scene_ElevationGrid.cpp

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#include "scene_ElevationGrid.hpp"
#include "opengl.hpp"
#include <float.h>
#include <gmtl/Intersection.h>

void ElevationGrid::drawPointLists( GLint listid )
{
  for (int iy = 0 ; iy < mYSteps ; ++iy)
  {
    for (int ix = 0; ix < mXSteps ; ++ix)
    {
      glPushMatrix();
      Point3d p = getPoint(ix,iy);
      glTranslated(p[0],p[1],p[2]);
      glCallList( listid );
      glPopMatrix();
    }
  } 
}

void ElevationGrid::drawPoints()
{
  glBegin(GL_POINTS);
  for (int iy = 0 ; iy < mYSteps ; ++iy)
  {
    for (int ix = 0; ix < mXSteps ; ++ix)
    {
      Point3d p = getPoint(ix,iy);
      glVertex3d(p[0],p[1],p[2]);
    }
  }
  glEnd();
}

void ElevationGrid::drawQuadStrips()
{
  for (int iy = 0 ; iy < mYSteps-1 ; ++iy)
  {
    glBegin(GL_QUAD_STRIP);
    for (int ix = 0; ix < mXSteps ; ++ix)
    {
      Point3d p = getPoint(ix,iy+1);
      glVertex3d(p[0],p[1],p[2]);
      p = getPoint(ix,iy);
      glVertex3d(p[0],p[1],p[2]);
    }
    glEnd();
  }
}

void ElevationGrid::computeNormals()
{
  int i = 0;
  for (int iy = 0; iy < mYSteps ; ++iy)
  {
    for (int ix = 0; ix < mXSteps ; ++ix)
    {
      Point3d p = getPoint(ix,iy);
      Point3d l = (ix > 0)? getPoint(ix-1,iy) : p;
      Point3d r = (ix < mXSteps-1)? getPoint(ix+1,iy) : p;
      Point3d b = (iy > 0)? getPoint(ix,iy-1) : p;
      Point3d u = (iy < mYSteps-1)? getPoint(ix,iy+1) : p;
      mNormals[i++] = makeNormal( makeCross( Vec3d(r - l), Vec3d(u - b) ) );
    }
  }
}

void ElevationGrid::drawQuadStripNormals()
{
  for (int iy = 0 ; iy < mYSteps-1 ; ++iy)
  {
    glBegin(GL_QUAD_STRIP);
    for (int ix = 0; ix < mXSteps ; ++ix)
    {

      Point3d p = getPoint(ix,iy+1);
      {
        const Vec3d& n = getNormal(ix,iy+1);
        glNormal3d(n[0],n[1],n[2]);
      }
      glVertex3d(p[0],p[1],p[2]);

      p = getPoint(ix,iy);
      {
        const Vec3d& n = getNormal(ix,iy);
        glNormal3d(n[0],n[1],n[2]);
      }
      glVertex3d(p[0],p[1],p[2]);

    }
    glEnd();
  }
}

void ElevationGrid::drawQuadStripNormalT1D()
{
  for (int iy = 0 ; iy < mYSteps-1 ; ++iy)
  {
    glBegin(GL_QUAD_STRIP);
    for (int ix = 0; ix < mXSteps ; ++ix)
    {

      Point3d p = getPoint(ix,iy+1);
      {
        const Vec3d& n = getNormal(ix,iy+1);
        glNormal3d(n[0],n[1],n[2]);
      }
      glTexCoord1d(p[2]*0.5);
      glVertex3d(p[0],p[1],p[2]);

      p = getPoint(ix,iy);
      {
        const Vec3d& n = getNormal(ix,iy);
        glNormal3d(n[0],n[1],n[2]);
      }
      glTexCoord1d(p[2]*0.5);
      glVertex3d(p[0],p[1],p[2]);

