gshhs.cpp

/******************************************************************************
 *
 * Project:  OpenCPN
 * Purpose:  GSHHS Chart Object (Global Self-consistent, Hierarchical,
 *High-resolution Shoreline) Author:   Jesper Weissglas for the OpenCPN port.
 *
 *           Derived from http://www.zygrib.org/ and
 *http://sourceforge.net/projects/qtvlm/ which has the original copyright:
 *   zUGrib: meteorologic GRIB file data viewer
 *   Copyright (C) 2008 - Jacques Zaninetti - http://www.zygrib.org
 *
 ***************************************************************************
 *   Copyright (C) 2012 by David S. Register                               *
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation; either version 2 of the License, or     *
 *   (at your option) any later version.                                   *
 *                                                                         *
 *   This program is distributed in the hope that it will be useful,       *
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
 *   GNU General Public License for more details.                          *
 *                                                                         *
 *   You should have received a copy of the GNU General Public License     *
 *   along with this program; if not, write to the                         *
 *   Free Software Foundation, Inc.,                                       *
 *   51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,  USA.         *
 ***************************************************************************
 *
 *
 */
 
#include <wx/wxprec.h>
 
#ifndef WX_PRECOMP
#include <wx/wx.h>
#endif
 
#include <wx/file.h>
 
#include "dychart.h"
 
// #if defined(__OCPN__ANDROID__)
// #include <GLES2/gl2.h>
// #elif defined(__WXQT__) || defined(__WXGTK__)
// #include <GL/glew.h>
// //#define GL_GLEXT_PROTOTYPES
// //#include <GL/gl.h>
// //#include <GL/glext.h>
// #endif
 
#include "ocpndc.h"
 
#ifdef ocpnUSE_GL
#include "glChartCanvas.h"
#endif
 
#include "gshhs.h"
#include "chartbase.h"  // for projections
#ifdef ocpnUSE_GL
#include "shaders.h"
#endif
 
#ifdef __WXMSW__
#define __CALL_CONVENTION  //__stdcall
#else
#define __CALL_CONVENTION
#endif
 
#include "linmath.h"
 
extern wxString gWorldMapLocation;
 
#if defined(USE_ANDROID_GLES2) || defined(ocpnUSE_GLSL)
static const GLchar *vertex_shader_source =
    "attribute vec2 position;\n"
    "uniform mat4 MVMatrix;\n"
    "uniform mat4 TransformMatrix;\n"
    "uniform vec4 color;\n"
    "varying vec4 fragColor;\n"
    "void main() {\n"
    "   fragColor = color;\n"
    "   gl_Position = MVMatrix * TransformMatrix * vec4(position, 0.0, 1.0);\n"
    "}\n";
 
static const GLchar *fragment_shader_source =
    "precision lowp float;\n"
    "varying vec4 fragColor;\n"
    "void main() {\n"
    "   gl_FragColor = fragColor;\n"
    "}\n";
 
static const GLfloat vertices2[] = {
    0.0f, 0.5f, 0.5f, -0.5f, -0.5f, -0.5f,
};
 
static const GLfloat vertices3[] = {
    0.0f, 0.5f, 0.0f, 0.5f, -0.5f, 0.0f, -0.5f, -0.5f, 0.0f,
};
 
enum Consts { INFOLOG_LEN = 512 };
GLchar infoLog[INFOLOG_LEN];
GLint fragment_shader;
// GLint shader_program;
GLint success;
GLint vertex_shader;
 
extern GLint color_tri_shader_program;
#endif
 
//-------------------------------------------------------------------------
 
GSHHSChart::GSHHSChart() {
  reader = NULL;
  land = wxColor(250, 250, 250);
  water = wxColor(0, 0, 0);
}
 
GSHHSChart::~GSHHSChart() {
  if (reader) delete reader;
}
 
void GSHHSChart::SetColorScheme(ColorScheme scheme) {
  land = wxColor(170, 175, 80);
  water = wxColor(170, 195, 240);
 
  float dim = 1.0;
 
  switch (scheme) {
    case GLOBAL_COLOR_SCHEME_DUSK:
      dim = 0.5;
      break;
    case GLOBAL_COLOR_SCHEME_NIGHT:
      dim = 0.25;
      break;
    default:
      return;
  }
 
  land.Set(land.Red() * dim, land.Green() * dim, land.Blue() * dim);
  water.Set(water.Red() * dim, water.Green() * dim, water.Blue() * dim);
}
 
void GSHHSChart::SetColorsDirect(wxColour newLand, wxColour newWater) {
  land = newLand;
  water = newWater;
}
 
void GSHHSChart::Reset() {
  if (reader) delete reader;
  reader = NULL;
}
 
int GSHHSChart::GetMinAvailableQuality() {
  if (!reader) reader = new GshhsReader();
  return reader->GetMinAvailableQuality();
}
 
int GSHHSChart::GetMaxAvailableQuality() {
  if (!reader) reader = new GshhsReader();
  return reader->GetMaxAvailableQuality();
}
 
void GSHHSChart::RenderViewOnDC(ocpnDC &dc, ViewPort &vp) {
  if (!reader) {
    reader = new GshhsReader();
    if (reader->GetPolyVersion() < 210 || reader->GetPolyVersion() > 240) {
      wxLogMessage(
          _T("GSHHS World chart files have wrong version. Found %d, expected ")
          _T("210-220."),
          reader->GetPolyVersion());
    } else {
      wxLogMessage(
          _T("Background world map loaded from GSHHS datafiles found in: ") +
          gWorldMapLocation);
    }
  }
 
  reader->drawContinents(dc, vp, water, land);
 
  /* this is very inefficient since it draws the entire world*/
  //    reader->drawBoundaries( dc, vp );
}
 
GshhsPolyCell::GshhsPolyCell(FILE *fpoly_, int x0_, int y0_,
                             PolygonFileHeader *header_) {
  header = header_;
  fpoly = fpoly_;
  x0cell = x0_;
  y0cell = y0_;
 
  for (int i = 0; i < 6; i++) polyv[i] = NULL;
 
