3 * Copyright (C) 2006-2007 Mathias Froehlich
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.
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.
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,
22 #ifndef SG_TEXTURED_TRIANGLE_BIN_HXX
23 #define SG_TEXTURED_TRIANGLE_BIN_HXX
26 #include <osg/Geometry>
27 #include <osg/PrimitiveSet>
29 #include <simgear/math/sg_random.h>
30 #include <simgear/math/SGMath.hxx>
31 #include "SGTriangleBin.hxx"
35 struct SGVertNormTex {
38 SGVertNormTex(const SGVec3f& v, const SGVec3f& n, const SGVec2f& t) :
39 vertex(v), normal(n), texCoord(t)
43 inline bool operator() (const SGVertNormTex& l,
44 const SGVertNormTex& r) const
46 if (l.vertex < r.vertex) return true;
47 else if (r.vertex < l.vertex) return false;
48 else if (l.normal < r.normal) return true;
49 else if (r.normal < l.normal) return false;
50 else return l.texCoord < r.texCoord;
59 // Use a DrawElementsUShort if there are few enough vertices,
60 // otherwise fallback to DrawElementsUInt. Hide the differences
61 // between the two from the rest of the code.
63 // We don't bother with DrawElementsUByte because that is generally
64 // not an advantage on modern hardware.
65 class DrawElementsFacade {
67 DrawElementsFacade(unsigned numVerts) :
68 _ushortElements(0), _uintElements(0)
72 = new osg::DrawElementsUInt(osg::PrimitiveSet::TRIANGLES);
75 = new osg::DrawElementsUShort(osg::PrimitiveSet::TRIANGLES);
78 void push_back(unsigned val)
81 _uintElements->push_back(val);
83 _ushortElements->push_back(val);
86 osg::DrawElements* getDrawElements()
90 return _ushortElements;
93 osg::DrawElementsUShort* _ushortElements;
94 osg::DrawElementsUInt* _uintElements;
97 class SGTexturedTriangleBin : public SGTriangleBin<SGVertNormTex> {
99 SGTexturedTriangleBin()
105 // Computes and adds random surface points to the points list.
106 // The random points are computed with a density of (coverage points)/1
107 // The points are offsetted away from the triangles in
108 // offset * positive normal direction.
109 void addRandomSurfacePoints(float coverage, float offset,
110 std::vector<SGVec3f>& points) const
112 unsigned num = getNumTriangles();
113 for (unsigned i = 0; i < num; ++i) {
114 triangle_ref triangleRef = getTriangleRef(i);
115 SGVec3f v0 = getVertex(triangleRef[0]).vertex;
116 SGVec3f v1 = getVertex(triangleRef[1]).vertex;
117 SGVec3f v2 = getVertex(triangleRef[2]).vertex;
118 SGVec3f normal = cross(v1 - v0, v2 - v0);
121 float area = 0.5f*length(normal);
122 if (area <= SGLimitsf::min())
125 // For partial units of area, use a zombie door method to
126 // create the proper random chance of a light being created
128 float unit = area + mt_rand(seed)*coverage;
130 SGVec3f offsetVector = offset*normalize(normal);
131 // generate a light point for each unit of area
132 while ( coverage < unit ) {
133 float a = mt_rand(seed);
134 float b = mt_rand(seed);
140 SGVec3f randomPoint = offsetVector + a*v0 + b*v1 + c*v2;
141 points.push_back(randomPoint);
147 void addRandomPoints(float coverage,
148 std::vector<SGVec3f>& points) const
150 unsigned num = getNumTriangles();
151 for (unsigned i = 0; i < num; ++i) {
152 triangle_ref triangleRef = getTriangleRef(i);
153 SGVec3f v0 = getVertex(triangleRef[0]).vertex;
154 SGVec3f v1 = getVertex(triangleRef[1]).vertex;
155 SGVec3f v2 = getVertex(triangleRef[2]).vertex;
156 SGVec3f normal = cross(v1 - v0, v2 - v0);
159 float area = 0.5f*length(normal);
160 if (area <= SGLimitsf::min())
163 // for partial units of area, use a zombie door method to
164 // create the proper random chance of an object being created
165 // for this triangle.
166 double num = area / coverage + mt_rand(seed);
168 // place an object each unit of area
169 while ( num > 1.0 ) {
170 float a = mt_rand(seed);
171 float b = mt_rand(seed);
177 SGVec3f randomPoint = a*v0 + b*v1 + c*v2;
178 points.push_back(randomPoint);
184 osg::Geometry* buildGeometry(const TriangleVector& triangles) const
186 // Do not build anything if there is nothing in here ...
187 if (empty() || triangles.empty())
190 // FIXME: do not include all values here ...
191 osg::Vec3Array* vertices = new osg::Vec3Array;
192 osg::Vec3Array* normals = new osg::Vec3Array;
193 osg::Vec2Array* texCoords = new osg::Vec2Array;
195 osg::Vec4Array* colors = new osg::Vec4Array;
196 colors->push_back(osg::Vec4(1, 1, 1, 1));
198 osg::Geometry* geometry = new osg::Geometry;
199 geometry->setVertexArray(vertices);
200 geometry->setNormalArray(normals);
201 geometry->setNormalBinding(osg::Geometry::BIND_PER_VERTEX);
202 geometry->setColorArray(colors);
203 geometry->setColorBinding(osg::Geometry::BIND_OVERALL);
204 geometry->setTexCoordArray(0, texCoords);
206 const unsigned invalid = ~unsigned(0);
207 std::vector<unsigned> indexMap(getNumVertices(), invalid);
209 DrawElementsFacade deFacade(vertices->size());
210 for (index_type i = 0; i < triangles.size(); ++i) {
211 triangle_ref triangle = triangles[i];
212 if (indexMap[triangle[0]] == invalid) {
213 indexMap[triangle[0]] = vertices->size();
214 vertices->push_back(getVertex(triangle[0]).vertex.osg());
215 normals->push_back(getVertex(triangle[0]).normal.osg());
216 texCoords->push_back(getVertex(triangle[0]).texCoord.osg());
218 deFacade.push_back(indexMap[triangle[0]]);
220 if (indexMap[triangle[1]] == invalid) {
221 indexMap[triangle[1]] = vertices->size();
222 vertices->push_back(getVertex(triangle[1]).vertex.osg());
223 normals->push_back(getVertex(triangle[1]).normal.osg());
224 texCoords->push_back(getVertex(triangle[1]).texCoord.osg());
226 deFacade.push_back(indexMap[triangle[1]]);
228 if (indexMap[triangle[2]] == invalid) {
229 indexMap[triangle[2]] = vertices->size();
230 vertices->push_back(getVertex(triangle[2]).vertex.osg());
231 normals->push_back(getVertex(triangle[2]).normal.osg());
232 texCoords->push_back(getVertex(triangle[2]).texCoord.osg());
234 deFacade.push_back(indexMap[triangle[2]]);
236 geometry->addPrimitiveSet(deFacade.getDrawElements());
241 osg::Geometry* buildGeometry() const
242 { return buildGeometry(getTriangles()); }
245 // Random seed for the triangle.