Study on the Key Technique of the Hill Shading Virtual Roaming System Based on XNA - Advances in Image and Graphics Technologies - page 233

Because the size of each terrain block file is the same 301×301, the array of
vertices indices need create in system initialization phase once.

Fig. 3. The lighting effect is not smooth in the seam

3.3 Terrain Splicing

The normals of vertices can be calculated based on the position of the vertices and the
indices defining triangles. A method of calculating vertex normal can be found in
reference [5]. But when a group of terrain blocks are splicing, because the vertices at
each block boundary miss parts of information about normal, the lighting effect is

Fig. 4. The lighting effect after terrain splicing