390 lines
11 KiB
C++
390 lines
11 KiB
C++
#ifdef HAVE_CONFIG_H
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# include <config.h>
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#endif
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#ifdef HAVE_WINDOWS_H
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# include <windows.h>
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#endif
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#include <float.h>
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#include <math.h>
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#include <GL/glut.h>
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#include <GL/gl.h>
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#include <simgear/constants.h>
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#include <simgear/sg_inlines.h>
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#include <simgear/debug/logstream.hxx>
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#include <simgear/math/point3d.hxx>
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#include <simgear/math/sg_geodesy.hxx>
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#include <simgear/math/vector.hxx>
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#include <Main/globals.hxx>
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#include <Main/viewer.hxx>
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#include "hitlist.hxx"
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extern ssgBranch *terrain;
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// check to see if the intersection point is
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// actually inside this face
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static bool sgdPointInTriangle( sgdVec3 point, sgdVec3 tri[3] )
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{
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double xmin, xmax, ymin, ymax, zmin, zmax;
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// punt if outside bouding cube
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if ( point[0] < (xmin = SG_MIN3 (tri[0][0], tri[1][0], tri[2][0])) ) {
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return false;
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} else if ( point[0] > (xmax = SG_MAX3 (tri[0][0], tri[1][0], tri[2][0])) ) {
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return false;
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} else if ( point[1] < (ymin = SG_MIN3 (tri[0][1], tri[1][1], tri[2][1])) ) {
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return false;
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} else if ( point[1] > (ymax = SG_MAX3 (tri[0][1], tri[1][1], tri[2][1])) ) {
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return false;
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} else if ( point[2] < (zmin = SG_MIN3 (tri[0][2], tri[1][2], tri[2][2])) ) {
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return false;
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} else if ( point[2] > (zmax = SG_MAX3 (tri[0][2], tri[1][2], tri[2][2])) ) {
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return false;
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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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double dx = xmax - xmin;
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double dy = ymax - ymin;
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double dz = zmax - zmin;
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double min_dim = SG_MIN3 (dx, dy, dz);
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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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double x1, y1, x2, y2, x3, y3, rx, ry;
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if ( fabs(min_dim-dx) <= SG_EPSILON ) {
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// x is the smallest dimension
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x1 = point[1];
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y1 = point[2];
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x2 = tri[0][1];
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y2 = tri[0][2];
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x3 = tri[1][1];
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y3 = tri[1][2];
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rx = tri[2][1];
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ry = tri[2][2];
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} else if ( fabs(min_dim-dy) <= SG_EPSILON ) {
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// y is the smallest dimension
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x1 = point[0];
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y1 = point[2];
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x2 = tri[0][0];
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y2 = tri[0][2];
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x3 = tri[1][0];
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y3 = tri[1][2];
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rx = tri[2][0];
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ry = tri[2][2];
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} else if ( fabs(min_dim-dz) <= SG_EPSILON ) {
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// z is the smallest dimension
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x1 = point[0];
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y1 = point[1];
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x2 = tri[0][0];
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y2 = tri[0][1];
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x3 = tri[1][0];
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y3 = tri[1][1];
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rx = tri[2][0];
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ry = tri[2][1];
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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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return true;
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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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double tmp = (y2 - y3) / (x2 - x3);
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int side1 = SG_SIGN (tmp * (rx - x3) + y3 - ry);
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int side2 = SG_SIGN (tmp * (x1 - x3) + y3 - y1);
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if ( side1 != side2 ) {
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// printf("failed side 1 check\n");
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return false;
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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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tmp = (y3 - ry) / (x3 - rx);
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side1 = SG_SIGN (tmp * (x2 - rx) + ry - y2);
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side2 = SG_SIGN (tmp * (x1 - rx) + ry - y1);
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if ( side1 != side2 ) {
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// printf("failed side 2 check\n");
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return false;
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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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tmp = (y2 - ry) / (x2 - rx);
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side1 = SG_SIGN (tmp * (x3 - rx) + ry - y3);
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side2 = SG_SIGN (tmp * (x1 - rx) + ry - y1);
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if ( side1 != side2 ) {
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// printf("failed side 3 check\n");
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return false;
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}
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return true;
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}
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static int sgdIsectInfLinePlane( sgdVec3 dst, const sgdVec3 l_org,
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const sgdVec3 l_vec, const sgdVec4 plane )
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{
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SGDfloat tmp = sgdScalarProductVec3 ( l_vec, plane ) ;
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/* Is line parallel to plane? */
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if ( fabs ( tmp ) < FLT_EPSILON )
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return false ;
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sgdScaleVec3 ( dst, l_vec, -( sgdScalarProductVec3 ( l_org, plane )
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+ plane[3] ) / tmp ) ;
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sgdAddVec3 ( dst, l_org ) ;
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return true ;
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}
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static void sgdXformPnt3 ( sgdVec3 dst, const sgVec3 src, const sgdMat4 mat )
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{
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SGDfloat t0 = src[ 0 ] ;
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SGDfloat t1 = src[ 1 ] ;
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SGDfloat t2 = src[ 2 ] ;
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dst[0] = ( t0 * mat[ 0 ][ 0 ] +
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t1 * mat[ 1 ][ 0 ] +
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t2 * mat[ 2 ][ 0 ] +
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mat[ 3 ][ 0 ] ) ;
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dst[1] = ( t0 * mat[ 0 ][ 1 ] +
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t1 * mat[ 1 ][ 1 ] +
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t2 * mat[ 2 ][ 1 ] +
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mat[ 3 ][ 1 ] ) ;
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dst[2] = ( t0 * mat[ 0 ][ 2 ] +
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t1 * mat[ 1 ][ 2 ] +
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t2 * mat[ 2 ][ 2 ] +
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mat[ 3 ][ 2 ] ) ;
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}
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/*
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Find the intersection of an infinite line with a leaf
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the line being defined by a point and direction.
