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-rw-r--r--source/Tracer.cpp400
1 files changed, 400 insertions, 0 deletions
diff --git a/source/Tracer.cpp b/source/Tracer.cpp
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index 000000000..444ab821a
--- /dev/null
+++ b/source/Tracer.cpp
@@ -0,0 +1,400 @@
+
+#include "Globals.h" // NOTE: MSVC stupidness requires this to be the same across all modules
+
+#include "Tracer.h"
+#include "World.h"
+
+#include "Vector3f.h"
+#include "Vector3i.h"
+#include "Vector3d.h"
+
+#include "BlockID.h"
+#include "Entity.h"
+
+#include "Defines.h"
+
+#ifndef _WIN32
+ #include <stdlib.h> // abs()
+#endif
+
+
+
+
+
+cTracer::cTracer(cWorld * a_World)
+ : m_World(a_World)
+{
+ m_NormalTable[0].Set(-1, 0, 0);
+ m_NormalTable[1].Set( 0, 0,-1);
+ m_NormalTable[2].Set( 1, 0, 0);
+ m_NormalTable[3].Set( 0, 0, 1);
+ m_NormalTable[4].Set( 0, 1, 0);
+ m_NormalTable[5].Set( 0,-1, 0);
+}
+
+
+
+
+
+cTracer::~cTracer()
+{
+}
+
+
+
+
+
+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
+ 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)
+{
+ if (a_Start.y < 0)
+ {
+ LOGD("%s: Start is below the world", __FUNCTION__);
+ return 0;
+ }
+
+ SetValues(a_Start, a_Direction);
+
+ Vector3f End = a_Start + (dir * (float)a_Distance);
+
+ if (End.y < 0)
+ {
+ float dist = -a_Start.y / dir.y;
+ End = a_Start + (dir * dist);
+ }
+
+ // 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))
+ {
+ 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;
+ }
+
+ BLOCKTYPE BlockID = m_World->GetBlock(pos.x, pos.y, pos.z);
+ // No collision with water ;)
+ if ((BlockID != E_BLOCK_AIR) || IsBlockWater(BlockID)) // _X 2013_03_29: Why is the IsBlockWater condition here? water equals 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 || IsBlockWater(BlockID))
+ 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;
+}
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-11 05:34:15 +0100