simgear/scene/tgdb/TreeBin.cxx

   1 /* -*-c++-*-
   2  *
   3  * Copyright (C) 2008 Stuart Buchanan
   4  *
   5  * This program is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU General Public License as
   7  * published by the Free Software Foundation; either version 2 of the
   8  * License, or (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful, but
  11  * WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, write to the Free Software
  17  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
  18  * MA 02110-1301, USA.
  19  *
  20  */
  21
  22 #include <algorithm>
  23 #include <vector>
  24 #include <string>
  25 #include <map>
  26
  27 #include <boost/tuple/tuple_comparison.hpp>
  28
  29 #include <osg/AlphaFunc>
  30 #include <osg/Billboard>
  31 #include <osg/BlendFunc>
  32 #include <osg/Geode>
  33 #include <osg/Geometry>
  34 #include <osg/Material>
  35 #include <osg/Math>
  36 #include <osg/MatrixTransform>
  37 #include <osg/Matrix>
  38 #include <osg/StateSet>
  39 #include <osg/Texture2D>
  40 #include <osg/TexEnv>
  41
  42 #include <osgDB/ReadFile>
  43 #include <osgDB/FileUtils>
  44
  45 #include <simgear/misc/sg_path.hxx>
  46 #include <simgear/scene/util/QuadTreeBuilder.hxx>
  47 #include <simgear/scene/util/RenderConstants.hxx>
  48 #include <simgear/scene/util/StateAttributeFactory.hxx>
  49
  50 #include "ShaderGeometry.hxx"
  51 #include "TreeBin.hxx"
  52
  53 #define SG_TREE_QUAD_TREE_DEPTH 3
  54
  55 // Comments from Tim Moore:
  56 // Some work remains for this code. Stuart's enhancement for multiple
  57 // textures per forest should be integrated. We should try to use one
  58 // ShaderGeometry for *all* the trees in the scene graph and do the
  59 // rotation and scale with a MatrixTransform above the trees quad
  60 // tree. The positions would of course have to be transformed by the
  61 // inverse of that transform. Also, we should investigate whether it
  62 // would be better to instantiate trees as polygons in a osg::Geometry
  63 // object instead of using the ShaderGeometry instancing technique.
  64
  65 using namespace osg;
  66
  67 namespace simgear
  68 {
  69
  70 // memoize geometry
  71 typedef boost::tuple<float, float, int> ForestTuple;
  72 typedef std::map<ForestTuple, ref_ptr<Geometry> > OrthQuadMap;
  73
  74 osg::Geometry* createOrthQuads(float w, float h, int varieties, const osg::Matrix& rotate)
  75 {
  76     static OrthQuadMap orthQuadMap;
  77     OrthQuadMap::iterator giter
  78         = orthQuadMap.find(ForestTuple(w, h, varieties));
  79     if (giter != orthQuadMap.end())
  80         return giter->second.get();
  81
  82     //const osg::Vec3& pos = osg::Vec3(0.0f,0.0f,0.0f),
  83     // set up the coords
  84     // Create front and back polygons so we don't need to screw around
  85     // with two-sided lighting in the shader.
  86     osg::Vec3Array& v = *(new osg::Vec3Array(8));
  87     osg::Vec3Array& n = *(new osg::Vec3Array(8));
  88     osg::Vec2Array& t = *(new osg::Vec2Array(8));
  89
  90     float cw = w*0.5f;
  91
  92     v[0].set(0.0f,-cw,0.0f);
  93     v[1].set(0.0f, cw,0.0f);
  94     v[2].set(0.0f, cw,h);
  95     v[3].set(0.0f,-cw,h);
  96
  97     v[4].set(-cw,0.0f,0.0f);
  98     v[5].set( cw,0.0f,0.0f);
  99     v[6].set( cw,0.0f,h);
 100     v[7].set(-cw,0.0f,h);
 101
 102     // The texture coordinate range is not the
 103     // entire coordinate space - as the texture
 104     // has a number of different trees on it.
 105     float tx = 1.0f/varieties;
 106
 107     t[0].set(0.0f,0.0f);
 108     t[1].set(  tx,0.0f);
 109     t[2].set(  tx,1.0f);
 110     t[3].set(0.0f,1.0f);
 111
 112     t[4].set(0.0f,0.0f);
 113     t[5].set(  tx,0.0f);
 114     t[6].set(  tx,1.0f);
 115     t[7].set(0.0f,1.0f);
 116
 117     // For now the normal is normal to the quad. If we want to get
 118     // fancier and approximate a cylindrical tree or something, then
 119     // we would really want more geometry.
 120     std::fill(n.begin(), n.begin() + 4, Vec3f(1.0f, 0.0f, 0.0f));
 121     std::fill(n.begin() + 4, n.end(), Vec3f(0.0f, -1.0f, 0.0f));
 122     for (unsigned int i = 0; i < 8; i++) {
 123         v[i] = v[i] * rotate;
 124         // Should be the inverse transpose, but assume that rotate is
 125         // orthonormal.
