diff --git a/src/libslic3r/Technologies.hpp b/src/libslic3r/Technologies.hpp index 23c516a34..401946b94 100644 --- a/src/libslic3r/Technologies.hpp +++ b/src/libslic3r/Technologies.hpp @@ -74,5 +74,7 @@ // Enable configurable paths export (fullpath or not) to 3mf and amf #define ENABLE_CONFIGURABLE_PATHS_EXPORT_TO_3MF_AND_AMF (1 && ENABLE_2_2_0_BETA1) +// Enable 6 degrees of freedom camera +#define ENABLE_6DOF_CAMERA (1 && ENABLE_2_2_0_BETA1) #endif // _technologies_h_ diff --git a/src/slic3r/GUI/3DBed.cpp b/src/slic3r/GUI/3DBed.cpp index c66c8efdd..698dbbc05 100644 --- a/src/slic3r/GUI/3DBed.cpp +++ b/src/slic3r/GUI/3DBed.cpp @@ -262,7 +262,11 @@ Point Bed3D::point_projection(const Point& point) const return m_polygon.point_projection(point); } +#if ENABLE_6DOF_CAMERA +void Bed3D::render(GLCanvas3D& canvas, bool bottom, float scale_factor, bool show_axes) const +#else void Bed3D::render(GLCanvas3D& canvas, float theta, float scale_factor, bool show_axes) const +#endif // ENABLE_6DOF_CAMERA { m_scale_factor = scale_factor; @@ -273,6 +277,15 @@ void Bed3D::render(GLCanvas3D& canvas, float theta, float scale_factor, bool sho switch (m_type) { +#if ENABLE_6DOF_CAMERA + case MK2: { render_prusa(canvas, "mk2", bottom); break; } + case MK3: { render_prusa(canvas, "mk3", bottom); break; } + case SL1: { render_prusa(canvas, "sl1", bottom); break; } + case MINI: { render_prusa(canvas, "mini", bottom); break; } + case ENDER3: { render_prusa(canvas, "ender3", bottom); break; } + default: + case Custom: { render_custom(canvas, bottom); break; } +#else case MK2: { render_prusa(canvas, "mk2", theta > 90.0f); break; } case MK3: { render_prusa(canvas, "mk3", theta > 90.0f); break; } case SL1: { render_prusa(canvas, "sl1", theta > 90.0f); break; } @@ -280,6 +293,7 @@ void Bed3D::render(GLCanvas3D& canvas, float theta, float scale_factor, bool sho case ENDER3: { render_prusa(canvas, "ender3", theta > 90.0f); break; } default: case Custom: { render_custom(canvas, theta > 90.0f); break; } +#endif // ENABLE_6DOF_CAMERA } glsafe(::glDisable(GL_DEPTH_TEST)); diff --git a/src/slic3r/GUI/3DBed.hpp b/src/slic3r/GUI/3DBed.hpp index cd2de862e..c1d3fdce7 100644 --- a/src/slic3r/GUI/3DBed.hpp +++ b/src/slic3r/GUI/3DBed.hpp @@ -110,7 +110,11 @@ public: bool contains(const Point& point) const; Point point_projection(const Point& point) const; +#if ENABLE_6DOF_CAMERA + void render(GLCanvas3D& canvas, bool bottom, float scale_factor, bool show_axes) const; +#else void render(GLCanvas3D& canvas, float theta, float scale_factor, bool show_axes) const; +#endif // ENABLE_6DOF_CAMERA private: void calc_bounding_boxes() const; diff --git a/src/slic3r/GUI/Camera.cpp b/src/slic3r/GUI/Camera.cpp index fa7a3be21..b22d27326 100644 --- a/src/slic3r/GUI/Camera.cpp +++ b/src/slic3r/GUI/Camera.cpp @@ -34,18 +34,27 @@ double Camera::FrustrumZMargin = 10.0; double Camera::MaxFovDeg = 60.0; Camera::Camera() +#if ENABLE_6DOF_CAMERA + : requires_zoom_to_bed(false) +#else : phi(45.0f) , requires_zoom_to_bed(false) , inverted_phi(false) +#endif // ENABLE_6DOF_CAMERA , m_type(Perspective) , m_target(Vec3d::Zero()) +#if !ENABLE_6DOF_CAMERA , m_theta(45.0f) +#endif // !ENABLE_6DOF_CAMERA , m_zoom(1.0) , m_distance(DefaultDistance) , m_gui_scale(1.0) , m_view_matrix(Transform3d::Identity()) , m_projection_matrix(Transform3d::Identity()) { +#if