fix shaders for the transform tool

src/canvas_modes.h

@@ -158,16 +158,16 @@ class CanvasModeTransform : public CanvasMode
     int corner_hl = -1;
     glm::vec3 m_center_point{};
     glm::vec2 m_center_point_uv{};
-    glm::mat4 m_xform{};
-    glm::mat4 m_xform_local{};
+    glm::mat4 m_xform{1};
+    glm::mat4 m_xform_local{1};
     int m_counter = 0;
     bool m_dragging = false;
     int m_drag_corner = -1;
     float m_drag_diag = 0;
     std::vector<glm::vec2> m_drag_corners2d{};
     glm::vec2 m_drag_start{};
-    glm::mat4 m_drag_xform{};
-    glm::mat4 m_drag_xform_local{};
+    glm::mat4 m_drag_xform{1};
+    glm::mat4 m_drag_xform_local{1};
     std::vector<vertex_t> m_points{};
     std::vector<glm::vec2> m_points2d{};
     std::map<int, int> m_dirty_planes{};