 126         n[i] = n[i] * rotate;
 127     }
 128
 129     osg::Geometry *geom = new osg::Geometry;
 130
 131     geom->setVertexArray(&v);
 132     geom->setTexCoordArray(0, &t);
 133     geom->setNormalArray(&n);
 134     geom->setNormalBinding(Geometry::BIND_PER_VERTEX);
 135     // No color for now; that's used to pass the position.
 136     geom->addPrimitiveSet(new osg::DrawArrays(osg::PrimitiveSet::QUADS,0,8));
 137
 138     orthQuadMap.insert(std::make_pair(ForestTuple(w, h, varieties), geom));
 139     return geom;
 140 }
 141
 142  static char vertexShaderSource[] =
 143     "varying float fogFactor;\n"
 144     "attribute float textureIndex;\n"
 145     "\n"
 146     "void main(void)\n"
 147     "{\n"
 148     "  gl_TexCoord[0] = gl_MultiTexCoord0 + vec4(textureIndex, 0.0, 0.0, 0.0);\n"
 149     "  vec3 position = gl_Vertex.xyz * gl_Color.w + gl_Color.xyz;\n"
 150     "  gl_Position   = gl_ModelViewProjectionMatrix * vec4(position,1.0);\n"
 151     "  vec3 ecPosition = vec3(gl_ModelViewMatrix * vec4(position, 1.0));\n"
 152     "  float n = dot(normalize(gl_LightSource[0].position.xyz), normalize(-ecPosition));\n"
 153     "  vec3 diffuse = gl_FrontMaterial.diffuse.rgb * max(0.1, n);\n"
 154     "  vec4 ambientColor = gl_FrontLightModelProduct.sceneColor + gl_LightSource[0].ambient * gl_FrontMaterial.ambient;\n"
 155     "  gl_FrontColor = ambientColor + gl_LightSource[0].diffuse * vec4(diffuse, 1.0);\n"
 156     "  gl_BackColor = gl_FrontColor;\n"
 157     "  float fogCoord = abs(ecPosition.z);\n"
 158     "  fogFactor = exp( -gl_Fog.density * gl_Fog.density * fogCoord * fogCoord);\n"
 159     "  fogFactor = clamp(fogFactor, 0.0, 1.0);\n"
 160     "}\n";
 161
 162 static char fragmentShaderSource[] =
 163     "uniform sampler2D baseTexture; \n"
 164     "varying float fogFactor;\n"
 165     "\n"
 166     "void main(void) \n"
 167     "{ \n"
 168     "  vec4 base = texture2D( baseTexture, gl_TexCoord[0].st);\n"
 169     "  vec4 finalColor = base * gl_Color;\n"
 170     "  gl_FragColor = mix(gl_Fog.color, finalColor, fogFactor );\n"
 171     "}\n";
 172
 173 typedef std::map<std::string, osg::ref_ptr<StateSet> > StateSetMap;
 174
 175 static StateSetMap treeTextureMap;
 176
 177 // Helper classes for creating the quad tree
 178 namespace
 179 {
 180 struct MakeTreesLeaf
 181 {
 182     MakeTreesLeaf(float range, Geometry* geometry, int varieties) :
 183         _range(range), _geometry(geometry), _varieties(varieties)
 184     {}
 185     MakeTreesLeaf(const MakeTreesLeaf& rhs) :
 186         _range(rhs._range), _geometry(rhs._geometry), _varieties(rhs._varieties) {}
 187     LOD* operator() () const
 188     {
 189         LOD* result = new LOD;
 190         Geode* geode = new Geode;
 191         ShaderGeometry* sg = new ShaderGeometry(_varieties);
 192         sg->setGeometry(_geometry);
 193         geode->addDrawable(sg);
 194         result->addChild(geode, 0, _range);
 195         return result;
 196     }
 197     float _range;
 198     int _varieties;
 199     Geometry* _geometry;
 200 };
 201
 202 struct AddTreesLeafObject
 203 {
 204     void operator() (LOD* lod, const TreeBin::Tree& tree) const
 205     {
 206         Geode* geode = static_cast<Geode*>(lod->getChild(0));
 207         ShaderGeometry* sg
 208             = static_cast<ShaderGeometry*>(geode->getDrawable(0));
 209         sg->addTree(tree);
 210     }
 211 };
 212
 213 struct GetTreeCoord
 214 {
 215     Vec3 operator() (const TreeBin::Tree& tree) const
 216     {
 217         return tree.position.osg();
 218     }
 219 };
 220
 221 typedef QuadTreeBuilder<LOD*, TreeBin::Tree, MakeTreesLeaf, AddTreesLeafObject,
 222                         GetTreeCoord> ShaderGeometryQuadtree;
 223 }
 224
 225 struct TreeTransformer
 226 {
 227     TreeTransformer(Matrix& mat_) : mat(mat_) {}
 228     TreeBin::Tree operator()(const TreeBin::Tree& tree) const
 229     {
 230         const Vec3& pos = tree.position.osg();
 231         return TreeBin::Tree(SGVec3f(pos * mat), tree.texture_index,
 232                              tree.scale);
 233     }
 234     Matrix mat;
 235 };
 236
 237 // This actually returns a MatrixTransform node. If we rotate the whole
 238 // forest into the local Z-up coordinate system we can reuse the
 239 // primitive tree geometry for all the forests of the same type.
