2 files changed, 10 insertions, 0 deletions
diff --git a/core/math/camera_matrix.cpp b/core/math/camera_matrix.cpp
index 9ec71af57f..7dbda1d149 100644
--- a/core/math/camera_matrix.cpp
+++ b/core/math/camera_matrix.cpp
@@ -74,6 +74,15 @@ Plane CameraMatrix::xform4(const Plane &p_vec4) const {
 	return ret;
 }
 
+void CameraMatrix::adjust_perspective_znear(real_t p_new_znear) {
+	real_t zfar = get_z_far();
+	real_t znear = p_new_znear;
+
+	real_t deltaZ = zfar - znear;
+	matrix[2][2] = -(zfar + znear) / deltaZ;
+	matrix[3][2] = -2 * znear * zfar / deltaZ;
+}
+
 void CameraMatrix::set_perspective(real_t p_fovy_degrees, real_t p_aspect, real_t p_z_near, real_t p_z_far, bool p_flip_fov) {
 	if (p_flip_fov) {
 		p_fovy_degrees = get_fovy(p_fovy_degrees, 1.0 / p_aspect);
diff --git a/core/math/camera_matrix.h b/core/math/camera_matrix.h
index 03068bc7ea..3f327d3bc4 100644
--- a/core/math/camera_matrix.h
+++ b/core/math/camera_matrix.h
@@ -59,6 +59,7 @@ struct CameraMatrix {
 	void set_orthogonal(real_t p_size, real_t p_aspect, real_t p_znear, real_t p_zfar, bool p_flip_fov = false);
 	void set_frustum(real_t p_left, real_t p_right, real_t p_bottom, real_t p_top, real_t p_near, real_t p_far);
 	void set_frustum(real_t p_size, real_t p_aspect, Vector2 p_offset, real_t p_near, real_t p_far, bool p_flip_fov = false);
+	void adjust_perspective_znear(real_t p_new_znear);
 
 	static real_t get_fovy(real_t p_fovx, real_t p_aspect) {
 		return Math::rad2deg(Math::atan(p_aspect * Math::tan(Math::deg2rad(p_fovx) * 0.5)) * 2.0);