ENABLE_6DOF_CAMERA + set_default_orientation(); +#endif // ENABLE_6DOF_CAMERA } std::string Camera::get_type_as_string() const @@ -91,6 +100,9 @@ void Camera::select_next_type() void Camera::set_target(const Vec3d& target) { +#if ENABLE_6DOF_CAMERA + translate_world(target - m_target); +#else BoundingBoxf3 test_box = m_scene_box; test_box.translate(-m_scene_box.center()); // We may let this factor be customizable @@ -101,8 +113,10 @@ void Camera::set_target(const Vec3d& target) m_target(0) = clamp(test_box.min(0), test_box.max(0), target(0)); m_target(1) = clamp(test_box.min(1), test_box.max(1), target(1)); m_target(2) = clamp(test_box.min(2), test_box.max(2), target(2)); +#endif // ENABLE_6DOF_CAMERA } +#if !ENABLE_6DOF_CAMERA void Camera::set_theta(float theta, bool apply_limit) { if (apply_limit) @@ -114,6 +128,7 @@ void Camera::set_theta(float theta, bool apply_limit) m_theta += 360.0f; } } +#endif // !ENABLE_6DOF_CAMERA void Camera::update_zoom(double delta_zoom) { @@ -130,7 +145,25 @@ void Camera::set_zoom(double zoom) // Don't allow to zoom too close to the scene. m_zoom = std::min(zoom, 100.0); } - +#if ENABLE_6DOF_CAMERA +void Camera::select_view(const std::string& direction) +{ + if (direction == "iso") + set_default_orientation(); + else if (direction == "left") + m_view_matrix = look_at(m_target - m_distance * Vec3d::UnitX(), m_target, Vec3d::UnitZ()); + else if (direction == "right") + m_view_matrix = look_at(m_target + m_distance * Vec3d::UnitX(), m_target, Vec3d::UnitZ()); + else if (direction == "top") + m_view_matrix = look_at(m_target + m_distance * Vec3d::UnitZ(), m_target, Vec3d::UnitY()); + else if (direction == "bottom") + m_view_matrix = look_at(m_target - m_distance * Vec3d::UnitZ(), m_target, -Vec3d::UnitY()); + else if (direction == "front") + m_view_matrix = look_at(m_target - m_distance * Vec3d::UnitY(), m_target, Vec3d::UnitZ()); + else if (direction == "rear") + m_view_matrix = look_at(m_target + m_distance * Vec3d::UnitY(), m_target, Vec3d::UnitZ()); +} +#else bool Camera::select_view(const std::string& direction) { const float* dir_vec = nullptr; @@ -159,6 +192,7 @@ bool Camera::select_view(const std::string& direction) else return false; } +#endif // ENABLE_6DOF_CAMERA double Camera::get_fov() const { @@ -180,20 +214,26 @@ void Camera::apply_viewport(int x, int y, unsigned int w, unsigned int h) const void Camera::apply_view_matrix() const { +#if !ENABLE_6DOF_CAMERA double theta_rad = Geometry::deg2rad(-(double)m_theta); double phi_rad = Geometry::deg2rad((double)phi); double sin_theta = ::sin(theta_rad); Vec3d camera_pos = m_target + m_distance * Vec3d(sin_theta * ::sin(phi_rad), sin_theta * ::cos(phi_rad), ::cos(theta_rad)); +#endif // !ENABLE_6DOF_CAMERA glsafe(::glMatrixMode(GL_MODELVIEW)); glsafe(::glLoadIdentity()); +#if ENABLE_6DOF_CAMERA + glsafe(::glMultMatrixd(m_view_matrix.data())); +#else glsafe(::glRotatef(-m_theta, 1.0f, 0.0f, 0.0f)); // pitch glsafe(::glRotatef(phi, 0.0f, 0.0f, 1.0f)); // yaw glsafe(::glTranslated(-camera_pos(0), -camera_pos(1), -camera_pos(2))); glsafe(::glGetDoublev(GL_MODELVIEW_MATRIX, m_view_matrix.data())); +#endif // ENABLE_6DOF_CAMERA } void Camera::apply_projection(const BoundingBoxf3& box, double near_z, double far_z) const @@ -300,7 +340,11 @@ void Camera::zoom_to_box(const BoundingBoxf3& box, int