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 <string>
  24 #include <map>
  25
  26 #include <osg/AlphaFunc>
  27 #include <osg/Billboard>
  28 #include <osg/BlendFunc>
  29 #include <osg/Geode>
  30 #include <osg/Geometry>
  31 #include <osg/Material>
  32 #include <osg/Math>
  33 #include <osg/MatrixTransform>
  34 #include <osg/Matrix>
  35 #include <osg/StateSet>
  36 #include <osg/Texture2D>
  37 #include <osg/TexEnv>
  38
  39 #include <osgDB/ReadFile>
  40 #include <osgDB/FileUtils>
  41
  42 #include <simgear/misc/sg_path.hxx>
  43 #include <simgear/scene/util/QuadTreeBuilder.hxx>
  44 #include <simgear/scene/util/RenderConstants.hxx>
  45 #include <simgear/scene/util/StateAttributeFactory.hxx>
  46
  47 #include "ShaderGeometry.hxx"
  48 #include "TreeBin.hxx"
  49
  50 #define SG_TREE_QUAD_TREE_DEPTH 3
  51
  52 // Comments from Tim Moore:
  53 // Some work remains for this code. Stuart's enhancement for multiple
  54 // textures per forest should be integrated. We should try to use one
  55 // ShaderGeometry for *all* the trees in the scene graph and do the
  56 // rotation and scale with a MatrixTransform above the trees quad
  57 // tree. The positions would of course have to be transformed by the
  58 // inverse of that transform. Also, we should investigate whether it
  59 // would be better to instantiate trees as polygons in a osg::Geometry
  60 // object instead of using the ShaderGeometry instancing technique.
  61
  62 using namespace osg;
  63
  64 namespace simgear
  65 {
  66
  67 osg::Geometry* createOrthQuads(float w, float h, int varieties, const osg::Matrix& rotate)
  68 {
  69
  70     //const osg::Vec3& pos = osg::Vec3(0.0f,0.0f,0.0f),
  71     // set up the coords
  72     // Create front and back polygons so we don't need to screw around
  73     // with two-sided lighting in the shader.
  74     osg::Vec3Array& v = *(new osg::Vec3Array(8));
  75     osg::Vec3Array& n = *(new osg::Vec3Array(8));
  76     osg::Vec2Array& t = *(new osg::Vec2Array(8));
  77
  78     float cw = w*0.5f;
  79
  80     v[0].set(0.0f,-cw,0.0f);
  81     v[1].set(0.0f, cw,0.0f);
  82     v[2].set(0.0f, cw,h);
  83     v[3].set(0.0f,-cw,h);
  84
  85     v[4].set(-cw,0.0f,0.0f);
  86     v[5].set( cw,0.0f,0.0f);
  87     v[6].set( cw,0.0f,h);
  88     v[7].set(-cw,0.0f,h);
  89
  90     // The texture coordinate range is not the
  91     // entire coordinate space - as the texture
  92     // has a number of different trees on it.
  93     float tx = 1.0f/varieties;
  94
  95     t[0].set(0.0f,0.0f);
  96     t[1].set(  tx,0.0f);
  97     t[2].set(  tx,1.0f);
  98     t[3].set(0.0f,1.0f);
  99
 100     t[4].set(0.0f,0.0f);
 101     t[5].set(  tx,0.0f);
 102     t[6].set(  tx,1.0f);
 103     t[7].set(0.0f,1.0f);
 104
 105     // For now the normal is normal to the quad. If we want to get
 106     // fancier and approximate a cylindrical tree or something, then
 107     // we would really want more geometry.
 108     std::fill(n.begin(), n.begin() + 4, Vec3f(1.0f, 0.0f, 0.0f));
 109     std::fill(n.begin() + 4, n.end(), Vec3f(0.0f, -1.0f, 0.0f));
 110     for (unsigned int i = 0; i < 8; i++) {
 111         v[i] = v[i] * rotate;
 112         // Should be the inverse transpose, but assume that rotate is
 113         // orthonormal.
 114         n[i] = n[i] * rotate;
 115     }
 116
 117     osg::Geometry *geom = new osg::Geometry;
 118
 119     geom->setVertexArray(&v);
 120     geom->setTexCoordArray(0, &t);
 121     geom->setNormalArray(&n);
 122     geom->setNormalBinding(Geometry::BIND_PER_VERTEX);
 123     // No color for now; that's used to pass the position.
