/* -*-c++-*-
*
- * Copyright (C) 2006-2007 Mathias Froehlich
+ * Copyright (C) 2006-2007 Mathias Froehlich, Tim Moore
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
#include "SGOceanTile.hxx"
+#include <math.h>
#include <simgear/compiler.h>
#include <osg/Geode>
#include <simgear/misc/texcoord.hxx>
#include <simgear/scene/material/mat.hxx>
#include <simgear/scene/material/matlib.hxx>
+#include <simgear/scene/util/VectorArrayAdapter.hxx>
-void fillDrawElements(int width, int height,
- osg::DrawElementsUShort::vector_type::iterator elements)
+using namespace simgear;
+// Ocean tile with curvature and apron to hide cracks. The cracks are
+// mostly with adjoining coastal tiles that assume a flat ocean
+// between corners of a tile; they also hide the micro cracks between
+// adjoining ocean tiles. This is probably over-engineered, but it
+// serves as a testbed for some things that will come later.
+
+// Helper class for building and accessing the mesh. The layout of the
+// points in the mesh is a little wacky. First is the bottom row of
+// the points for the apron. Next is the left apron point, the points
+// in the mesh, and the right apron point, for each of the rows of the
+// mesh; the points for the top apron come last. This order should
+// help with things like vertex caching in the OpenGL driver, though
+// it may be superfluous for such a small mesh.
+namespace
{
- for (int j = 0; j < height - 1; j++) {
- for (int i = 0; i < width - 1; i++) {
- *elements++ = j * width + i;
- *elements++ = j * width + i + 1;
- *elements++ = (j + 1) * width + i;
- *elements++ = (j + 1) * width + i;
- *elements++ = j * width + i + 1;
- *elements++ = (j + 1) * width + i + 1;
+const int lonPoints = 5;
+const int latPoints = 5;
+
+class OceanMesh {
+public:
+ OceanMesh():
+ geoPoints(latPoints * lonPoints + 2 * (lonPoints + latPoints)),
+ geod_nodes(latPoints * lonPoints),
+ vl(new osg::Vec3Array(geoPoints)),
+ nl(new osg::Vec3Array(geoPoints)),
+ tl(new osg::Vec2Array(geoPoints)),
+ vlArray(*vl, lonPoints + 2, lonPoints, 1),
+ nlArray(*nl, lonPoints + 2, lonPoints, 1),
+ tlArray(*tl, lonPoints + 2, lonPoints, 1)
+ {
+ }
+ const int geoPoints;
+ SGGeod geod[latPoints][lonPoints];
+ SGVec3f normals[latPoints][lonPoints];
+ SGVec3d rel[latPoints][lonPoints];
+
+ point_list geod_nodes;
+
+ osg::Vec3Array* vl;
+ osg::Vec3Array* nl;
+ osg::Vec2Array* tl;
+ VectorArrayAdapter<osg::Vec3Array> vlArray;
+ VectorArrayAdapter<osg::Vec3Array> nlArray;
+ VectorArrayAdapter<osg::Vec2Array> tlArray;
+
+ void calcMesh(const SGVec3d& cartCenter, double clon, double clat,
+ double height, double width, double tex_width);
+ void calcApronPt(int latIdx, int lonIdx, int latInner, int lonInner,
+ int destIdx, double tex_width);
+ void calcApronPts(double tex_width);
+
+};
+}
+
+void OceanMesh::calcMesh(const SGVec3d& cartCenter, double clon, double clat,
+ double height, double width, double tex_width)
+{
+ // Calculate vertices. By splitting the tile up into 4 quads on a
+ // side we avoid curvature-of-the-earth problems; the error should
+ // be less than .5 meters.