canvas_w, int canvas_h) { m_zoom = zoom; // center view around box center +#if ENABLE_6DOF_CAMERA + set_target(box.center()); +#else m_target = box.center(); +#endif // ENABLE_6DOF_CAMERA } } @@ -313,7 +357,11 @@ void Camera::zoom_to_volumes(const GLVolumePtrs& volumes, int canvas_w, int canv { m_zoom = zoom; // center view around the calculated center +#if ENABLE_6DOF_CAMERA + set_target(center); +#else m_target = center; +#endif // ENABLE_6DOF_CAMERA } } #endif // ENABLE_THUMBNAIL_GENERATOR @@ -360,6 +408,43 @@ void Camera::debug_render() const } #endif // ENABLE_CAMERA_STATISTICS +#if ENABLE_6DOF_CAMERA +void Camera::translate_world(const Vec3d& displacement) +{ + Vec3d new_target = validate_target(m_target + displacement); + Vec3d new_displacement = new_target - m_target; + if (!new_displacement.isApprox(Vec3d::Zero())) + { + m_target += new_displacement; + m_view_matrix.translate(-new_displacement); + } +} + +void Camera::rotate_on_sphere(double delta_azimut_rad, double delta_zenit_rad, bool apply_limit) +{ + Vec3d target = m_target; + translate_world(-target); + m_view_matrix.rotate(Eigen::AngleAxisd(delta_zenit_rad, get_dir_right())); + m_view_matrix.rotate(Eigen::AngleAxisd(delta_azimut_rad, Vec3d::UnitZ())); + translate_world(target); +} + +void Camera::rotate_local_around_target(const Vec3d& rotation_rad) +{ + Vec3d target = m_target; + translate_world(-target); + m_view_matrix.rotate(Eigen::AngleAxisd(rotation_rad(0), get_dir_right())); + m_view_matrix.rotate(Eigen::AngleAxisd(rotation_rad(1), get_dir_up())); + m_view_matrix.rotate(Eigen::AngleAxisd(rotation_rad(2), get_dir_forward())); + translate_world(target); +} + +bool Camera::is_looking_downward() const +{ + return get_dir_forward().dot(Vec3d::UnitZ()) < 0.0; +} +#endif // ENABLE_6DOF_CAMERA + std::pair Camera::calc_tight_frustrum_zs_around(const BoundingBoxf3& box) const { std::pair ret; @@ -540,6 +625,63 @@ void Camera::set_distance(double distance) const apply_view_matrix(); } +#if ENABLE_6DOF_CAMERA +Transform3d Camera::look_at(const Vec3d& position, const Vec3d& target, const Vec3d& up) const +{ + Vec3d unit_z = (position - target).normalized(); + Vec3d unit_x = up.cross(unit_z).normalized(); + Vec3d unit_y = unit_z.cross(unit_x).normalized(); + + Transform3d matrix; + + matrix(0, 0) = unit_x(0); + matrix(0, 1) = unit_x(1); + matrix(0, 2) = unit_x(2); + matrix(0, 3) = -unit_x.dot(position); + + matrix(1, 0) = unit_y(0); + matrix(1, 1) = unit_y(1); + matrix(1, 2) = unit_y(2); + matrix(1, 3) = -unit_y.dot(position); + + matrix(2, 0) = unit_z(0); + matrix(2, 1) = unit_z(1); + matrix(2, 2) = unit_z(2); + matrix(2, 3) = -unit_z.dot(position); + + matrix(3, 0) = 0.0; + matrix(3, 1) = 0.0; + matrix(3, 2) = 0.0; + matrix(3, 3) = 1.0; + + return matrix; +} + +void Camera::set_default_orientation() +{ + double theta_rad = Geometry::deg2rad(-45.0); + double phi_rad = Geometry::deg2rad(45.0); + double sin_theta = ::sin(theta_rad); + Vec3d camera_pos = m_target + m_distance * Vec3d(sin_theta * ::sin(phi_rad), sin_theta * ::cos(phi_rad), ::cos(theta_rad)); + m_view_matrix = Transform3d::Identity(); + m_view_matrix.rotate(Eigen::AngleAxisd(theta_rad, Vec3d::UnitX())).rotate(Eigen::AngleAxisd(phi_rad, Vec3d::UnitZ())).translate(-camera_pos); +} + +Vec3d Camera::validate_target(const Vec3d& target) const +{ + BoundingBoxf3 