the rendering code) becomes a necessity.

**Q**: Why Projection and not Matrix4?
**A**: Godot does not use Matrix2, Matrix3, Matrix4x3, etc. naming convention because, within the engine, these types always have a *purpose*. As such, Godot names them: Transform2D, Transform3D or Basis. In this case, this 4x4 matrix is _always_ used as a _Projection_, hence the naming.

3 files changed, 17 insertions, 17 deletions

diff --git a/scene/3d/camera_3d.cpp b/scene/3d/camera_3d.cpp
index 10348b1eb6..da4a14394d 100644
--- a/scene/3d/camera_3d.cpp
+++ b/scene/3d/camera_3d.cpp
@@ -31,7 +31,7 @@
 #include "camera_3d.h"
 
 #include "collision_object_3d.h"
-#include "core/math/camera_matrix.h"
+#include "core/math/projection.h"
 #include "scene/main/viewport.h"
 
 void Camera3D::_update_audio_listener_state() {
@@ -197,7 +197,7 @@ void Camera3D::set_frustum(real_t p_size, Vector2 p_offset, real_t p_z_near, rea
 	update_gizmos();
 }
 
-void Camera3D::set_projection(Camera3D::Projection p_mode) {
+void Camera3D::set_projection(ProjectionType p_mode) {
 	if (p_mode == PROJECTION_PERSPECTIVE || p_mode == PROJECTION_ORTHOGONAL || p_mode == PROJECTION_FRUSTUM) {
 		mode = p_mode;
 		_update_camera_mode();
@@ -265,7 +265,7 @@ Vector3 Camera3D::project_local_ray_normal(const Point2 &p_pos) const {
 	if (mode == PROJECTION_ORTHOGONAL) {
 		ray = Vector3(0, 0, -1);
 	} else {
-		CameraMatrix cm;
+		Projection cm;
 		cm.set_perspective(fov, viewport_size.aspect(), near, far, keep_aspect == KEEP_WIDTH);
 		Vector2 screen_he = cm.get_viewport_half_extents();
 		ray = Vector3(((cpos.x / viewport_size.width) * 2.0 - 1.0) * screen_he.x, ((1.0 - (cpos.y / viewport_size.height)) * 2.0 - 1.0) * screen_he.y, -near).normalized();
@@ -314,7 +314,7 @@ Vector<Vector3> Camera3D::get_near_plane_points() const {
 
 	Size2 viewport_size = get_viewport()->get_visible_rect().size;
 
-	CameraMatrix cm;
+	Projection cm;
 
 	if (mode == PROJECTION_ORTHOGONAL) {
 		cm.set_orthogonal(size, viewport_size.aspect(), near, far, keep_aspect == KEEP_WIDTH);
@@ -340,7 +340,7 @@ Point2 Camera3D::unproject_position(const Vector3 &p_pos) const {
 
 	Size2 viewport_size = get_viewport()->get_visible_rect().size;
 
-	CameraMatrix cm;
+	Projection cm;
 
 	if (mode == PROJECTION_ORTHOGONAL) {
 		cm.set_orthogonal(size, viewport_size.aspect(), near, far, keep_aspect == KEEP_WIDTH);
@@ -368,7 +368,7 @@ Vector3 Camera3D::project_position(const Point2 &p_point, real_t p_z_depth) cons
 	}
 	Size2 viewport_size = get_viewport()->get_visible_rect().size;
 
-	CameraMatrix cm;
+	Projection cm;
 
 	if (mode == PROJECTION_ORTHOGONAL) {
 		cm.set_orthogonal(size, viewport_size.aspect(), p_z_depth, far, keep_aspect == KEEP_WIDTH);
@@ -544,7 +544,7 @@ real_t Camera3D::get_far() const {
 	return far;
 }
 
-Camera3D::Projection Camera3D::get_projection() const {
+Camera3D::ProjectionType Camera3D::get_projection() const {
 	return mode;
 }
 
@@ -607,7 +607,7 @@ Vector<Plane> Camera3D::get_frustum() const {
 	ERR_FAIL_COND_V(!is_inside_world(), Vector<Plane>());
 
 	Size2 viewport_size = get_viewport()->get_visible_rect().size;
-	CameraMatrix cm;
+	Projection cm;
 	if (mode == PROJECTION_PERSPECTIVE) {
 		cm.set_perspective(fov, viewport_size.aspect(), near, far, keep_aspect == KEEP_WIDTH);
 	} else {
diff --git a/scene/3d/camera_3d.h b/scene/3d/camera_3d.h
index 9f2f8ceed1..711a682e3d 100644
--- a/scene/3d/camera_3d.h
+++ b/scene/3d/camera_3d.h
@@ -40,7 +40,7 @@ class Camera3D : public Node3D {
 	GDCLASS(Camera3D, Node3D);
 
 public:
-	enum Projection {
+	enum ProjectionType {
 		PROJECTION_PERSPECTIVE,
 		PROJECTION_ORTHOGONAL,
 		PROJECTION_FRUSTUM
@@ -62,7 +62,7 @@ private:
 	bool current = false;
 	Viewport *viewport = nullptr;
 
