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flightgear/Main/views.cxx
curt 0848e16410 Integration of Steve's plib conglomeration. 
Optimizations (tm) by Norman Vine.
1999-04-03 04:21:01 +00:00

1223 lines
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// views.cxx -- data structures and routines for managing and view
// parameters.
//
// Written by Curtis Olson, started August 1997.
//
// Copyright (C) 1997 Curtis L. Olson - curt@infoplane.com
//
// 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., 675 Mass Ave, Cambridge, MA 02139, USA.
//
// $Id$
// (Log is kept at end of this file)
#ifdef HAVE_CONFIG_H
# include <config.h>
#endif
#include <Aircraft/aircraft.hxx>
#include <Cockpit/panel.hxx>
#include <Debug/logstream.hxx>
#include <Include/fg_constants.h>
#include <Math/mat3.h>
#include <Math/point3d.hxx>
#include <Math/polar3d.hxx>
#include <Math/vector.hxx>
#include <Scenery/scenery.hxx>
#include <Time/fg_time.hxx>
#include "options.hxx"
#include "views.hxx"
// Define following to extract various vectors directly
// from matrices we have allready computed
// rather then performing 'textbook algebra' to rederive them
// Norman Vine -- nhv@yahoo.com
// #define FG_VIEW_INLINE_OPTIMIZATIONS
// temporary (hopefully) hack
static int panel_hist = 0;
// specify code paths ... these are done as variable rather than
// #define's because down the road we may want to choose between them
// on the fly for different flight models ... this way magic carpet
// and external modes wouldn't need to recreate the LaRCsim matrices
// themselves.
static const bool use_larcsim_local_to_body = false;
// This is a record containing current view parameters
FGView current_view;
// Constructor
FGView::FGView( void ) {
MAT3identity(WORLD);
}
// Initialize a view structure
void FGView::Init( void ) {
FG_LOG( FG_VIEW, FG_INFO, "Initializing View parameters" );
view_offset = 0.0;
goal_view_offset = 0.0;
winWidth = current_options.get_xsize();
winHeight = current_options.get_ysize();
if ( ! current_options.get_panel_status() ) {
current_view.set_win_ratio( (GLfloat) winWidth / (GLfloat) winHeight );
} else {
current_view.set_win_ratio( (GLfloat) winWidth /
((GLfloat) (winHeight)*0.4232) );
}
force_update_fov_math();
}
// Update the field of view coefficients
void FGView::UpdateFOV( const fgOPTIONS& o ) {
double fov, theta_x, theta_y;
fov = o.get_fov();
// printf("win_ratio = %.2f\n", win_ratio);
// calculate sin() and cos() of fov / 2 in X direction;
theta_x = (fov * win_ratio * DEG_TO_RAD) / 2.0;
// printf("theta_x = %.2f\n", theta_x);
sin_fov_x = sin(theta_x);
cos_fov_x = cos(theta_x);
slope_x = -cos_fov_x / sin_fov_x;
// printf("slope_x = %.2f\n", slope_x);
// fov_x_clip and fov_y_clip convoluted algebraic simplification
// see code executed in tilemgr.cxx when USE_FAST_FOV_CLIP not
// defined Norman Vine -- nhv@yahoo.com
#if defined( USE_FAST_FOV_CLIP )
fov_x_clip = slope_x*cos_fov_x - sin_fov_x;
#endif // defined( USE_FAST_FOV_CLIP )
// calculate sin() and cos() of fov / 2 in Y direction;
theta_y = (fov * DEG_TO_RAD) / 2.0;
// printf("theta_y = %.2f\n", theta_y);
sin_fov_y = sin(theta_y);
cos_fov_y = cos(theta_y);
slope_y = cos_fov_y / sin_fov_y;
// printf("slope_y = %.2f\n", slope_y);
#if defined( USE_FAST_FOV_CLIP )
fov_y_clip = -(slope_y*cos_fov_y + sin_fov_y);
#endif // defined( USE_FAST_FOV_CLIP )
}
// Basically, this is a modified version of the Mesa gluLookAt()
// function that's been modified slightly so we can capture the
// result before sending it off to OpenGL land.
void FGView::LookAt( GLdouble eyex, GLdouble eyey, GLdouble eyez,
GLdouble centerx, GLdouble centery, GLdouble centerz,
GLdouble upx, GLdouble upy, GLdouble upz ) {
GLdouble *m;
GLdouble x[3], y[3], z[3];
GLdouble mag;
m = current_view.MODEL_VIEW;
/* Make rotation matrix */
/* Z vector */
z[0] = eyex - centerx;
z[1] = eyey - centery;
z[2] = eyez - centerz;
mag = sqrt( z[0]*z[0] + z[1]*z[1] + z[2]*z[2] );
if (mag) { /* mpichler, 19950515 */
z[0] /= mag;
z[1] /= mag;
z[2] /= mag;
}
/* Y vector */
y[0] = upx;
y[1] = upy;
y[2] = upz;
/* X vector = Y cross Z */
x[0] = y[1]*z[2] - y[2]*z[1];
x[1] = -y[0]*z[2] + y[2]*z[0];
x[2] = y[0]*z[1] - y[1]*z[0];
/* Recompute Y = Z cross X */
y[0] = z[1]*x[2] - z[2]*x[1];
y[1] = -z[0]*x[2] + z[2]*x[0];
y[2] = z[0]*x[1] - z[1]*x[0];
/* mpichler, 19950515 */
/* cross product gives area of parallelogram, which is < 1.0 for
* non-perpendicular unit-length vectors; so normalize x, y here
*/
mag = sqrt( x[0]*x[0] + x[1]*x[1] + x[2]*x[2] );
if (mag) {
x[0] /= mag;
x[1] /= mag;
x[2] /= mag;
}
mag = sqrt( y[0]*y[0] + y[1]*y[1] + y[2]*y[2] );
if (mag) {
y[0] /= mag;
y[1] /= mag;
y[2] /= mag;
}
#define M(row,col) m[col*4+row]
M(0,0) = x[0]; M(0,1) = x[1]; M(0,2) = x[2]; M(0,3) = 0.0;
M(1,0) = y[0]; M(1,1) = y[1]; M(1,2) = y[2]; M(1,3) = 0.0;
M(2,0) = z[0]; M(2,1) = z[1]; M(2,2) = z[2]; M(2,3) = 0.0;
// the following is part of the original gluLookAt(), but we are
