1 /* -*-c++-*-
2 *
3 * Copyright (C) 2006-2007 Mathias Froehlich, Tim Moore
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 #ifdef HAVE_CONFIG_H
23 # include <simgear_config.h>
24 #endif
25
26 #include "SGOceanTile.hxx"
27
28 #include <math.h>
29 #include <simgear/compiler.h>
30
31 #include <osg/Geode>
32 #include <osg/Geometry>
33 #include <osg/MatrixTransform>
34 #include <osg/StateSet>
35
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/Effect.hxx>
41 #include <simgear/scene/material/EffectGeode.hxx>
42 #include <simgear/scene/material/mat.hxx>
43 #include <simgear/scene/material/matlib.hxx>
44 #include <simgear/scene/model/BoundingVolumeBuildVisitor.hxx>
45 #include <simgear/scene/util/OsgMath.hxx>
46 #include <simgear/scene/util/VectorArrayAdapter.hxx>
47 #include <simgear/scene/util/SGNodeMasks.hxx>
48
49 using namespace simgear;
50 // Ocean tile with curvature and apron to hide cracks. The cracks are
51 // mostly with adjoining coastal tiles that assume a flat ocean
52 // between corners of a tile; they also hide the micro cracks between
53 // adjoining ocean tiles. This is probably over-engineered, but it
54 // serves as a testbed for some things that will come later.
55
56 // Helper class for building and accessing the mesh. The layout of the
57 // points in the mesh is a little wacky. First is the bottom row of
58 // the points for the apron. Next is the left apron point, the points
59 // in the mesh, and the right apron point, for each of the rows of the
60 // mesh; the points for the top apron come last. This order should
61 // help with things like vertex caching in the OpenGL driver, though
62 // it may be superfluous for such a small mesh.
63 namespace
64 {
65 class OceanMesh {
66 public:
OceanMesh(int latP,int lonP)67 OceanMesh(int latP, int lonP):
68 latPoints(latP),
69 lonPoints(lonP),
70 geoPoints(latPoints * lonPoints + 2 * (lonPoints + latPoints)),
71 geod_nodes(latPoints * lonPoints),
72 vl(new osg::Vec3Array(geoPoints)),
73 nl(new osg::Vec3Array(geoPoints)),
74 tl(new osg::Vec2Array(geoPoints)),
75 vlArray(*vl, lonPoints + 2, lonPoints, 1),
76 nlArray(*nl, lonPoints + 2, lonPoints, 1),
77 tlArray(*tl, lonPoints + 2, lonPoints, 1)
78 {
79 int numPoints = latPoints * lonPoints;
80 geod = new SGGeod[numPoints];
81 normals = new SGVec3f[numPoints];
82 rel = new SGVec3d[numPoints];
83 }
84
~OceanMesh()85 ~OceanMesh()
86 {
87 delete[] geod;
88 delete[] normals;
89 delete[] rel;
90 }
91
92 const int latPoints, lonPoints;
93 const int geoPoints;
94 SGGeod* geod;
95 SGVec3f* normals;
96 SGVec3d* rel;
97
98 std::vector<SGGeod> geod_nodes;
99
100 osg::Vec3Array* vl;
101 osg::Vec3Array* nl;
102 osg::Vec2Array* tl;
103 VectorArrayAdapter<osg::Vec3Array> vlArray;
104 VectorArrayAdapter<osg::Vec3Array> nlArray;
105 VectorArrayAdapter<osg::Vec2Array> tlArray;
106
107 void calcMesh(const SGVec3d& cartCenter, const SGQuatd& orient,
108 double clon, double clat,
109 double height, double width, double tex_width);
110 void calcApronPt(int latIdx, int lonIdx, int latInner, int lonInner,
111 int destIdx, double tex_width);
112 void calcApronPts(double tex_width);
113
114 };
115
calcMesh(const SGVec3d & cartCenter,const SGQuatd & orient,double clon,double clat,double height,double width,double tex_width)116 void OceanMesh::calcMesh(const SGVec3d& cartCenter, const SGQuatd& orient,
117 double clon, double clat,
118 double height, double width, double tex_width)
119 {
120 // Calculate vertices. By splitting the tile up into 4 quads on a
121 // side we avoid curvature-of-the-earth problems; the error should
122 // be less than .5 meters.