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Variables
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In:
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ssgLeaf pointer -- leaf
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qualified matrix -- m
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line origin -- orig
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line direction -- dir
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Out:
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result -- intersection point
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normal -- intersected tri's normal
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Returns:
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true if intersection found
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false otherwise
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*/
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int FGHitList::IntersectLeaf( ssgLeaf *leaf, sgdMat4 m,
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sgdVec3 orig, sgdVec3 dir )
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{
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int num_hits = 0;
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for ( int i = 0; i < leaf->getNumTriangles(); ++i ) {
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short i1, i2, i3;
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leaf->getTriangle( i, &i1, &i2, &i3 );
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sgdVec3 tri[3];
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sgdXformPnt3( tri[0], leaf->getVertex( i1 ), m );
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sgdXformPnt3( tri[1], leaf->getVertex( i2 ), m );
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sgdXformPnt3( tri[2], leaf->getVertex( i3 ), m );
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sgdVec4 plane;
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sgdMakePlane( plane, tri[0], tri[1], tri[2] );
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sgdVec3 point;
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if( sgdIsectInfLinePlane( point, orig, dir, plane ) ) {
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if( sgdPointInTriangle( point, tri ) ) {
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add(leaf,i,point,plane);
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num_hits++;
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}
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}
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}
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return num_hits;
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}
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void FGHitList::IntersectBranch( ssgBranch *branch, sgdMat4 m,
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sgdVec3 orig, sgdVec3 dir )
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{
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sgSphere *bsphere;
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for ( ssgEntity *kid = branch->getKid( 0 );
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kid != NULL;
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kid = branch->getNextKid() )
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{
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if ( kid->getTraversalMask() & SSGTRAV_HOT ) {
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bsphere = kid->getBSphere();
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sgVec3 fcenter;
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sgCopyVec3( fcenter, bsphere->getCenter() );
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sgdVec3 center;
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center[0] = fcenter[0];
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center[1] = fcenter[1];
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center[2] = fcenter[2];
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sgdXformPnt3( center, m ) ;
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// watch out for overflow
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if ( sgdClosestPointToLineDistSquared( center, orig, dir ) <
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double(bsphere->getRadius() * bsphere->getRadius()) )
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{
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// possible intersections
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if ( kid->isAKindOf ( ssgTypeBranch() ) ) {
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sgdMat4 m_new;
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sgdCopyMat4(m_new, m);
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if ( kid->isA( ssgTypeTransform() ) ) {
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sgMat4 fxform;
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((ssgTransform *)kid)->getTransform( fxform );
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sgdMat4 xform;
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sgdSetMat4( xform, fxform );
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sgdPreMultMat4( m_new, xform );
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}
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IntersectBranch( (ssgBranch *)kid, m_new, orig, dir );
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} else if ( kid->isAKindOf ( ssgTypeLeaf() ) ) {
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IntersectLeaf( (ssgLeaf *)kid, m, orig, dir );
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}
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} else {
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// end of the line for this branch
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}
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} else {
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// branch requested not to be traversed
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}
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}
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}
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// This expects the inital m to the identity transform
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void ssgGetEntityTransform(ssgEntity *branch, sgMat4 m )
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{
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for ( ssgEntity *parent = branch->getParent(0);
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parent != NULL;
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parent = parent->getNextParent() )
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{
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// recurse till we are at the scene root
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// then just unwinding the stack should
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// give us our cumulative transform :-) NHV
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ssgGetEntityTransform( parent, m );
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if ( parent->isA( ssgTypeTransform() ) ) {
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sgMat4 xform;
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((ssgTransform *)parent)->getTransform( xform );
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sgPreMultMat4( m, xform );
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}
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}
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}
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// return the passed entitity's bsphere's center point radius and
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// fully formed current model matrix for entity