// commenting it out because we know we are going to be doing a
// translation below which will set these values anyways
// M(3,0) = 0.0; M(3,1) = 0.0; M(3,2) = 0.0; M(3,3) = 1.0;
#undef M
// Translate Eye to Origin
// replaces: glTranslated( -eyex, -eyey, -eyez );
// this has been slightly modified from the original glTranslate()
// code because we know that coming into this m[12] = m[13] =
// m[14] = 0.0, and m[15] = 1.0;
m[12] = m[0] * -eyex + m[4] * -eyey + m[8] * -eyez /* + m[12] */;
m[13] = m[1] * -eyex + m[5] * -eyey + m[9] * -eyez /* + m[13] */;
m[14] = m[2] * -eyex + m[6] * -eyey + m[10] * -eyez /* + m[14] */;
m[15] = 1.0 /* m[3] * -eyex + m[7] * -eyey + m[11] * -eyez + m[15] */;
// xglMultMatrixd( m );
xglLoadMatrixd( m );
}
// Update the view volume, position, and orientation
void FGView::UpdateViewParams( void ) {
FGInterface *f = current_aircraft.fdm_state;
UpdateViewMath(f);
UpdateWorldToEye(f);
if ((current_options.get_panel_status() != panel_hist) && (current_options.get_panel_status()))
{
FGPanel::OurPanel->ReInit( 0, 0, 1024, 768);
}
if ( ! current_options.get_panel_status() ) {
xglViewport(0, 0 , (GLint)(winWidth), (GLint)(winHeight) );
} else {
xglViewport(0, (GLint)((winHeight)*0.5768), (GLint)(winWidth),
(GLint)((winHeight)*0.4232) );
}
// Tell GL we are about to modify the projection parameters
xglMatrixMode(GL_PROJECTION);
xglLoadIdentity();
if ( f->get_Altitude() * FEET_TO_METER - scenery.cur_elev > 10.0 ) {
gluPerspective(current_options.get_fov(), win_ratio, 10.0, 100000.0);
} else {
gluPerspective(current_options.get_fov(), win_ratio, 0.5, 100000.0);
// printf("Near ground, minimizing near clip plane\n");
}
// }
xglMatrixMode(GL_MODELVIEW);
xglLoadIdentity();
// set up our view volume (default)
#if !defined(FG_VIEW_INLINE_OPTIMIZATIONS)
LookAt(view_pos.x(), view_pos.y(), view_pos.z(),
view_pos.x() + view_forward[0],
view_pos.y() + view_forward[1],
view_pos.z() + view_forward[2],
view_up[0], view_up[1], view_up[2]);
// look almost straight up (testing and eclipse watching)
/* LookAt(view_pos.x(), view_pos.y(), view_pos.z(),
view_pos.x() + view_up[0] + .001,
view_pos.y() + view_up[1] + .001,
view_pos.z() + view_up[2] + .001,
view_up[0], view_up[1], view_up[2]); */
// lock view horizontally towards sun (testing)
/* LookAt(view_pos.x(), view_pos.y(), view_pos.z(),
view_pos.x() + surface_to_sun[0],
view_pos.y() + surface_to_sun[1],
view_pos.z() + surface_to_sun[2],
view_up[0], view_up[1], view_up[2]); */
// lock view horizontally towards south (testing)
/* LookAt(view_pos.x(), view_pos.y(), view_pos.z(),
view_pos.x() + surface_south[0],
view_pos.y() + surface_south[1],
view_pos.z() + surface_south[2],
view_up[0], view_up[1], view_up[2]); */
#else // defined(FG_VIEW_INLINE_OPTIMIZATIONS)
//void FGView::LookAt( GLdouble eyex, GLdouble eyey, GLdouble eyez,
// GLdouble centerx, GLdouble centery, GLdouble centerz,
// GLdouble upx, GLdouble upy, GLdouble upz )
{
GLdouble *m;
GLdouble x[3], y[3], z[3];
// GLdouble mag;
m = current_view.MODEL_VIEW;
/* Make rotation matrix */
/* Z vector */
z[0] = -view_forward[0]; //eyex - centerx;
z[1] = -view_forward[1]; //eyey - centery;
z[2] = -view_forward[2]; //eyez - centerz;
// In our case this is a unit vector NHV
// mag = sqrt( z[0]*z[0] + z[1]*z[1] + z[2]*z[2] );
// if (mag) { /* mpichler, 19950515 */
// mag = 1.0/mag;
// printf("mag(%f) ", mag);
// z[0] *= mag;
// z[1] *= mag;
// z[2] *= mag;
// }
/* Y vector */
y[0] = view_up[0]; //upx;
y[1] = view_up[1]; //upy;
y[2] = view_up[2]; //upz;
/* X vector = Y cross Z */
x[0] = y[1]*z[2] - y[2]*z[1];
x[1] = -y[0]*z[2] + y[2]*z[0];
x[2] = y[0]*z[1] - y[1]*z[0];
// printf(" %f %f %f ", y[0], y[1], y[2]);
/* Recompute Y = Z cross X */
// y[0] = z[1]*x[2] - z[2]*x[1];
// y[1] = -z[0]*x[2] + z[2]*x[0];
// y[2] = z[0]*x[1] - z[1]*x[0];
// printf(" %f %f %f\n", y[0], y[1], y[2]);
// In our case these are unit vectors NHV
/* mpichler, 19950515 */
/* cross product gives area of parallelogram, which is < 1.0 for
* non-perpendicular unit-length vectors; so normalize x, y here
*/
// mag = sqrt( x[0]*x[0] + x[1]*x[1] + x[2]*x[2] );
// if (mag) {
// mag = 1.0/mag;
// printf("mag2(%f) ", mag);
// x[0] *= mag;
// x[1] *= mag;
// x[2] *= mag;
// }
// mag = sqrt( y[0]*y[0] + y[1]*y[1] + y[2]*y[2] );
// if (mag) {
// mag = 1.0/mag;
// printf("mag3(%f)\n", mag);
// y[0] *= mag;
// y[1] *= mag;
// y[2] *= mag;
// }
#define M(row,col) m[col*4+row]
M(0,0) = x[0]; M(0,1) = x[1]; M(0,2) = x[2]; M(0,3) = 0.0;
M(1,0) = y[0]; M(1,1) = y[1]; M(1,2) = y[2]; M(1,3) = 0.0;
M(2,0) = z[0]; M(2,1) = z[1]; M(2,2) = z[2]; M(2,3) = 0.0;
// the following is part of the original gluLookAt(), but we are
// commenting it out because we know we are going to be doing a
// translation below which will set these values anyways
// M(3,0) = 0.0; M(3,1) = 0.0; M(3,2) = 0.0; M(3,3) = 1.0;
#undef M
// Translate Eye to Origin