  ReadPolygonFile();
 
  for (int i = 0; i < GSSH_SUBM * GSSH_SUBM; i++) high_res_map[i] = NULL;
}
 
GshhsPolyCell::~GshhsPolyCell() {
  ClearPolyV();
 
  for (int i = 0; i < GSSH_SUBM * GSSH_SUBM; i++) delete high_res_map[i];
  for (int i = 0; i < 6; i++) delete[] polyv[i];
}
 
void GshhsPolyCell::ClearPolyV() {
  for (int i = 0; i < 6; i++) {
    delete[] polyv[i];
    polyv[i] = NULL;
  }
}
 
void GshhsPolyCell::ReadPoly(contour_list &poly) {
  double X, Y;
  contour tmp_contour;
  int32_t num_vertices, num_contours;
  poly.clear();
  if (fread(&num_contours, sizeof num_contours, 1, fpoly) != 1) goto fail;
 
  for (int c = 0; c < num_contours; c++) {
    int32_t value;
    if (fread(&value, sizeof value, 1, fpoly) !=
            1 || /* discarding hole value */
        fread(&value, sizeof value, 1, fpoly) != 1)
      goto fail;
 
    num_vertices = value;
 
    tmp_contour.clear();
    for (int v = 0; v < num_vertices; v++) {
      if (fread(&X, sizeof X, 1, fpoly) != 1 ||
          fread(&Y, sizeof Y, 1, fpoly) != 1)
        goto fail;
 
      tmp_contour.push_back(wxRealPoint(X * GSHHS_SCL, Y * GSHHS_SCL));
    }
    poly.push_back(tmp_contour);
  }
  return;
 
fail:
  wxLogMessage(_T("gshhs ReadPoly failed"));
}
 
void GshhsPolyCell::ReadPolygonFile() {
  if (!fpoly) return;
 
  int pos_data;
  int tab_data;
 
  tab_data = (x0cell / header->pasx) * (180 / header->pasy) +
             (y0cell + 90) / header->pasy;
  fseek(fpoly, sizeof(PolygonFileHeader) + tab_data * sizeof(int), SEEK_SET);
  if (fread(&pos_data, sizeof(int), 1, fpoly) != 1) goto fail;
 
  fseek(fpoly, pos_data, SEEK_SET);
 
  ReadPoly(poly1);
  ReadPoly(poly2);
  ReadPoly(poly3);
  ReadPoly(poly4);
  ReadPoly(poly5);
  return;
 
fail:
  wxLogMessage(_T("gshhs ReadPolygon failed"));
}
 
wxPoint2DDouble GetDoublePixFromLL(ViewPort &vp, double lat, double lon) {
  wxPoint2DDouble p = vp.GetDoublePixFromLL(lat, lon);
  p.m_x -= vp.rv_rect.x, p.m_y -= vp.rv_rect.y;
  return p;
}
 
void GshhsPolyCell::DrawPolygonFilled(ocpnDC &pnt, contour_list *p, double dx,
                                      ViewPort &vp, wxColor const &color) {
  if (!p->size()) /* size of 0 is very common, and setting the brush is
                     actually quite slow, so exit early */
    return;
 
  int x, y;
  unsigned int c, v;
  int pointCount;
 
  int x_old = 0;
  int y_old = 0;
 
  pnt.SetBrush(color);
 
  for (c = 0; c < p->size(); c++) {
    if (!p->at(c).size()) continue;
 
    wxPoint *poly_pt = new wxPoint[p->at(c).size()];
 
    contour &cp = p->at(c);
    pointCount = 0;
 
    for (v = 0; v < p->at(c).size(); v++) {
      wxRealPoint &ccp = cp.at(v);
      wxPoint2DDouble q = GetDoublePixFromLL(vp, ccp.y, ccp.x + dx);
      if (std::isnan(q.m_x)) {
        pointCount = 0;
        break;
      }
 
      x = q.m_x, y = q.m_y;
 
      if (v == 0 || x != x_old || y != y_old) {
        poly_pt[pointCount].x = x;
        poly_pt[pointCount].y = y;
        pointCount++;
        x_old = x;
        y_old = y;
      }
    }
 
    if (pointCount > 1) pnt.DrawPolygonTessellated(pointCount, poly_pt, 0, 0);
 
    delete[] poly_pt;
  }
}
 
#ifdef ocpnUSE_GL
 
typedef union {
  GLdouble data[6];
  struct sGLvertex {
    GLdouble x;
    GLdouble y;
    GLdouble z;
    GLdouble r;
    GLdouble g;
    GLdouble b;
  } info;
} GLvertex;
 
#include <list>
 
static std::list<float_2Dpt> g_pv;
static std::list<GLvertex *> g_vertexes;
static int g_type, g_pos;
static float_2Dpt g_p1, g_p2;
 
void __CALL_CONVENTION gshhscombineCallback(GLdouble coords[3],
                                            GLdouble *vertex_data[4],
                                            GLfloat weight[4],
                                            GLdouble **dataOut) {
  GLvertex *vertex;
 
  vertex = new GLvertex();
  g_vertexes.push_back(vertex);
 
  vertex->info.x = coords[0];
  vertex->info.y = coords[1];
 
  *dataOut = vertex->data;
}
 
void __CALL_CONVENTION gshhsvertexCallback(GLvoid *arg) {
  GLvertex *vertex;
  vertex = (GLvertex *)arg;
  float_2Dpt p;
  p.y = vertex->info.x;
  p.x = vertex->info.y;
 
  // convert strips and fans into triangles
  if (g_type != GL_TRIANGLES) {
    if (g_pos > 2) {
      g_pv.push_back(g_p1);
      g_pv.push_back(g_p2);
    }
 
    if (g_type == GL_TRIANGLE_STRIP)
      g_p1 = g_p2;
    else if (g_pos == 0)
      g_p1 = p;
    g_p2 = p;
  }
 
  g_pv.push_back(p);
  g_pos++;
}
 
void __CALL_CONVENTION gshhserrorCallback(GLenum errorCode) {
  const GLubyte *estring;
  estring = gluErrorString(errorCode);
  // wxLogMessage( _T("OpenGL Tessellation Error: %s"), estring );
}
 
void __CALL_CONVENTION gshhsbeginCallback(GLenum type) {
  switch (type) {
    case GL_TRIANGLES:
    case GL_TRIANGLE_STRIP:
    case GL_TRIANGLE_FAN:
      g_type = type;
      break;
    default:
      printf("tess unhandled begin type: %d\n", type);
  }
 
  g_pos = 0;
}
 
void __CALL_CONVENTION gshhsendCallback() {}
 
void GshhsPolyCell::DrawPolygonFilledGL(ocpnDC &pnt, contour_list *p,
                                        float_2Dpt **pv, int *pvc, ViewPort &vp,
                                        wxColor const &color, bool idl) {
  if (!p->size())  // size of 0 is very common, exit early
    return;
 
  // build the contour vertex array converted to normalized coordinates (if
  // needed)
  if (!*pv) {
    for (unsigned int c = 0; c < p->size(); c++) {
      if (!p->at(c).size()) continue;
 
      contour &cp = p->at(c);
 