 240
 241 osg::Group* createForest(TreeBin& forest, const osg::Matrix& transform)
 242 {
 243     Matrix transInv = Matrix::inverse(transform);
 244     static Matrix ident;
 245     // Set up some shared structures.
 246     osg::Geometry* shared_geometry = createOrthQuads(forest.width,
 247                                                      forest.height,
 248                                                      forest.texture_varieties,
 249                                                      ident);
 250
 251     ref_ptr<Group> group;
 252
 253     osg::StateSet* stateset = 0;
 254     StateSetMap::iterator iter = treeTextureMap.find(forest.texture);
 255     if (iter == treeTextureMap.end()) {
 256         osg::Texture2D *tex = new osg::Texture2D;
 257         tex->setWrap( osg::Texture2D::WRAP_S, osg::Texture2D::CLAMP );
 258         tex->setWrap( osg::Texture2D::WRAP_T, osg::Texture2D::CLAMP );
 259         tex->setImage(osgDB::readImageFile(forest.texture));
 260
 261         static ref_ptr<AlphaFunc> alphaFunc;
 262         static ref_ptr<Program> program;
 263         static ref_ptr<Uniform> baseTextureSampler;
 264         static ref_ptr<Material> material;
 265
 266         stateset = new osg::StateSet;
 267         stateset->setTextureAttributeAndModes(0, tex, osg::StateAttribute::ON );
 268         stateset->setRenderBinDetails(RANDOM_OBJECTS_BIN, "DepthSortedBin");
 269         if (!program.valid()) {
 270             alphaFunc = new AlphaFunc;
 271             alphaFunc->setFunction(AlphaFunc::GEQUAL,0.33f);
 272             program  = new Program;
 273             baseTextureSampler = new osg::Uniform("baseTexture", 0);
 274             Shader* vertex_shader = new Shader(Shader::VERTEX, vertexShaderSource);
 275             program->addShader(vertex_shader);
 276             program->addBindAttribLocation("textureIndex", 1);
 277
 278             Shader* fragment_shader = new Shader(Shader::FRAGMENT,
 279                                                  fragmentShaderSource);
 280             program->addShader(fragment_shader);
 281             material = new Material;
 282             // Don´t track vertex color
 283             material->setColorMode(Material::OFF);
 284             material->setAmbient(Material::FRONT_AND_BACK,
 285                                  Vec4(1.0f, 1.0f, 1.0f, 1.0f));
 286             material->setDiffuse(Material::FRONT_AND_BACK,
 287                                  Vec4(1.0f, 1.0f, 1.0f, 1.0f));
 288         }
 289         stateset->setAttributeAndModes(alphaFunc.get());
 290         stateset->setAttribute(program.get());
 291         stateset->addUniform(baseTextureSampler.get());
 292         stateset->setMode(GL_VERTEX_PROGRAM_TWO_SIDE, StateAttribute::ON);
 293         stateset->setAttribute(material.get());
 294
 295         treeTextureMap.insert(StateSetMap::value_type(forest.texture,
 296                                                       stateset));
 297     } else {
 298         stateset = iter->second.get();
 299     }
 300     // Now, create a quadtree for the forest.
 301     {
 302         ShaderGeometryQuadtree quadtree(GetTreeCoord(),
 303                                         AddTreesLeafObject(),
 304                                         SG_TREE_QUAD_TREE_DEPTH,
 305                                         MakeTreesLeaf(forest.range,
 306                                                       shared_geometry,
 307                                                       forest.texture_varieties));
 308         // Transform tree positions from the "geocentric" positions we
 309         // get from the scenery polys into the local Z-up coordinate
 310         // system.
 311         std::vector<TreeBin::Tree> rotatedTrees;
 312         rotatedTrees.reserve(forest._trees.size());
 313         std::transform(forest._trees.begin(), forest._trees.end(),
 314                        std::back_inserter(rotatedTrees),
 315                        TreeTransformer(transInv));
 316         quadtree.buildQuadTree(rotatedTrees.begin(), rotatedTrees.end());
 317         group = quadtree.getRoot();
 318     }
 319     MatrixTransform* mt = new MatrixTransform(transform);
 320     for (int i = 0; i < group->getNumChildren(); ++i)
 321         mt->addChild(group->getChild(i));
 322     mt->setStateSet(stateset);
 323     return mt;
 324 }
 325
 326 }