mcserver/source/cTracer.cpp

378 lines
9.5 KiB
C++

#include "cTracer.h"
#include "cWorld.h"
#include "Vector3f.h"
#include "Vector3i.h"
#include "Vector3d.h"
#include "BlockID.h"
#include "cMCLogger.h"
#include "cEntity.h"
#ifndef _WIN32
#include <stdlib.h> // abs()
#endif
cTracer::cTracer(cWorld* a_World)
: m_World( a_World )
{
m_NormalTable[0] = new Vector3f(-1, 0, 0);
m_NormalTable[1] = new Vector3f( 0, 0,-1);
m_NormalTable[2] = new Vector3f( 1, 0, 0);
m_NormalTable[3] = new Vector3f( 0, 0, 1);
m_NormalTable[4] = new Vector3f( 0, 1, 0);
m_NormalTable[5] = new Vector3f( 0,-1, 0);
DotPos = new Vector3f();
BoxOffset = new Vector3f();
BlockHitPosition = new Vector3f();
HitNormal = new Vector3f();
RealHit = new Vector3f();
dir = new Vector3f();
tDelta = new Vector3f();
pos = new Vector3i();
end1 = new Vector3i();
step = new Vector3i();
tMax = new Vector3f();
}
cTracer::~cTracer()
{
for( int i = 0; i < 6; ++i )
{
delete m_NormalTable[i];
m_NormalTable[i] = 0;
}
delete DotPos; DotPos = 0;
delete BoxOffset; BoxOffset = 0;
delete BlockHitPosition; BlockHitPosition = 0;
delete HitNormal; HitNormal = 0;
delete RealHit; RealHit = 0;
delete dir; dir = 0;
delete tDelta; tDelta = 0;
delete pos; pos = 0;
delete end1; end1 = 0;
delete step; step = 0;
delete tMax; tMax = 0;
}
float cTracer::SigNum( float a_Num )
{
if (a_Num < 0.f) return -1.f;
if (a_Num > 0.f) return 1.f;
return 0.f;
}
void cTracer::SetValues( const Vector3f & a_Start, const Vector3f & a_Direction )
{
// calculate the direction of the ray (linear algebra)
*dir = a_Direction;
// decide which direction to start walking in
step->x = (int) SigNum(dir->x);
step->y = (int) SigNum(dir->y);
step->z = (int) SigNum(dir->z);
// normalize the direction vector
if( dir->SqrLength() > 0.f ) dir->Normalize();
// how far we must move in the ray direction before
// we encounter a new voxel in x-direction
// same but y-direction
if( dir->x != 0.f ) tDelta->x = 1/fabs(dir->x);
else tDelta->x = 0;
if( dir->y != 0.f ) tDelta->y = 1/fabs(dir->y);
else tDelta->y = 0;
if( dir->z != 0.f ) tDelta->z = 1/fabs(dir->z);
else tDelta->z = 0;
// start voxel coordinates
// use your
// transformer
// function here
pos->x = (int)floorf(a_Start.x);
pos->y = (int)floorf(a_Start.y);
pos->z = (int)floorf(a_Start.z);
// calculate distance to first intersection in the voxel we start from
if(dir->x < 0)
{
tMax->x = ((float)pos->x - a_Start.x) / dir->x;
}
else
{
tMax->x = (((float)pos->x + 1) - a_Start.x) / dir->x;
}
if(dir->y < 0)
{
tMax->y = ((float)pos->y - a_Start.y) / dir->y;
}
else
{
tMax->y = (((float)pos->y + 1) - a_Start.y) / dir->y;
}
if(dir->z < 0)
{
tMax->z = ((float)pos->z - a_Start.z) / dir->z;
}
else
{
tMax->z = (((float)pos->z + 1) - a_Start.z) / dir->z;
}
}
int cTracer::Trace( const Vector3f & a_Start, const Vector3f & a_Direction, int a_Distance)
{
SetValues( a_Start, a_Direction );