+ double longInc = width * .25;
+ double latInc = height * .25;
+ double startLat = clat - height * .5;
+ double startLon = clon - width * .5;
+ for (int j = 0; j < latPoints; j++) {
+ double lat = startLat + j * latInc;
+ for (int i = 0; i < lonPoints; i++) {
+ geod[j][i] = SGGeod::fromDeg(startLon + i * longInc, lat);
+ SGVec3d cart = SGVec3d::fromGeod(geod[j][i]);
+ rel[j][i] = cart - cartCenter;
+ normals[j][i] = toVec3f(normalize(cart));
+ }
+ }
+
+ // Calculate texture coordinates
+ point_list geod_nodes(latPoints * lonPoints);
+ VectorArrayAdapter<point_list> geodNodesArray(geod_nodes, lonPoints);
+ int_list rectangle(latPoints * lonPoints);
+ VectorArrayAdapter<int_list> rectArray(rectangle, lonPoints);
+ for (int j = 0; j < latPoints; j++) {
+ for (int i = 0; i < lonPoints; i++) {
+ geodNodesArray(j, i) = Point3D(geod[j][i].getLongitudeDeg(),
+ geod[j][i].getLatitudeDeg(),
+ geod[j][i].getElevationM());
+ rectArray(j, i) = j * 5 + i;
+ }
+ }
+ point_list texs = sgCalcTexCoords( clat, geod_nodes, rectangle,
+ 1000.0 / tex_width );
+ VectorArrayAdapter<point_list> texsArray(texs, lonPoints);
+
+ for (int j = 0; j < latPoints; j++) {
+ for (int i = 0; i < lonPoints; ++i) {
+ vlArray(j, i) = rel[j][i].osg();
+ nlArray(j, i) = normals[j][i].osg();
+ tlArray(j, i) = texsArray(j, i).toSGVec2f().osg();
}
}
+
+}
+
+// Apron points. For each point on the edge we'll go 150
+// metres "down" and 40 metres "out" to create a nice overlap. The
+// texture should be applied according to this dimension. The
+// normals of the apron polygons will be the same as the those of
+// the points on the edge to better disguise the apron.
+void OceanMesh::calcApronPt(int latIdx, int lonIdx, int latInner, int lonInner,
+ int destIdx, double tex_width)
+{
+ static const float downDist = 150.0f;
+ static const float outDist = 40.0f;
+ // Get vector along edge, in the right direction to make a cross
+ // product with the normal vector that will point out from the
+ // mesh.
+ osg::Vec3f edgePt = vlArray(latIdx, lonIdx);
+ osg::Vec3f edgeVec;
+ if (lonIdx == lonInner) { // bottom or top edge
+ if (lonIdx > 0)
+ edgeVec = vlArray(latIdx, lonIdx - 1) - edgePt;
+ else
+ edgeVec = edgePt - vlArray(latIdx, lonIdx + 1);
+ if (latIdx > latInner)
+ edgeVec = -edgeVec; // Top edge
+ } else { // right or left edge
+ if (latIdx > 0)
+ edgeVec = edgePt - vlArray(latIdx - 1, lonIdx);
+ else
+ edgeVec = vlArray(latIdx + 1, lonIdx) - edgePt;
+ if (lonIdx > lonInner) // right edge
+ edgeVec = -edgeVec;
+ }
+ edgeVec.normalize();
+ osg::Vec3f outVec = nlArray(latIdx, lonIdx) ^ edgeVec;
+ (*vl)[destIdx]
+ = edgePt - nlArray(latIdx, lonIdx) * downDist + outVec * outDist;
+ (*nl)[destIdx] = nlArray(latIdx, lonIdx);
+ static const float apronDist
+ = sqrtf(downDist * downDist + outDist * outDist);
+ float texDelta = apronDist / tex_width;
+ if (lonIdx == lonInner) {
+ if (latIdx > latInner)
+ (*tl)[destIdx]
+ = tlArray(latIdx, lonIdx) + osg::Vec2f(0.0f, texDelta);
+ else
+ (*tl)[destIdx]
+ = tlArray(latIdx, lonIdx) - osg::Vec2f(0.0f, texDelta);
+ } else {
+ if (lonIdx > lonInner)
+ (*tl)[destIdx]
+ = tlArray(latIdx, lonIdx) + osg::Vec2f(texDelta, 0.0f);
+ else
+ (*tl)[destIdx]
+ = tlArray(latIdx, lonIdx) - osg::Vec2f(texDelta, 0.0f);
+ }
+}
+
+void OceanMesh::calcApronPts(double tex_width)
+{
+ for (int i = 0; i < lonPoints; i++)
+ calcApronPt(0, i, 1, i, i, tex_width);
+ int topApronOffset = latPoints + (2 + lonPoints) * latPoints;
+ for (int i = 0; i < lonPoints; i++)
+ calcApronPt(latPoints - 1, i, latPoints - 2, i,
+ i + topApronOffset, tex_width);
+ for (int i = 0; i < latPoints; i++) {
+ calcApronPt(i, 0, i, 1, lonPoints + i * (lonPoints + 2), tex_width);
+ calcApronPt(i, lonPoints - 1, i, lonPoints - 2,
+ lonPoints + i * (lonPoints + 2) + 1 + lonPoints, tex_width);
+ }
+}
+
+namespace
+{
+// Enter the vertices of triangles that fill one row of the
+// mesh. The vertices are entered in counter-clockwise order.
