Engine Pipelines  
 

Main engine loop is:


1 - keyboard input - detect if program must terminate,

    set a viewer move direction vector and viewer
    
    rotation angles;

2 - detect collision - can change the move directon vector or

    make portal crossing detection;

3 - update viewer reference system

4 - make sockets communication - send viewer position and

    receive objects position;

5 - render frame

6 - goto step 1.


Rendering pipeline overview:


Before rendering, must be already defined, the start

sector - sector where viewer is and, the clip edge buffer,

must be initialized with viewport limits.

The main rendering steps are:

1 - transform sector mesh to camera reference system;

2 - project and ajust mesh to viewport;

3 - for each polygon:

3.1 - copy projected polygon vertexes to an array and

      count how much of them are behing near Z clip plan or

      outside viewport (only horizontal or vertical) limits.

3.2 - if the polygon is completety outside the viewer area

      skip polygon, goto step 3;

3.3 - make backface culling (usefull to avoid engine deathlock

      and remove some invisible polygons).
    
      The engine deathlock happens when a previous rendered
    
      sector is rendered again. Recursively, is
    
      called the render algorithm from a destin sector to a
    
      previous sector.

      If polygon not visible, goto step 3;

3.4 - create a new clipped polygon, if polygon intersect

      near Z clip plan;

3.5 - verify if the polygon is a portal

3.6 - if is a portal:

         set a new clip edge buffer for the destin sector,
         
         verify if some portal part is visible. If yes, call
         
         recursively the rendering (goto step 1). Before
         
         end rendering the destin sector, is needed make
         
         steps 1 and 2 again for the current sector.

         3DFC v0.0.1 use the same structure, for all

         redendered meshes, to store camera and

         projected data. On next versions this would change.

      if the polygon is not a portal:

         render a textured polygon making portal clip.

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