504 lines
13 KiB
C++
504 lines
13 KiB
C++
// tile.cxx -- routines to handle a scenery tile
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//
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// Written by Curtis Olson, started May 1998.
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//
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// Copyright (C) 1998 Curtis L. Olson - curt@infoplane.com
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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 "tile.hxx"
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#if 0
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// return the sign of a value
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#define FG_SIGN( x ) ((x) < 0 ? -1 : 1)
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// return min or max of two values
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#define FG_MIN(A,B) ((A) < (B) ? (A) : (B))
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#define FG_MAX(A,B) ((A) > (B) ? (A) : (B))
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fgFACE :: fgFACE () :
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n1(0), n2(0), n3(0)
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{
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}
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fgFACE :: ~fgFACE()
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{
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}
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fgFACE :: fgFACE( const fgFACE & image ) :
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n1( image.n1), n2( image.n2), n3( image.n3)
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{
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}
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bool fgFACE :: operator < (const fgFACE & rhs )
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{
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return ( n1 < rhs.n1 ? true : false);
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}
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bool fgFACE :: operator == (const fgFACE & rhs )
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{
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return ((n1 == rhs.n1) && (n2 == rhs.n2) && ( n3 == rhs.n3));
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}
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// Constructor
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fgFRAGMENT::fgFRAGMENT ( void ) {
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}
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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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num_faces ( rhs.num_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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// Add a face to the face list
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void fgFRAGMENT::add_face(int n1, int n2, int n3) {
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fgFACE face;
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face.n1 = n1;
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face.n2 = n2;
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face.n3 = n3;
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faces.push_back(face);
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num_faces++;
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}
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/*
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// return the sign of a value
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static int fg_sign( double x ) {
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if ( x >= 0 ) {
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return(1);
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} else {
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return(-1);
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}
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}
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// return the minimum of the three values
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static double fg_min( double a, double b, double c ) {
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double result;
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result = a;
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if (result > b) result = b;
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if (result > c) result = c;
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return(result);
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}
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// return the maximum of the three values
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static double fg_max( double a, double b, double c ) {
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double result;
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result = a;
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if (result < b) result = b;
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if (result < c) result = c;
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return(result);
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}
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*/
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// return the minimum of the three values
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static double fg_min3 (double a, double b, double 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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static double fg_max3 (double a, double b, double 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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// 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( fgPoint3d *end0, fgPoint3d *end1, int side_flag,
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fgPoint3d *result)
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{
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fgTILE *t;
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fgFACE face;
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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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list < fgFACE > :: iterator current;
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list < fgFACE > :: iterator last;
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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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current = faces.begin();
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last = faces.end();
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while ( current != last ) {
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face = *current;
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current++;
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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[face.n1], center);
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MAT3_ADD_VEC(p2, t->nodes[face.n2], center);
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MAT3_ADD_VEC(p3, t->nodes[face.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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// Destructor
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fgFRAGMENT::~fgFRAGMENT ( void ) {
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// Step through the face list deleting the items until the list is
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// empty
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// printf("destructing a fragment with %d faces\n", faces.size());
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while ( faces.size() ) {
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// printf("emptying face list\n");
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faces.pop_front();
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}
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}
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// equality operator
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bool fgFRAGMENT :: operator == ( const fgFRAGMENT & rhs)
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{
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if(( center.x - rhs.center.x ) < FG_EPSILON) {
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if(( center.y - rhs.center.y) < FG_EPSILON) {
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if(( center.z - rhs.center.z) < FG_EPSILON) {
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return true;
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}
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}
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}
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return false;
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}
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// comparison operator
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bool fgFRAGMENT :: operator < ( const fgFRAGMENT &rhs)
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{
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// This is completely arbitrary. It satisfies RW's STL implementation
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return bounding_radius < rhs.bounding_radius;
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}
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#endif
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// Constructor
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fgTILE::fgTILE ( void ) {
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nodes = new double[MAX_NODES][3];
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}
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// Destructor
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fgTILE::~fgTILE ( void ) {
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free(nodes);
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}
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// $Log$
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// Revision 1.10 1998/08/25 16:52:42 curt
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// material.cxx material.hxx obj.cxx obj.hxx texload.c texload.h moved to
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// ../Objects
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//
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// Revision 1.9 1998/08/24 20:11:39 curt
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// Tweaks ...
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//
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// Revision 1.8 1998/08/22 14:49:58 curt
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// Attempting to iron out seg faults and crashes.
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// Did some shuffling to fix a initialization order problem between view
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// position, scenery elevation.
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//
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// Revision 1.7 1998/08/20 15:12:05 curt
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// Used a forward declaration of classes fgTILE and fgMATERIAL to eliminate
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// the need for "void" pointers and casts.
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// Quick hack to count the number of scenery polygons that are being drawn.
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//
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// Revision 1.6 1998/08/12 21:13:05 curt
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// material.cxx: don't load textures if they are disabled
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// obj.cxx: optimizations from Norman Vine
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// tile.cxx: minor tweaks
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// tile.hxx: addition of num_faces
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// tilemgr.cxx: minor tweaks
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//
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// Revision 1.5 1998/07/24 21:42:08 curt
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// material.cxx: whups, double method declaration with no definition.
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// obj.cxx: tweaks to avoid errors in SGI's CC.
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// tile.cxx: optimizations by Norman Vine.
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// tilemgr.cxx: optimizations by Norman Vine.
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//
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// Revision 1.4 1998/07/22 21:41:42 curt
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// Add basic fgFACE methods contributed by Charlie Hotchkiss.
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// intersect optimization from Norman Vine.
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//
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// Revision 1.3 1998/07/16 17:34:24 curt
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// Ground collision detection optimizations contributed by Norman Vine.
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//
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// Revision 1.2 1998/07/12 03:18:28 curt
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// Added ground collision detection. This involved:
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// - saving the entire vertex list for each tile with the tile records.
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// - saving the face list for each fragment with the fragment records.
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// - code to intersect the current vertical line with the proper face in
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// an efficient manner as possible.
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// Fixed a bug where the tiles weren't being shifted to "near" (0,0,0)
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//
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// Revision 1.1 1998/05/23 14:09:21 curt
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// Added tile.cxx and tile.hxx.
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// Working on rewriting the tile management system so a tile is just a list
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// fragments, and the fragment record contains the display list for that fragment.
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//
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