      GLUtesselator *tobj = gluNewTess();
 
      gluTessCallback(tobj, GLU_TESS_VERTEX, (_GLUfuncptr)&gshhsvertexCallback);
      gluTessCallback(tobj, GLU_TESS_BEGIN, (_GLUfuncptr)&gshhsbeginCallback);
      gluTessCallback(tobj, GLU_TESS_END, (_GLUfuncptr)&gshhsendCallback);
      gluTessCallback(tobj, GLU_TESS_COMBINE,
                      (_GLUfuncptr)&gshhscombineCallback);
      gluTessCallback(tobj, GLU_TESS_ERROR, (_GLUfuncptr)&gshhserrorCallback);
 
      gluTessNormal(tobj, 0, 0, 1);
      gluTessProperty(tobj, GLU_TESS_WINDING_RULE, GLU_TESS_WINDING_NONZERO);
 
      gluTessBeginPolygon(tobj, NULL);
      gluTessBeginContour(tobj);
 
      for (unsigned int v = 0; v < p->at(c).size(); v++) {
        wxRealPoint &ccp = cp.at(v);
 
        if (v == 0 || ccp != cp.at(v - 1)) {
          GLvertex *vertex = new GLvertex();
          g_vertexes.push_back(vertex);
 
          wxPoint2DDouble q;
          if (glChartCanvas::HasNormalizedViewPort(vp))
            q = GetDoublePixFromLL(vp, ccp.y, ccp.x);
          else  // tesselation directly from lat/lon
            q.m_x = ccp.y, q.m_y = ccp.x;
 
          if (vp.m_projection_type != PROJECTION_POLAR) {
            // need to correctly pick +180 or -180 longitude for projections
            // that have a discontiguous date line
 
            if (idl && ccp.x == 180) {
              if (vp.m_projection_type != PROJECTION_MERCATOR &&
                  vp.m_projection_type != PROJECTION_EQUIRECTANGULAR)
                q.m_x -= 360;  // lat/lon coordinates
            }
          }
 
          vertex->info.x = q.m_x;
          vertex->info.y = q.m_y;
 
          gluTessVertex(tobj, (GLdouble *)vertex, (GLdouble *)vertex);
        }
      }
 
      gluTessEndContour(tobj);
      gluTessEndPolygon(tobj);
      gluDeleteTess(tobj);
 
      for (std::list<GLvertex *>::iterator it = g_vertexes.begin();
           it != g_vertexes.end(); it++)
        delete *it;
      g_vertexes.clear();
    }
 
    *pv = new float_2Dpt[g_pv.size()];
    int i = 0;
    for (std::list<float_2Dpt>::iterator it = g_pv.begin(); it != g_pv.end();
         it++)
      (*pv)[i++] = *it;
 
    *pvc = g_pv.size();
    g_pv.clear();
  }
 
#if defined(USE_ANDROID_GLES2) || defined(ocpnUSE_GLSL)
 
#if 0
  // Are the shaders ready?
  if (!vertex_shader) {
    /* Vertex shader */
    vertex_shader = glCreateShader(GL_VERTEX_SHADER);
    glShaderSource(vertex_shader, 1, &vertex_shader_source, NULL);
    glCompileShader(vertex_shader);
    glGetShaderiv(vertex_shader, GL_COMPILE_STATUS, &success);
    if (!success) {
      glGetShaderInfoLog(vertex_shader, INFOLOG_LEN, NULL, infoLog);
      printf("ERROR::SHADER::VERTEX::COMPILATION_FAILED\n%s\n", infoLog);
    }
  }
 
  if (!fragment_shader) {
    /* Fragment shader */
    fragment_shader = glCreateShader(GL_FRAGMENT_SHADER);
    glShaderSource(fragment_shader, 1, &fragment_shader_source, NULL);
    glCompileShader(fragment_shader);
    glGetShaderiv(fragment_shader, GL_COMPILE_STATUS, &success);
    if (!success) {
      glGetShaderInfoLog(fragment_shader, INFOLOG_LEN, NULL, infoLog);
      printf("ERROR::SHADER::FRAGMENT::COMPILATION_FAILED\n%s\n", infoLog);
    }
  }
 
  if (!shader_program) {
    /* Link shaders */
    shader_program = glCreateProgram();
    glAttachShader(shader_program, vertex_shader);
    glAttachShader(shader_program, fragment_shader);
    glLinkProgram(shader_program);
    glGetProgramiv(shader_program, GL_LINK_STATUS, &success);
    if (!success) {
      glGetProgramInfoLog(shader_program, INFOLOG_LEN, NULL, infoLog);
      printf("ERROR::SHADER::PROGRAM::LINKING_FAILED\n%s\n", infoLog);
    }
  }
#endif
  GLuint vbo = 0;
 
  //  Build the shader viewport transform matrix
  mat4x4 m, mvp;
  mat4x4_identity(m);
  mat4x4_scale_aniso(mvp, m, 2.0 / (float)vp.pix_width,
                     2.0 / (float)vp.pix_height, 1.0);
  mat4x4_translate_in_place(mvp, -vp.pix_width / 2, vp.pix_height / 2, 0);
 
  if (glChartCanvas::HasNormalizedViewPort(vp)) {
#if 0
    GLint pos = glGetAttribLocation(color_tri_shader_program, "position");
    glVertexAttribPointer(pos, 2, GL_FLOAT, GL_FALSE, 2 * sizeof(float), *pv);
    glEnableVertexAttribArray(pos);
 
    // FIXME        glUniformMatrix4fv( matloc, 1, GL_FALSE, (const
    // GLfloat*)vp.vp_transform);
    mat4x4 m;
    mat4x4_identity(m);
    GLint tmatloc = glGetUniformLocation(color_tri_shader_program, "TransformMatrix");
    glUniformMatrix4fv(tmatloc, 1, GL_FALSE, (const GLfloat*)m);
 
    glUseProgram(color_tri_shader_program);
    glDrawArrays(GL_TRIANGLES, 0, *pvc);
#endif
  } else {
    float *pvt = new float[2 * (*pvc)];
    for (int i = 0; i < *pvc; i++) {
      float_2Dpt *pc = *pv + i;
      wxPoint2DDouble q = vp.GetDoublePixFromLL(pc->y, pc->x);
      pvt[i * 2] = q.m_x;
      pvt[(i * 2) + 1] = q.m_y;
    }
 
    GLShaderProgram *shader = pcolor_tri_shader_program[pnt.m_canvasIndex];
    shader->Bind();
 
    float colorv[4];
    colorv[0] = color.Red() / float(256);
    colorv[1] = color.Green() / float(256);
    colorv[2] = color.Blue() / float(256);
    colorv[3] = 1.0;
    shader->SetUniform4fv("color", colorv);
 
    shader->SetAttributePointerf("position", pvt);
 
    glDrawArrays(GL_TRIANGLES, 0, *pvc);
 
    delete[] pvt;
    glDeleteBuffers(1, &vbo);
    shader->UnBind();
  }
 
#else
#endif
}
#endif  // #ifdef ocpnUSE_GL
 
#define DRAW_POLY_FILLED(POLY, COL) \
  if (POLY) DrawPolygonFilled(pnt, POLY, dx, vp, COL);
#define DRAW_POLY_FILLED_GL(NUM, COL) \
  DrawPolygonFilledGL(pnt, &poly##NUM, &polyv[NUM], &polyc[NUM], vp, COL, idl);
 
void GshhsPolyCell::drawMapPlain(ocpnDC &pnt, double dx, ViewPort &vp,
                                 wxColor seaColor, wxColor landColor,
                                 bool idl) {
#ifdef ocpnUSE_GL
  if (!pnt.GetDC()) {  // opengl
#if !defined(USE_ANDROID_GLES2) && !defined(ocpnUSE_GLSL)
#define NORM_FACTOR 4096.0
    if (dx && (vp.m_projection_type == PROJECTION_MERCATOR ||
               vp.m_projection_type == PROJECTION_EQUIRECTANGULAR)) {
      double ts =
          40058986 * NORM_FACTOR; /* 360 degrees in normalized viewport */
      glPushMatrix();
      glTranslated(dx > 0 ? ts : -ts, 0, 0);
    }
#endif
    DRAW_POLY_FILLED_GL(1, landColor);
    DRAW_POLY_FILLED_GL(2, seaColor);
    DRAW_POLY_FILLED_GL(3, landColor);
    DRAW_POLY_FILLED_GL(4, seaColor);
    DRAW_POLY_FILLED_GL(5, landColor);
 