+void fillDrawElementsRow(int width, short row0Start, short row1Start,
+ osg::DrawElementsUShort::vector_type::iterator&
+ elements)
+{
+ short row0Idx = row0Start;
+ short row1Idx = row1Start;
+ for (int i = 0; i < width - 1; i++, row0Idx++, row1Idx++) {
+ *elements++ = row0Idx;
+ *elements++ = row0Idx + 1;
+ *elements++ = row1Idx;
+ *elements++ = row1Idx;
+ *elements++ = row0Idx + 1;
+ *elements++ = row1Idx + 1;
+ }
+}
+
+void fillDrawElementsWithApron(short height, short width,
+ osg::DrawElementsUShort::vector_type::iterator
+ elements)
+{
+ // First apron row
+ fillDrawElementsRow(width, 0, width + 1, elements);
+ for (short i = 0; i < height - 1; i++)
+ fillDrawElementsRow(width + 2, width + i * (width + 2),
+ width + (i + 1) * (width + 2),
+ elements);
+ // Last apron row
+ short topApronBottom = width + (height - 1) * (width + 2) + 1;
+ fillDrawElementsRow(width, topApronBottom, topApronBottom + width + 1,
+ elements);
+}
}
-// Generate an ocean tile
osg::Node* SGOceanTile(const SGBucket& b, SGMaterialLib *matlib)
{
- osg::StateSet *stateSet = 0;
+ osg::StateSet *stateSet = 0;
- double tex_width = 1000.0;
-
- // find Ocean material in the properties list
- SGMaterial *mat = matlib->find( "Ocean" );
- if ( mat != NULL ) {
- // set the texture width and height values for this
- // material
- tex_width = mat->get_xsize();
-
- // set ssgState
- stateSet = mat->get_state();
- } else {
- SG_LOG( SG_TERRAIN, SG_ALERT, "Ack! unknown use material name = Ocean");
- }
-
- // Calculate center point
- SGVec3d cartCenter = SGVec3d::fromGeod(b.get_center());
+ double tex_width = 1000.0;
- double clon = b.get_center_lon();
- double clat = b.get_center_lat();
- double height = b.get_height();
- double width = b.get_width();
-
- // Calculate vertices. By splitting the tile up into 4 quads on a
- // side we avoid curvature-of-the-earth problems; the error should
- // be less than .5 meters.