// replaces: glTranslated( -eyex, -eyey, -eyez );
// this has been slightly modified from the original glTranslate()
// code because we know that coming into this m[12] = m[13] =
// m[14] = 0.0, and m[15] = 1.0;
m[12] = m[0] * -view_pos.x() + m[4] * -view_pos.y() + m[8] * -view_pos.z() /* + m[12] */;
m[13] = m[1] * -view_pos.x() + m[5] * -view_pos.y() + m[9] * -view_pos.z() /* + m[13] */;
m[14] = m[2] * -view_pos.x() + m[6] * -view_pos.y() + m[10] * -view_pos.z() /* + m[14] */;
m[15] = 1.0 /* m[3] * -view_pos.x() + m[7] * -view_pos.y() + m[11] * -view_pos.z() + m[15] */;
// xglMultMatrixd( m );
xglLoadMatrixd( m );
}
#endif // FG_VIEW_INLINE_OPTIMIZATIONS
panel_hist = current_options.get_panel_status();
}
void getRotMatrix(double* out, MAT3vec vec, double radians)
{
/* This function contributed by Erich Boleyn (erich@uruk.org) */
/* This function used from the Mesa OpenGL code (matrix.c) */
double s, c; // mag,
double vx, vy, vz, xy, yz, zx, xs, ys, zs, one_c; //, xx, yy, zz
MAT3identity(out);
s = sin(radians);
c = cos(radians);
// mag = getMagnitude();
vx = vec[0];
vy = vec[1];
vz = vec[2];
#define M(row,col) out[row*4 + col]
/*
* Arbitrary axis rotation matrix.
*
* This is composed of 5 matrices, Rz, Ry, T, Ry', Rz', multiplied
* like so: Rz * Ry * T * Ry' * Rz'. T is the final rotation
* (which is about the X-axis), and the two composite transforms
* Ry' * Rz' and Rz * Ry are (respectively) the rotations necessary
* from the arbitrary axis to the X-axis then back. They are
* all elementary rotations.
*
* Rz' is a rotation about the Z-axis, to bring the axis vector
* into the x-z plane. Then Ry' is applied, rotating about the
* Y-axis to bring the axis vector parallel with the X-axis. The
* rotation about the X-axis is then performed. Ry and Rz are
* simply the respective inverse transforms to bring the arbitrary
* axis back to it's original orientation. The first transforms
* Rz' and Ry' are considered inverses, since the data from the
* arbitrary axis gives you info on how to get to it, not how
* to get away from it, and an inverse must be applied.
*
* The basic calculation used is to recognize that the arbitrary
* axis vector (x, y, z), since it is of unit length, actually
* represents the sines and cosines of the angles to rotate the
* X-axis to the same orientation, with theta being the angle about
* Z and phi the angle about Y (in the order described above)
* as follows:
*
* cos ( theta ) = x / sqrt ( 1 - z^2 )
* sin ( theta ) = y / sqrt ( 1 - z^2 )
*
* cos ( phi ) = sqrt ( 1 - z^2 )
* sin ( phi ) = z
*
* Note that cos ( phi ) can further be inserted to the above
* formulas:
*
* cos ( theta ) = x / cos ( phi )
* sin ( theta ) = y / cos ( phi )
*
* ...etc. Because of those relations and the standard trigonometric
* relations, it is pssible to reduce the transforms down to what
* is used below. It may be that any primary axis chosen will give the
* same results (modulo a sign convention) using thie method.
*
* Particularly nice is to notice that all divisions that might
* have caused trouble when parallel to certain planes or
* axis go away with care paid to reducing the expressions.
* After checking, it does perform correctly under all cases, since
* in all the cases of division where the denominator would have
* been zero, the numerator would have been zero as well, giving
* the expected result.
*/
one_c = 1.0F - c;
// xx = vx * vx;
// yy = vy * vy;
// zz = vz * vz;
// xy = vx * vy;
// yz = vy * vz;
// zx = vz * vx;
M(0,0) = (one_c * vx * vx) + c;
xs = vx * s;
yz = vy * vz * one_c;
M(1,2) = yz + xs;
M(2,1) = yz - xs;
M(1,1) = (one_c * vy * vy) + c;
ys = vy * s;
zx = vz * vx * one_c;
M(0,2) = zx - ys;
M(2,0) = zx + ys;
M(2,2) = (one_c * vz *vz) + c;
zs = vz * s;
xy = vx * vy * one_c;
M(0,1) = xy + zs;
M(1,0) = xy - zs;
// M(0,0) = (one_c * xx) + c;
// M(1,0) = (one_c * xy) - zs;
// M(2,0) = (one_c * zx) + ys;
// M(0,1) = (one_c * xy) + zs;
// M(1,1) = (one_c * yy) + c;
// M(2,1) = (one_c * yz) - xs;
// M(0,2) = (one_c * zx) - ys;
// M(1,2) = (one_c * yz) + xs;
// M(2,2) = (one_c * zz) + c;
#undef M
}
// Update the view parameters
void FGView::UpdateViewMath( FGInterface *f ) {
Point3D p;
MAT3vec vec, forward, v0, minus_z;
MAT3mat R, TMP, UP, LOCAL, VIEW;
double ntmp;
if ( update_fov ) {
// printf("Updating fov\n");
UpdateFOV( current_options );
update_fov = false;
}
scenery.center = scenery.next_center;
#if !defined(FG_VIEW_INLINE_OPTIMIZATIONS)
// printf("scenery center = %.2f %.2f %.2f\n", scenery.center.x,
// scenery.center.y, scenery.center.z);
// calculate the cartesion coords of the current lat/lon/0 elev
p = Point3D( f->get_Longitude(),
f->get_Lat_geocentric(),
f->get_Sea_level_radius() * FEET_TO_METER );
cur_zero_elev = fgPolarToCart3d(p) - scenery.center;
// calculate view position in current FG view coordinate system
// p.lon & p.lat are already defined earlier, p.radius was set to
// the sea level radius, so now we add in our altitude.
