diff --git a/include/gfx/seadGraphics.h b/include/gfx/seadGraphics.h
index 1beb2c34..0321838a 100644
--- a/include/gfx/seadGraphics.h
+++ b/include/gfx/seadGraphics.h
@@ -30,6 +30,9 @@ class Graphics : public IDisposer
     void initializeDrawLockContext(Heap*);
 
     static Graphics* instance() { return sInstance; }
+    static DevicePosture sDefaultDevicePosture;
+    static f32 sDefaultDeviceZScale;
+    static f32 sDefaultDeviceZOffset;
 
 private:
     UnknownCallback _20;
diff --git a/include/gfx/seadProjection.h b/include/gfx/seadProjection.h
index 4f70db7d..f3d64fa7 100644
--- a/include/gfx/seadProjection.h
+++ b/include/gfx/seadProjection.h
@@ -3,7 +3,6 @@
 
 #include <basis/seadTypes.h>
 #include <gfx/seadGraphics.h>
-#include <gfx/seadViewport.h>
 #include <math/seadBoundBox.h>
 #include <math/seadMatrix.h>
 #include <math/seadVector.h>
@@ -11,13 +10,18 @@
 
 namespace sead
 {
+class Camera;
+template <typename T>
+class Ray;
+class Viewport;
+
 class Projection
 {
     SEAD_RTTI_BASE(Projection)
 
 public:
     Projection();
-    virtual ~Projection();
+    virtual ~Projection() = default;
 
     virtual f32 getNear() const = 0;
     virtual f32 getFar() const = 0;
@@ -28,10 +32,19 @@ class Projection
     virtual u32 getProjectionType() const = 0;
     virtual void doUpdateMatrix(Matrix44f* mtx) const = 0;
     virtual void doUpdateDeviceMatrix(Matrix44f*, const Matrix44f&, Graphics::DevicePosture) const;
-    virtual void doScreenPosToCameraPosTo(Vector3f*, const Vector3f&) const = 0;
+    virtual void doScreenPosToCameraPosTo(Vector3f* camera_pos,
+                                          const Vector3f& screen_pos) const = 0;
 
+    const Matrix44f& getProjectionMatrix() const;
     void updateMatrixImpl_() const;
+    Matrix44f* getProjectionMatrixMutable();
     const Matrix44f& getDeviceProjectionMatrix() const;
+    void cameraPosToScreenPos(Vector3f* screen_pos, const Vector3f& camera_pos) const;
+    void screenPosToCameraPos(Vector3f* camera_pos, const Vector3f& screen_pos) const;
+    void screenPosToCameraPos(Vector3f* camera_pos, const Vector2f& screen_pos) const;
+    void project(Vector2f* dst, const Vector3f& camera_pos, const Viewport& viewport) const;
+    void unproject(Vector3f* world_pos, const Vector3f& screen_pos, const Camera& camera) const;
+    void unprojectRay(Ray<Vector3f>* dst, const Vector3f& screen_pos, const Camera& camera) const;
 
     void setDirty() { mDirty = true; }
     void setDeviceDirty() { mDeviceDirty = true; }
@@ -43,8 +56,8 @@ class Projection
     }
 
 private:
-    mutable bool mDirty;
-    mutable bool mDeviceDirty;
+    mutable bool mDirty = true;
+    mutable bool mDeviceDirty = true;
     Matrix44f mMatrix;
     Matrix44f mDeviceMatrix;
     Graphics::DevicePosture mDevicePosture;
diff --git a/include/math/seadVector.h b/include/math/seadVector.h
index 20263987..0d2e97be 100644
--- a/include/math/seadVector.h
+++ b/include/math/seadVector.h
@@ -81,6 +81,7 @@ struct Vector3 : public Policies<T>::Vec3Base
 {
     using Mtx33 = typename Policies<T>::Mtx33Base;
     using Mtx34 = typename Policies<T>::Mtx34Base;
+    using Mtx44 = typename Policies<T>::Mtx44Base;
     using Quat = typename Policies<T>::QuatBase;
 
     /// @warning This constructor leaves member variables uninitialized.
@@ -111,6 +112,7 @@ struct Vector3 : public Policies<T>::Vec3Base
     Vector3& operator*=(T t);
     Vector3& operator*=(const Mtx33& m);
     Vector3& operator*=(const Mtx34& m);
+    Vector3& operator*=(const Mtx44& m);
     friend Vector3 operator*(const Vector3& a, T t)
     {
         Vector3 o;
@@ -130,6 +132,12 @@ struct Vector3 : public Policies<T>::Vec3Base
         o.setMul(m, a);
         return o;
     }
+    friend Vector3 operator*(const Mtx44& m, const Vector3& a)
+    {
+        Vector3 o;
+        o.setMul(m, a);
+        return o;
+    }
 
