diff --git a/android/src/main/cpp/main.cpp b/android/src/main/cpp/main.cpp
index f28ca4e..69546e8 100755
--- a/android/src/main/cpp/main.cpp
+++ b/android/src/main/cpp/main.cpp
@@ -437,10 +437,11 @@ static int32_t engine_handle_input(struct android_app* app, AInputEvent* event)
         {
             float y = AMotionEvent_getY(event, 0);
             float x = AMotionEvent_getX(event, 0);
-            tracked = 0;
             p0.id = -1;
             p1.id = -1;
-            App::I.mouse_up(0, x, y);
+            if (tracked == 1)
+                App::I.mouse_up(0, x, y);
+            tracked = 0;
             //LOG("first up");
             return 1;
         }
@@ -461,7 +462,7 @@ static int32_t engine_handle_input(struct android_app* app, AInputEvent* event)
             return 1;
         }
         case AMOTION_EVENT_ACTION_MOVE:
-            if (count == 1)
+            if (count == 1 && tracked == 1)
             {
                 float y = AMotionEvent_getY(event, 0);
                 float x = AMotionEvent_getX(event, 0);
diff --git a/data/layout.xml b/data/layout.xml
index 3f298ce..1ce82dd 100644
--- a/data/layout.xml
+++ b/data/layout.xml
@@ -362,7 +362,8 @@
         <button id="btn-erase" width="60" height="100%" margin="0 0 0 0" text="Erase"/>
         <button id="btn-line" width="50" height="100%" margin="0 0 0 0" text="Line"/>
         <button id="btn-cam" width="70" height="100%" margin="0 0 0 0" text="Camera"/>
-        <!-- 
+        <button id="btn-normal" width="70" height="100%" margin="0 0 0 0" text="Normal"/>
+        <!--
         <button-custom id="btn-layer" width="50" height="100%" margin="0 5 0 0" thickness="1" border-color="0 0 0 1" pad="6" align="center" justify="center">
           <icon width="100%" height="100%" icon="disk"/>
         </button-custom>
diff --git a/engine/app.cpp b/engine/app.cpp
index 8bde62d..02b4113 100644
--- a/engine/app.cpp
+++ b/engine/app.cpp
@@ -472,6 +472,7 @@ void App::initLayout()
                 layout[main_id]->find<NodeButton>("btn-erase")->set_color(color_button_normal);
                 layout[main_id]->find<NodeButton>("btn-line")->set_color(color_button_normal);
                 layout[main_id]->find<NodeButton>("btn-cam")->set_color(color_button_normal);
+                layout[main_id]->find<NodeButton>("btn-normal")->set_color(color_button_normal);
                 Canvas::set_mode(Canvas::kCanvasMode::Draw);
             };
             layout[main_id]->find<NodeButton>("btn-pen")->set_color(color_button_hlight);
@@ -484,6 +485,7 @@ void App::initLayout()
                 layout[main_id]->find<NodeButton>("btn-erase")->set_color(color_button_hlight);
                 layout[main_id]->find<NodeButton>("btn-line")->set_color(color_button_normal);
                 layout[main_id]->find<NodeButton>("btn-cam")->set_color(color_button_normal);
+                layout[main_id]->find<NodeButton>("btn-normal")->set_color(color_button_normal);
                 Canvas::set_mode(Canvas::kCanvasMode::Erase);
             };
         }
@@ -494,6 +496,7 @@ void App::initLayout()
                 layout[main_id]->find<NodeButton>("btn-erase")->set_color(color_button_normal);
                 layout[main_id]->find<NodeButton>("btn-line")->set_color(color_button_hlight);
                 layout[main_id]->find<NodeButton>("btn-cam")->set_color(color_button_normal);
+                layout[main_id]->find<NodeButton>("btn-normal")->set_color(color_button_normal);
                 Canvas::set_mode(Canvas::kCanvasMode::Line);
             };
         }
@@ -504,9 +507,21 @@ void App::initLayout()
                 layout[main_id]->find<NodeButton>("btn-erase")->set_color(color_button_normal);
                 layout[main_id]->find<NodeButton>("btn-line")->set_color(color_button_normal);
                 layout[main_id]->find<NodeButton>("btn-cam")->set_color(color_button_hlight);