if ( f->get_Altitude() * FEET_TO_METER >
(scenery.cur_elev + 0.5 * METER_TO_FEET) ) {
p.setz( p.radius() + f->get_Altitude() * FEET_TO_METER );
} else {
p.setz( p.radius() + scenery.cur_elev + 0.5 * METER_TO_FEET );
}
abs_view_pos = fgPolarToCart3d(p);
#else // FG_VIEW_INLINE_OPTIMIZATIONS
double tmp_radius = f->get_Sea_level_radius() * FEET_TO_METER;
double tmp = f->get_cos_lat_geocentric() * tmp_radius;
cur_zero_elev.setx(f->get_cos_longitude()*tmp - scenery.center.x());
cur_zero_elev.sety(f->get_sin_longitude()*tmp - scenery.center.y());
cur_zero_elev.setz(f->get_sin_lat_geocentric()*tmp_radius - scenery.center.z());
// calculate view position in current FG view coordinate system
// p.lon & p.lat are already defined earlier, p.radius was set to
// the sea level radius, so now we add in our altitude.
if ( f->get_Altitude() * FEET_TO_METER >
(scenery.cur_elev + 0.5 * METER_TO_FEET) ) {
tmp_radius += f->get_Altitude() * FEET_TO_METER;
} else {
tmp_radius += scenery.cur_elev + 0.5 * METER_TO_FEET ;
}
tmp = f->get_cos_lat_geocentric() * tmp_radius;
abs_view_pos.setx(f->get_cos_longitude()*tmp);
abs_view_pos.sety(f->get_sin_longitude()*tmp);
abs_view_pos.setz(f->get_sin_lat_geocentric()*tmp_radius);
#endif // FG_VIEW_INLINE_OPTIMIZATIONS
view_pos = abs_view_pos - scenery.center;
FG_LOG( FG_VIEW, FG_DEBUG, "Polar view pos = " << p );
FG_LOG( FG_VIEW, FG_DEBUG, "Absolute view pos = " << abs_view_pos );
FG_LOG( FG_VIEW, FG_DEBUG, "Relative view pos = " << view_pos );
// Derive the LOCAL aircraft rotation matrix (roll, pitch, yaw)
// from FG_T_local_to_body[3][3]
if ( use_larcsim_local_to_body ) {
// Question: Why is the LaRCsim matrix arranged so differently
// than the one we need???
// Answer (I think): The LaRCsim matrix is generated in a
// different reference frame than we've set up for our world
LOCAL[0][0] = f->get_T_local_to_body_33();
LOCAL[0][1] = -f->get_T_local_to_body_32();
LOCAL[0][2] = -f->get_T_local_to_body_31();
LOCAL[0][3] = 0.0;
LOCAL[1][0] = -f->get_T_local_to_body_23();
LOCAL[1][1] = f->get_T_local_to_body_22();
LOCAL[1][2] = f->get_T_local_to_body_21();
LOCAL[1][3] = 0.0;
LOCAL[2][0] = -f->get_T_local_to_body_13();
LOCAL[2][1] = f->get_T_local_to_body_12();
LOCAL[2][2] = f->get_T_local_to_body_11();
LOCAL[2][3] = 0.0;
LOCAL[3][0] = LOCAL[3][1] = LOCAL[3][2] = LOCAL[3][3] = 0.0;
LOCAL[3][3] = 1.0;
// printf("LaRCsim LOCAL matrix\n");
// MAT3print(LOCAL, stdout);
} else {
// code to calculate LOCAL matrix calculated from Phi, Theta, and
// Psi (roll, pitch, yaw) in case we aren't running LaRCsim as our
// flight model
MAT3_SET_VEC(vec, 0.0, 0.0, 1.0);
MAT3rotate(R, vec, f->get_Phi());
/* printf("Roll matrix\n"); */
/* MAT3print(R, stdout); */
MAT3_SET_VEC(vec, 0.0, 1.0, 0.0);
/* MAT3mult_vec(vec, vec, R); */
MAT3rotate(TMP, vec, f->get_Theta());
/* printf("Pitch matrix\n"); */
/* MAT3print(TMP, stdout); */
MAT3mult(R, R, TMP);
MAT3_SET_VEC(vec, 1.0, 0.0, 0.0);
/* MAT3mult_vec(vec, vec, R); */
/* MAT3rotate(TMP, vec, FG_Psi - FG_PI_2); */
MAT3rotate(TMP, vec, -f->get_Psi());
/* printf("Yaw matrix\n");
MAT3print(TMP, stdout); */
MAT3mult(LOCAL, R, TMP);
// printf("FG derived LOCAL matrix\n");
// MAT3print(LOCAL, stdout);
} // if ( use_larcsim_local_to_body )
#if !defined(FG_VIEW_INLINE_OPTIMIZATIONS)
// Derive the local UP transformation matrix based on *geodetic*
// coordinates
MAT3_SET_VEC(vec, 0.0, 0.0, 1.0);
MAT3rotate(R, vec, f->get_Longitude()); // R = rotate about Z axis
// printf("Longitude matrix\n");
// MAT3print(R, stdout);
MAT3_SET_VEC(vec, 0.0, 1.0, 0.0);
MAT3mult_vec(vec, vec, R);
MAT3rotate(TMP, vec, -f->get_Latitude()); // TMP = rotate about X axis
// printf("Latitude matrix\n");
// MAT3print(TMP, stdout);
MAT3mult(UP, R, TMP);
// printf("Local up matrix\n");
// MAT3print(UP, stdout);
MAT3_SET_VEC(local_up, 1.0, 0.0, 0.0);
MAT3mult_vec(local_up, local_up, UP);
// printf( "Local Up = (%.4f, %.4f, %.4f)\n",
// local_up[0], local_up[1], local_up[2]);
// Alternative method to Derive local up vector based on
// *geodetic* coordinates
// alt_up = fgPolarToCart(FG_Longitude, FG_Latitude, 1.0);
// printf( " Alt Up = (%.4f, %.4f, %.4f)\n",
// alt_up.x, alt_up.y, alt_up.z);
// Calculate the VIEW matrix
MAT3mult(VIEW, LOCAL, UP);
// printf("VIEW matrix\n");
// MAT3print(VIEW, stdout);
// generate the current up, forward, and fwrd-view vectors
MAT3_SET_VEC(vec, 1.0, 0.0, 0.0);
MAT3mult_vec(view_up, vec, VIEW);
MAT3_SET_VEC(vec, 0.0, 0.0, 1.0);
MAT3mult_vec(forward, vec, VIEW);
// printf( "Forward vector is (%.2f,%.2f,%.2f)\n", forward[0], forward[1],
// forward[2]);
MAT3rotate(TMP, view_up, view_offset);
MAT3mult_vec(view_forward, forward, TMP);
// make a vector to the current view position
MAT3_SET_VEC(v0, view_pos.x(), view_pos.y(), view_pos.z());
// Given a vector pointing straight down (-Z), map into onto the
// local plane representing "horizontal". This should give us the
// local direction for moving "south".