- SGGeod geod[5][5];
- SGVec3f normals[5][5];
- SGVec3d rel[5][5];
- double longInc = width * .25;
- double latInc = height * .25;
- double startLat = clat - height * .5;
- double startLon = clon - width * .5;
- for (int j = 0; j < 5; j++) {
- double lat = startLat + j * latInc;
- for (int i = 0; i < 5; i++) {
- geod[i][j] = SGGeod::fromDeg(startLon + i * longInc, lat);
- SGVec3d cart = SGVec3d::fromGeod(geod[i][j]);
- rel[i][j] = cart - cartCenter;
- normals[i][j] = toVec3f(normalize(cart));
- }
- }
+ // find Ocean material in the properties list
+ SGMaterial *mat = matlib->find( "Ocean" );
+ if ( mat != NULL ) {
+ // set the texture width and height values for this
+ // material
+ tex_width = mat->get_xsize();
- // Calculate texture coordinates
- point_list geod_nodes;
- geod_nodes.reserve(5 * 5);
- int_list rectangle;
- rectangle.reserve(5 * 5);
- for (int j = 0; j < 5; j++) {
- for (int i = 0; i < 5; ++i) {
- geod_nodes.push_back(Point3D(geod[i][j].getLongitudeDeg(),
- geod[i][j].getLatitudeDeg(),
- geod[i][j].getElevationM()));
- rectangle.push_back(j * 5 + i);
+ // set OSG State
+ stateSet = mat->get_state();
+ } else {
+ SG_LOG( SG_TERRAIN, SG_ALERT, "Ack! unknown use material name = Ocean");
}
- }
- point_list texs = sgCalcTexCoords( b, geod_nodes, rectangle,
- 1000.0 / tex_width );
+ OceanMesh grid;
+ // Calculate center point
+ SGVec3d cartCenter = SGVec3d::fromGeod(b.get_center());
- // Allocate osg structures
- osg::Vec3Array *vl = new osg::Vec3Array;
- osg::Vec3Array *nl = new osg::Vec3Array;
- osg::Vec2Array *tl = new osg::Vec2Array;
-
- for (int j = 0; j < 5; j++) {
- for (int i = 0; i < 5; ++i) {
- vl->push_back(rel[i][j].osg());
- nl->push_back(normals[i][j].osg());
- tl->push_back(texs[j * 5 + i].toSGVec2f().osg());
- }
- }
+ double clon = b.get_center_lon();
+ double clat = b.get_center_lat();
+ double height = b.get_height();
+ double width = b.get_width();
+
+ grid.calcMesh(cartCenter, clon, clat, height, width, tex_width);
+ grid.calcApronPts(tex_width);
- osg::Vec4Array* cl = new osg::Vec4Array;
- cl->push_back(osg::Vec4(1, 1, 1, 1));
+ osg::Vec4Array* cl = new osg::Vec4Array;
+ cl->push_back(osg::Vec4(1, 1, 1, 1));
- osg::Geometry* geometry = new osg::Geometry;
- geometry->setVertexArray(vl);
- geometry->setNormalArray(nl);
- geometry->setNormalBinding(osg::Geometry::BIND_PER_VERTEX);
- geometry->setColorArray(cl);
- geometry->setColorBinding(osg::Geometry::BIND_OVERALL);
- geometry->setTexCoordArray(0, tl);
-
- osg::DrawElementsUShort* drawElements
- = new osg::DrawElementsUShort(GL_TRIANGLES, 32 * 3);
- fillDrawElements(5, 5, drawElements->begin());
- geometry->addPrimitiveSet(drawElements);
-
- osg::Geode* geode = new osg::Geode;
- geode->setName("Ocean tile");
- geode->addDrawable(geometry);
- geode->setStateSet(stateSet);
-
- osg::MatrixTransform* transform = new osg::MatrixTransform;
- transform->setName("Ocean");
- transform->setMatrix(osg::Matrix::translate(cartCenter.osg()));
- transform->addChild(geode);
+ osg::Geometry* geometry = new osg::Geometry;
+ geometry->setVertexArray(grid.vl);
+ geometry->setNormalArray(grid.nl);
+ geometry->setNormalBinding(osg::Geometry::BIND_PER_VERTEX);
+ geometry->setColorArray(cl);
+ geometry->setColorBinding(osg::Geometry::BIND_OVERALL);
+ geometry->setTexCoordArray(0, grid.tl);
+
+ // Allocate the indices for triangles in the mesh and the apron
+ osg::DrawElementsUShort* drawElements
+ = new osg::DrawElementsUShort(GL_TRIANGLES,
+ 6 * ((latPoints - 1) * (lonPoints + 1)
+ + 2 * (latPoints - 1)));
+ fillDrawElementsWithApron(latPoints, lonPoints, drawElements->begin());
+ geometry->addPrimitiveSet(drawElements);
+
+ osg::Geode* geode = new osg::Geode;
+ geode->setName("Ocean tile");
+ geode->addDrawable(geometry);
+ geode->setStateSet(stateSet);
+
+ osg::MatrixTransform* transform = new osg::MatrixTransform;
+ transform->setName("Ocean");
+ transform->setMatrix(osg::Matrix::translate(cartCenter.osg()));
+ transform->addChild(geode);
- return transform;
+ return transform;
}
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