+                layout[main_id]->find<NodeButton>("btn-normal")->set_color(color_button_normal);
                 Canvas::set_mode(Canvas::kCanvasMode::Camera);
             };
         }
+        if (auto* button = layout[main_id]->find<NodeButton>("btn-normal"))
+        {
+            button->on_click = [this](Node*) {
+                layout[main_id]->find<NodeButton>("btn-pen")->set_color(color_button_normal);
+                layout[main_id]->find<NodeButton>("btn-erase")->set_color(color_button_normal);
+                layout[main_id]->find<NodeButton>("btn-line")->set_color(color_button_normal);
+                layout[main_id]->find<NodeButton>("btn-cam")->set_color(color_button_normal);
+                layout[main_id]->find<NodeButton>("btn-normal")->set_color(color_button_hlight);
+                Canvas::set_mode(Canvas::kCanvasMode::Normal);
+            };
+        }
         if (auto* button = layout[main_id]->find<NodeButtonCustom>("btn-bucket"))
         {
             button->on_click = [this](Node*) {
diff --git a/engine/canvas.cpp b/engine/canvas.cpp
index 90844a2..d04178d 100644
--- a/engine/canvas.cpp
+++ b/engine/canvas.cpp
@@ -8,6 +8,7 @@ std::vector<CanvasMode*> ui::Canvas::modes[] = {
     { new CanvasModePen, new CanvasModeBasicCamera },
     { new CanvasModeLine, new CanvasModeBasicCamera },
     { new CanvasModeCamera, new CanvasModeBasicCamera },
+    { new CanvasModeNormal, new CanvasModeBasicCamera },
 };
 glm::vec3 ui::Canvas::m_plane_origin[6] = {
     { 0, 0,-1}, // front
@@ -127,32 +128,11 @@ void ui::Canvas::stroke_draw()
             ShaderManager::u_vec2(kShaderUniform::Resolution, { m_width, m_height });
             for (const auto& s : samples)
             {
-                auto unproject = [](glm::vec2 loc, glm::vec4 vp, glm::mat4 camera, glm::mat4 proj, glm::vec3& out_origin, glm::vec3& out_dir) {
-                    auto clip_space = glm::vec2(loc.x, vp.w - loc.y - 1.f) / vp.zw() * 2.f - 1.f;
-                    auto inv = glm::inverse(proj * camera);
-                    auto wp0 = inv * glm::vec4(clip_space, 0, 1);
-                    auto wp1 = inv * glm::vec4(clip_space, .5, 1);
-                    out_origin = (wp0 / wp0.w).xyz();
-                    out_dir = glm::normalize((wp1 / wp1.w).xyz() - out_origin);
-                };
-                auto intersect = [](glm::vec3 ray_origin, glm::vec3 ray_dir, glm::vec3 plane_origin, glm::vec3 plane_normal, glm::vec3 plane_tangent, glm::vec3& out_hit) {
-                    float den = glm::dot(ray_dir, plane_normal);
-                    if (den == 0)
-                        return false;  // no intersection
-                    float num = glm::dot(plane_origin - ray_origin, plane_normal);
-                    float t = num / den;
-                    if (t > 0)
-                        out_hit = ray_origin + ray_dir * t;
-                    else
-                        // negative intersection
-                        return false;
-                    return true;
-                }; 
                 glm::vec3 ray_origin, ray_dir;
-                unproject(s.pos, { 0, 0, m_box.zw }, m_mv, m_proj, ray_origin, ray_dir);
+                point_unproject(s.pos, { 0, 0, m_box.zw }, m_mv, m_proj, ray_origin, ray_dir);
                 glm::vec3 hit;
                 glm::vec2 fb_pos;
-                if (intersect(ray_origin, ray_dir, m_plane_origin[i], m_plane_normal[i], m_plane_tangent[i], hit))
+                if (ray_intersect(ray_origin, ray_dir, m_plane_origin[i], m_plane_normal[i], m_plane_tangent[i], hit))
                 {
                     glm::mat4 plane_camera = glm::lookAt(m_plane_origin[i], m_plane_normal[i], m_plane_tangent[i]);
                     glm::vec4 plane_local = plane_camera * glm::vec4(hit, 1);
@@ -252,6 +232,74 @@ void ui::Canvas::stroke_draw()