MAT3_SET_VEC(minus_z, 0.0, 0.0, -1.0);
map_vec_onto_cur_surface_plane(local_up, v0, minus_z, surface_south);
MAT3_NORMALIZE_VEC(surface_south, ntmp);
// printf( "Surface direction directly south %.2f %.2f %.2f\n",
// surface_south[0], surface_south[1], surface_south[2]);
// now calculate the surface east vector
MAT3rotate(TMP, view_up, FG_PI_2);
MAT3mult_vec(surface_east, surface_south, TMP);
// printf( "Surface direction directly east %.2f %.2f %.2f\n",
// surface_east[0], surface_east[1], surface_east[2]);
// printf( "Should be close to zero = %.2f\n",
// MAT3_DOT_PRODUCT(surface_south, surface_east));
#else // FG_VIEW_INLINE_OPTIMIZATIONS
// // Build spherical to cartesian transform matrix directly
double cos_lat = f->get_cos_latitude(); // cos(-f->get_Latitude());
double sin_lat = -f->get_sin_latitude(); // sin(-f->get_Latitude());
double cos_lon = f->get_cos_longitude(); //cos(f->get_Longitude());
double sin_lon = f->get_sin_longitude(); //sin(f->get_Longitude());
double *mat = (double *)UP;
mat[0] = cos_lat*cos_lon;
mat[1] = cos_lat*sin_lon;
mat[2] = -sin_lat;
mat[3] = 0.0;
mat[4] = -sin_lon;
mat[5] = cos_lon;
mat[6] = 0.0;
mat[7] = 0.0;
mat[8] = sin_lat*cos_lon;
mat[9] = sin_lat*sin_lon;
mat[10] = cos_lat;
mat[11] = mat[12] = mat[13] = mat[14] = 0.0;
mat[15] = 1.0;
MAT3mult(VIEW, LOCAL, UP);
// THESE COULD JUST BE POINTERS !!!
MAT3_SET_VEC(local_up, mat[0], mat[1], mat[2]);
MAT3_SET_VEC(view_up, VIEW[0][0], VIEW[0][1], VIEW[0][2]);
MAT3_SET_VEC(forward, VIEW[2][0], VIEW[2][1], VIEW[2][2]);
getRotMatrix((double *)TMP, view_up, view_offset);
MAT3mult_vec(view_forward, forward, TMP);
// make a vector to the current view position
MAT3_SET_VEC(v0, view_pos.x(), view_pos.y(), view_pos.z());
// Given a vector pointing straight down (-Z), map into onto the
// local plane representing "horizontal". This should give us the
// local direction for moving "south".
MAT3_SET_VEC(minus_z, 0.0, 0.0, -1.0);
map_vec_onto_cur_surface_plane(local_up, v0, minus_z, surface_south);
MAT3_NORMALIZE_VEC(surface_south, ntmp);
// printf( "Surface direction directly south %.6f %.6f %.6f\n",
// surface_south[0], surface_south[1], surface_south[2]);
// now calculate the surface east vector
getRotMatrix((double *)TMP, view_up, FG_PI_2);
MAT3mult_vec(surface_east, surface_south, TMP);
// printf( "Surface direction directly east %.6f %.6f %.6f\n",
// surface_east[0], surface_east[1], surface_east[2]);
// printf( "Should be close to zero = %.6f\n",
// MAT3_DOT_PRODUCT(surface_south, surface_east));
#endif // !defined(FG_VIEW_INLINE_OPTIMIZATIONS)
}
// Update the "World to Eye" transformation matrix
// This is most useful for view frustum culling
void FGView::UpdateWorldToEye( FGInterface *f ) {
MAT3mat R_Phi, R_Theta, R_Psi, R_Lat, R_Lon, T_view;
MAT3mat TMP;
MAT3hvec vec;
if ( use_larcsim_local_to_body ) {
// Question: hey this is even different then LOCAL[][] above??
// Answer: yet another coordinate system, this time the
// coordinate system in which we do our view frustum culling.
