Second Life source Analysis (11) The realization of the ground display

After all the validation, the second life will be connected to the GRID server, from the server to get a lot of information, such as the role of the location, virtual world time and so on. Then will be based on this information to construct a frame of the picture displayed, here first look at the following picture: Cai Junsheng  2008/1/8 qq:9073204 Shenzhen from this picture, you can see the sky, there is ground, there are houses, people and trees and so on. So many things are the same as real time rendering out, now to see how the ground is constructed. The current 3D technology uses grids and textures to construct real-time rendering, so the second Life rendering is the same. So the grid data from the ground comes from there. The texture of the ground picture is coming from there. In the second Life, the ground grid data is relatively simple, only a plane, directly in the program construction can be. Texture pictures are downloaded from the server, as long as the replacement of different texture pictures can achieve different ground patterns.   Below is the code to create the ground grid model: #001  bool llvoground::updategeometry (lldrawable *drawable) #002  {#003    Llstrider<llvector3> Verticesp; #004   LLStrider<LLVector3> NORMALSP; #005   LLStrider<LLVector2> TEXCOORDSP; #006   LLStrider<U32> Indicesp; #007   s32 Index_offset; #008   llface *face;   #009   #010   lldrawpoolground *poolp = (lldrawpoolground*) Gpipeline.getpool (lldrawpool::P ool_ground); #011   #012   if (Drawable->getnumfaces () < 1) #013           Drawable->addface (POOLP, NULL); #014   face = drawable->getface (0); #015          above get No. 0 surface mesh.   #016   if (Face->mvertexbuffer.isnull ()) #017   {#018           face->setsize (5, 12); Sets the number of vertices and indexes for a planar construct.   #019          face->mvertexbuffer = new Llvertexbuffer ( Lldrawpoolground::vertex_data_mask, Gl_stream_draw_arb); #020          Face->mvertexbuffer->allocatebuffer (face-> Getgeomcount (), Face->getindicescount (), TRUE); Creates a vertex buffer and allocates the size of the memory.   #021          face->setgeomindex (0); #022          face->setindicesindex (0); #023  &nbsp} #024    #025   index_offset = Face->getgeometry (VERTICESP,NORMALSP, TEXCOORDSP, INDICESP); #026   if ( -1 = index_offset) #027   {#028          return TRUE; #029  &nbsp} #030   #031   ///////////////////////////////////////#032   //#033    //#034   //#035   llvector3 at_dir = Gcamera->getataxis (); #036   at_dir.mv[vz] = 0.f; #037   if (At_dir.normvec () < 0.01) #038   {#039          //We really don ' t care, as We ' re not looking anywhere near the horizon. #040  &nbsp} #041   llvector3 left_dir = Gcamera->getleftaxis (); #042   left_dir.mv[vz] = 0.f; #043   left_dir.normvec (); #044   #045   //Our center-point #046   llcolor4 ground_color = Gsky.getfogcolor (); #047   ground_color.mv[3] = 1.f; #048   face->setfacecolor (Ground_color); Set the color of the ground.   #049    #050   * (verticesp++)  = LLVector3 (64, 64, 0); #051   * (verticesp++)  = LLVector3 (-64, 64, 0);#052   * (verticesp++)  = LLVector3 (-64,-64, 0); #053   * (verticesp++)  = LLVector3 (64,-64, 0); #054   * (verticesp++)  = LLVector3 (0, 0,-1024); #055    Sets the coordinates of 5 vertices.   #056    #057   //triangles for each side #058   *indicesp++ = index_offset + 0; #059   *indicesp++ = index_offset + 1; #060   *indicesp++ = Index_offset + 4; #061   #062   *indicesp++ = index_offset + 1; #063   *indicesp++ = Index_offset + 2; #064   *indicesp++ = Index_offset + 4; #065   #066   *indicesp++ = Index_offset + 2; #067   *indicesp++ = Index_offset + 3; #068   *indicesp++ = Index_offset + 4; #069   #070   *indicesp++ = Index_offset + 3; #071   *indicesp++ = index_offset + 0; #072   *indicesp++ = Index_offset + 4; #073   Sets the index of 4 triangles to form a ground plane.   #074   * (texcoordsp++) = LLVector2 (0.F, 0.F); #075   * (texcoordsp++) = LLVector2 (1.f, 0.F); #076   * (texcoordsp++) = LLVector2 (1.f, 1.F); #077   * (texcoordsp++) = LLVector2 (0.F, 1.F); #078   * (texcoordsp++) = LLVector2 (0.5f, 0.5f); #079    The texture coordinates of the texture surface are set above.   #080   LLPipeline::sCompiles++; #081   return TRUE; #082 &nbsp} #083     Constructs a four-triangle planar grid with the above code and sets the texture coordinates. Before rendering the ground, the texture image of the ground is downloaded from the server and set into the texture channel of OPENGL, which can be displayed as the ground on the image.