const Vector3f End = a_Start + ((*dir) * (float)a_Distance);
// end voxel coordinates
end1->x = (int)floorf(End.x);
end1->y = (int)floorf(End.y);
end1->z = (int)floorf(End.z);
// check if first is occupied
if( pos->Equals( end1 ) )
{
LOG("WARNING: cTracer: Start and end in same block");
return 0;
}
bool reachedX = false, reachedY = false, reachedZ = false;
int Iterations = 0;
while ( Iterations < a_Distance )
{
Iterations++;
if(tMax->x < tMax->y && tMax->x < tMax->z)
{
tMax->x += tDelta->x;
pos->x += step->x;
}
else if(tMax->y < tMax->z)
{
tMax->y += tDelta->y;
pos->y += step->y;
}
else
{
tMax->z += tDelta->z;
pos->z += step->z;
}
if(step->x > 0.0f)
{
if(pos->x >= end1->x)
{
reachedX = true;
}
}
else if(pos->x <= end1->x)
{
reachedX = true;
}
if(step->y > 0.0f)
{
if(pos->y >= end1->y)
{
reachedY = true;
}
}
else if(pos->y <= end1->y)
{
reachedY = true;
}
if(step->z > 0.0f)
{
if(pos->z >= end1->z)
{
reachedZ = true;
}
}
else if(pos->z <= end1->z)
{
reachedZ = true;
}
if (reachedX && reachedY && reachedZ)
{
return false;
}
char BlockID = m_World->GetBlock( pos->x, pos->y, pos->z );
if ( BlockID != E_BLOCK_AIR )
{
*BlockHitPosition = pos;
int Normal = GetHitNormal(a_Start, End, *pos );
if(Normal > 0)
{
*HitNormal = *m_NormalTable[Normal-1];
}
return 1;
}
}
return 0;
}
// return 1 = hit, other is not hit
int LinesCross(float x0,float y0,float x1,float y1,float x2,float y2,float x3,float y3)
{
//float linx, liny;
float d=(x1-x0)*(y3-y2)-(y1-y0)*(x3-x2);
if (abs(d)<0.001) {return 0;}
float AB=((y0-y2)*(x3-x2)-(x0-x2)*(y3-y2))/d;
if (AB>=0.0 && AB<=1.0)
{
float CD=((y0-y2)*(x1-x0)-(x0-x2)*(y1-y0))/d;
if (CD>=0.0 && CD<=1.0)
{
//linx=x0+AB*(x1-x0);
//liny=y0+AB*(y1-y0);
return 1;
}
}
return 0;
}
// intersect3D_SegmentPlane(): intersect a segment and a plane
// Input: a_Ray = a segment, and a_Plane = a plane = {Point V0; Vector n;}
// Output: *I0 = the intersect point (when it exists)
// Return: 0 = disjoint (no intersection)
// 1 = intersection in the unique point *I0
// 2 = the segment lies in the plane
int cTracer::intersect3D_SegmentPlane( const Vector3f & a_Origin, const Vector3f & a_End, const Vector3f & a_PlanePos, const Vector3f & a_PlaneNormal )
{
Vector3f u = a_End - a_Origin;//a_Ray.P1 - S.P0;
Vector3f w = a_Origin - a_PlanePos;//S.P0 - Pn.V0;
float D = a_PlaneNormal.Dot( u );//dot(Pn.n, u);
float N = -(a_PlaneNormal.Dot( w ) );//-dot(a_Plane.n, w);
const float EPSILON = 0.0001f;
if (fabs(D) < EPSILON) { // segment is parallel to plane
if (N == 0) // segment lies in plane
return 2;
return 0; // no intersection
}
// they are not parallel
// compute intersect param
float sI = N / D;
if (sI < 0 || sI > 1)
return 0; // no intersection
//Vector3f I ( a_Ray->GetOrigin() + sI * u );//S.P0 + sI * u; // compute segment intersect point
*RealHit = a_Origin + u * sI;
return 1;
}
int cTracer::GetHitNormal(const Vector3f & start, const Vector3f & end, const Vector3i & a_BlockPos)
