b4abef6ab8
duplicating work.) Tweaked fgTileMgrRender() do not calc tile matrix unless necessary. removed some unneeded stuff from fgTileMgrCurElev()
403 lines
12 KiB
C++
403 lines
12 KiB
C++
// fragment.cxx -- routines to handle "atomic" display objects
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//
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// Written by Curtis Olson, started August 1998.
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//
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// Copyright (C) 1998 Curtis L. Olson - curt@me.umn.edu
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//
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// This program is free software; you can redistribute it and/or
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// modify it under the terms of the GNU General Public License as
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// published by the Free Software Foundation; either version 2 of the
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// License, or (at your option) any later version.
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//
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// This program is distributed in the hope that it will be useful, but
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// WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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// General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with this program; if not, write to the Free Software
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// Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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//
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// $Id$
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// (Log is kept at end of this file)
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#include <Include/fg_constants.h>
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#include <Include/fg_types.h>
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#include <Math/mat3.h>
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#include <Scenery/tile.hxx>
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#include "fragment.hxx"
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template <class T>
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inline const int FG_SIGN(const T& x) {
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return x < T(0) ? -1 : 1;
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}
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template <class T>
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inline const T& FG_MIN(const T& a, const T& b) {
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return b < a ? b : a;
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}
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template <class T>
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inline const T& FG_MAX(const T& a, const T& b) {
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return a < b ? b : a;
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}
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// return the minimum of the three values
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template <class T>
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inline const T& fg_min3( const T& a, const T& b, const T& c)
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{
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return (a > b ? FG_MIN (b, c) : FG_MIN (a, c));
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}
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// return the maximum of the three values
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template <class T>
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inline const T& fg_max3 (const T& a, const T& b, const T& c)
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{
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return (a < b ? FG_MAX (b, c) : FG_MAX (a, c));
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}
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// Add a face to the face list
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// Copy constructor
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fgFRAGMENT::fgFRAGMENT ( const fgFRAGMENT & rhs ) :
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center ( rhs.center ),
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bounding_radius( rhs.bounding_radius ),
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material_ptr ( rhs.material_ptr ),
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tile_ptr ( rhs.tile_ptr ),
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display_list ( rhs.display_list ),
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faces ( rhs.faces )
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{
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}
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fgFRAGMENT & fgFRAGMENT::operator = ( const fgFRAGMENT & rhs )
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{
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if(!(this == &rhs )) {
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center = rhs.center;
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bounding_radius = rhs.bounding_radius;
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material_ptr = rhs.material_ptr;
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tile_ptr = rhs.tile_ptr;
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// display_list = rhs.display_list;
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faces = rhs.faces;
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}
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return *this;
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}
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// test if line intesects with this fragment. p0 and p1 are the two
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// line end points of the line. If side_flag is true, check to see
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// that end points are on opposite sides of face. Returns 1 if it
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// intersection found, 0 otherwise. If it intesects, result is the
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// point of intersection
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int fgFRAGMENT::intersect( const fgPoint3d *end0,
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const fgPoint3d *end1,
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int side_flag,
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fgPoint3d *result) const
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{
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fgTILE *t;
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MAT3vec v1, v2, n, center;
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double p1[3], p2[3], p3[3];
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double x, y, z; // temporary holding spot for result
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double a, b, c, d;
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double x0, y0, z0, x1, y1, z1, a1, b1, c1;
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double t1, t2, t3;
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double xmin, xmax, ymin, ymax, zmin, zmax;
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double dx, dy, dz, min_dim, x2, y2, x3, y3, rx, ry;
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int side1, side2;
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// find the associated tile
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t = tile_ptr;
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// printf("Intersecting\n");
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// traverse the face list for this fragment
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const_iterator last = faces.end();
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for ( const_iterator current = faces.begin(); current != last; ++current )
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{
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// printf(".");
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// get face vertex coordinates
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center[0] = t->center.x;
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center[1] = t->center.y;
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center[2] = t->center.z;
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MAT3_ADD_VEC(p1, t->nodes[(*current).n1], center);
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MAT3_ADD_VEC(p2, t->nodes[(*current).n2], center);