#if !defined(USE_ANDROID_GLES2) && !defined(ocpnUSE_GLSL)
    if (dx) glPopMatrix();
#endif
 
  } else
#endif
  {
    DRAW_POLY_FILLED(&poly1, landColor);
    DRAW_POLY_FILLED(&poly2, seaColor);
    DRAW_POLY_FILLED(&poly3, landColor);
    DRAW_POLY_FILLED(&poly4, seaColor);
    DRAW_POLY_FILLED(&poly5, landColor);
  }
}
 
void GshhsPolyCell::DrawPolygonContour(ocpnDC &pnt, contour_list *p, double dx,
                                       ViewPort &vp) {
  double x1, y1, x2, y2;
  double long_max, lat_max, long_min, lat_min;
 
  long_min = (double)x0cell;
  lat_min = (double)y0cell;
  long_max = ((double)x0cell + (double)header->pasx);
  lat_max = ((double)y0cell + (double)header->pasy);
 
  // qWarning()  << long_min << "," << lat_min << long_max << "," << lat_max;
 
  for (unsigned int i = 0; i < p->size(); i++) {
    if (!p->at(i).size()) continue;
 
    unsigned int v;
    for (v = 0; v < (p->at(i).size() - 1); v++) {
      x1 = p->at(i).at(v).x;
      y1 = p->at(i).at(v).y;
      x2 = p->at(i).at(v + 1).x;
      y2 = p->at(i).at(v + 1).y;
 
      // Elimination des traits verticaux et horizontaux
      if ((((x1 == x2) && ((x1 == long_min) || (x1 == long_max))) ||
           ((y1 == y2) && ((y1 == lat_min) || (y1 == lat_max)))) == 0) {
        wxPoint2DDouble AB = GetDoublePixFromLL(vp, x1 + dx, y1);
        wxPoint2DDouble CD = GetDoublePixFromLL(vp, x2 + dx, y1);
        pnt.DrawLine(AB.m_x, AB.m_y, CD.m_x, CD.m_y);
      }
    }
 
    x1 = p->at(i).at(v).x;
    y1 = p->at(i).at(v).y;
    x2 = p->at(i).at(0).x;
    y2 = p->at(i).at(0).y;
 
    if ((((x1 == x2) && ((x1 == long_min) || (x1 == long_max))) ||
         ((y1 == y2) && ((y1 == lat_min) || (y1 == lat_max)))) == 0) {
      wxPoint2DDouble AB = GetDoublePixFromLL(vp, x1 + dx, y1);
      wxPoint2DDouble CD = GetDoublePixFromLL(vp, x2 + dx, y1);
      pnt.DrawLine(AB.m_x, AB.m_y, CD.m_x, CD.m_y);
    }
  }
}
 
#define DRAW_POLY_CONTOUR(POLY) \
  if (POLY) DrawPolygonContour(pnt, POLY, dx, vp);
 
void GshhsPolyCell::drawSeaBorderLines(ocpnDC &pnt, double dx, ViewPort &vp) {
  coasts.clear();
  DRAW_POLY_CONTOUR(&poly1)
  DRAW_POLY_CONTOUR(&poly2)
  DRAW_POLY_CONTOUR(&poly3)
  DRAW_POLY_CONTOUR(&poly4)
  DRAW_POLY_CONTOUR(&poly5)
}
 
//========================================================================
 
GshhsPolyReader::GshhsPolyReader(int quality) {
  fpoly = NULL;
 
  for (int i = 0; i < 360; i++) {
    for (int j = 0; j < 180; j++) {
      allCells[i][j] = NULL;
    }
  }
  currentQuality = -1;
  polyHeader.version = -1;
  InitializeLoadQuality(quality);
}
 
//-------------------------------------------------------------------------
GshhsPolyReader::~GshhsPolyReader() {
  for (int i = 0; i < 360; i++) {
    for (int j = 0; j < 180; j++) {
      if (allCells[i][j] != NULL) {
        delete allCells[i][j];
        allCells[i][j] = NULL;
      }
    }
  }
 
  if (fpoly) {
    fclose(fpoly);
  }
}
 
//-------------------------------------------------------------------------
int GshhsPolyReader::ReadPolyVersion() {
  wxString fname = GshhsReader::getFileName_Land(0);
  if (fpoly) fclose(fpoly);
  fpoly = fopen(fname.mb_str(), "rb");
 
  /* init header */
  if (!fpoly) return 0;
 
  readPolygonFileHeader(fpoly, &polyHeader);
 
  return polyHeader.version;
}
 
void GshhsPolyReader::InitializeLoadQuality(
    int quality)  // 5 levels: 0=low ... 4=full
{
  if (currentQuality != quality) {
    currentQuality = quality;
 
    wxString fname = GshhsReader::getFileName_Land(quality);
 
    if (fpoly) fclose(fpoly);
 
    fpoly = fopen(fname.mb_str(), "rb");
    if (fpoly) readPolygonFileHeader(fpoly, &polyHeader);
 
    for (int i = 0; i < 360; i++) {
      for (int j = 0; j < 180; j++) {
        if (allCells[i][j] != NULL) {
          delete allCells[i][j];
          allCells[i][j] = NULL;
        }
      }
    }
  }
}
 
static inline bool my_intersects(const wxLineF &line1, const wxLineF &line2) {
  double x1 = line1.m_p1.x, y1 = line1.m_p1.y, x2 = line1.m_p2.x,
         y2 = line1.m_p2.y;
  double x3 = line2.m_p1.x, y3 = line2.m_p1.y, x4 = line2.m_p2.x,
         y4 = line2.m_p2.y;
 
  // implementation is based on Graphics Gems III's "Faster Line Segment
  // Intersection"
  double ax = x2 - x1, ay = y2 - y1;
  double bx = x3 - x4, by = y3 - y4;
  double cx = x1 - x3, cy = y1 - y3;
 