test_box = m_scene_box; + test_box.translate(-m_scene_box.center()); + // We may let this factor be customizable + static const double ScaleFactor = 1.5; + test_box.scale(ScaleFactor); + test_box.translate(m_scene_box.center()); + + return Vec3d(std::clamp(target(0), test_box.min(0), test_box.max(0)), + std::clamp(target(1), test_box.min(1), test_box.max(1)), + std::clamp(target(2), test_box.min(2), test_box.max(2))); +} +#endif // ENABLE_6DOF_CAMERA + } // GUI } // Slic3r diff --git a/src/slic3r/GUI/Camera.hpp b/src/slic3r/GUI/Camera.hpp index 6cd1b75a5..cfb0fd797 100644 --- a/src/slic3r/GUI/Camera.hpp +++ b/src/slic3r/GUI/Camera.hpp @@ -30,21 +30,29 @@ struct Camera Num_types }; +#if !ENABLE_6DOF_CAMERA float phi; - bool requires_zoom_to_bed; bool inverted_phi; +#endif // !ENABLE_6DOF_CAMERA + bool requires_zoom_to_bed; private: EType m_type; Vec3d m_target; +#if !ENABLE_6DOF_CAMERA float m_theta; +#endif // !ENABLE_6DOF_CAMERA double m_zoom; // Distance between camera position and camera target measured along the camera Z axis mutable double m_distance; mutable double m_gui_scale; mutable std::array m_viewport; +#if ENABLE_6DOF_CAMERA + Transform3d m_view_matrix; +#else mutable Transform3d m_view_matrix; +#endif // ENABLE_6DOF_CAMERA mutable Transform3d m_projection_matrix; mutable std::pair m_frustrum_zs; @@ -66,8 +74,10 @@ public: double get_distance() const { return m_distance; } double get_gui_scale() const { return m_gui_scale; } +#if !ENABLE_6DOF_CAMERA float get_theta() const { return m_theta; } void set_theta(float theta, bool apply_limit); +#endif // !ENABLE_6DOF_CAMERA double get_zoom() const { return m_zoom; } void update_zoom(double delta_zoom); @@ -76,7 +86,11 @@ public: const BoundingBoxf3& get_scene_box() const { return m_scene_box; } void set_scene_box(const BoundingBoxf3& box) { m_scene_box = box; } +#if ENABLE_6DOF_CAMERA + void select_view(const std::string& direction); +#else bool select_view(const std::string& direction); +#endif // ENABLE_6DOF_CAMERA const std::array& get_viewport() const { return m_viewport; } const Transform3d& get_view_matrix() const { return m_view_matrix; } @@ -110,6 +124,21 @@ public: void debug_render() const; #endif // ENABLE_CAMERA_STATISTICS +#if ENABLE_6DOF_CAMERA + // translate the camera in world space + void translate_world(const Vec3d& displacement); + + // rotate the camera on a sphere having center == m_target and radius == m_distance + // using the given variations of spherical coordinates + void rotate_on_sphere(double delta_azimut_rad, double delta_zenit_rad, bool apply_limit); + + // rotate the camera around three axes parallel to the camera local axes and passing through m_target + void rotate_local_around_target(const Vec3d& rotation_rad); + + // returns true if the camera z axis (forward) is pointing in the negative direction of the world z axis + bool is_looking_downward() const; +#endif // ENABLE_6DOF_CAMERA + private: // returns tight values for nearZ and farZ plane around the given bounding box // the camera MUST be outside of the bounding box in eye coordinate of the given box @@ -121,6 +150,12 @@ private: double calc_zoom_to_bounding_box_factor(const BoundingBoxf3& box, int canvas_w, int canvas_h) const; #endif // ENABLE_THUMBNAIL_GENERATOR void set_distance(double distance) const; + +#if ENABLE_6DOF_CAMERA + Transform3d look_at(const Vec3d& position, const Vec3d& target, const Vec3d& up) const; + void set_default_orientation(); + Vec3d validate_target(const Vec3d& target) const; +#endif // ENABLE_6DOF_CAMERA }; } // GUI diff --git a/src/slic3r/GUI/GLCanvas3D.cpp b/src/slic3r/GUI/GLCanvas3D.cpp index d2428cf96..860eab0fb 100644 --- a/src/slic3r/GUI/GLCanvas3D.cpp +++ b/src/slic3r/GUI/GLCanvas3D.cpp @@ -1792,8 +1792,14 @@ void GLCanvas3D::zoom_to_selection() void GLCanvas3D::select_view(const std::string& direction) { +#if ENABLE_6DOF_CAMERA + m_camera.select_view(direction); + if (m_canvas != nullptr) + m_canvas->Refresh(); +#else if (m_camera.select_view(direction) && (m_canvas != nullptr)) m_canvas->Refresh(); +#endif // ENABLE_6DOF_CAMERA } void GLCanvas3D::update_volumes_colors_by_extruder() @@ -1850,10 +1856,12 @@ void GLCanvas3D::render() GLfloat position_top[4] = { -0.5f, -0.5f, 1.0f, 0.0f }; glsafe(::glLightfv(GL_LIGHT0, GL_POSITION, position_top)); +#if !ENABLE_6DOF_CAMERA float theta = m_camera.get_theta(); if (theta > 180.f) // absolute value of the rotation theta = 360.f - theta; +#endif // !ENABLE_6DOF_CAMERA wxGetApp().imgui()->new_frame(); @@ -1878,7 +1886,11 @@ void GLCanvas3D::render() _render_objects(); _render_sla_slices(); _render_selection(); +#if ENABLE_6DOF_CAMERA + _render_bed(!m_camera.is_looking_downward(), true); +#else _render_bed(theta, true); +#endif // ENABLE_6DOF_CAMERA #if ENABLE_RENDER_SELECTION_CENTER _render_selection_center(); @@ -3213,7 +3225,11 @@ void GLCanvas3D::on_mouse(wxMouseEvent& evt) // we do not want to translate objects if the user just clicked on an object while pressing shift to remove it from the selection and then drag if (m_selection.contains_volume(get_first_hover_volume_idx())) { +#if ENABLE_6DOF_CAMERA + if (std::abs(m_camera.get_dir_forward()(2)) < EPSILON) +#else if (m_camera.get_theta() == 90.0f) +#endif // ENABLE_6DOF_CAMERA { // side view -> move selected volumes orthogonally to camera view direction Linef3 ray = mouse_ray(pos); @@ -3273,9 +3289,15 @@ void GLCanvas3D::on_mouse(wxMouseEvent& evt) if (m_hover_volume_idxs.empty() && m_mouse.is_start_position_3D_defined()) { const Vec3d& orig = m_mouse.drag.start_position_3D; +#if ENABLE_6DOF_CAMERA + m_camera.rotate_on_sphere(Geometry::deg2rad((pos(0) - orig(0))* (double)TRACKBALLSIZE), + Geometry::deg2rad((pos(1) - orig(1))* (double)TRACKBALLSIZE), + wxGetApp().preset_bundle->printers.get_edited_preset().printer_technology() != ptSLA); +#else float sign = m_camera.inverted_phi ? -1.0f : 1.0f; m_camera.phi += sign * ((float)pos(0) - (float)orig(0)) * TRACKBALLSIZE; m_camera.set_theta(m_camera.get_theta() - ((float)pos(1) - (float)orig(1)) * TRACKBALLSIZE, wxGetApp().preset_bundle->printers.get_edited_preset().printer_technology() != ptSLA); +#endif // ENABLE_6DOF_CAMERA m_dirty = true; } m_mouse.drag.start_position_3D = Vec3d((double)pos(0), (double)pos(1), 0.0); @@ -3325,9 +3347,11 @@ void GLCanvas3D::on_mouse(wxMouseEvent& evt) if (!evt.ShiftDown() && m_picking_enabled) deselect_all(); } +#if !ENABLE_6DOF_CAMERA else if (evt.LeftUp() && m_mouse.dragging) // Flips X mouse deltas if bed is upside down m_camera.inverted_phi = (m_camera.get_dir_up()(2) < 0.0); +#endif // !ENABLE_6DOF_CAMERA else if (evt.RightUp()) { m_mouse.position = pos.cast(); @@ -3932,6 +3956,9 @@ void