3 * Copyright (C) 2006-2007 Mathias Froehlich, Tim Moore
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,
23 # include <simgear_config.h>
26 #include "SGOceanTile.hxx"
29 #include <simgear/compiler.h>
32 #include <osg/Geometry>
33 #include <osg/MatrixTransform>
34 #include <osg/StateSet>
36 #include <simgear/bucket/newbucket.hxx>
37 #include <simgear/math/sg_geodesy.hxx>
38 #include <simgear/math/sg_types.hxx>
39 #include <simgear/misc/texcoord.hxx>
40 #include <simgear/scene/material/mat.hxx>
41 #include <simgear/scene/material/matlib.hxx>
42 #include <simgear/scene/util/VectorArrayAdapter.hxx>
44 using namespace simgear;
45 // Ocean tile with curvature and apron to hide cracks. The cracks are
46 // mostly with adjoining coastal tiles that assume a flat ocean
47 // between corners of a tile; they also hide the micro cracks between
48 // adjoining ocean tiles. This is probably over-engineered, but it
49 // serves as a testbed for some things that will come later.
51 // Helper class for building and accessing the mesh. The layout of the
52 // points in the mesh is a little wacky. First is the bottom row of
53 // the points for the apron. Next is the left apron point, the points
54 // in the mesh, and the right apron point, for each of the rows of the
55 // mesh; the points for the top apron come last. This order should
56 // help with things like vertex caching in the OpenGL driver, though
57 // it may be superfluous for such a small mesh.
60 const int lonPoints = 5;
61 const int latPoints = 5;
66 geoPoints(latPoints * lonPoints + 2 * (lonPoints + latPoints)),
67 geod_nodes(latPoints * lonPoints),
68 vl(new osg::Vec3Array(geoPoints)),
69 nl(new osg::Vec3Array(geoPoints)),
70 tl(new osg::Vec2Array(geoPoints)),
71 vlArray(*vl, lonPoints + 2, lonPoints, 1),
72 nlArray(*nl, lonPoints + 2, lonPoints, 1),
73 tlArray(*tl, lonPoints + 2, lonPoints, 1)
77 SGGeod geod[latPoints][lonPoints];
78 SGVec3f normals[latPoints][lonPoints];
79 SGVec3d rel[latPoints][lonPoints];
81 point_list geod_nodes;
86 VectorArrayAdapter<osg::Vec3Array> vlArray;
87 VectorArrayAdapter<osg::Vec3Array> nlArray;
88 VectorArrayAdapter<osg::Vec2Array> tlArray;
90 void calcMesh(const SGVec3d& cartCenter, double clon, double clat,
91 double height, double width, double tex_width);
92 void calcApronPt(int latIdx, int lonIdx, int latInner, int lonInner,
93 int destIdx, double tex_width);
94 void calcApronPts(double tex_width);
99 void OceanMesh::calcMesh(const SGVec3d& cartCenter, double clon, double clat,
100 double height, double width, double tex_width)
102 // Calculate vertices. By splitting the tile up into 4 quads on a
103 // side we avoid curvature-of-the-earth problems; the error should
104 // be less than .5 meters.
105 double longInc = width * .25;
106 double latInc = height * .25;
107 double startLat = clat - height * .5;
108 double startLon = clon - width * .5;
109 for (int j = 0; j < latPoints; j++) {
110 double lat = startLat + j * latInc;
111 for (int i = 0; i < lonPoints; i++) {
112 geod[j][i] = SGGeod::fromDeg(startLon + i * longInc, lat);
113 SGVec3d cart = SGVec3d::fromGeod(geod[j][i]);
114 rel[j][i] = cart - cartCenter;
115 normals[j][i] = toVec3f(normalize(cart));
119 // Calculate texture coordinates
120 point_list geod_nodes(latPoints * lonPoints);
121 VectorArrayAdapter<point_list> geodNodesArray(geod_nodes, lonPoints);
122 int_list rectangle(latPoints * lonPoints);
123 VectorArrayAdapter<int_list> rectArray(rectangle, lonPoints);
124 for (int j = 0; j < latPoints; j++) {
125 for (int i = 0; i < lonPoints; i++) {
126 geodNodesArray(j, i) = Point3D(geod[j][i].getLongitudeDeg(),
127 geod[j][i].getLatitudeDeg(),
128 geod[j][i].getElevationM());
129 rectArray(j, i) = j * 5 + i;
132 point_list texs = sgCalcTexCoords( clat, geod_nodes, rectangle,
133 1000.0 / tex_width );
134 VectorArrayAdapter<point_list> texsArray(texs, lonPoints);
136 for (int j = 0; j < latPoints; j++) {
137 for (int i = 0; i < lonPoints; ++i) {
138 vlArray(j, i) = rel[j][i].osg();
139 nlArray(j, i) = normals[j][i].osg();
140 tlArray(j, i) = texsArray(j, i).toSGVec2f().osg();
146 // Apron points. For each point on the edge we'll go 150
147 // metres "down" and 40 metres "out" to create a nice overlap. The
148 // texture should be applied according to this dimension. The
149 // normals of the apron polygons will be the same as the those of
150 // the points on the edge to better disguise the apron.