{
Vector3i SmallBlockPos = a_BlockPos;
char BlockID = m_World->GetBlock( a_BlockPos.x, a_BlockPos.y, a_BlockPos.z );
if( BlockID == E_BLOCK_AIR )
return 0;
Vector3f BlockPos;
BlockPos = Vector3f(SmallBlockPos);
Vector3f Look = (end - start);
Look.Normalize();
float dot = Look.Dot( Vector3f(-1, 0, 0) ); // first face normal is x -1
if(dot < 0)
{
int Lines = LinesCross( start.x, start.y, end.x, end.y, BlockPos.x, BlockPos.y, BlockPos.x, BlockPos.y + 1 );
if(Lines == 1)
{
Lines = LinesCross( start.x, start.z, end.x, end.z, BlockPos.x, BlockPos.z, BlockPos.x, BlockPos.z + 1 );
if(Lines == 1)
{
intersect3D_SegmentPlane( start, end, BlockPos, Vector3f(-1, 0, 0) );
return 1;
}
}
}
dot = Look.Dot( Vector3f(0, 0, -1) ); // second face normal is z -1
if(dot < 0)
{
int Lines = LinesCross( start.z, start.y, end.z, end.y, BlockPos.z, BlockPos.y, BlockPos.z, BlockPos.y + 1 );
if(Lines == 1)
{
Lines = LinesCross( start.z, start.x, end.z, end.x, BlockPos.z, BlockPos.x, BlockPos.z, BlockPos.x + 1 );
if(Lines == 1)
{
intersect3D_SegmentPlane( start, end, BlockPos, Vector3f(0, 0, -1) );
return 2;
}
}
}
dot = Look.Dot( Vector3f(1, 0, 0) ); // third face normal is x 1
if(dot < 0)
{
int Lines = LinesCross( start.x, start.y, end.x, end.y, BlockPos.x + 1, BlockPos.y, BlockPos.x + 1, BlockPos.y + 1 );
if(Lines == 1)
{
Lines = LinesCross( start.x, start.z, end.x, end.z, BlockPos.x + 1, BlockPos.z, BlockPos.x + 1, BlockPos.z + 1 );
if(Lines == 1)
{
intersect3D_SegmentPlane( start, end, BlockPos + Vector3f(1, 0, 0), Vector3f(1, 0, 0) );
return 3;
}
}
}
dot = Look.Dot( Vector3f(0, 0, 1) ); // fourth face normal is z 1
if(dot < 0)
{
int Lines = LinesCross( start.z, start.y, end.z, end.y, BlockPos.z + 1, BlockPos.y, BlockPos.z + 1, BlockPos.y + 1 );
if(Lines == 1)
{
Lines = LinesCross( start.z, start.x, end.z, end.x, BlockPos.z + 1, BlockPos.x, BlockPos.z + 1, BlockPos.x + 1 );
if(Lines == 1)
{
intersect3D_SegmentPlane( start, end, BlockPos + Vector3f(0, 0, 1), Vector3f(0, 0, 1) );
return 4;
}
}
}
dot = Look.Dot( Vector3f(0, 1, 0) ); // fifth face normal is y 1
if(dot < 0)
{
int Lines = LinesCross( start.y, start.x, end.y, end.x, BlockPos.y + 1, BlockPos.x, BlockPos.y + 1, BlockPos.x + 1 );
if(Lines == 1)
{
Lines = LinesCross( start.y, start.z, end.y, end.z, BlockPos.y + 1, BlockPos.z, BlockPos.y + 1, BlockPos.z + 1 );
if(Lines == 1)
{
intersect3D_SegmentPlane( start, end, BlockPos + Vector3f(0, 1, 0), Vector3f(0, 1, 0) );
return 5;
}
}
}
dot = Look.Dot( Vector3f(0, -1, 0) ); // sixth face normal is y -1
if(dot < 0)
{
int Lines = LinesCross( start.y, start.x, end.y, end.x, BlockPos.y, BlockPos.x, BlockPos.y, BlockPos.x + 1 );
if(Lines == 1)
{
Lines = LinesCross( start.y, start.z, end.y, end.z, BlockPos.y, BlockPos.z, BlockPos.y, BlockPos.z + 1 );
if(Lines == 1)
{
intersect3D_SegmentPlane( start, end, BlockPos, Vector3f(0, -1, 0) );
return 6;
}
}
}
return 0;
}