     Vector3& operator/=(T t);
     friend Vector3 operator/(const Vector3& a, T t) { return {a.x / t, a.y / t, a.z / t}; }
@@ -156,6 +164,8 @@ struct Vector3 : public Policies<T>::Vec3Base
     void mul(const Mtx33& m);
     /// Apply a transformation `m` (rotation then translation) to this vector.
     void mul(const Mtx34& m);
+    /// Apply a transformation `m` (rotation, translation, homogenous coordinates) to this vector.
+    void mul(const Mtx44& m);
     /// Apply a rotation `m` to this vector.
     void rotate(const Mtx33& m);
     /// Apply a rotation `m` to this vector.
@@ -174,6 +184,7 @@ struct Vector3 : public Policies<T>::Vec3Base
     void setScaleAdd(T t, const Vector3<T>& a, const Vector3<T>& b);
     void setMul(const Mtx33& m, const Vector3& a);
     void setMul(const Mtx34& m, const Vector3& a);
+    void setMul(const Mtx44& m, const Vector3& a);
     void setRotated(const Mtx33& m, const Vector3& a);
     void setRotated(const Mtx34& m, const Vector3& a);
     void setRotated(const Quat& q, const Vector3& a);
diff --git a/include/math/seadVector.hpp b/include/math/seadVector.hpp
index c48afb2a..26868815 100644
--- a/include/math/seadVector.hpp
+++ b/include/math/seadVector.hpp
@@ -179,6 +179,13 @@ inline Vector3<T>& Vector3<T>::operator*=(const Mtx34& m)
     return *this;
 }
 
+template <typename T>
+inline Vector3<T>& Vector3<T>::operator*=(const Mtx44& m)
+{
+    mul(m);
+    return *this;
+}
+
 template <typename T>
 inline Vector3<T>& Vector3<T>::operator/=(T t)
 {
@@ -230,6 +237,12 @@ inline void Vector3<T>::mul(const Mtx34& m)
     setMul(m, *this);
 }
 
+template <typename T>
+inline void Vector3<T>::mul(const Mtx44& m)
+{
+    setMul(m, *this);
+}
+
 template <typename T>
 inline void Vector3<T>::rotate(const Mtx33& m)
 {
@@ -314,6 +327,12 @@ inline void Vector3<T>::setMul(const Mtx34& m, const Vector3<T>& a)
     Vector3CalcCommon<T>::mul(*this, m, a);
 }
 
+template <typename T>
+inline void Vector3<T>::setMul(const Mtx44& m, const Vector3<T>& a)
+{
+    Vector3CalcCommon<T>::mul(*this, m, a);
+}
+
 template <typename T>
 inline void Vector3<T>::setRotated(const Mtx33& m, const Vector3<T>& a)
 {
diff --git a/include/math/seadVectorCalcCommon.h b/include/math/seadVectorCalcCommon.h
index c84b8275..8918d9c6 100644
--- a/include/math/seadVectorCalcCommon.h
+++ b/include/math/seadVectorCalcCommon.h
@@ -33,6 +33,7 @@ class Vector3CalcCommon
     using Base = typename Policies<T>::Vec3Base;
     using Mtx33 = typename Policies<T>::Mtx33Base;
     using Mtx34 = typename Policies<T>::Mtx34Base;
+    using Mtx44 = typename Policies<T>::Mtx44Base;
     using Quat = typename Policies<T>::QuatBase;
 
     static void add(Base& o, const Base& a, const Base& b);
@@ -41,6 +42,8 @@ class Vector3CalcCommon
     static void mul(Base& o, const Mtx33& m, const Base& a);
     /// Apply a transformation `m` (rotation then translation) to the vector `a`.
     static void mul(Base& o, const Mtx34& m, const Base& a);
+    /// Apply a transformation `m` (rotation, translation, homogenous coord) to the vector `a`.
+    static void mul(Base& o, const Mtx44& m, const Base& a);
 
     /// Apply a rotation `m` to the vector `a`.
     static void rotate(Base& o, const Mtx33& m, const Base& a);
diff --git a/include/math/seadVectorCalcCommon.hpp b/include/math/seadVectorCalcCommon.hpp
index 572608a3..801274a2 100644
--- a/include/math/seadVectorCalcCommon.hpp
+++ b/include/math/seadVectorCalcCommon.hpp
@@ -146,6 +146,17 @@ inline void Vector3CalcCommon<T>::mul(Base& o, const Mtx34& m, const Base& a)
     o.z = m.m[2][0] * tmp.x + m.m[2][1] * tmp.y + m.m[2][2] * tmp.z + m.m[2][3];
 }
 
