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   Use 'MeshOverlay' for rendering semi transparent images on solid surfaces (like bullet holes).

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struct MeshOverlay // Mesh Overlay - used for rendering semi transparent images on solid surfaces (like bullet holes), this is an alternative to 'Decal' which affects also nearby objects
{
   Bool createStatic  (C Mesh &mesh, C MaterialPtr &material, C Matrix &overlay_matrix, C Matrix *mesh_matrix=null); // create from source 'mesh', 'material'=overlay material, 'overlay_matrix'=matrix of the overlay in world space (with 'overlay_matrix.x overlay_matrix.y' being the surface vectors and 'overlay_matrix.z' being the direction vector, length of all the vectors determines overlay size), 'mesh_matrix'=source mesh matrix at the moment of applying the overlay (if null 'MatrixIdentity' will be used), returns false when no mesh has been created
   Bool createAnimated(C Mesh &mesh, C MaterialPtr &material, C Matrix &overlay_matrix, C Matrix *mesh_matrix=null); // create from source 'mesh', 'material'=overlay material, 'overlay_matrix'=matrix of the overlay in world space (with 'overlay_matrix.x overlay_matrix.y' being the surface vectors and 'overlay_matrix.z' being the direction vector, length of all the vectors determines overlay size), 'mesh_matrix'=source mesh matrix at the moment of applying the overlay (if null 'MatrixIdentity' will be used), returns false when no mesh has been created

#if EE_PRIVATE
   void zero     ();
   void setShader();
   void setParams(Flt alpha)C;
#endif

   // get / set
   MeshOverlay& material(C MaterialPtr &material);   C MaterialPtr& material()C {return _material;} // set/get material

   // draw, 'MeshOverlay' should be drawn in each frame with the same 'Matrix' or 'AnimatedSkeleton' as the source 'mesh' from which 'MeshOverlay' has been created, drawing should be called only in RM_OVERLAY rendering mode, doesn't use automatic Frustum culling
   void draw(                               Flt alpha=1)C; // draw with  current    matrix  , 'alpha'=opacity
   void draw(C MatrixM          &matrix   , Flt alpha=1)C; // draw with 'matrix'    matrix  , 'alpha'=opacity
   void draw(C AnimatedSkeleton &anim_skel, Flt alpha=1)C; // draw with 'anim_skel' matrixes, 'alpha'=opacity

   // io
   Bool save(File &f, CChar *path=null)C; // save, 'path'=path at which resource is located (this is needed so that the sub-resources can be accessed with relative path), false on fail
   Bool load(File &f, CChar *path=null) ; // load, 'path'=path at which resource is located (this is needed so that the sub-resources can be accessed with relative path), false on fail

   MeshOverlay& del(); // delete manually
   MeshOverlay();

#if !EE_PRIVATE
private:
#endif
   struct Lod
   {
      Flt        dist2;
      MeshRender mshr;
   };
   Vec         _lod_center;
   Extent      _ext;
   Matrix      _matrix;
   Mems<Lod>   _lods;
   MaterialPtr _material;
   Shader     *_shader;
#if EE_PRIVATE
 C MeshRender& getDrawLod(C Matrix  &matrix)C;
 C MeshRender& getDrawLod(C MatrixM &matrix)C;
#endif
};
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