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MAT3_ADD_VEC(p3, t->nodes[(*current).n3], center);
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// printf("point 1 = %.2f %.2f %.2f\n", p1[0], p1[1], p1[2]);
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// printf("point 2 = %.2f %.2f %.2f\n", p2[0], p2[1], p2[2]);
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// printf("point 3 = %.2f %.2f %.2f\n", p3[0], p3[1], p3[2]);
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// calculate two edge vectors, and the face normal
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MAT3_SUB_VEC(v1, p2, p1);
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MAT3_SUB_VEC(v2, p3, p1);
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MAT3cross_product(n, v1, v2);
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// calculate the plane coefficients for the plane defined by
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// this face. If n is the normal vector, n = (a, b, c) and p1
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// is a point on the plane, p1 = (x0, y0, z0), then the
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// equation of the line is a(x-x0) + b(y-y0) + c(z-z0) = 0
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a = n[0];
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b = n[1];
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c = n[2];
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d = a * p1[0] + b * p1[1] + c * p1[2];
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// printf("a, b, c, d = %.2f %.2f %.2f %.2f\n", a, b, c, d);
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// printf("p1(d) = %.2f\n", a * p1[0] + b * p1[1] + c * p1[2]);
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// printf("p2(d) = %.2f\n", a * p2[0] + b * p2[1] + c * p2[2]);
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// printf("p3(d) = %.2f\n", a * p3[0] + b * p3[1] + c * p3[2]);
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// calculate the line coefficients for the specified line
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x0 = end0->x; x1 = end1->x;
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y0 = end0->y; y1 = end1->y;
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z0 = end0->z; z1 = end1->z;
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if ( fabs(x1 - x0) > FG_EPSILON ) {
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a1 = 1.0 / (x1 - x0);
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} else {
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// we got a big divide by zero problem here
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a1 = 0.0;
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}
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b1 = y1 - y0;
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c1 = z1 - z0;
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// intersect the specified line with this plane
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t1 = b * b1 * a1;
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t2 = c * c1 * a1;
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// printf("a = %.2f t1 = %.2f t2 = %.2f\n", a, t1, t2);
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if ( fabs(a + t1 + t2) > FG_EPSILON ) {
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x = (t1*x0 - b*y0 + t2*x0 - c*z0 + d) / (a + t1 + t2);
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t3 = a1 * (x - x0);
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y = b1 * t3 + y0;
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z = c1 * t3 + z0;
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// printf("result(d) = %.2f\n", a * x + b * y + c * z);
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} else {
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// no intersection point
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continue;
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}
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if ( side_flag ) {
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// check to see if end0 and end1 are on opposite sides of
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// plane
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if ( (x - x0) > FG_EPSILON ) {
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t1 = x;
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t2 = x0;
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t3 = x1;
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} else if ( (y - y0) > FG_EPSILON ) {
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t1 = y;
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t2 = y0;
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t3 = y1;
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} else if ( (z - z0) > FG_EPSILON ) {
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t1 = z;
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t2 = z0;
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t3 = z1;
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} else {
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// everything is too close together to tell the difference
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// so the current intersection point should work as good
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// as any
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result->x = x;
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result->y = y;
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result->z = z;
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return(1);
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}
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side1 = FG_SIGN (t1 - t2);
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side2 = FG_SIGN (t1 - t3);
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if ( side1 == side2 ) {
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// same side, punt
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continue;
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}
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}
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// check to see if intersection point is in the bounding
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// cube of the face
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#ifdef XTRA_DEBUG_STUFF
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xmin = fg_min3 (p1[0], p2[0], p3[0]);
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xmax = fg_max3 (p1[0], p2[0], p3[0]);
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ymin = fg_min3 (p1[1], p2[1], p3[1]);
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ymax = fg_max3 (p1[1], p2[1], p3[1]);
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zmin = fg_min3 (p1[2], p2[2], p3[2]);
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zmax = fg_max3 (p1[2], p2[2], p3[2]);
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printf("bounding cube = %.2f,%.2f,%.2f %.2f,%.2f,%.2f\n",
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xmin, ymin, zmin, xmax, ymax, zmax);
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#endif
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// punt if outside bouding cube
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if ( x < (xmin = fg_min3 (p1[0], p2[0], p3[0])) ) {
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continue;
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} else if ( x > (xmax = fg_max3 (p1[0], p2[0], p3[0])) ) {
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continue;
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} else if ( y < (ymin = fg_min3 (p1[1], p2[1], p3[1])) ) {
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continue;
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} else if ( y > (ymax = fg_max3 (p1[1], p2[1], p3[1])) ) {
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continue;
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} else if ( z < (zmin = fg_min3 (p1[2], p2[2], p3[2])) ) {
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continue;
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} else if ( z > (zmax = fg_max3 (p1[2], p2[2], p3[2])) ) {
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continue;
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}
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// (finally) check to see if the intersection point is
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// actually inside this face
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//first, drop the smallest dimension so we only have to work
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//in 2d.