AIRCRAFT[0][0] = -f->get_T_local_to_body_22();
AIRCRAFT[0][1] = -f->get_T_local_to_body_23();
AIRCRAFT[0][2] = f->get_T_local_to_body_21();
AIRCRAFT[0][3] = 0.0;
AIRCRAFT[1][0] = f->get_T_local_to_body_32();
AIRCRAFT[1][1] = f->get_T_local_to_body_33();
AIRCRAFT[1][2] = -f->get_T_local_to_body_31();
AIRCRAFT[1][3] = 0.0;
AIRCRAFT[2][0] = f->get_T_local_to_body_12();
AIRCRAFT[2][1] = f->get_T_local_to_body_13();
AIRCRAFT[2][2] = -f->get_T_local_to_body_11();
AIRCRAFT[2][3] = 0.0;
AIRCRAFT[3][0] = AIRCRAFT[3][1] = AIRCRAFT[3][2] = AIRCRAFT[3][3] = 0.0;
AIRCRAFT[3][3] = 1.0;
} else {
// Roll Matrix
MAT3_SET_HVEC(vec, 0.0, 0.0, -1.0, 1.0);
MAT3rotate(R_Phi, vec, f->get_Phi());
// printf("Roll matrix (Phi)\n");
// MAT3print(R_Phi, stdout);
// Pitch Matrix
MAT3_SET_HVEC(vec, 1.0, 0.0, 0.0, 1.0);
MAT3rotate(R_Theta, vec, f->get_Theta());
// printf("\nPitch matrix (Theta)\n");
// MAT3print(R_Theta, stdout);
// Yaw Matrix
MAT3_SET_HVEC(vec, 0.0, -1.0, 0.0, 1.0);
MAT3rotate(R_Psi, vec, f->get_Psi() + FG_PI /* - view_offset */ );
// MAT3rotate(R_Psi, vec, f->get_Psi() + FG_PI - view_offset );
// printf("\nYaw matrix (Psi)\n");
// MAT3print(R_Psi, stdout);
// aircraft roll/pitch/yaw
MAT3mult(TMP, R_Phi, R_Theta);
MAT3mult(AIRCRAFT, TMP, R_Psi);
} // if ( use_larcsim_local_to_body )
#if !defined(FG_VIEW_INLINE_OPTIMIZATIONS)
// printf("AIRCRAFT matrix\n");
// MAT3print(AIRCRAFT, stdout);
// View rotation matrix relative to current aircraft orientation
MAT3_SET_HVEC(vec, 0.0, -1.0, 0.0, 1.0);
MAT3mult_vec(vec, vec, AIRCRAFT);
// printf("aircraft up vector = %.2f %.2f %.2f\n",
// vec[0], vec[1], vec[2]);
MAT3rotate(TMP, vec, -view_offset );
MAT3mult(VIEW_OFFSET, AIRCRAFT, TMP);
// printf("VIEW_OFFSET matrix\n");
// MAT3print(VIEW_OFFSET, stdout);
// View position in scenery centered coordinates
MAT3_SET_HVEC(vec, view_pos.x(), view_pos.y(), view_pos.z(), 1.0);
MAT3translate(T_view, vec);
// printf("\nTranslation matrix\n");
// MAT3print(T_view, stdout);
// Latitude
MAT3_SET_HVEC(vec, 1.0, 0.0, 0.0, 1.0);
// R_Lat = rotate about X axis
MAT3rotate(R_Lat, vec, f->get_Latitude());
// printf("\nLatitude matrix\n");
// MAT3print(R_Lat, stdout);
// Longitude
MAT3_SET_HVEC(vec, 0.0, 0.0, 1.0, 1.0);
// R_Lon = rotate about Z axis
MAT3rotate(R_Lon, vec, f->get_Longitude() - FG_PI_2 );
// printf("\nLongitude matrix\n");
// MAT3print(R_Lon, stdout);
// lon/lat
MAT3mult(WORLD, R_Lat, R_Lon);
// printf("\nworld\n");
// MAT3print(WORLD, stdout);
MAT3mult(EYE_TO_WORLD, VIEW_OFFSET, WORLD);
MAT3mult(EYE_TO_WORLD, EYE_TO_WORLD, T_view);
// printf("\nEye to world\n");
// MAT3print(EYE_TO_WORLD, stdout);
MAT3invert(WORLD_TO_EYE, EYE_TO_WORLD);
// printf("\nWorld to eye\n");
// MAT3print(WORLD_TO_EYE, stdout);
// printf( "\nview_pos = %.2f %.2f %.2f\n",
// view_pos.x, view_pos.y, view_pos.z );
// MAT3_SET_HVEC(eye, 0.0, 0.0, 0.0, 1.0);
// MAT3mult_vec(vec, eye, EYE_TO_WORLD);
// printf("\neye -> world = %.2f %.2f %.2f\n", vec[0], vec[1], vec[2]);
// MAT3_SET_HVEC(vec1, view_pos.x, view_pos.y, view_pos.z, 1.0);
// MAT3mult_vec(vec, vec1, WORLD_TO_EYE);
// printf( "\nabs_view_pos -> eye = %.2f %.2f %.2f\n",
// vec[0], vec[1], vec[2]);
#else // FG_VIEW_INLINE_OPTIMIZATIONS
MAT3_SET_HVEC(vec, -AIRCRAFT[1][0], -AIRCRAFT[1][1], -AIRCRAFT[1][2], -AIRCRAFT[1][3]);
getRotMatrix((double *)TMP, vec, -view_offset );
MAT3mult(VIEW_OFFSET, AIRCRAFT, TMP);
// MAT3print_formatted(VIEW_OFFSET, stdout, "VIEW_OFFSET matrix:\n",
// NULL, "%#8.6f ", "\n");
// Build spherical to cartesian transform matrix directly
double *mat = (double *)WORLD; //T_view; //WORLD;
double cos_lat = f->get_cos_latitude(); //cos(f->get_Latitude());
double sin_lat = f->get_sin_latitude(); //sin(f->get_Latitude());
// using trig identities this:
// mat[0] = cos(f->get_Longitude() - FG_PI_2);//cos_lon;
// mat[1] = sin(f->get_Longitude() - FG_PI_2);//sin_lon;
// becomes this: :-)
mat[0] = f->get_sin_longitude(); //cos_lon;
mat[1] = -f->get_cos_longitude(); //sin_lon;
mat[4] = -cos_lat*mat[1]; //mat[1]=sin_lon;
mat[5] = cos_lat*mat[0]; //mat[0]=cos_lon;
mat[6] = sin_lat;
mat[8] = sin_lat*mat[1]; //mat[1]=sin_lon;
mat[9] = -sin_lat*mat[0]; //mat[0]=cos_lon;
mat[10] = cos_lat;
// BUILD EYE_TO_WORLD = AIRCRAFT * WORLD
// and WORLD_TO_EYE = Inverse( EYE_TO_WORLD) concurrently
// by Transposing the 3x3 rotation sub-matrix
WORLD_TO_EYE[0][0] = EYE_TO_WORLD[0][0] =
VIEW_OFFSET[0][0]*mat[0] + VIEW_OFFSET[0][1]*mat[4] + VIEW_OFFSET[0][2]*mat[8];
WORLD_TO_EYE[1][0] = EYE_TO_WORLD[0][1] =
VIEW_OFFSET[0][0]*mat[1] + VIEW_OFFSET[0][1]*mat[5] + VIEW_OFFSET[0][2]*mat[9];
WORLD_TO_EYE[2][0] = EYE_TO_WORLD[0][2] =