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void ssgGetCurrentBSphere( ssgEntity *entity, sgVec3 center,
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float *radius, sgMat4 m )
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{
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sgSphere *bsphere = entity->getBSphere();
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*radius = (double)bsphere->getRadius();
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sgCopyVec3( center, bsphere->getCenter() );
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sgMakeIdentMat4 ( m ) ;
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ssgGetEntityTransform( entity, m );
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}
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void FGHitList::IntersectCachedLeaf( sgdMat4 m,
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sgdVec3 orig, sgdVec3 dir)
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{
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if ( last_hit() ) {
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float radius;
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sgVec3 fcenter;
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sgMat4 fxform;
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// ssgEntity *ent = last_hit();
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ssgGetCurrentBSphere( last_hit(), fcenter, &radius, fxform );
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sgdMat4 m;
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sgdVec3 center;
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sgdSetMat4( m, fxform );
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sgdXformPnt3( center, m );
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if ( sgdClosestPointToLineDistSquared( center, orig, dir ) <
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double(radius*radius) )
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{
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IntersectLeaf( (ssgLeaf *)last_hit(), m, orig, dir );
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}
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}
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}
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static void CurrentNormalInLocalPlane(sgVec3 dst, sgVec3 src) {
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sgVec3 tmp;
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sgSetVec3(tmp, src[0], src[1], src[2] );
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sgMat4 TMP;
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sgTransposeNegateMat4 ( TMP, globals->get_current_view()->get_UP() ) ;
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sgXformVec3(tmp, tmp, TMP);
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sgSetVec3(dst, tmp[2], tmp[1], tmp[0] );
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}
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// a temporary hack until we get everything rewritten with sgdVec3
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static inline Point3D operator + (const Point3D& a, const sgdVec3 b)
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{
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return Point3D(a.x()+b[0], a.y()+b[1], a.z()+b[2]);
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}
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// Determine scenery altitude via ssg. Normally this just happens
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// when we render the scene, but we'd also like to be able to do this
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// explicitely. lat & lon are in radians. view_pos in current world
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// coordinate translated near (0,0,0) (in meters.) Returns result in
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// meters.
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bool fgCurrentElev( sgdVec3 abs_view_pos, sgdVec3 scenery_center,
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FGHitList *hit_list,
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double *terrain_elev, double *radius, double *normal)
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{
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sgdVec3 view_pos;
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sgdSubVec3( view_pos, abs_view_pos, scenery_center );
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sgdVec3 orig, dir;
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sgdCopyVec3(orig, view_pos );
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sgdCopyVec3(dir, abs_view_pos );
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hit_list->Intersect( terrain, orig, dir );
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int this_hit=0;
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Point3D geoc;
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double result = -9999;
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Point3D sc(scenery_center[0], scenery_center[1], scenery_center[2]) ;
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int hitcount = hit_list->num_hits();
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for ( int i = 0; i < hitcount; ++i ) {
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geoc = sgCartToPolar3d( sc + hit_list->get_point(i) );
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double lat_geod, alt, sea_level_r;
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sgGeocToGeod(geoc.lat(), geoc.radius(), &lat_geod,
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&alt, &sea_level_r);
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if ( alt > result && alt < 10000 ) {
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result = alt;
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this_hit = i;
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}
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}
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if ( result > -9000 ) {
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*terrain_elev = result;
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*radius = geoc.radius();
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sgVec3 tmp;
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sgSetVec3(tmp, hit_list->get_normal(this_hit));
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// cout << "cur_normal: " << tmp[0] << " " << tmp[1] << " "
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// << tmp[2] << endl;
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/* ssgState *IntersectedLeafState =
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((ssgLeaf*)hit_list->get_entity(this_hit))->getState(); */
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CurrentNormalInLocalPlane(tmp, tmp);
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sgdSetVec3( normal, tmp );
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// cout << "NED: " << tmp[0] << " " << tmp[1] << " " << tmp[2] << endl;
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return true;
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} else {
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SG_LOG( SG_TERRAIN, SG_INFO, "no terrain intersection" );
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*terrain_elev = 0.0;
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float *up = globals->get_current_view()->get_world_up();
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sgdSetVec3(normal, up[0], up[1], up[2]);
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return false;
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}
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}
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