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dx = xmax - xmin;
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dy = ymax - ymin;
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dz = zmax - zmin;
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min_dim = fg_min3 (dx, dy, dz);
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if ( fabs(min_dim - dx) <= FG_EPSILON ) {
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// x is the smallest dimension
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x1 = p1[1];
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y1 = p1[2];
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x2 = p2[1];
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y2 = p2[2];
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x3 = p3[1];
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y3 = p3[2];
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rx = y;
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ry = z;
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} else if ( fabs(min_dim - dy) <= FG_EPSILON ) {
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// y is the smallest dimension
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x1 = p1[0];
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y1 = p1[2];
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x2 = p2[0];
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y2 = p2[2];
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x3 = p3[0];
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y3 = p3[2];
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rx = x;
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ry = z;
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} else if ( fabs(min_dim - dz) <= FG_EPSILON ) {
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// z is the smallest dimension
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x1 = p1[0];
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y1 = p1[1];
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x2 = p2[0];
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y2 = p2[1];
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x3 = p3[0];
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y3 = p3[1];
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rx = x;
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ry = y;
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} else {
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// all dimensions are really small so lets call it close
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// enough and return a successful match
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result->x = x;
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result->y = y;
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result->z = z;
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return(1);
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}
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// check if intersection point is on the same side of p1 <-> p2 as p3
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t1 = (y1 - y2) / (x1 - x2);
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side1 = FG_SIGN (t1 * ((x3) - x2) + y2 - (y3));
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side2 = FG_SIGN (t1 * ((rx) - x2) + y2 - (ry));
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if ( side1 != side2 ) {
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// printf("failed side 1 check\n");
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continue;
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}
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// check if intersection point is on correct side of p2 <-> p3 as p1
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t1 = (y2 - y3) / (x2 - x3);
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side1 = FG_SIGN (t1 * ((x1) - x3) + y3 - (y1));
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side2 = FG_SIGN (t1 * ((rx) - x3) + y3 - (ry));
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if ( side1 != side2 ) {
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// printf("failed side 2 check\n");
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continue;
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}
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// check if intersection point is on correct side of p1 <-> p3 as p2
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t1 = (y1 - y3) / (x1 - x3);
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side1 = FG_SIGN (t1 * ((x2) - x3) + y3 - (y2));
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side2 = FG_SIGN (t1 * ((rx) - x3) + y3 - (ry));
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if ( side1 != side2 ) {
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// printf("failed side 3 check\n");
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continue;
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}
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// printf( "intersection point = %.2f %.2f %.2f\n", x, y, z);
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result->x = x;
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result->y = y;
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result->z = z;
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return(1);
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}
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// printf("\n");
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return(0);
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}
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// $Log$
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// Revision 1.4 1998/09/15 01:35:03 curt
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// cleaned up my fragment.num_faces hack :-) to use the STL (no need in
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// duplicating work.)
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// Tweaked fgTileMgrRender() do not calc tile matrix unless necessary.
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// removed some unneeded stuff from fgTileMgrCurElev()
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//
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// Revision 1.3 1998/09/08 21:40:42 curt
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// Updates from Bernie Bright.
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//
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// Revision 1.2 1998/09/01 19:03:07 curt
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// Changes contributed by Bernie Bright <bbright@c031.aone.net.au>
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// - The new classes in libmisc.tgz define a stream interface into zlib.
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// I've put these in a new directory, Lib/Misc. Feel free to rename it
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// to something more appropriate. However you'll have to change the
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// include directives in all the other files. Additionally you'll have
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// add the library to Lib/Makefile.am and Simulator/Main/Makefile.am.
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//
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// The StopWatch class in Lib/Misc requires a HAVE_GETRUSAGE autoconf
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// test so I've included the required changes in config.tgz.
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//
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// There are a fair few changes to Simulator/Objects as I've moved
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// things around. Loading tiles is quicker but thats not where the delay
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// is. Tile loading takes a few tenths of a second per file on a P200
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// but it seems to be the post-processing that leads to a noticeable
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// blip in framerate. I suppose its time to start profiling to see where
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// the delays are.
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//
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// I've included a brief description of each archives contents.
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//
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// Lib/Misc/
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// zfstream.cxx
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// zfstream.hxx
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// C++ stream interface into zlib.
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// Taken from zlib-1.1.3/contrib/iostream/.
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// Minor mods for STL compatibility.
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// There's no copyright associated with these so I assume they're
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// covered by zlib's.
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//
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// fgstream.cxx
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// fgstream.hxx
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// FlightGear input stream using gz_ifstream. Tries to open the
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// given filename. If that fails then filename is examined and a
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// ".gz" suffix is removed or appended and that file is opened.
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//
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// stopwatch.hxx
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// A simple timer for benchmarking. Not used in production code.
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// Taken from the Blitz++ project. Covered by GPL.
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//
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// strutils.cxx
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// strutils.hxx
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// Some simple string manipulation routines.
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//
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// Simulator/Airports/
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// Load airports database using fgstream.
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// Changed fgAIRPORTS to use set<> instead of map<>.
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// Added bool fgAIRPORTS::search() as a neater way doing the lookup.
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// Returns true if found.
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//
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// Simulator/Astro/
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// Modified fgStarsInit() to load stars database using fgstream.
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//
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// Simulator/Objects/
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// Modified fgObjLoad() to use fgstream.
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// Modified fgMATERIAL_MGR::load_lib() to use fgstream.
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// Many changes to fgMATERIAL.
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// Some changes to fgFRAGMENT but I forget what!
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//
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// Revision 1.1 1998/08/25 16:51:23 curt
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// Moved from ../Scenery
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//
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//
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