         m_commit_delayed = false;
     }
 }
+bool ui::Canvas::point_trace(glm::vec2 loc, glm::vec3& ray_origin, glm::vec3& ray_dir,
+                             glm::vec3& hit_pos, glm::vec3& hit_normal, int& out_plane_id)
+{
+    point_unproject(loc, { 0, 0, m_box.zw }, m_mv, m_proj, ray_origin, ray_dir);
+    glm::vec3 hit;
+    glm::vec2 fb_pos;
+    for (int i = 0; i < 6; i++)
+    {
+        if (ray_intersect(ray_origin, ray_dir, m_plane_origin[i], m_plane_normal[i], m_plane_tangent[i], hit))
+        {
+            glm::mat4 plane_camera = glm::lookAt(m_plane_origin[i], m_plane_normal[i], m_plane_tangent[i]);
+            glm::vec4 plane_local = plane_camera * glm::vec4(hit, 1);
+            if (glm::abs(plane_local.x) < 1.f && glm::abs(plane_local.y) < 1.f)
+            {
+                fb_pos.x = -(plane_local.x * 0.5f - 0.5f) * m_width;
+                fb_pos.y = (plane_local.y * 0.5f + 0.5f) * m_height;
+                hit_pos = hit;
+                hit_normal = m_plane_normal[i];
+                out_plane_id = i;
+                return true;
+            }
+            else continue;
+        }
+        else continue;
+    }
+    return false;
+}
+bool ui::Canvas::point_trace_plane(glm::vec2 loc, glm::vec3& ray_origin, glm::vec3& ray_dir,
+                             glm::vec3& hit_pos, glm::vec3& hit_normal, int plane_id)
+{
+    point_unproject(loc, { 0, 0, m_box.zw }, m_mv, m_proj, ray_origin, ray_dir);
+    glm::vec3 hit;
+    glm::vec2 fb_pos;
+    if (ray_intersect(ray_origin, ray_dir, m_plane_origin[plane_id],
+                      m_plane_normal[plane_id], m_plane_tangent[plane_id], hit))
+    {
+        glm::mat4 plane_camera = glm::lookAt(m_plane_origin[plane_id], m_plane_normal[plane_id], m_plane_tangent[plane_id]);
+        hit_pos = hit;
+        hit_normal = m_plane_normal[plane_id];
+        return true;
+    }
+    return false;
+}
+bool ui::Canvas::ray_intersect(glm::vec3 ray_origin, glm::vec3 ray_dir, glm::vec3 plane_origin,
+                               glm::vec3 plane_normal, glm::vec3 plane_tangent, glm::vec3& out_hit)
+{
+    float den = glm::dot(ray_dir, plane_normal);
+    if (den == 0)
+        return false;  // no intersection
+    float num = glm::dot(plane_origin - ray_origin, plane_normal);
+    float t = num / den;
+    if (t > 0)
+        out_hit = ray_origin + ray_dir * t;
+    else
+        // negative intersection
+        return false;
+    return true;
+};
+void ui::Canvas::point_unproject(glm::vec2 loc, glm::vec4 vp, glm::mat4 camera, glm::mat4 proj,
+                                 glm::vec3& out_origin, glm::vec3& out_dir)
+{
+    auto clip_space = glm::vec2(loc.x, vp.w - loc.y - 1.f) / vp.zw() * 2.f - 1.f;
+    auto inv = glm::inverse(proj * camera);
+    auto wp0 = inv * glm::vec4(clip_space, 0, 1);
+    auto wp1 = inv * glm::vec4(clip_space, .5, 1);
+    out_origin = (wp0 / wp0.w).xyz();
+    out_dir = glm::normalize((wp1 / wp1.w).xyz() - out_origin);
+};
 void ui::Canvas::stroke_commit()
 {
     if (!m_dirty || m_layers.empty())
@@ -723,6 +771,37 @@ ui::Image ui::Canvas::thumbnail_read(std::string data_path)
     return std::move(thumb);
 }
 
+void ui::Canvas::draw_objects(std::function<void(const glm::mat4& camera, const glm::mat4& proj)> observer)
+{
+    // save viewport and clear color states
+    GLint vp[4];
+    GLfloat cc[4];
+    glGetIntegerv(GL_VIEWPORT, vp);
+    glGetFloatv(GL_COLOR_CLEAR_VALUE, cc);
+    GLboolean blend = glIsEnabled(GL_BLEND);
+
+    // prepare common states
+    glViewport(0, 0, m_width, m_height);
+    glDisable(GL_BLEND);
+
+    glm::mat4 proj = glm::perspective(glm::radians(90.f), 1.f, .1f, 100.f);
+    for (int i = 0; i < 6; i++)
+    {
+        glm::mat4 plane_camera = glm::lookAt(glm::vec3(0), m_plane_origin[i], m_plane_tangent[i]);
+        m_layers[m_current_layer_idx].m_rtt[i].bindFramebuffer();
