Reconstruct base camera object matrix with priority on up vector

[libs/vr.git] / source / headtrackingcamera.cpp

diff --git a/source/headtrackingcamera.cpp b/source/headtrackingcamera.cpp
index 95868e2f12f107a512dda7d39e1dca0dc8fdce14..a296639315634c0f2f4feb689dd988e81746bd49 100644 (file)
--- a/source/headtrackingcamera.cpp
+++ b/source/headtrackingcamera.cpp
@@ -4,14 +4,27 @@ namespace Msp {
 namespace VR {
 
 HeadTrackingCamera::HeadTrackingCamera(const GL::Camera &c):
-       base_camera(c)
+       base_camera(c),
+       elevation_offset(0)
 { }
 
+void HeadTrackingCamera::set_elevation_offset(float o)
+{
+       elevation_offset = o;
+}
+
 void HeadTrackingCamera::update_from_matrix(const GL::Matrix &hmd_matrix)
 {
-       GL::Matrix matrix = base_camera.get_object_matrix()*hmd_matrix;
+       const GL::Vector3 &up_dir = base_camera.get_up_direction();
+       GL::Vector3 right_dir = normalize(cross(base_camera.get_look_direction(), up_dir));
+       GL::Vector4 columns[4];
+       columns[0] = compose(right_dir, 0.0f);
+       columns[1] = compose(up_dir, 0.0f);
+       columns[2] = compose(cross(right_dir, up_dir), 0.0f);
+       columns[3] = compose(base_camera.get_position(), 1.0f);
+       GL::Matrix matrix = GL::Matrix::from_columns(columns)*hmd_matrix;
 
-       set_position(matrix*GL::Vector3());
+       set_position(matrix*GL::Vector3()+base_camera.get_up_direction()*elevation_offset);
        set_look_direction((matrix*GL::Vector4(0, 0, -1, 0)).slice<3>(0));
        set_up_direction((matrix*GL::Vector4(0, 1, 0, 0)).slice<3>(0));