ryzom/client/src/landscape_poly_drawer.h

   1 // Ryzom - MMORPG Framework <http://dev.ryzom.com/projects/ryzom/>
   2 // Copyright (C) 2010  Winch Gate Property Limited
   3 //
   4 // This source file has been modified by the following contributors:
   5 // Copyright (C) 2013-2014  Jan BOON (Kaetemi) <jan.boon@kaetemi.be>
   6 //
   7 // This program is free software: you can redistribute it and/or modify
   8 // it under the terms of the GNU Affero General Public License as
   9 // published by the Free Software Foundation, either version 3 of the
  10 // License, or (at your option) any later version.
  11 //
  12 // This program is distributed in the hope that it will be useful,
  13 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 // GNU Affero General Public License for more details.
  16 //
  17 // You should have received a copy of the GNU Affero General Public License
  18 // along with this program.  If not, see <http://www.gnu.org/licenses/>.
  19
  20 #ifndef CL_LANDSCAPE_POLY_DRAWER_H
  21 #define CL_LANDSCAPE_POLY_DRAWER_H
  22
  23 // Misc
  24 #include "nel/misc/aabbox.h"
  25 #include "nel/misc/polygon.h"
  26 #include "nel/misc/singleton.h"
  27
  28 // 3D
  29 #include "nel/3d/index_buffer.h"
  30 #include "nel/3d/vertex_buffer.h"
  31
  32
  33 //-----------------------------------------------------------------------------------------------------------
  34 //---------------------------------------- CInitStencil -----------------------------------------------------
  35 //-----------------------------------------------------------------------------------------------------------
  36 // CInitStencil inherits from the abstract NEL class ILandscapePolyDrawingCallback, attribut of UScene.
  37 // An instance of CInitStencil is initialized at the time of CLandscapePolyDrawer initialization
  38 // and passed to current scene. Thus, when stencil operation must be modified in a NEL class,
  39 // this instance is used with its callbacks without any NEL class knows CLandscapePolyDrawer class.
  40 //-----------------------------------------------------------------------------------------------------------
  41 class CInitStencil : public NL3D::ILandscapePolyDrawingCallback
  42 {
  43
  44 public:
  45
  46         // This instance is passed to current scene as its ILandscapePolyDrawingCallback instance.
  47         // (UScene::setLandscapePolyDrawingCallback is called)
  48         void init();
  49
  50 private:
  51         // from NL3D::ILandscapePolyDrawingCallback
  52         // This method is called before landscape render to modify stencil operation.
  53         // The eighth bit will be written with a 1 during next render. Thus we will differentiate stencil buffer parts
  54         // which will support Shadow Volume algorithm (landscape) and the other parts (veget...)
  55         virtual void beginPolyDrawing();
  56
  57         // from NL3D::ILandscapePolyDrawingCallback
  58         // This method is called after landscape render and before veget render to modify back stencil operation.
  59         // The eighth bit will be again written with a 0 during next render.
  60         virtual void endPolyDrawing();
  61 };
  62
  63
  64 //-----------------------------------------------------------------------------------------------------------
  65 //---------------------------------- CLandscapePolyDrawer ---------------------------------------------------
  66 //-----------------------------------------------------------------------------------------------------------
  67 // CLandscapePolyDrawer class manages display of a polygonal zones group, thanks to a Robust Shadow Volume algorithm.
  68 // To avoid intersection between a shadow volume and the frustum, the "Far" plane of this one is pushed back
  69 // to infinity during shadow volume display.
  70 // To a best robustness and to join depth range [depthMin, depthMax] used in display of main scene, an epsilon
  71 // factor is calculated to transpose Z buffer values from [depthMin, 1] to [depthMin, depthMax]
  72 // while in [depthMin, 1] depth range is used during shadow volume display.
  73 //-----------------------------------------------------------------------------------------------------------
  74 class CLandscapePolyDrawer : public NLMISC::CSingleton<CLandscapePolyDrawer>
  75 {
  76
  77 public:
  78
  79         // Constructor
  80         CLandscapePolyDrawer();
  81
  82         // Destructor
  83         ~CLandscapePolyDrawer();
  84
  85         // At every frame, polygons list is intialized and filled with addPloy calls.