VIEW_OFFSET[0][1]*mat[6] + VIEW_OFFSET[0][2]*mat[10];
WORLD_TO_EYE[0][1] = EYE_TO_WORLD[1][0] =
VIEW_OFFSET[1][0]*mat[0] + VIEW_OFFSET[1][1]*mat[4] + VIEW_OFFSET[1][2]*mat[8];
WORLD_TO_EYE[1][1] = EYE_TO_WORLD[1][1] =
VIEW_OFFSET[1][0]*mat[1] + VIEW_OFFSET[1][1]*mat[5] + VIEW_OFFSET[1][2]*mat[9];
WORLD_TO_EYE[2][1] = EYE_TO_WORLD[1][2] =
VIEW_OFFSET[1][1]*mat[6] + VIEW_OFFSET[1][2]*mat[10];
WORLD_TO_EYE[0][2] = EYE_TO_WORLD[2][0] =
VIEW_OFFSET[2][0]*mat[0] + VIEW_OFFSET[2][1]*mat[4] + VIEW_OFFSET[2][2]*mat[8];
WORLD_TO_EYE[1][2] = EYE_TO_WORLD[2][1] =
VIEW_OFFSET[2][0]*mat[1] + VIEW_OFFSET[2][1]*mat[5] + VIEW_OFFSET[2][2]*mat[9];
WORLD_TO_EYE[2][2] = EYE_TO_WORLD[2][2] =
VIEW_OFFSET[2][1]*mat[6] + VIEW_OFFSET[2][2]*mat[10];
// TRANSLATE TO VIEW POSITION
EYE_TO_WORLD[3][0] = view_pos.x();
EYE_TO_WORLD[3][1] = view_pos.y();
EYE_TO_WORLD[3][2] = view_pos.z();
// FILL 0 ENTRIES
WORLD_TO_EYE[0][3] = WORLD_TO_EYE[1][3] = WORLD_TO_EYE[2][3] =
EYE_TO_WORLD[0][3] = EYE_TO_WORLD[1][3] = EYE_TO_WORLD[2][3] = 0.0;
// FILL UNITY ENTRIES
WORLD_TO_EYE[3][3] = EYE_TO_WORLD[3][3] = 1.0;
/* MAKE THE INVERTED TRANSLATIONS */
mat = (double *)EYE_TO_WORLD;
WORLD_TO_EYE[3][0] = -mat[12]*mat[0]
-mat[13]*mat[1]
-mat[14]*mat[2];
WORLD_TO_EYE[3][1] = -mat[12]*mat[4]
-mat[13]*mat[5]
-mat[14]*mat[6];
WORLD_TO_EYE[3][2] = -mat[12]*mat[8]
-mat[13]*mat[9]
-mat[14]*mat[10];
// MAT3print_formatted(EYE_TO_WORLD, stdout, "EYE_TO_WORLD matrix:\n",
// NULL, "%#8.6f ", "\n");
// MAT3print_formatted(WORLD_TO_EYE, stdout, "WORLD_TO_EYE matrix:\n",
// NULL, "%#8.6f ", "\n");
#endif // defined(FG_VIEW_INLINE_OPTIMIZATIONS)
}
#if 0
// Reject non viewable spheres from current View Frustrum by Curt
// Olson curt@me.umn.edu and Norman Vine nhv@yahoo.com with 'gentle
// guidance' from Steve Baker sbaker@link.com
int
FGView::SphereClip( const Point3D& cp, const double radius )
{
double x1, y1;
MAT3vec eye;
double *mat;
double x, y, z;
x = cp->x;
y = cp->y;
z = cp->z;
mat = (double *)(WORLD_TO_EYE);
eye[2] = x*mat[2] + y*mat[6] + z*mat[10] + mat[14];
// Check near and far clip plane
if( ( eye[2] > radius ) ||
( eye[2] + radius + current_weather.visibility < 0) )
// ( eye[2] + radius + far_plane < 0) )
{
return 1;
}
// check right and left clip plane (from eye perspective)
x1 = radius * fov_x_clip;
eye[0] = (x*mat[0] + y*mat[4] + z*mat[8] + mat[12]) * slope_x;
if( (eye[2] > -(eye[0]+x1)) || (eye[2] > (eye[0]-x1)) ) {
return(1);
}
// check bottom and top clip plane (from eye perspective)
y1 = radius * fov_y_clip;
eye[1] = (x*mat[1] + y*mat[5] + z*mat[9] + mat[13]) * slope_y;
if( (eye[2] > -(eye[1]+y1)) || (eye[2] > (eye[1]-y1)) ) {
return 1;
}
return 0;
}
#endif
// Destructor
FGView::~FGView( void ) {
}
// $Log$
// Revision 1.35 1999/04/03 04:21:04 curt
// Integration of Steve's plib conglomeration.
// Optimizations (tm) by Norman Vine.
//
// Revision 1.34 1999/03/08 21:56:41 curt
// Added panel changes sent in by Friedemann.
// Added a splash screen randomization since we have several nice splash screens.
//
// Revision 1.33 1999/02/05 21:29:14 curt
// Modifications to incorporate Jon S. Berndts flight model code.
//
// Revision 1.32 1999/01/07 20:25:12 curt
// Updated struct fgGENERAL to class FGGeneral.
//
// Revision 1.31 1998/12/11 20:26:28 curt
// Fixed view frustum culling accuracy bug so we can look out the sides and
// back without tri-stripes dropping out.
//
// Revision 1.30 1998/12/09 18:50:28 curt
// Converted "class fgVIEW" to "class FGView" and updated to make data
// members private and make required accessor functions.
//
// Revision 1.29 1998/12/05 15:54:24 curt
// Renamed class fgFLIGHT to class FGState as per request by JSB.
//
// Revision 1.28 1998/12/03 01:17:20 curt
// Converted fgFLIGHT to a class.
//
// Revision 1.27 1998/11/16 14:00:06 curt
// Added pow() macro bug work around.
// Added support for starting FGFS at various resolutions.
// Added some initial serial port support.
// Specify default log levels in main().
//
// Revision 1.26 1998/11/09 23:39:25 curt
// Tweaks for the instrument panel.
//
// Revision 1.25 1998/11/06 21:18:15 curt
// Converted to new logstream debugging facility. This allows release
// builds with no messages at all (and no performance impact) by using
// the -DFG_NDEBUG flag.
//
// Revision 1.24 1998/10/18 01:17:19 curt
// Point3D tweaks.
//
// Revision 1.23 1998/10/17 01:34:26 curt
// C++ ifying ...
//
// Revision 1.22 1998/10/16 00:54:03 curt
// Converted to Point3D class.
//
// Revision 1.21 1998/09/17 18:35:33 curt
// Added F8 to toggle fog and F9 to toggle texturing.
//
// Revision 1.20 1998/09/08 15:04:35 curt
// Optimizations by Norman Vine.