123 double longInc = width * .25;
124 double latInc = height * .25;
125 double startLat = clat - height * .5;
126 double startLon = clon - width * .5;
127 for (int j = 0; j < latPoints; j++) {
128 double lat = startLat + j * latInc;
129 for (int i = 0; i < lonPoints; i++) {
130 int index = (j * lonPoints) + i;
131 geod[index] = SGGeod::fromDeg(startLon + i * longInc, lat);
132 SGVec3d cart = SGVec3d::fromGeod(geod[index]);
133 rel[index] = orient.transform(cart - cartCenter);
134 normals[index] = toVec3f(orient.transform(normalize(cart)));
135 }
136 }
137
138 // Calculate texture coordinates
139 typedef std::vector<SGGeod> GeodVector;
140
141 GeodVector geod_nodes(latPoints * lonPoints);
142 VectorArrayAdapter<GeodVector> geodNodesArray(geod_nodes, lonPoints);
143 int_list rectangle(latPoints * lonPoints);
144 VectorArrayAdapter<int_list> rectArray(rectangle, lonPoints);
145 for (int j = 0; j < latPoints; j++) {
146 for (int i = 0; i < lonPoints; i++) {
147 int index = (j * lonPoints) + i;
148 geodNodesArray(j, i) = geod[index];
149 rectArray(j, i) = index;
150 }
151 }
152
153 typedef std::vector<SGVec2f> Vec2Array;
154 Vec2Array texs = sgCalcTexCoords( clat, geod_nodes, rectangle,
155 1000.0 / tex_width );
156
157
158 VectorArrayAdapter<Vec2Array> texsArray(texs, lonPoints);
159
160 for (int j = 0; j < latPoints; j++) {
161 for (int i = 0; i < lonPoints; ++i) {
162 int index = (j * lonPoints) + i;
163 vlArray(j, i) = toOsg(rel[index]);
164 nlArray(j, i) = toOsg(normals[index]);
165 tlArray(j, i) = toOsg(texsArray(j, i));
166 }
167 }
168
169 }
170
171 // Apron points. For each point on the edge we'll go 150
172 // metres "down" and 40 metres "out" to create a nice overlap. The
173 // texture should be applied according to this dimension. The
174 // normals of the apron polygons will be the same as the those of
175 // the points on the edge to better disguise the apron.
calcApronPt(int latIdx,int lonIdx,int latInner,int lonInner,int destIdx,double tex_width)176 void OceanMesh::calcApronPt(int latIdx, int lonIdx, int latInner, int lonInner,
177 int destIdx, double tex_width)
178 {
179 static const float downDist = 150.0f;
180 static const float outDist = 40.0f;
181 // Get vector along edge, in the right direction to make a cross
182 // product with the normal vector that will point out from the
183 // mesh.
184 osg::Vec3f edgePt = vlArray(latIdx, lonIdx);
185 osg::Vec3f edgeVec;
186 if (lonIdx == lonInner) { // bottom or top edge
187 if (lonIdx > 0)
188 edgeVec = vlArray(latIdx, lonIdx - 1) - edgePt;
189 else
190 edgeVec = edgePt - vlArray(latIdx, lonIdx + 1);
191 if (latIdx > latInner)
192 edgeVec = -edgeVec; // Top edge
193 } else { // right or left edge
194 if (latIdx > 0)
195 edgeVec = edgePt - vlArray(latIdx - 1, lonIdx);
196 else
197 edgeVec = vlArray(latIdx + 1, lonIdx) - edgePt;
198 if (lonIdx > lonInner) // right edge
199 edgeVec = -edgeVec;
200 }
201 edgeVec.normalize();
202 osg::Vec3f outVec = nlArray(latIdx, lonIdx) ^ edgeVec;
203 (*vl)[destIdx]
204 = edgePt - nlArray(latIdx, lonIdx) * downDist + outVec * outDist;
205 (*nl)[destIdx] = nlArray(latIdx, lonIdx);
206 static const float apronDist
207 = sqrtf(downDist * downDist + outDist * outDist);
208 float texDelta = apronDist / tex_width;
209 if (lonIdx == lonInner) {
210 if (latIdx > latInner)
211 (*tl)[destIdx]
212 = tlArray(latIdx, lonIdx) + osg::Vec2f(0.0f, texDelta);
213 else
214 (*tl)[destIdx]
215 = tlArray(latIdx, lonIdx) - osg::Vec2f(0.0f, texDelta);
216 } else {
217 if (lonIdx > lonInner)
218 (*tl)[destIdx]
219 = tlArray(latIdx, lonIdx) + osg::Vec2f(texDelta, 0.0f);
220 else
221 (*tl)[destIdx]
222 = tlArray(latIdx, lonIdx) - osg::Vec2f(texDelta, 0.0f);
223 }
224 }
225
calcApronPts(double tex_width)226 void OceanMesh::calcApronPts(double tex_width)
227 {
228 for (int i = 0; i < lonPoints; i++)
229 calcApronPt(0, i, 1, i, i, tex_width);
230 int topApronOffset = latPoints + (2 + lonPoints) * latPoints;
231 for (int i = 0; i < lonPoints; i++)
232 calcApronPt(latPoints - 1, i, latPoints - 2, i,
233 i + topApronOffset, tex_width);
234 for (int i = 0; i < latPoints; i++) {
235 calcApronPt(i, 0, i, 1, lonPoints + i * (lonPoints + 2), tex_width);
236 calcApronPt(i, lonPoints - 1, i, lonPoints - 2,
237 lonPoints + i * (lonPoints + 2) + 1 + lonPoints, tex_width);
238 }
239 }
240
241 // Enter the vertices of triangles that fill one row of the
242 // mesh. The vertices are entered in counter-clockwise order.