    }
    glEnd();
  }
}



void ElevationGrid::drawGrid()
{
  for (int iy = 0 ; iy < mYSteps ; ++iy)
  {
    glBegin(GL_LINE_STRIP);
    for (int ix = 0; ix < mXSteps ; ++ix)
    {
      Point3d p = getPoint(ix,iy);
      glVertex3d(p[0],p[1],p[2]);
    }
    glEnd();
  }
  for (int ix = 0; ix < mXSteps ; ++ix)
  {
    glBegin(GL_LINE_STRIP);
    for (int iy = 0 ; iy < mYSteps ; ++iy)
    {
      Point3d p = getPoint(ix,iy);
      glVertex3d(p[0],p[1],p[2]);
    }
    glEnd();
  }
}

void ElevationGrid::drawNormalLines(double s)
{
  glBegin(GL_LINES);
  for (int iy = 0 ; iy < mYSteps ; ++iy)
  {
    for (int ix = 0; ix < mXSteps ; ++ix)
    {
      Point3d p = getPoint(ix,iy);
      Vec3d n = getNormal(ix,iy);
      glVertex3d(p[0],p[1],p[2]);
      glVertex3d(p[0]+n[0]*s,p[1]+n[1]*s,p[2]+n[2]*s);
    }
  }
  glEnd();

}

bool ElevationGrid::intersect(const Rayd& ray, int& hitix, int& hitiy, double hitRadius)
{  
  double tsmallest = DBL_MAX;
  // TODO: use plane/ray intersection test
  for (int iy = 0 ; iy < mYSteps ; ++iy)
  {
    for (int ix = 0; ix < mXSteps ; ++ix)
    {
      Sphered s( getPoint(ix,iy), hitRadius );
      
      int numHits;
      double t0,t1;
      if ( gmtl::intersect(s, ray, numHits, t0, t1) )
      {
        double t = (t0+t1)*0.5;
        if ( t < tsmallest )
        {
          tsmallest = t;
          hitix = ix;
          hitiy = iy;
        }
      }
    }
  }

  if (tsmallest != DBL_MAX)
    return true;

  return false;
}

void ElevationGrid::initGrid()
{
  int i = 0;
  for (int iy = 0 ; iy < mYSteps ; ++iy)
  {
    for (int ix = 0; ix < mXSteps ; ++ix)
    {
      mPositions[i++] = Point3d(
          mXLimits[0] + double(mSize[0] * ix) / double(mXSteps-1)
        , mYLimits[0] + double(mSize[1] * iy) / double(mYSteps-1)
        , 0
      );
    }
  }
}

/*
void ElevationGrid::computeNormals2()
{
  int i = 0;
  for (int iy = 0; iy < mYSteps ; ++iy)
  {
    for (int ix = 0; ix < mXSteps ; ++ix)
    {      
      Point3d p = getPoint(ix,iy);
      Point3d l = (ix > 0)? getPoint(ix-1,iy) : p;
      Point3d r = (ix < mXSteps-1)? getPoint(ix+1,iy) : p;
      Point3d b = (iy > 0)? getPoint(ix,iy-1) : p;
      Point3d u = (iy < mYSteps-1)? getPoint(ix,iy+1) : p;

      makeNormal(Vec3d(l - p),Vec3d(

      mNormals[i++] = makeCross( makeNormal( Vec3d(r - l) ), makeNormal( Vec3d(u - b) ) );
    }
  }
}
*/


/*
void ElevationGrid::drawQuadStripN3T1()
{
  for (int iy = 0 ; iy < mYSteps-1 ; ++iy)
  {
    glBegin(GL_QUAD_STRIP);
    for (int ix = 0; ix < mXSteps ; ++ix)
    {
      {
        const Vec3d& n = getNormal(ix,iy+1);
        glNormal3d(n[0],n[1],n[2]);
        glTexCoord1d(p[2]);
      }
      Point3d p = getPoint(ix,iy+1);
      glVertex3d(p[0],p[1],p[2]);
      p = getPoint(ix,iy);
      glVertex3d(p[0],p[1],p[2]);
      {
        const Vec3d& n = getNormal(ix,iy);
        glNormal3d(n[0],n[1],n[2]);
        glTexCoord1d(p[2]);
      }
    }
    glEnd();
  }
}
*/