#define INTER_LIMIT 1e-7
  double denominator = ay * bx - ax * by;
  if (denominator < 1e-10) {
    if (fabs((y1 * ax - ay * x1) * bx - (y3 * bx - by * x3) * ax) > INTER_LIMIT)
      return false; /* different intercepts, no intersection */
    if (fabs((x1 * ay - ax * y1) * by - (x3 * by - bx * y3) * ay) > INTER_LIMIT)
      return false; /* different intercepts, no intersection */
 
    return true;
  }
 
  const double reciprocal = 1 / denominator;
  const double na = (by * cx - bx * cy) * reciprocal;
 
  if (na < -INTER_LIMIT || na > 1 + INTER_LIMIT) return false;
 
  const double nb = (ax * cy - ay * cx) * reciprocal;
  if (nb < -INTER_LIMIT || nb > 1 + INTER_LIMIT) return false;
 
  return true;
}
 
bool GshhsPolyReader::crossing1(wxLineF trajectWorld) {
  double x1 = trajectWorld.p1().x, y1 = trajectWorld.p1().y;
  double x2 = trajectWorld.p2().x, y2 = trajectWorld.p2().y;
 
  int clonmin, clonmax, clatmax, clatmin;
  clonmin = (int)floor(GSSH_SUBM * wxMin(x1, x2));
  clonmax = (int)ceil(GSSH_SUBM * wxMax(x1, x2));
 
  if (clonmin < 0) {
    clonmin += GSSH_SUBM * 360;
    clonmax += GSSH_SUBM * 360;
  }
 
  if (clonmax - clonmin > GSSH_SUBM * 180) { /* dont go long way around world */
    clonmin = (int)floor(GSSH_SUBM * wxMax(x1, x2)) - GSSH_SUBM * 360;
    clonmax = (int)ceil(GSSH_SUBM * wxMin(x1, x2));
  }
 
  clatmin = (int)floor(GSSH_SUBM * wxMin(y1, y2));
  clatmax = (int)ceil(GSSH_SUBM * wxMax(y1, y2));
  wxASSERT(clatmin >= -GSSH_SUBM * 90 && clatmax <= GSSH_SUBM * 89);
 
  // TODO: optimize by traversing only the cells the segment passes through,
  //       rather than all of the cells which fit in the bounding box,
  //       this may make a worthwhile difference for longer segments in some
  //       cases.
  int clon, clonx, clat;
  for (clon = clonmin; clon < clonmax; clon++) {
    clonx = clon;
    while (clonx < 0) clonx += GSSH_SUBM * 360;
    while (clonx >= GSSH_SUBM * 360) clonx -= GSSH_SUBM * 360;
 
    wxASSERT(clonx >= 0 && clonx < GSSH_SUBM * 360);
 
    if (clonx < GSSH_SUBM * 180) {
      if (x1 > 180) x1 -= 360;
      if (x2 > 180) x2 -= 360;
    } else {
      if (x1 < 180) x1 += 360;
      if (x2 < 180) x2 += 360;
    }
 
    wxLineF rtrajectWorld(x1, y1, x2, y2);
 
    for (clat = clatmin; clat < clatmax; clat++) {
      int cloni = clonx / GSSH_SUBM,
          clati = (GSSH_SUBM * 90 + clat) / GSSH_SUBM;
      GshhsPolyCell *&cel = allCells[cloni][clati];
      if (!cel) {
        mutex1.Lock();
        if (!cel) {
          /* load the needed cell from disk */
          cel = new GshhsPolyCell(fpoly, cloni, clati - 90, &polyHeader);
          wxASSERT(cel);
        }
        mutex1.Unlock();
      }
 
      int hash = GSSH_SUBM * (GSSH_SUBM * (90 - clati) + clat - cloni) + clonx;
      std::vector<wxLineF> *&high_res_map = cel->high_res_map[hash];
      wxASSERT(hash >= 0 && hash < GSSH_SUBM * GSSH_SUBM);
      if (!high_res_map) {
        mutex2.Lock();
        if (!high_res_map) {
          /* Build the needed sub cell of line segments from the cell */
          contour_list &poly1 = cel->getPoly1();
 
          double minlat = (double)clat / GSSH_SUBM,
                 maxlat = (double)(clat + 1) / GSSH_SUBM;
          double minlon = (double)clonx / GSSH_SUBM,
                 maxlon = (double)(clonx + 1) / GSSH_SUBM;
          high_res_map = new std::vector<wxLineF>;
          for (unsigned int pi = 0; pi < poly1.size(); pi++) {
            contour &c = poly1[pi];
            double lx = c[c.size() - 1].x, ly = c[c.size() - 1].y;
            /* must compute states because sometimes a
               segment starts and ends outside our cell, but passes
               through it so must be included */
            int lstatex = lx < minlon ? -1 : lx > maxlon ? 1 : 0;
            int lstatey = ly < minlat ? -1 : ly > maxlat ? 1 : 0;
 
            for (unsigned int pj = 0; pj < c.size(); pj++) {
              double clon = c[pj].x, clat = c[pj].y;
              // gshhs data shouldn't, but sometimes contains zero segments
              // which enlarges our table, but
              // more importantly, the fast segment intersection test
              // and doesn't correctly account for it
              if (lx == clon && ly == clat) continue;
 
              int statex = clon < minlon ? -1 : clon > maxlon ? 1 : 0;
              int statey = clat < minlat ? -1 : clat > maxlat ? 1 : 0;
 
              if ((!statex || lstatex != statex) &&
                  (!statey || lstatey != statey))
                high_res_map->push_back(wxLineF(lx, ly, clon, clat));
 
              lx = clon, ly = clat;
              lstatex = statex, lstatey = statey;
            }
          }
        }
        mutex2.Unlock();
      }
 
      for (std::vector<wxLineF>::iterator it2 = high_res_map->begin();
           it2 != high_res_map->end(); it2++)
        if (my_intersects(rtrajectWorld, *it2)) return true;
    }
  }
 
  return false;
}
 
void GshhsPolyReader::readPolygonFileHeader(FILE *polyfile,
                                            PolygonFileHeader *header) {
  fseek(polyfile, 0, SEEK_SET);
  if (fread(header, sizeof(PolygonFileHeader), 1, polyfile) != 1)
    wxLogMessage(_T("gshhs ReadPolygonFileHeader failed"));
}
 
//-------------------------------------------------------------------------
void GshhsPolyReader::drawGshhsPolyMapPlain(ocpnDC &pnt, ViewPort &vp,
                                            wxColor const &seaColor,
                                            wxColor const &landColor) {
  if (!fpoly) return;
 
  pnt.SetPen(wxNullPen);
 
  int clonmin, clonmax, clatmax, clatmin;  // cellules visibles
  LLBBox bbox = vp.GetBBox();
  clonmin = bbox.GetMinLon(), clonmax = bbox.GetMaxLon(),
  clatmin = bbox.GetMinLat(), clatmax = bbox.GetMaxLat();
  if (clatmin <= 0) clatmin--;
  if (clatmax >= 0) clatmax++;
  if (clonmin <= 0) clonmin--;
  if (clonmax >= 0) clonmax++;
  int dx, clon, clonx, clat;
  GshhsPolyCell *cel;
 