GLCanvas3D::_render_thumbnail_internal(ThumbnailData& thumbnail_data, bool Camera camera; camera.set_type(Camera::Ortho); +#if ENABLE_6DOF_CAMERA + camera.set_scene_box(scene_bounding_box()); +#endif // ENABLE_6DOF_CAMERA camera.zoom_to_volumes(visible_volumes, thumbnail_data.width, thumbnail_data.height); camera.apply_viewport(0, 0, thumbnail_data.width, thumbnail_data.height); camera.apply_view_matrix(); @@ -3982,7 +4009,11 @@ void GLCanvas3D::_render_thumbnail_internal(ThumbnailData& thumbnail_data, bool glsafe(::glDisable(GL_DEPTH_TEST)); if (show_bed) +#if ENABLE_6DOF_CAMERA + _render_bed(!camera.is_looking_downward(), false); +#else _render_bed(camera.get_theta(), false); +#endif // ENABLE_6DOF_CAMERA if (transparent_background) glsafe(::glClearColor(1.0f, 1.0f, 1.0f, 1.0f)); diff --git a/src/slic3r/GUI/Mouse3DController.cpp b/src/slic3r/GUI/Mouse3DController.cpp index 8485c4b27..3dd12e021 100644 --- a/src/slic3r/GUI/Mouse3DController.cpp +++ b/src/slic3r/GUI/Mouse3DController.cpp @@ -168,12 +168,17 @@ bool Mouse3DController::State::apply(Camera& camera) if (has_rotation()) { +#if ENABLE_6DOF_CAMERA + Vec3d rotation = (m_rotation_params.scale * m_rotation.queue.front()).cast(); + camera.rotate_local_around_target(Vec3d(Geometry::deg2rad(rotation(0)), Geometry::deg2rad(-rotation(2)), Geometry::deg2rad(-rotation(1)))); +#else const Vec3f& rotation = m_rotation.queue.front(); float theta = m_rotation_params.scale * rotation(0); float phi = m_rotation_params.scale * rotation(2); float sign = camera.inverted_phi ? -1.0f : 1.0f; camera.phi += sign * phi; camera.set_theta(camera.get_theta() + theta, wxGetApp().preset_bundle->printers.get_edited_preset().printer_technology() != ptSLA); +#endif // ENABLE_6DOF_CAMERA m_rotation.queue.pop(); ret = true; } @@ -877,9 +882,15 @@ bool Mouse3DController::handle_packet_translation(const DataPacket& packet) bool Mouse3DController::handle_packet_rotation(const DataPacket& packet, unsigned int first_byte) { double deadzone = (double)m_state.get_rotation_deadzone(); +#if ENABLE_6DOF_CAMERA + Vec3f rotation((float)convert_input(packet[first_byte + 0], packet[first_byte + 1], deadzone), + (float)convert_input(packet[first_byte + 2], packet[first_byte + 3], deadzone), + (float)convert_input(packet[first_byte + 4], packet[first_byte + 5], deadzone)); +#else Vec3f rotation(-(float)convert_input(packet[first_byte + 0], packet[first_byte + 1], deadzone), (float)convert_input(packet[first_byte + 2], packet[first_byte + 3], deadzone), -(float)convert_input(packet[first_byte + 4], packet[first_byte + 5], deadzone)); +#endif // ENABLE_6DOF_CAMERA if (!rotation.isApprox(Vec3f::Zero())) { diff --git a/src/slic3r/GUI/Selection.cpp b/src/slic3r/GUI/Selection.cpp index 13be48289..224f5007d 100644 --- a/src/slic3r/GUI/Selection.cpp +++ b/src/slic3r/GUI/Selection.cpp @@ -2004,7 +2004,11 @@ void Selection::render_sidebar_layers_hints(const std::string& sidebar_field) co const float max_y = box.max(1) + Margin; // view dependend order of rendering to keep correct transparency +#if ENABLE_6DOF_CAMERA + bool camera_on_top = wxGetApp().plater()->get_camera().is_looking_downward(); +#else bool camera_on_top = wxGetApp().plater()->get_camera().get_theta() <= 90.0f; +#endif // ENABLE_6DOF_CAMERA float z1 = camera_on_top ? min_z : max_z; float z2 = camera_on_top ? max_z : min_z;