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::Geode& geode);
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)
50    {
51    }
52    void makeMesh(osg::Geometry& geom);
53    void makeMesh();
54};
55
56// Optimize the triangle order in a mesh for best use of the GPU's
57// post-transform cache. This uses Tom Forsyth's algorithm described
58// at http://home.comcast.net/~tom_forsyth/papers/fast_vert_cache_opt.html
59class OSGUTIL_EXPORT VertexCacheVisitor : public GeometryCollector
60{
61public:
62    VertexCacheVisitor(Optimizer* optimizer = 0)
63        : GeometryCollector(optimizer, Optimizer::VERTEX_POSTTRANSFORM)
64    {
65    }
66
67    void optimizeVertices(osg::Geometry& geom);
68    void optimizeVertices();
69private:
70    void doVertexOptimization(osg::Geometry& geom,
71                              std::vector<unsigned>& vertDrawList);
72};
73
74// Gather statistics on post-transform cache misses for geometry
75class OSGUTIL_EXPORT VertexCacheMissVisitor : public osg::NodeVisitor
76{
77public:
78    VertexCacheMissVisitor(unsigned cacheSize = 16);
79    void reset();
80    virtual void apply(osg::Geode& geode);
81    void doGeometry(osg::Geometry& geom);
82    unsigned misses;
83    unsigned triangles;
84protected:
85    const unsigned _cacheSize;
86};
87
88// Optimize the use of the GPU pre-transform cache by arranging vertex
89// attributes in the order they are used.
90class OSGUTIL_EXPORT VertexAccessOrderVisitor : public GeometryCollector
91{
92    struct OrderByPrimitiveMode
93    {
94        inline bool operator() (const osg::ref_ptr<osg::PrimitiveSet>& prim1, const osg::ref_ptr<osg::PrimitiveSet>& prim2)
95        {
96            if(prim1 && prim2) {
97                return prim1->getMode() > prim2->getMode();
98            }
99            else if(prim1) {
100                return true;
101            }
102            return false;
103        }
104    } order_by_primitive_mode;
105
106public:
107    VertexAccessOrderVisitor(Optimizer* optimizer = 0)
108        : GeometryCollector(optimizer, Optimizer::VERTEX_PRETRANSFORM)
109    {
110    }
111    void optimizeOrder();
112    void optimizeOrder(osg::Geometry& geom);
113};
114
115class OSGUTIL_EXPORT SharedArrayOptimizer
116{
117public:
118    void findDuplicatedUVs(const osg::Geometry& geometry);
119    void deduplicateUVs(osg::Geometry& geometry);
120protected:
121    std::map<unsigned int, unsigned int> _deduplicateUvs;
122}; // SharedArrayOptimizer
123
124}
125#endif
126