fillDrawElementsRow(int width,short row0Start,short row1Start,osg::DrawElementsUShort::vector_type::iterator & elements)243 void fillDrawElementsRow(int width, short row0Start, short row1Start,
244 osg::DrawElementsUShort::vector_type::iterator&
245 elements)
246 {
247 short row0Idx = row0Start;
248 short row1Idx = row1Start;
249 for (int i = 0; i < width - 1; i++, row0Idx++, row1Idx++) {
250 *elements++ = row0Idx;
251 *elements++ = row0Idx + 1;
252 *elements++ = row1Idx;
253 *elements++ = row1Idx;
254 *elements++ = row0Idx + 1;
255 *elements++ = row1Idx + 1;
256 }
257 }
258
fillDrawElementsWithApron(short height,short width,osg::DrawElementsUShort::vector_type::iterator elements)259 void fillDrawElementsWithApron(short height, short width,
260 osg::DrawElementsUShort::vector_type::iterator
261 elements)
262 {
263 // First apron row
264 fillDrawElementsRow(width, 0, width + 1, elements);
265 for (short i = 0; i < height - 1; i++)
266 fillDrawElementsRow(width + 2, width + i * (width + 2),
267 width + (i + 1) * (width + 2),
268 elements);
269 // Last apron row
270 short topApronBottom = width + (height - 1) * (width + 2) + 1;
271 fillDrawElementsRow(width, topApronBottom, topApronBottom + width + 1,
272 elements);
273 }
274 }
275
SGOceanTile(const SGBucket & b,SGMaterialLib * matlib,int latPoints,int lonPoints)276 osg::Node* SGOceanTile(const SGBucket& b, SGMaterialLib *matlib, int latPoints, int lonPoints)
277 {
278 Effect *effect = 0;
279
280 double tex_width = 1000.0;
281
282 // find Ocean material in the properties list
283 SGMaterialCache* matcache = matlib->generateMatCache(b.get_center());
284 SGMaterial* mat = matcache->find( "Ocean" );
285 delete matcache;
286
287 if ( mat != NULL ) {
288 // set the texture width and height values for this
289 // material
290 tex_width = mat->get_xsize();
291
292 // set OSG State
293 effect = mat->get_effect();
294 } else {
295 SG_LOG( SG_TERRAIN, SG_ALERT, "Ack! unknown use material name = Ocean");
296 }
297 OceanMesh grid(latPoints, lonPoints);
298 // Calculate center point
299 SGVec3d cartCenter = SGVec3d::fromGeod(b.get_center());
300 SGGeod geodPos = SGGeod::fromCart(cartCenter);
301 SGQuatd hlOr = SGQuatd::fromLonLat(geodPos)*SGQuatd::fromEulerDeg(0, 0, 180);
302
303 double clon = b.get_center_lon();
304 double clat = b.get_center_lat();
305 double height = b.get_height();
306 double width = b.get_width();
307
308 grid.calcMesh(cartCenter, hlOr, clon, clat, height, width, tex_width);
309 grid.calcApronPts(tex_width);
310
311 osg::Vec4Array* cl = new osg::Vec4Array;
312 cl->push_back(osg::Vec4(1, 1, 1, 1));
313
314 osg::Geometry* geometry = new osg::Geometry;
315 geometry->setDataVariance(osg::Object::STATIC);
316 geometry->setVertexArray(grid.vl);
317 geometry->setNormalArray(grid.nl);
318 geometry->setNormalBinding(osg::Geometry::BIND_PER_VERTEX);
319 geometry->setColorArray(cl);
320 geometry->setColorBinding(osg::Geometry::BIND_OVERALL);
321 geometry->setTexCoordArray(0, grid.tl);
322
323 // Allocate the indices for triangles in the mesh and the apron
324 osg::DrawElementsUShort* drawElements
325 = new osg::DrawElementsUShort(GL_TRIANGLES,
326 6 * ((latPoints - 1) * (lonPoints + 1)
327 + 2 * (latPoints - 1)));
328 fillDrawElementsWithApron(latPoints, lonPoints, drawElements->begin());
329 geometry->addPrimitiveSet(drawElements);
330
331 EffectGeode* geode = new EffectGeode;
332 geode->setName("Ocean tile");
333 geode->setEffect(effect);
334 geode->addDrawable(geometry);
335 geode->runGenerators(geometry);
336
337 osg::MatrixTransform* transform = new osg::MatrixTransform;
338 transform->setName("Ocean");
339 transform->setMatrix(osg::Matrix::rotate(toOsg(hlOr))*
340 osg::Matrix::translate(toOsg(cartCenter)));
341 transform->addChild(geode);
342 transform->setNodeMask( ~(simgear::CASTSHADOW_BIT | simgear::MODELLIGHT_BIT) );
343
344 // Create a BVH at this point. This is normally provided by the file loader, but as we create the
345 // geometry programmatically, no file loader is involved.
346 BoundingVolumeBuildVisitor bvhBuilder(false);
347 transform->accept(bvhBuilder);
348
349 return transform;
350 }
351