 124     geom->addPrimitiveSet(new osg::DrawArrays(osg::PrimitiveSet::QUADS,0,8));
 125
 126     return geom;
 127 }
 128
 129  static char vertexShaderSource[] =
 130     "varying float fogFactor;\n"
 131     "attribute float textureIndex;\n"
 132     "\n"
 133     "void main(void)\n"
 134     "{\n"
 135     "  gl_TexCoord[0] = gl_MultiTexCoord0 + vec4(textureIndex, 0.0, 0.0, 0.0);\n"
 136     "  vec3 position = gl_Vertex.xyz * gl_Color.w + gl_Color.xyz;\n"
 137     "  gl_Position   = gl_ModelViewProjectionMatrix * vec4(position,1.0);\n"
 138     "  vec3 ecPosition = vec3(gl_ModelViewMatrix * vec4(position, 1.0));\n"
 139     "  vec3 N = normalize(gl_NormalMatrix * gl_Normal);\n"
 140     "  vec3 diffuse = gl_FrontMaterial.diffuse.rgb * max(0.0, dot(N, gl_LightSource[0].position.xyz));\n"
 141     "  vec3 backDiffuse = gl_FrontMaterial.diffuse.rgb * max(0.0, dot(-N, gl_LightSource[0].position.xyz));\n"
 142     " vec4 ambientColor = gl_FrontLightModelProduct.sceneColor + gl_LightSource[0].ambient * gl_FrontMaterial.ambient;\n"
 143     " gl_FrontColor = ambientColor + gl_LightSource[0].diffuse * vec4(diffuse, 1.0);\n"
 144     " gl_BackColor = ambientColor + gl_LightSource[0].diffuse * vec4(backDiffuse, 1.0)\n;"
 145 //    "  gl_TexCoord[0] = gl_MultiTexCoord0;\n"
 146     " float fogCoord = abs(ecPosition.z);\n"
 147     "  fogFactor = exp( -gl_Fog.density * gl_Fog.density * fogCoord * fogCoord);\n"
 148     "  fogFactor = clamp(fogFactor, 0.0, 1.0);\n"
 149     "}\n";
 150
 151 static char fragmentShaderSource[] =
 152     "uniform sampler2D baseTexture; \n"
 153     "varying float fogFactor;\n"
 154     "\n"
 155     "void main(void) \n"
 156     "{ \n"
 157     "  vec4 base = texture2D( baseTexture, gl_TexCoord[0].st);\n"
 158     "  vec4 finalColor = base * gl_Color;\n"
 159     "  gl_FragColor = mix(gl_Fog.color, finalColor, fogFactor );\n"
 160     "}\n";
 161
 162 typedef std::map<std::string, osg::ref_ptr<StateSet> > StateSetMap;
 163
 164 static StateSetMap treeTextureMap;
 165
 166 // Helper classes for creating the quad tree
 167 namespace
 168 {
 169 struct MakeTreesLeaf
 170 {
 171     MakeTreesLeaf(float range, Geometry* geometry, int varieties) :
 172         _range(range), _geometry(geometry), _varieties(varieties)
 173     {}
 174     MakeTreesLeaf(const MakeTreesLeaf& rhs) :
 175         _range(rhs._range), _geometry(rhs._geometry), _varieties(rhs._varieties) {}
 176     LOD* operator() () const
 177     {
 178         LOD* result = new LOD;
 179         Geode* geode = new Geode;
 180         ShaderGeometry* sg = new ShaderGeometry(_varieties);
 181         sg->setGeometry(_geometry);
 182         geode->addDrawable(sg);
 183         result->addChild(geode, 0, _range);
 184         return result;
 185     }
 186     float _range;
 187     int _varieties;
 188     Geometry* _geometry;
 189 };
 190
 191 struct AddTreesLeafObject
 192 {
 193     void operator() (LOD* lod, const TreeBin::Tree& tree) const
 194     {
 195         Geode* geode = static_cast<Geode*>(lod->getChild(0));
 196         ShaderGeometry* sg
 197             = static_cast<ShaderGeometry*>(geode->getDrawable(0));
 198         sg->addTree(tree);
 199     }
 200 };
 201
 202 struct GetTreeCoord
 203 {
 204     GetTreeCoord(const Matrix& transform) : _transform(transform) {}
 205     GetTreeCoord(const GetTreeCoord& rhs) : _transform(rhs._transform) {}
 206     Vec3 operator() (const TreeBin::Tree& tree) const
 207     {
 208         return tree.position.osg() * _transform;
 209     }
 210     Matrix _transform;
 211 };
 212
 213 typedef QuadTreeBuilder<LOD*, TreeBin::Tree, MakeTreesLeaf, AddTreesLeafObject,
 214                         GetTreeCoord> ShaderGeometryQuadtree;
 215 }
 216
 217 osg::Group* createForest(TreeBin& forest, const osg::Matrix& transform)
 218 {
 219     // Set up some shared structures.