  ViewPort nvp = vp;
#ifdef ocpnUSE_GL
  if (!pnt.GetDC()) {  // opengl
    // clear cached data when the projection changes
    if (vp.m_projection_type != last_rendered_vp.m_projection_type ||
        (last_rendered_vp.m_projection_type == PROJECTION_POLAR &&
         last_rendered_vp.clat * vp.clat <= 0)) {
      last_rendered_vp = vp;
      for (int clon = 0; clon < 360; clon++)
        for (int clat = 0; clat < 180; clat++)
          if (allCells[clon][clat]) allCells[clon][clat]->ClearPolyV();
    }
#if !defined(USE_ANDROID_GLES2) && !defined(ocpnUSE_GLSL)
    glEnableClientState(GL_VERTEX_ARRAY);
 
    // use a viewport that allows the vertexes to be reused over many frames
    // TODO fix for multicanvas
    if (glChartCanvas::HasNormalizedViewPort(vp)) {
      glPushMatrix();
      glChartCanvas::MultMatrixViewPort(vp);
      nvp = glChartCanvas::NormalizedViewPort(vp);
    }
#endif
  }
#endif
  for (clon = clonmin; clon < clonmax; clon++) {
    clonx = clon;
    while (clonx < 0) clonx += 360;
    while (clonx >= 360) clonx -= 360;
 
    for (clat = clatmin; clat < clatmax; clat++) {
      if (clonx >= 0 && clonx <= 359 && clat >= -90 && clat <= 89) {
        if (allCells[clonx][clat + 90] == NULL) {
          cel = new GshhsPolyCell(fpoly, clonx, clat, &polyHeader);
          wxASSERT(cel);
          allCells[clonx][clat + 90] = cel;
        } else {
          cel = allCells[clonx][clat + 90];
        }
        bool idl = false;
 
        // only mercator needs the special idl fixes
        if (vp.m_projection_type != PROJECTION_MERCATOR &&
            vp.m_projection_type != PROJECTION_EQUIRECTANGULAR)
          dx = 0;
        else if (pnt.GetDC())  // dc
          dx = clon - clonx;
        else {  // opengl
          int clonn = clonx;
          if (clonn >= 180) {
            clonn -= 360;
            idl = true;
          }
          if (vp.clon - clonn > 180)
            dx = 1;
          else if (vp.clon - clonn < -180)
            dx = -1;
          else
            dx = 0;
        }
 
        cel->drawMapPlain(pnt, dx, nvp, seaColor, landColor, idl);
      }
    }
  }
 
#ifdef ocpnUSE_GL
#if !defined(USE_ANDROID_GLES2) && !defined(ocpnUSE_GLSL)
  if (!pnt.GetDC()) {  // opengl
    if (glChartCanvas::HasNormalizedViewPort(vp)) glPopMatrix();
    glDisableClientState(GL_VERTEX_ARRAY);
  }
#endif
#endif
}
 
//-------------------------------------------------------------------------
void GshhsPolyReader::drawGshhsPolyMapSeaBorders(ocpnDC &pnt, ViewPort &vp) {
  if (!fpoly) return;
  int clonmin, clonmax, clatmax, clatmin;  // cellules visibles
  LLBBox bbox = vp.GetBBox();
  clonmin = bbox.GetMinLon(), clonmax = bbox.GetMaxLon(),
  clatmin = bbox.GetMinLat(), clatmax = bbox.GetMaxLat();
 
  int dx, clon, clonx, clat;
  GshhsPolyCell *cel;
 
  for (clon = clonmin; clon < clonmax; clon++) {
    clonx = clon;
    while (clonx < 0) clonx += 360;
    while (clonx >= 360) clonx -= 360;
 
    for (clat = clatmin; clat < clatmax; clat++) {
      if (clonx >= 0 && clonx <= 359 && clat >= -90 && clat <= 89) {
        if (allCells[clonx][clat + 90] == NULL) {
          cel = new GshhsPolyCell(fpoly, clonx, clat, &polyHeader);
          wxASSERT(cel);
          allCells[clonx][clat + 90] = cel;
        } else {
          cel = allCells[clonx][clat + 90];
        }
        dx = clon - clonx;
        cel->drawSeaBorderLines(pnt, dx, vp);
      }
    }
  }
}
 
int GshhsPolygon::readInt4() {
  union {
    unsigned int n;
    unsigned char buf[4];
  } res;
 
  unsigned char in[4];
 
  int nb = 0;
  nb += fread(&in, 1, 4, file);
  res.buf[3] = in[0];
  res.buf[2] = in[1];
  res.buf[1] = in[2];
  res.buf[0] = in[3];
 
  if (nb != 4) {
    ok = false;
    res.n = 0;
  }
 
  return res.n;
}
 
int GshhsPolygon::readInt2() {
  union {
    unsigned int n;
    unsigned char buf[4];
  } v;
 
  int nb = 0;
  nb += fread(&v.buf[0], 2, 1, file);
  if (nb != 2) {
    ok = false;
    v.n = 0;
  }
  return v.buf[1] << 8 | v.buf[0];
}
 
GshhsPolygon::GshhsPolygon(FILE *file_) {
  file = file_;
  ok = true;
  id = readInt4();
  n = readInt4();
  flag = readInt4();
  west = readInt4() * 1e-6;
  east = readInt4() * 1e-6;
  south = readInt4() * 1e-6;
  north = readInt4() * 1e-6;
  area = readInt4();
 
  if (((flag >> 8) & 255) >= 7) {  // GSHHS Release 2.0
    areaFull = readInt4();
    container = readInt4();
    ancestor = readInt4();
 
    greenwich = (flag >> 16) & 1;
    antarctic = (west == 0 && east == 360);
    if (ok) {
      double x = 0, y = 0;
      for (int i = 0; i < n; i++) {
        x = readInt4() * 1e-6;
        if (greenwich && x > 270) x -= 360;
        y = readInt4() * 1e-6;
        lsPoints.push_back(new GshhsPoint(x, y));
      }
      if (antarctic) {
        lsPoints.insert(lsPoints.begin(), new GshhsPoint(360, y));
        lsPoints.insert(lsPoints.begin(), new GshhsPoint(360, -90));
        lsPoints.push_back(new GshhsPoint(0, -90));
      }
    }
  } else {
    greenwich = (flag >> 16) & 1;
    antarctic = (west == 0 && east == 360);
    if (ok) {
      for (int i = 0; i < n; i++) {
        double x = 0, y = 0;
        x = readInt4() * 1e-6;
        if (greenwich && x > 270) x -= 360;
        y = readInt4() * 1e-6;
        lsPoints.push_back(new GshhsPoint(x, y));
      }
    }
  }
}
 