+template <typename T>
+inline void Vector3CalcCommon<T>::mul(Base& o, const Mtx44& m, const Base& a)
+{
+    const Base tmp = a;
+    T inv = T(1) / (m.m[3][0] * tmp.x + m.m[3][1] * tmp.y + m.m[3][2] * tmp.z + m.m[3][3]);
+
+    o.x = inv * (m.m[0][0] * tmp.x + m.m[0][1] * tmp.y + m.m[0][2] * tmp.z + m.m[0][3]);
+    o.y = inv * (m.m[1][0] * tmp.x + m.m[1][1] * tmp.y + m.m[1][2] * tmp.z + m.m[1][3]);
+    o.z = inv * (m.m[2][0] * tmp.x + m.m[2][1] * tmp.y + m.m[2][2] * tmp.z + m.m[2][3]);
+}
+
 template <typename T>
 inline void Vector3CalcCommon<T>::rotate(Base& o, const Mtx33& m, const Base& a)
 {
diff --git a/modules/src/gfx/seadProjection.cpp b/modules/src/gfx/seadProjection.cpp
index 4179f1e9..9cd07d2d 100644
--- a/modules/src/gfx/seadProjection.cpp
+++ b/modules/src/gfx/seadProjection.cpp
@@ -1,30 +1,89 @@
 #include <gfx/seadProjection.h>
 
+#include <gfx/seadCamera.h>
+#include <gfx/seadViewport.h>
+
 namespace sead
 {
+Projection::Projection()
+{
+    mDevicePosture = Graphics::sDefaultDevicePosture;
+    mDeviceZScale = Graphics::sDefaultDeviceZScale;
+    mDeviceZOffset = Graphics::sDefaultDeviceZOffset;
+}
+
+void Projection::updateAttributesForDirectProjection() {}
+
+const Matrix44f& Projection::getProjectionMatrix() const
+{
+    updateMatrixImpl_();
+    return mMatrix;
+}
+
 void Projection::updateMatrixImpl_() const
 {
     if (mDirty)
     {
         doUpdateMatrix(const_cast<Matrix44f*>(&mMatrix));
         mDirty = false;
-
         mDeviceDirty = true;
-        doUpdateDeviceMatrix(const_cast<Matrix44f*>(&mDeviceMatrix), mMatrix, mDevicePosture);
-        mDeviceDirty = false;
     }
 
-    else if (mDeviceDirty)
+    if (mDeviceDirty)
     {
         doUpdateDeviceMatrix(const_cast<Matrix44f*>(&mDeviceMatrix), mMatrix, mDevicePosture);
         mDeviceDirty = false;
     }
 }
 
+Matrix44f* Projection::getProjectionMatrixMutable()
+{
+    updateMatrixImpl_();
+    return &mMatrix;
+}
+
 const Matrix44f& Projection::getDeviceProjectionMatrix() const
 {
     updateMatrixImpl_();
     return mDeviceMatrix;
 }
 
+void Projection::cameraPosToScreenPos(Vector3f* screen_pos, const Vector3f& camera_pos) const
+{
+    screen_pos->setMul(getProjectionMatrix(), camera_pos);
+}
+
+void Projection::screenPosToCameraPos(Vector3f* camera_pos, const Vector3f& screen_pos) const
+{
+    doScreenPosToCameraPosTo(camera_pos, screen_pos);
+}
+
+void Projection::screenPosToCameraPos(Vector3f* camera_pos, const Vector2f& screen_pos) const
+{
+    screenPosToCameraPos(camera_pos, {screen_pos.x, screen_pos.y, 0.0f});
+}
+
+void Projection::project(Vector2f* dst, const Vector3f& camera_pos, const Viewport& viewport) const
+{
+    Vector3f screen_pos;
+    cameraPosToScreenPos(&screen_pos, camera_pos);
+    viewport.project(dst, screen_pos);
+}
+
+void Projection::unproject(Vector3f* world_pos, const Vector3f& screen_pos,
+                           const Camera& camera) const
+{
+    Vector3f camera_pos;
+    screenPosToCameraPos(&camera_pos, screen_pos);
+    camera.cameraPosToWorldPosByMatrix(world_pos, camera_pos);
+}
+
+void Projection::unprojectRay(Ray<Vector3f>* dst, const Vector3f& screen_pos,
+                              const Camera& camera) const
+{
+    Vector3f camera_pos;
+    screenPosToCameraPos(&camera_pos, screen_pos);
+    camera.unprojectRayByMatrix(dst, camera_pos);
+}
+
 }  // namespace sead