+
+        observer(plane_camera, proj);
+
+        m_layers[m_current_layer_idx].m_rtt[i].unbindFramebuffer();
+    }
+
+    // restore viewport and clear color states
+    blend ? glEnable(GL_BLEND) : glDisable(GL_BLEND);
+    glViewport(vp[0], vp[1], vp[2], vp[3]);
+    glClearColor(cc[0], cc[1], cc[2], cc[3]);
+    glActiveTexture(GL_TEXTURE0);
+}
+
 ///////////////////////////////////////////////////////////////////////////////////////////
 
 void ui::Layer::destroy()
diff --git a/engine/canvas.h b/engine/canvas.h
index 40f1c29..4dae640 100644
--- a/engine/canvas.h
+++ b/engine/canvas.h
@@ -71,7 +71,7 @@ public:
     glm::vec3 m_cam_pos;
     float m_cam_fov = 85;
 
-    enum class kCanvasMode { Draw, Erase, Line, Camera, COUNT };
+    enum class kCanvasMode { Draw, Erase, Line, Camera, Normal, COUNT };
     kCanvasMode m_state{ kCanvasMode::Draw };
     static std::vector<CanvasMode*> modes[];
     std::vector<CanvasMode*>* m_mode;
@@ -106,6 +106,15 @@ public:
     ui::Image thumbnail_generate(int w, int h);
     ui::Image thumbnail_read(std::string data_path);
     void preview_generate();
+    void draw_objects(std::function<void(const glm::mat4& camera, const glm::mat4& proj)>);
+    bool ray_intersect(glm::vec3 ray_origin, glm::vec3 ray_dir, glm::vec3 plane_origin,
+                          glm::vec3 plane_normal, glm::vec3 plane_tangent, glm::vec3 &out_hit);
+    void point_unproject(glm::vec2 loc, glm::vec4 vp, glm::mat4 camera, glm::mat4 proj,
+                         glm::vec3 &out_origin, glm::vec3 &out_dir);
+    bool point_trace(glm::vec2 loc, glm::vec3& ray_origin, glm::vec3& ray_dir,
+                     glm::vec3& hit_pos, glm::vec3& hit_normal, int& out_plane_id);
+    bool point_trace_plane(glm::vec2 loc, glm::vec3& ray_origin, glm::vec3& ray_dir,
+                     glm::vec3& hit_pos, glm::vec3& hit_normal, int plane_id);
 };
 
 class ActionStroke : public Action
diff --git a/engine/canvas_modes.cpp b/engine/canvas_modes.cpp
index 287ee38..fbff423 100644
--- a/engine/canvas_modes.cpp
+++ b/engine/canvas_modes.cpp
@@ -120,6 +120,7 @@ void CanvasModeLine::on_MouseEvent(MouseEvent* me, glm::vec2& loc)
             break;
         case kEventType::MouseCancel:
             node->mouse_release();
+            m_dragging = false;
             break;
         default:
             break;
@@ -172,6 +173,7 @@ void CanvasModeCamera::on_MouseEvent(MouseEvent* me, glm::vec2& loc)
             canvas->m_cam_pos.xy = m_pos_start + (me->m_pos - m_drag_start) * glm::vec2(1, -1) * 0.01f;
         break;
     case kEventType::MouseCancel:
+        m_dragging = false;
         node->mouse_release();
         break;
     default:
@@ -183,15 +185,76 @@ void CanvasModeCamera::on_MouseEvent(MouseEvent* me, glm::vec2& loc)
 
 void CanvasModeNormal::on_MouseEvent(MouseEvent* me, glm::vec2& loc)
 {
-
+    switch (me->m_type)
+    {
+        case kEventType::MouseDownL:
+        {
+            node->mouse_capture();
+            glm::vec3 ro, rd, hit_o, hit_d;
+            if (canvas->point_trace(loc, ro, rd, hit_o, hit_d, m_plane_id))
+            {
+                origin = hit_o;
+                dir = hit_d;
+                m_dragging = true;
+            }
+            break;
+        }
+        case kEventType::MouseUpL:
+            node->mouse_release();
+            m_dragging = false;
+            commit();
+            break;
+        case kEventType::MouseMove:
+        {
+            glm::vec3 ro, rd, hit_o, hit_d;
+            if (m_dragging && canvas->point_trace_plane(loc, ro, rd, hit_o, hit_d, m_plane_id))
+            {
+                origin = hit_o;
+                dir = hit_d;
+                m_dragging = true;
+            }
+            break;
+        }
+        case kEventType::MouseCancel:
+            m_dragging = false;
+            node->mouse_release();