//--------------------------------------------------------
 
GshhsPolygon::~GshhsPolygon() {
  std::vector<GshhsPoint *>::iterator itp;
  for (itp = lsPoints.begin(); itp != lsPoints.end(); itp++) {
    delete *itp;
    *itp = NULL;
  }
  lsPoints.clear();
}
 
//==========================================================
 
GshhsReader::GshhsReader() {
  maxQualityAvailable = -1;
  minQualityAvailable = -1;
 
  for (int i = 0; i < 5; i++) {
    qualityAvailable[i] = false;
    if (GshhsReader::gshhsFilesExists(i)) {
      qualityAvailable[i] = true;
      if (minQualityAvailable < 0) minQualityAvailable = i;
      maxQualityAvailable = i;
    }
  }
 
  if (maxQualityAvailable < 0) {
    wxString msg(
        _T("Unable to initialize background world map. No GSHHS datafiles ")
        _T("found in "));
    msg += gWorldMapLocation;
    wxLogMessage(msg);
  }
 
  //    int q = selectBestQuality( vp );
  //    if( ! qualityAvailable[q] ) {
  //    int q = maxQualityAvailable;
  //    }
 
  int q = 0;
 
  gshhsPoly_reader = new GshhsPolyReader(q);
 
  for (int qual = 0; qual < 5; qual++) {
    lsPoly_boundaries[qual] = new std::vector<GshhsPolygon *>;
    lsPoly_rivers[qual] = new std::vector<GshhsPolygon *>;
  }
 
  quality = -1;
  LoadQuality(q);
}
 
int GshhsReader::ReadPolyVersion() {
  return gshhsPoly_reader->ReadPolyVersion();
}
 
//-------------------------------------------------------
 
GshhsReader::~GshhsReader() {
  clearLists();
  delete gshhsPoly_reader;
}
 
//-----------------------------------------------------------------------
void GshhsReader::clearLists() {
  std::vector<GshhsPolygon *>::iterator itp;
  for (int qual = 0; qual < 5; qual++) {
    for (itp = lsPoly_boundaries[qual]->begin();
         itp != lsPoly_boundaries[qual]->end(); itp++) {
      delete *itp;
      *itp = NULL;
    }
    for (itp = lsPoly_rivers[qual]->begin(); itp != lsPoly_rivers[qual]->end();
         itp++) {
      delete *itp;
      *itp = NULL;
    }
 
    lsPoly_boundaries[qual]->clear();
    lsPoly_rivers[qual]->clear();
    delete lsPoly_boundaries[qual];
    delete lsPoly_rivers[qual];
  }
}
//-----------------------------------------------------------------------
 
wxString GshhsReader::getNameExtension(int quality) {
  wxString ext;
  switch (quality) {
    case 0:
      ext = _T("c");
      break;
    case 1:
      ext = _T("l");
      break;
    case 2:
      ext = _T("i");
      break;
    case 3:
      ext = _T("h");
      break;
    case 4:
      ext = _T("f");
      break;
    default:
      ext = _T("l");
      break;
  }
  return ext;
}
 
wxString GshhsReader::getFileName_Land(int quality) {
  wxString ext = GshhsReader::getNameExtension(quality);
  wxString fname =
      gWorldMapLocation + wxString::Format(_T("poly-%c-1.dat"), ext.GetChar(0));
  return fname;
}
 
wxString GshhsReader::getFileName_boundaries(int quality) {
  wxString ext = GshhsReader::getNameExtension(quality);
  wxString fname = gWorldMapLocation +
                   wxString::Format(_T("wdb_borders_%c.b"), ext.GetChar(0));
  return fname;
}
 
wxString GshhsReader::getFileName_rivers(int quality) {
  wxString ext = GshhsReader::getNameExtension(quality);
  wxString fname = gWorldMapLocation +
                   wxString::Format(_T("wdb_rivers_%c.b"), ext.GetChar(0));
  return fname;
}
 
//-----------------------------------------------------------------------
bool GshhsReader::gshhsFilesExists(int quality) {
  if (!wxFile::Access(GshhsReader::getFileName_Land(quality), wxFile::read))
    return false;
  // Borders disabled anyway since the perf optimizations if( ! wxFile::Access(
  // GshhsReader::getFileName_boundaries( quality ), wxFile::read ) ) return
  // false; Rivers disabled anyway since the perf optimizations if( !
  // wxFile::Access( GshhsReader::getFileName_rivers( quality ), wxFile::read )
  // ) return false;
 
  return true;
}
 
//-----------------------------------------------------------------------
void GshhsReader::LoadQuality(int newQuality)  // 5 levels: 0=low ... 4=full
{
  if (quality == newQuality) return;
 
  wxStopWatch perftimer;
 
  wxString fname;
 
  quality = newQuality;
  if (quality < 0)
    quality = 0;
  else if (quality > 4)
    quality = 4;
 
  gshhsPoly_reader->InitializeLoadQuality(quality);
#if 0 /* too slow to load the whole world at once */
    if( lsPoly_boundaries[quality]->size() == 0 ) {
        fname = getFileName_boundaries( quality );
        file = fopen( fname.mb_str(), "rb" );
 
        if( file != NULL ) {
            ok = true;
            while( ok ) {
                GshhsPolygon *poly = new GshhsPolygon( file );
 
                ok = poly->isOk();
                if( ok )
                    if( poly->getLevel() < 2 )
                        lsPoly_boundaries[quality]->push_back( poly );
                    else delete poly;
                else delete poly;
            }
            fclose( file );
        }
    }
 
    if( lsPoly_rivers[quality]->size() == 0 ) {
        fname = getFileName_rivers( quality );
        file = fopen( fname.mb_str(), "rb" );
        if( file != NULL ) {
            ok = true;
            while( ok ) {
                GshhsPolygon *poly = new GshhsPolygon( file );
                ok = poly->isOk();
                if( ok ) {
                    lsPoly_rivers[quality]->push_back( poly );
                }
                else delete poly;
            }
            fclose( file );
        }
    }
#endif
  wxLogMessage(_T("Loading World Chart Q=%d in %ld ms."), quality,
               perftimer.Time());
}
 
//-----------------------------------------------------------------------
std::vector<GshhsPolygon *> &GshhsReader::getList_boundaries() {
  return *lsPoly_boundaries[quality];
}
//-----------------------------------------------------------------------
std::vector<GshhsPolygon *> &GshhsReader::getList_rivers() {
  return *lsPoly_rivers[quality];
}
 
//=====================================================================
 
int GshhsReader::GSHHS_scaledPoints(GshhsPolygon *pol, wxPoint *pts,
                                    double declon, ViewPort &vp) {
  LLBBox box;
  box.Set(pol->south, pol->west + declon, pol->north, pol->east + declon);
  if (vp.GetBBox().IntersectOut(box)) return 0;
 
  // Remove small polygons.
 