 220     osg::Geometry* shared_geometry = createOrthQuads(forest.width,
 221                                                      forest.height,
 222                                                      forest.texture_varieties,
 223                                                      transform);
 224
 225     ref_ptr<Group> group;
 226
 227     osg::StateSet* stateset = 0;
 228     StateSetMap::iterator iter = treeTextureMap.find(forest.texture);
 229     if (iter == treeTextureMap.end()) {
 230         osg::Texture2D *tex = new osg::Texture2D;
 231         tex->setWrap( osg::Texture2D::WRAP_S, osg::Texture2D::CLAMP );
 232         tex->setWrap( osg::Texture2D::WRAP_T, osg::Texture2D::CLAMP );
 233         tex->setImage(osgDB::readImageFile(forest.texture));
 234
 235         static ref_ptr<AlphaFunc> alphaFunc;
 236         static ref_ptr<Program> program;
 237         static ref_ptr<Uniform> baseTextureSampler;
 238         static ref_ptr<Material> material;
 239
 240         stateset = new osg::StateSet;
 241         stateset->setTextureAttributeAndModes(0, tex, osg::StateAttribute::ON );
 242         stateset->setRenderBinDetails(RANDOM_OBJECTS_BIN, "DepthSortedBin");
 243         if (!program.valid()) {
 244             alphaFunc = new AlphaFunc;
 245             alphaFunc->setFunction(AlphaFunc::GEQUAL,0.33f);
 246             program  = new Program;
 247             baseTextureSampler = new osg::Uniform("baseTexture", 0);
 248             Shader* vertex_shader = new Shader(Shader::VERTEX, vertexShaderSource);
 249             program->addShader(vertex_shader);
 250             program->addBindAttribLocation("textureIndex", 1);
 251
 252             Shader* fragment_shader = new Shader(Shader::FRAGMENT,
 253                                                  fragmentShaderSource);
 254             program->addShader(fragment_shader);
 255             material = new Material;
 256             // Don´t track vertex color
 257             material->setColorMode(Material::OFF);
 258             material->setAmbient(Material::FRONT_AND_BACK,
 259                                  Vec4(.8f, .8f, .8f, 1.0f));
 260             material->setDiffuse(Material::FRONT_AND_BACK,
 261                                  Vec4(.2f, .2f, .2f, 1.0f));
 262         }
 263         stateset->setAttributeAndModes(alphaFunc.get());
 264         stateset->setAttribute(program.get());
 265         stateset->addUniform(baseTextureSampler.get());
 266         stateset->setMode(GL_VERTEX_PROGRAM_TWO_SIDE, StateAttribute::ON);
 267         stateset->setAttribute(material.get());
 268
 269         treeTextureMap.insert(StateSetMap::value_type(forest.texture,
 270                                                       stateset));
 271     } else {
 272         stateset = iter->second.get();
 273     }
 274     // Now, create a quadtree for the forest.
 275     {
 276         ShaderGeometryQuadtree quadtree(GetTreeCoord(Matrix::inverse(transform)),
 277                                         AddTreesLeafObject(),
 278                                         SG_TREE_QUAD_TREE_DEPTH,
 279                                         MakeTreesLeaf(forest.range,
 280                                                       shared_geometry,
 281                                                       forest.texture_varieties));
 282         quadtree.buildQuadTree(forest._trees.begin(), forest._trees.end());
 283         group = quadtree.getRoot();
 284     }
 285     group->setStateSet(stateset);
 286     return group.release();
 287 }
 288
 289 }