//
// Revision 1.19 1998/08/20 20:32:34 curt
// Reshuffled some of the code in and around views.[ch]xx
//
// Revision 1.18 1998/07/24 21:57:02 curt
// Set near clip plane to 0.5 meters when close to the ground. Also, let the view get a bit closer to the ground before hitting the hard limit.
//
// Revision 1.17 1998/07/24 21:39:12 curt
// Debugging output tweaks.
// Cast glGetString to (char *) to avoid compiler errors.
// Optimizations to fgGluLookAt() by Norman Vine.
//
// Revision 1.16 1998/07/13 21:01:41 curt
// Wrote access functions for current fgOPTIONS.
//
// Revision 1.15 1998/07/12 03:14:43 curt
// Added ground collision detection.
// Did some serious horsing around to be able to "hug" the ground properly
// and still be able to take off.
// Set the near clip plane to 1.0 meters when less than 10 meters above the
// ground.
// Did some serious horsing around getting the initial airplane position to be
// correct based on rendered terrain elevation.
// Added a little cheat/hack that will prevent the view position from ever
// dropping below the terrain, even when the flight model doesn't quite
// put you as high as you'd like.
//
// Revision 1.14 1998/07/08 14:45:08 curt
// polar3d.h renamed to polar3d.hxx
// vector.h renamed to vector.hxx
// updated audio support so it waits to create audio classes (and tie up
// /dev/dsp) until the mpg123 player is finished.
//
// Revision 1.13 1998/07/04 00:52:27 curt
// Add my own version of gluLookAt() (which is nearly identical to the
// Mesa/glu version.) But, by calculating the Model View matrix our selves
// we can save this matrix without having to read it back in from the video
// card. This hopefully allows us to save a few cpu cycles when rendering
// out the fragments because we can just use glLoadMatrixd() with the
// precalculated matrix for each tile rather than doing a push(), translate(),
// pop() for every fragment.
//
// Panel status defaults to off for now until it gets a bit more developed.
//
// Extract OpenGL driver info on initialization.
//
// Revision 1.12 1998/06/03 00:47:15 curt
// Updated to compile in audio support if OSS available.
// Updated for new version of Steve's audio library.
// STL includes don't use .h
// Small view optimizations.
//
// Revision 1.11 1998/05/27 02:24:05 curt
// View optimizations by Norman Vine.
//
// Revision 1.10 1998/05/17 16:59:03 curt
// First pass at view frustum culling now operational.
//
// Revision 1.9 1998/05/16 13:08:37 curt
// C++ - ified views.[ch]xx
// Shuffled some additional view parameters into the fgVIEW class.
// Changed tile-radius to tile-diameter because it is a much better
// name.
// Added a WORLD_TO_EYE transformation to views.cxx. This allows us
// to transform world space to eye space for view frustum culling.
//
// Revision 1.8 1998/05/02 01:51:01 curt
// Updated polartocart conversion routine.
//
// Revision 1.7 1998/04/30 12:34:20 curt
// Added command line rendering options:
// enable/disable fog/haze
// specify smooth/flat shading
// disable sky blending and just use a solid color
// enable wireframe drawing mode
//
// Revision 1.6 1998/04/28 01:20:23 curt
// Type-ified fgTIME and fgVIEW.
// Added a command line option to disable textures.
//
// Revision 1.5 1998/04/26 05:10:04 curt
// "struct fgLIGHT" -> "fgLIGHT" because fgLIGHT is typedef'd.
//
// Revision 1.4 1998/04/25 22:04:53 curt
// Use already calculated LaRCsim values to create the roll/pitch/yaw
// transformation matrix (we call it LOCAL)
//
// Revision 1.3 1998/04/25 20:24:02 curt
// Cleaned up initialization sequence to eliminate interdependencies
// between sun position, lighting, and view position. This creates a
// valid single pass initialization path.
//
// Revision 1.2 1998/04/24 00:49:22 curt
// Wrapped "#include <config.h>" in "#ifdef HAVE_CONFIG_H"
// Trying out some different option parsing code.
// Some code reorganization.
//
// Revision 1.1 1998/04/22 13:25:45 curt
// C++ - ifing the code.
// Starting a bit of reorganization of lighting code.
//
// Revision 1.16 1998/04/18 04:11:29 curt
// Moved fg_debug to it's own library, added zlib support.
//
// Revision 1.15 1998/02/20 00:16:24 curt
// Thursday's tweaks.
//
// Revision 1.14 1998/02/09 15:07:50 curt
// Minor tweaks.
//
// Revision 1.13 1998/02/07 15:29:45 curt
// Incorporated HUD changes and struct/typedef changes from Charlie Hotchkiss
// <chotchkiss@namg.us.anritsu.com>
//
// Revision 1.12 1998/01/29 00:50:28 curt
// Added a view record field for absolute x, y, z position.
//
// Revision 1.11 1998/01/27 00:47:58 curt
// Incorporated Paul Bleisch's <pbleisch@acm.org> new debug message
// system and commandline/config file processing code.
//
// Revision 1.10 1998/01/19 19:27:09 curt
// Merged in make system changes from Bob Kuehne <rpk@sgi.com>
// This should simplify things tremendously.
//
// Revision 1.9 1998/01/13 00:23:09 curt
// Initial changes to support loading and management of scenery tiles. Note,
// there's still a fair amount of work left to be done.
//
// Revision 1.8 1997/12/30 22:22:33 curt
// Further integration of event manager.
//
// Revision 1.7 1997/12/30 20:47:45 curt
// Integrated new event manager with subsystem initializations.
//
// Revision 1.6 1997/12/22 04:14:32 curt
// Aligned sky with sun so dusk/dawn effects can be correct relative to the sun.
//
// Revision 1.5 1997/12/18 04:07:02 curt
// Worked on properly translating and positioning the sky dome.
//
// Revision 1.4 1997/12/17 23:13:36 curt
// Began working on rendering a sky.
//
// Revision 1.3 1997/12/15 23:54:50 curt
// Add xgl wrappers for debugging.
// Generate terrain normals on the fly.
//
// Revision 1.2 1997/12/10 22:37:48 curt
// Prepended "fg" on the name of all global structures that didn't have it yet.
// i.e. "struct WEATHER {}" became "struct fgWEATHER {}"
//
// Revision 1.1 1997/08/27 21:31:17 curt
// Initial revision.
//
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