  wxPoint2DDouble p1 = GetDoublePixFromLL(vp, pol->west + declon, pol->north);
  wxPoint2DDouble p2 = GetDoublePixFromLL(vp, pol->east + declon, pol->south);
 
  if (p1.m_x == p2.m_x && p1.m_y == p2.m_y) return 0;
 
  double x, y;
  std::vector<GshhsPoint *>::iterator itp;
  int xx, yy, oxx = 0, oyy = 0;
  int j = 0;
 
  for (itp = (pol->lsPoints).begin(); itp != (pol->lsPoints).end(); itp++) {
    x = (*itp)->lon + declon;
    y = (*itp)->lat;
    wxPoint2DDouble p = GetDoublePixFromLL(vp, y, x);
    xx = p.m_x, yy = p.m_y;
    if (j == 0 || (oxx != xx || oyy != yy)) {  // Remove close points
      oxx = xx;
      oyy = yy;
      pts[j].x = xx;
      pts[j].y = yy;
      j++;
    }
  }
 
  return j;
}
 
//-----------------------------------------------------------------------
void GshhsReader::GsshDrawLines(ocpnDC &pnt, std::vector<GshhsPolygon *> &lst,
                                ViewPort &vp, bool isClosed) {
  std::vector<GshhsPolygon *>::iterator iter;
  GshhsPolygon *pol;
  wxPoint *pts = NULL;
  int i;
  int nbp;
 
  int nbmax = 10000;
  pts = new wxPoint[nbmax];
  wxASSERT(pts);
 
  for (i = 0, iter = lst.begin(); iter != lst.end(); iter++, i++) {
    pol = *iter;
 
    if (nbmax < pol->n + 2) {
      nbmax = pol->n + 2;
      delete[] pts;
      pts = new wxPoint[nbmax];
      wxASSERT(pts);
    }
 
    nbp = GSHHS_scaledPoints(pol, pts, 0, vp);
    if (nbp > 1) {
      if (pol->isAntarctic()) {
        pts++;
        nbp -= 2;
        pnt.DrawLines(nbp, pts);
        pts--;
      } else {
        pnt.DrawLines(nbp, pts);
        if (isClosed)
          pnt.DrawLine(pts[0].x, pts[0].y, pts[nbp - 1].x, pts[nbp - 1].y);
      }
    }
 
    nbp = GSHHS_scaledPoints(pol, pts, -360, vp);
    if (nbp > 1) {
      if (pol->isAntarctic()) {
        pts++;
        nbp -= 2;
        pnt.DrawLines(nbp, pts);
        pts--;
      } else {
        pnt.DrawLines(nbp, pts);
        if (isClosed)
          pnt.DrawLine(pts[0].x, pts[0].y, pts[nbp - 1].x, pts[nbp - 1].y);
      }
    }
  }
  delete[] pts;
}
 
//-----------------------------------------------------------------------
void GshhsReader::drawContinents(ocpnDC &pnt, ViewPort &vp,
                                 wxColor const &seaColor,
                                 wxColor const &landColor) {
  LoadQuality(selectBestQuality(vp));
  gshhsPoly_reader->drawGshhsPolyMapPlain(pnt, vp, seaColor, landColor);
}
 
//-----------------------------------------------------------------------
void GshhsReader::drawSeaBorders(ocpnDC &pnt, ViewPort &vp) {
  pnt.SetBrush(*wxTRANSPARENT_BRUSH);
  gshhsPoly_reader->drawGshhsPolyMapSeaBorders(pnt, vp);
}
 
//-----------------------------------------------------------------------
void GshhsReader::drawBoundaries(ocpnDC &pnt, ViewPort &vp) {
  pnt.SetBrush(*wxTRANSPARENT_BRUSH);
 
  if (pnt.GetDC()) {
    wxPen *pen = wxThePenList->FindOrCreatePen(*wxBLACK, 1, wxPENSTYLE_DOT);
    pnt.SetPen(*pen);
  } else {
    wxPen *pen = wxThePenList->FindOrCreatePen(wxColor(0, 0, 0, 80), 2,
                                               wxPENSTYLE_LONG_DASH);
    pnt.SetPen(*pen);
  }
  GsshDrawLines(pnt, getList_boundaries(), vp, false);
}
 
//-----------------------------------------------------------------------
void GshhsReader::drawRivers(ocpnDC &pnt, ViewPort &vp) {
  GsshDrawLines(pnt, getList_rivers(), vp, false);
}
 
//-----------------------------------------------------------------------
int GshhsReader::selectBestQuality(ViewPort &vp) {
  int bestQuality = 0;
 
  if (vp.chart_scale < 500000 && qualityAvailable[4])
    bestQuality = 4;
  else if (vp.chart_scale < 2000000 && qualityAvailable[3])
    bestQuality = 3;
  else if (vp.chart_scale < 8000000 && qualityAvailable[2])
    bestQuality = 2;
  else if (vp.chart_scale < 20000000 && qualityAvailable[1])
    bestQuality = 1;
  else if (qualityAvailable[0])
    bestQuality = 0;
  else
    while (!qualityAvailable[bestQuality] &&
           bestQuality <=
               4)  // Find the worst quality actually available and use that
                   // (normally we would use crude, but it is missing)
      bestQuality++;
 
  while (!qualityAvailable[bestQuality]) {
    bestQuality--;
    if (bestQuality < 0) break;
  }
 
  //    if( bestQuality < 0 )
  //        for( int i=0; i<5; i++ )
  //            if( qualityAvailable[i] ) bestQuality = i;
 
  return bestQuality;
}
 
// A GshhsReader instance which is used to detect if a trajectory
// crosses land.
static GshhsReader *gshhs_reader = NULL;
 
/* so plugins can determine if a line segment crosses land, must call from main
   thread once at startup to initialize array */
void gshhsCrossesLandInit() {
  wxLogMessage("GSHHSChart::gshhsCrossesLandInit()");
  if (!gshhs_reader) {
    gshhs_reader = new GshhsReader();
  }
  /* load best possible quality for crossing tests */
  int bestQuality = 4;
  while (!gshhs_reader->qualityAvailable[bestQuality] && bestQuality > 0)
    bestQuality--;
  gshhs_reader->LoadQuality(bestQuality);
  wxLogMessage("GSHHG: Loaded quality %d for land crossing detection.",
               bestQuality);
}
 
void gshhsCrossesLandReset() {
  wxLogMessage("GSHHSChart::gshhsCrossesLandReset()");
  if (gshhs_reader) delete gshhs_reader;
  gshhs_reader = NULL;
  gshhsCrossesLandInit();
}
 
bool gshhsCrossesLand(double lat1, double lon1, double lat2, double lon2) {
  if (!gshhs_reader) {
    gshhsCrossesLandInit();
  }
  if (lon1 < 0) lon1 += 360;
  if (lon2 < 0) lon2 += 360;
 
  wxLineF trajectWorld(lon1, lat1, lon2, lat2);
  return gshhs_reader->crossing1(trajectWorld);
}