+            break;
+        default:
+            break;
+    }
 }
 
 void CanvasModeNormal::on_Draw(const glm::mat4& ortho, const glm::mat4& proj, const glm::mat4& camera)
 {
-
+    if (m_dragging)
+    {
+        ui::ShaderManager::use(ui::kShader::Color);
+        ui::ShaderManager::u_mat4(ui::kShaderUniform::MVP, proj * camera);
+        ui::ShaderManager::u_vec4(ui::kShaderUniform::Col, {1, 0, 0, 1});
+        static glm::vec4 AB[2];
+        AB[0] = {origin - dir * 10.f, 1};
+        AB[1] = {origin + dir * 10.f, 1 };
+        m_line.update_vertices(AB);
+        m_line.draw_stroke();
+    }
 }
 
 void CanvasModeNormal::init()
 {
     m_line.create();
 }
+
+void CanvasModeNormal::commit()
+{
+    auto drawer = [this](const glm::mat4& camera, const glm::mat4& proj){
+        ui::ShaderManager::use(ui::kShader::Color);
+        ui::ShaderManager::u_mat4(ui::kShaderUniform::MVP, proj * camera);
+        ui::ShaderManager::u_vec4(ui::kShaderUniform::Col, {1, 0, 0, 1});
+        static glm::vec4 AB[2];
+        AB[0] = {origin - dir * 10.f, 1};
+        AB[1] = {origin + dir * 10.f, 1 };
+        m_line.update_vertices(AB);
+        m_line.draw_stroke();
+    };
+    canvas->draw_objects(std::bind(drawer, std::placeholders::_1, std::placeholders::_2));
+}
diff --git a/engine/canvas_modes.h b/engine/canvas_modes.h
index 5ecb415..9d0c561 100644
--- a/engine/canvas_modes.h
+++ b/engine/canvas_modes.h
@@ -59,13 +59,15 @@ public:
 class CanvasModeNormal : public CanvasMode
 {
     ui::LineSegment m_line;
+    glm::vec3 origin;
+    glm::vec3 dir;
+    int m_plane_id;
     bool m_dragging = false;
-    glm::vec2 m_drag_start;
-    glm::vec2 m_drag_pos;
 public:
     virtual void on_MouseEvent(MouseEvent* me, glm::vec2& loc) override;
     virtual void on_Draw(const glm::mat4& ortho, const glm::mat4& proj, const glm::mat4& camera) override;
     virtual void init() override;
+    void commit();
 };
 
 class CanvasModeCamera : public CanvasMode
diff --git a/engine/layout.h b/engine/layout.h
index 59464fa..ac44fde 100644
--- a/engine/layout.h
+++ b/engine/layout.h
@@ -1979,15 +1979,15 @@ public:
     {
         m_mouse_ignore = false;
         m_canvas = std::make_unique<ui::Canvas>();
+        m_canvas->create(1024, 1024);
+        m_sampler.create();
+        m_face_plane.create<1>(2, 2);
+        m_line.create();
         CanvasMode::node = this;
         CanvasMode::canvas = m_canvas.get();
         for (int i = 0; i < (int)ui::Canvas::kCanvasMode::COUNT; i++)
             for (auto m : ui::Canvas::modes[i])
                 m->init();
-        m_canvas->create(1024, 1024);
-        m_sampler.create();
-        m_face_plane.create<1>(2, 2);
-        m_line.create();
     }
     virtual void restore_context() override
     {
@@ -1996,12 +1996,18 @@ public:
         m_sampler.create();
         m_face_plane.create<1>(2, 2);
         m_canvas->snapshot_restore();
+        CanvasMode::node = this;
+        CanvasMode::canvas = m_canvas.get();
+        for (int i = 0; i < (int)ui::Canvas::kCanvasMode::COUNT; i++)
+            for (auto m : ui::Canvas::modes[i])
+                m->init();
     }
     virtual void clear_context() override
     {
         Node::clear_context();
         m_canvas->snapshot_save(data_path);
         m_canvas->clear_context();
+        // TODO: clear CanvasMode objects
     }
     virtual void draw() override
     {
diff --git a/engine/main.cpp b/engine/main.cpp
index 6d989a3..949a9ce 100644
--- a/engine/main.cpp
+++ b/engine/main.cpp
@@ -268,6 +268,14 @@ static CVReturn MyDisplayLinkCallback(CVDisplayLinkRef displayLink, const CVTime
     auto chars = [theEvent characters];
     App::I.key_up(convert_key(keyCode));
     CGLUnlockContext([[self openGLContext] CGLContextObj]);
+}
+- (void)tabletPoint:(NSEvent *)theEvent
+{
+    
+}
+- (void)tabletProximity:(NSEvent *)theEvent
+{
+    
 }
 @end