151 void OceanMesh::calcApronPt(int latIdx, int lonIdx, int latInner, int lonInner,
152 int destIdx, double tex_width)
154 static const float downDist = 150.0f;
155 static const float outDist = 40.0f;
156 // Get vector along edge, in the right direction to make a cross
157 // product with the normal vector that will point out from the
159 osg::Vec3f edgePt = vlArray(latIdx, lonIdx);
161 if (lonIdx == lonInner) { // bottom or top edge
163 edgeVec = vlArray(latIdx, lonIdx - 1) - edgePt;
165 edgeVec = edgePt - vlArray(latIdx, lonIdx + 1);
166 if (latIdx > latInner)
167 edgeVec = -edgeVec; // Top edge
168 } else { // right or left edge
170 edgeVec = edgePt - vlArray(latIdx - 1, lonIdx);
172 edgeVec = vlArray(latIdx + 1, lonIdx) - edgePt;
173 if (lonIdx > lonInner) // right edge
177 osg::Vec3f outVec = nlArray(latIdx, lonIdx) ^ edgeVec;
179 = edgePt - nlArray(latIdx, lonIdx) * downDist + outVec * outDist;
180 (*nl)[destIdx] = nlArray(latIdx, lonIdx);
181 static const float apronDist
182 = sqrtf(downDist * downDist + outDist * outDist);
183 float texDelta = apronDist / tex_width;
184 if (lonIdx == lonInner) {
185 if (latIdx > latInner)
187 = tlArray(latIdx, lonIdx) + osg::Vec2f(0.0f, texDelta);
190 = tlArray(latIdx, lonIdx) - osg::Vec2f(0.0f, texDelta);
192 if (lonIdx > lonInner)
194 = tlArray(latIdx, lonIdx) + osg::Vec2f(texDelta, 0.0f);
197 = tlArray(latIdx, lonIdx) - osg::Vec2f(texDelta, 0.0f);
201 void OceanMesh::calcApronPts(double tex_width)
203 for (int i = 0; i < lonPoints; i++)
204 calcApronPt(0, i, 1, i, i, tex_width);
205 int topApronOffset = latPoints + (2 + lonPoints) * latPoints;
206 for (int i = 0; i < lonPoints; i++)
207 calcApronPt(latPoints - 1, i, latPoints - 2, i,
208 i + topApronOffset, tex_width);
209 for (int i = 0; i < latPoints; i++) {
210 calcApronPt(i, 0, i, 1, lonPoints + i * (lonPoints + 2), tex_width);
211 calcApronPt(i, lonPoints - 1, i, lonPoints - 2,
212 lonPoints + i * (lonPoints + 2) + 1 + lonPoints, tex_width);
218 // Enter the vertices of triangles that fill one row of the
219 // mesh. The vertices are entered in counter-clockwise order.
220 void fillDrawElementsRow(int width, short row0Start, short row1Start,
221 osg::DrawElementsUShort::vector_type::iterator&
224 short row0Idx = row0Start;
225 short row1Idx = row1Start;
226 for (int i = 0; i < width - 1; i++, row0Idx++, row1Idx++) {
227 *elements++ = row0Idx;
228 *elements++ = row0Idx + 1;
229 *elements++ = row1Idx;
230 *elements++ = row1Idx;
231 *elements++ = row0Idx + 1;
232 *elements++ = row1Idx + 1;
236 void fillDrawElementsWithApron(short height, short width,
237 osg::DrawElementsUShort::vector_type::iterator
241 fillDrawElementsRow(width, 0, width + 1, elements);
242 for (short i = 0; i < height - 1; i++)
243 fillDrawElementsRow(width + 2, width + i * (width + 2),
244 width + (i + 1) * (width + 2),
247 short topApronBottom = width + (height - 1) * (width + 2) + 1;
248 fillDrawElementsRow(width, topApronBottom, topApronBottom + width + 1,
253 osg::Node* SGOceanTile(const SGBucket& b, SGMaterialLib *matlib)
255 osg::StateSet *stateSet = 0;
257 double tex_width = 1000.0;
259 // find Ocean material in the properties list
260 SGMaterial *mat = matlib->find( "Ocean" );
262 // set the texture width and height values for this
264 tex_width = mat->get_xsize();
267 stateSet = mat->get_state();
269 SG_LOG( SG_TERRAIN, SG_ALERT, "Ack! unknown use material name = Ocean");
272 // Calculate center point
273 SGVec3d cartCenter = SGVec3d::fromGeod(b.get_center());
275 double clon = b.get_center_lon();
276 double clat = b.get_center_lat();
277 double height = b.get_height();
278 double width = b.get_width();
280 grid.calcMesh(cartCenter, clon, clat, height, width, tex_width);
281 grid.calcApronPts(tex_width);
283 osg::Vec4Array* cl = new osg::Vec4Array;
284 cl->push_back(osg::Vec4(1, 1, 1, 1));
286 osg::Geometry* geometry = new osg::Geometry;
287 geometry->setVertexArray(grid.vl);
288 geometry->setNormalArray(grid.nl);
289 geometry->setNormalBinding(osg::Geometry::BIND_PER_VERTEX);
290 geometry->setColorArray(cl);
291 geometry->setColorBinding(osg::Geometry::BIND_OVERALL);
292 geometry->setTexCoordArray(0, grid.tl);
294 // Allocate the indices for triangles in the mesh and the apron
295 osg::DrawElementsUShort* drawElements
296 = new osg::DrawElementsUShort(GL_TRIANGLES,
297 6 * ((latPoints - 1) * (lonPoints + 1)
298 + 2 * (latPoints - 1)));
299 fillDrawElementsWithApron(latPoints, lonPoints, drawElements->begin());
300 geometry->addPrimitiveSet(drawElements);
302 osg::Geode* geode = new osg::Geode;
303 geode->setName("Ocean tile");
304 geode->addDrawable(geometry);
305 geode->setStateSet(stateSet);
307 osg::MatrixTransform* transform = new osg::MatrixTransform;
308 transform->setName("Ocean");
309 transform->setMatrix(osg::Matrix::translate(cartCenter.osg()));
310 transform->addChild(geode);