1/* -*-c++-*- OpenSceneGraph - Copyright (C) 1998-2006 Robert Osfield
2 *
3 * This library is open source and may be redistributed and/or modified under
4 * the terms of the OpenSceneGraph Public License (OSGPL) version 0.0 or
5 * (at your option) any later version.  The full license is in LICENSE file
6 * included with this distribution, and on the openscenegraph.org website.
7 *
8 * This library is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
11 * OpenSceneGraph Public License for more details.
12*/
13
14#ifndef OSGUTIL_MESHOPTIMIZERS
15#define OSGUTIL_MESHOPTIMIZERS 1
16
17#include <set>
18#include <vector>
19
20#include <osg/Geode>
21#include <osg/Geometry>
22#include <osg/NodeVisitor>
23
24#include <osgUtil/Optimizer>
25
26namespace osgUtil
27{
28// Helper that collects all the unique Geometry objects in a subgraph.
29class OSGUTIL_EXPORT GeometryCollector : public BaseOptimizerVisitor
30{
31public:
32    GeometryCollector(Optimizer* optimizer,
33                      Optimizer::OptimizationOptions options)
34        : BaseOptimizerVisitor(optimizer, options) {}
35    void reset();
36    void apply(osg::Geometry& geom);
37    typedef std::set<osg::Geometry*> GeometryList;
38    GeometryList& getGeometryList() { return _geometryList; };
39protected:
40    GeometryList _geometryList;
41};
42
43// Convert geometry that uses DrawArrays to DrawElements i.e.,
44// construct a real mesh. This removes duplicate vertices.
45class OSGUTIL_EXPORT IndexMeshVisitor : public GeometryCollector
46{
47public:
48    IndexMeshVisitor(Optimizer* optimizer = 0)
49        : GeometryCollector(optimizer, Optimizer::INDEX_MESH), _generateNewIndicesOnAllGeometries(false)
50    {
51    }
52    inline void setGenerateNewIndicesOnAllGeometries(bool b) { _generateNewIndicesOnAllGeometries = b; }
53    inline bool getGenerateNewIndicesOnAllGeometries() const { return _generateNewIndicesOnAllGeometries; }
54
55    void makeMesh(osg::Geometry& geom);
56    void makeMesh();
57protected:
58    bool _generateNewIndicesOnAllGeometries;
59};
60
61// Optimize the triangle order in a mesh for best use of the GPU's
62// post-transform cache. This uses Tom Forsyth's algorithm described
63// at http://home.comcast.net/~tom_forsyth/papers/fast_vert_cache_opt.html
64class OSGUTIL_EXPORT VertexCacheVisitor : public GeometryCollector
65{
66public:
67    VertexCacheVisitor(Optimizer* optimizer = 0)
68        : GeometryCollector(optimizer, Optimizer::VERTEX_POSTTRANSFORM)
69    {
70    }
71
72    void optimizeVertices(osg::Geometry& geom);
73    void optimizeVertices();
74private:
75    void doVertexOptimization(osg::Geometry& geom,
76                              std::vector<unsigned>& vertDrawList);
77};
78
79// Gather statistics on post-transform cache misses for geometry
80class OSGUTIL_EXPORT VertexCacheMissVisitor : public osg::NodeVisitor
81{
82public:
83    VertexCacheMissVisitor(unsigned cacheSize = 16);
84    void reset();
85    virtual void apply(osg::Geometry& geom);
86    void doGeometry(osg::Geometry& geom);
87    unsigned misses;
88    unsigned triangles;
89protected:
90    const unsigned _cacheSize;
91};
92
93// Optimize the use of the GPU pre-transform cache by arranging vertex
94// attributes in the order they are used.
95class OSGUTIL_EXPORT VertexAccessOrderVisitor : public GeometryCollector
96{
97    struct OrderByPrimitiveMode
98    {
99        inline bool operator() (const osg::ref_ptr<osg::PrimitiveSet>& prim1, const osg::ref_ptr<osg::PrimitiveSet>& prim2)
100        {
101            if(prim1 && prim2) {
102                return prim1->getMode() > prim2->getMode();
103            }
104            else if(prim1) {
105                return true;
106            }
107            return false;
108        }
109    } order_by_primitive_mode;
110
111public:
112    VertexAccessOrderVisitor(Optimizer* optimizer = 0)
113        : GeometryCollector(optimizer, Optimizer::VERTEX_PRETRANSFORM)
114    {
115    }
116    void optimizeOrder();
117    void optimizeOrder(osg::Geometry& geom);
118};
119
120class OSGUTIL_EXPORT SharedArrayOptimizer
121{
122public:
123    void findDuplicatedUVs(const osg::Geometry& geometry);
124    void deduplicateUVs(osg::Geometry& geometry);
125protected:
126    std::map<unsigned int, unsigned int> _deduplicateUvs;
127}; // SharedArrayOptimizer
128
129
130inline void optimizeMesh(osg::Node* node)
131{
132    IndexMeshVisitor imv;
133    node->accept(imv);
134    imv.makeMesh();
135
136    VertexCacheVisitor vcv;
137    node->accept(vcv);
138    vcv.optimizeVertices();
139
140    VertexAccessOrderVisitor vaov;
141    node->accept(vaov);
142    vaov.optimizeOrder();
143}
144
145}
146#endif
147