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Diffstat (limited to '')
| -rw-r--r-- | source/cTracer.cpp | 377 |
1 files changed, 377 insertions, 0 deletions
diff --git a/source/cTracer.cpp b/source/cTracer.cpp new file mode 100644 index 000000000..28e5c49b5 --- /dev/null +++ b/source/cTracer.cpp @@ -0,0 +1,377 @@ +#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;
+}
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