-	Projection mode = PROJECTION_PERSPECTIVE;
+	ProjectionType mode = PROJECTION_PERSPECTIVE;
 
 	real_t fov = 0.0;
 	real_t size = 1.0;
@@ -112,7 +112,7 @@ public:
 	void set_perspective(real_t p_fovy_degrees, real_t p_z_near, real_t p_z_far);
 	void set_orthogonal(real_t p_size, real_t p_z_near, real_t p_z_far);
 	void set_frustum(real_t p_size, Vector2 p_offset, real_t p_z_near, real_t p_z_far);
-	void set_projection(Camera3D::Projection p_mode);
+	void set_projection(Camera3D::ProjectionType p_mode);
 
 	void make_current();
 	void clear_current(bool p_enable_next = true);
@@ -127,7 +127,7 @@ public:
 	real_t get_near() const;
 	Vector2 get_frustum_offset() const;
 
-	Projection get_projection() const;
+	ProjectionType get_projection() const;
 
 	void set_fov(real_t p_fov);
 	void set_size(real_t p_size);
@@ -181,7 +181,7 @@ public:
 	~Camera3D();
 };
 
-VARIANT_ENUM_CAST(Camera3D::Projection);
+VARIANT_ENUM_CAST(Camera3D::ProjectionType);
 VARIANT_ENUM_CAST(Camera3D::KeepAspect);
 VARIANT_ENUM_CAST(Camera3D::DopplerTracking);
 
diff --git a/scene/3d/xr_nodes.cpp b/scene/3d/xr_nodes.cpp
index 1dad6078b4..40a43043c6 100644
--- a/scene/3d/xr_nodes.cpp
+++ b/scene/3d/xr_nodes.cpp
@@ -120,7 +120,7 @@ Vector3 XRCamera3D::project_local_ray_normal(const Point2 &p_pos) const {
 	Vector3 ray;
 
 	// Just use the first view, if multiple views are supported this function has no good result
-	CameraMatrix cm = xr_interface->get_projection_for_view(0, viewport_size.aspect(), get_near(), get_far());
+	Projection cm = xr_interface->get_projection_for_view(0, viewport_size.aspect(), get_near(), get_far());
 	Vector2 screen_he = cm.get_viewport_half_extents();
 	ray = Vector3(((cpos.x / viewport_size.width) * 2.0 - 1.0) * screen_he.x, ((1.0 - (cpos.y / viewport_size.height)) * 2.0 - 1.0) * screen_he.y, -get_near()).normalized();
 
@@ -143,7 +143,7 @@ Point2 XRCamera3D::unproject_position(const Vector3 &p_pos) const {
 	Size2 viewport_size = get_viewport()->get_visible_rect().size;
 
 	// Just use the first view, if multiple views are supported this function has no good result
-	CameraMatrix cm = xr_interface->get_projection_for_view(0, viewport_size.aspect(), get_near(), get_far());
+	Projection cm = xr_interface->get_projection_for_view(0, viewport_size.aspect(), get_near(), get_far());
 
 	Plane p(get_camera_transform().xform_inv(p_pos), 1.0);
 
@@ -173,7 +173,7 @@ Vector3 XRCamera3D::project_position(const Point2 &p_point, real_t p_z_depth) co
 	Size2 viewport_size = get_viewport()->get_visible_rect().size;
 
 	// Just use the first view, if multiple views are supported this function has no good result
-	CameraMatrix cm = xr_interface->get_projection_for_view(0, viewport_size.aspect(), get_near(), get_far());
+	Projection cm = xr_interface->get_projection_for_view(0, viewport_size.aspect(), get_near(), get_far());
 
 	Vector2 vp_he = cm.get_viewport_half_extents();
 
@@ -202,7 +202,7 @@ Vector<Plane> XRCamera3D::get_frustum() const {
 
 	Size2 viewport_size = get_viewport()->get_visible_rect().size;
 	// TODO Just use the first view for now, this is mostly for debugging so we may look into using our combined projection here.
-	CameraMatrix cm = xr_interface->get_projection_for_view(0, viewport_size.aspect(), get_near(), get_far());
+	Projection cm = xr_interface->get_projection_for_view(0, viewport_size.aspect(), get_near(), get_far());
 	return cm.get_projection_planes(get_camera_transform());
 };