//-----------------------------------------------------------------------------
// calculate viewing region
void MapCodegenState::calc_viewingregion(pointf f[], double *minz, double *maxz) {
/* calculate rays through projection plane */
ntlVec3d camera( -gCamX, -gCamY, -gCamZ );
ntlVec3d lookat( -gLookatX, -gLookatY, 0.0 );
ntlVec3d direction = lookat - camera;
double fovy = 90.0;
double aspect = (double)gViewSizeX/gViewSizeY;
/* calculate width of screen using perpendicular triangle diven by
* viewing direction and screen plane */
double screenWidth = direction.getNorm()*tan( (fovy*0.5/180.0)*M_PI );
/* calculate vector orthogonal to up and viewing direction */
ntlVec3d upVec(0.0, 1.0, 0.0);
ntlVec3d rightVec( upVec.crossProd(direction) );
rightVec.normalize();
/* calculate screen plane up vector, perpendicular to viewdir and right vec */
upVec = ntlVec3d( rightVec.crossProd(direction) );
upVec.normalize();
/* check if vectors are valid FIXME what to do if not? */
if( (upVec==ntlVec3d(0.0)) || (rightVec==ntlVec3d(0.0)) ) {
return;
}
/* length from center to border of screen plane */
rightVec *= (screenWidth*aspect * -1.0);
upVec *= (screenWidth * -1.0);
/* calc edges positions */
double zplane = 0.0;
double maxzcnt = ABS(camera[2]-zplane);
double minzcnt = maxzcnt;
ntlVec3d e[4];
e[0] = direction + rightVec + upVec;
e[1] = direction - rightVec + upVec;
e[2] = direction + rightVec - upVec;
e[3] = direction - rightVec - upVec;
for(int i=0;i<4;i++) {
if((zplane-e[i][2])>1.0) { // only treat negative directions
e[i][0] /= (zplane-e[i][2]);
e[i][1] /= (zplane-e[i][2]);
}
//ntlVec3d p1( camera[0] + e[i][0] * camera[2], camera[1] + e[i][1] * camera[2], 0.0 );
f[i].x = gViewRegion[i].x = camera[0] + e[i][0] * camera[2];
f[i].y = gViewRegion[i].y = camera[1] + e[i][1] * camera[2];
//double currz = ABS(e[i][2] + zplane);
ntlVec3d fiVec = ntlVec3d(f[i].x,f[i].y,zplane);
double currz = (fiVec-camera).getNorm();
//cout << " f"<<i<<" "<<fiVec<<" c:"<< camera <<" d:"<<(fiVec-camera)<<" curr:"<<currz<<endl;
//if(i==0) {
//minzcnt = currz;
//maxzcnt = currz;
//} else {
if( minzcnt > currz) minzcnt = currz;
if( maxzcnt < currz) maxzcnt = currz;
//}
}
// save min./max. z distance
*maxz = maxzcnt;
*minz = minzcnt;
}
ntlVec3d Attribute::getAsVec3d() {
return ntlVec3d(0.);
}