  86         void addPoly(const NLMISC::CPolygon2D &poly, const NLMISC::CRGBA & color, const NLMISC::CAABBox & bBox);
  87
  88         // At every frame end, polygons list is released. This allows an easy management to dynamic destructions,
  89         // addition or modifications of polygons.
  90         void deletePolygons();
  91
  92         // Compute bbox of enclosed patch of a landscape from a delimiting 2D polygon.
  93         static void computeBBoxFromPolygon(const NLMISC::CPolygon2D &poly2D, NLMISC::CAABBox &destBBox);
  94
  95         // Called to initialize ILandscapePolyDrawingCallback instance of current scene with _InitStencil attribut.
  96         void  initLandscapePolyDrawingCallback();
  97
  98
  99 private:
 100
 101         // renderScene is called in main loop. It can called beginRenderLandscapePolyPart and renderLandscapePolyPart
 102         // methods.
 103         friend void beginRenderScene();
 104         friend void drawRenderScene(bool wantTraversals, bool keepTraversals);
 105         friend void endRenderScene(bool keepTraversals);
 106
 107         // Enable stencil test and initialize function and operation of stencil at the beginning of renderScene method,
 108         // before opaque render of canopy and main scene parts.
 109         // The eighth bit will be written with a 0 during next render to mark stencil buffer parts which will
 110         // support Shadow Volume algorithm.
 111         void beginRenderLandscapePolyPart();
 112
 113         // Render polygons after opaque render of canopy and main scene parts and before transparency parts render.
 114         // ZFail algorithm is only applied to stencil buffer parts whose eighth bit is equal to 1
 115         // (avoid to color vegetation)
 116         void renderLandscapePolyPart();
 117
 118         // Build vertex and index buffer of the associated polygon when addPloy is called.
 119         // Vertices coordinates aren't calculated immediately but in drawShadowVolume method,
 120         // because they are calculated in camera location.
 121         void buildShadowVolume(uint poly);
 122
 123         // Render shadow volume of a polygon (color and depth buffers updates are disable).
 124         // This method is called twice  durong the both passes of ZFail algorithm.
 125         // Coordinates of shadow volume vertex buffer are calculated in first pass.
 126         void drawShadowVolume(uint poly, bool firstPass);
 127
 128         // Render polygon by displaying a quad which covers all zone delimited by scissor test.
 129         // This quad is applied only to stencil buffer parts whose 7 last bits aren't equal to 0,
 130         // thus the polygon projection on lanscape is delimited.
 131         void drawPolygon(uint poly);
 132
 133         // Setup an infinite frustum and a [0, 1] depth range  in a way Z Buffer values coincide
 134         // with those of main scene with the depth range of main scene.
 135         void infiniteFrustum();
 136
 137         // Setup initial projection matrix and depth range
 138         void finiteFrustum();
 139
 140         // Setup scissor delimitation for polygon
 141         void setScissor(uint polyId);
 142
 143
 144         // This callback allows to setup stencil operation before and after vegetables and shadow render,
 145         // in order to separate them of landscape stencil buffer values.
 146         CInitStencil *                                          _InitStencil;
 147
 148         // Vectors of polygons and their respective barycenters, colors, bounding boxes,
 149         // vertex and index buffers.
 150         std::vector<NLMISC::CPolygon2D>         _Polygons;
 151         std::vector<NLMISC::CVector2f>          _Barycenters;
 152         std::vector<NLMISC::CRGBA>                      _PolyColor;
 153         std::vector<NLMISC::CAABBox>            _BBoxes;
 154
 155         std::vector<NL3D::CVertexBuffer>        _PolyVB;
 156         std::vector<NL3D::CIndexBuffer>         _PolyIB;
 157
 158         // Quad used to display polygons on marked parts of stencil buffer.
 159         NLMISC::CQuad                                           _Shadow;
 160
 161         // Initial frustum used before shadow volumes display and stored to reset old values at the end of this display.
 162         NL3D::CFrustum                                          _FiniteFrustum;
 163
 164         // Max depth range used before shadow volumes display and stored to reset old values back at the end of this display.
 165         float                                                           _MaxDepthRange;
 166
 167         // View matrix used before shadow volumes display and stored to reset old values at the end of this display.
 168         NLMISC::CMatrix                                         _OldViewMatrix;
 169 };
 170
 171 #endif