From 675b4aa878f16291ce33fced48a2bc7425f635ae Mon Sep 17 00:00:00 2001 From: Alexander Harkness Date: Sun, 24 Nov 2013 14:19:41 +0000 Subject: Moved source to src --- src/Tracer.cpp | 398 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 398 insertions(+) create mode 100644 src/Tracer.cpp (limited to 'src/Tracer.cpp') diff --git a/src/Tracer.cpp b/src/Tracer.cpp new file mode 100644 index 000000000..ef136302f --- /dev/null +++ b/src/Tracer.cpp @@ -0,0 +1,398 @@ + +#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 "Entities/Entity.h" + +#ifndef _WIN32 + #include // 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; + } +} + + + + + +bool cTracer::Trace( const Vector3f & a_Start, const Vector3f & a_Direction, int a_Distance, bool a_LineOfSight) +{ + if ((a_Start.y < 0) || (a_Start.y >= cChunkDef::Height)) + { + LOGD("%s: Start Y is outside the world (%.2f), not tracing.", __FUNCTION__, a_Start.y); + return false; + } + + 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 false; + } + + 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); + // Block is counted as a collision if we are not doing a line of sight and it is solid, + // or if the block is not air and not water. That way mobs can still see underwater. + if ((!a_LineOfSight && g_BlockIsSolid[BlockID]) || (a_LineOfSight && (BlockID != E_BLOCK_AIR) && !IsBlockWater(BlockID))) + { + BlockHitPosition = pos; + int Normal = GetHitNormal(a_Start, End, pos ); + if(Normal > 0) + { + HitNormal = m_NormalTable[Normal-1]; + } + return true; + } + } + return false; +} + + + + + +// 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; +} -- cgit v1.2.3