From 5fe7008966f70de2af53cce7fc13014c220ab721 Mon Sep 17 00:00:00 2001 From: madmaxoft Date: Sun, 4 Aug 2013 13:25:48 +0200 Subject: First attempt at implementing a cLineBlockTracer class Not yet tested, will probably have lots of bugs, if it is at all usable. --- source/LineBlockTracer.cpp | 258 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 258 insertions(+) create mode 100644 source/LineBlockTracer.cpp (limited to 'source/LineBlockTracer.cpp') diff --git a/source/LineBlockTracer.cpp b/source/LineBlockTracer.cpp new file mode 100644 index 000000000..c5939cb78 --- /dev/null +++ b/source/LineBlockTracer.cpp @@ -0,0 +1,258 @@ + +// LineBlockTracer.cpp + +// Implements the cLineBlockTracer class representing a cBlockTracer that traces along a straight line between two points + +#include "Globals.h" +#include "LineBlockTracer.h" +#include "Vector3d.h" +#include "World.h" +#include "Chunk.h" + + + + + + +cLineBlockTracer::cLineBlockTracer(cWorld & a_World, cCallbacks & a_Callbacks) : + super(a_World, a_Callbacks) +{ +} + + + + + +bool cLineBlockTracer::Trace(cWorld & a_World, cBlockTracer::cCallbacks & a_Callbacks, const Vector3d & a_Start, const Vector3d & a_End) +{ + cLineBlockTracer Tracer(a_World, a_Callbacks); + return Tracer.Trace(a_Start.x, a_Start.y, a_Start.z, a_End.x, a_End.y, a_End.z); +} + + + + + +bool cLineBlockTracer::Trace(cWorld & a_World, cBlockTracer::cCallbacks &a_Callbacks, double a_StartX, double a_StartY, double a_StartZ, double a_EndX, double a_EndY, double a_EndZ) +{ + cLineBlockTracer Tracer(a_World, a_Callbacks); + return Tracer.Trace(a_StartX, a_StartY, a_StartZ, a_EndX, a_EndY, a_EndZ); +} + + + + + +bool cLineBlockTracer::Trace(double a_StartX, double a_StartY, double a_StartZ, double a_EndX, double a_EndY, double a_EndZ) +{ + // Initialize the member veriables: + m_StartX = a_StartX; + m_StartY = a_StartY; + m_StartZ = a_StartZ; + m_EndX = a_EndX; + m_EndY = a_EndY; + m_EndZ = a_EndZ; + m_DirX = (m_StartX < m_EndX) ? 1 : -1; + m_DirY = (m_StartY < m_EndY) ? 1 : -1; + m_DirZ = (m_StartZ < m_EndZ) ? 1 : -1; + + // Check the start coords, adjust into the world: + if (m_StartY < 0) + { + if (m_EndY < 0) + { + // Nothing to trace + m_Callbacks->OnNoMoreHits(); + return true; + } + FixStartBelowWorld(); + m_Callbacks->OnIntoWorld(m_StartX, m_StartY, m_StartZ); + } + else if (m_StartY >= cChunkDef::Height) + { + if (m_EndY >= cChunkDef::Height) + { + m_Callbacks->OnNoMoreHits(); + return true; + } + FixStartAboveWorld(); + m_Callbacks->OnIntoWorld(m_StartX, m_StartY, m_StartZ); + } + + m_CurrentX = (int)floor(m_StartX); + m_CurrentY = (int)floor(m_StartY); + m_CurrentZ = (int)floor(m_StartZ); + + m_DiffX = m_EndX - m_StartX; + m_DiffY = m_EndY - m_StartY; + m_DiffZ = m_EndZ - m_StartZ; + + // The actual trace is handled with ChunkMapCS locked by calling our Item() for the specified chunk + int BlockX = (int)floor(m_StartX); + int BlockZ = (int)floor(m_StartZ); + int ChunkX, ChunkZ; + cChunkDef::BlockToChunk(BlockX, BlockZ, ChunkX, ChunkZ); + return m_World->DoWithChunk(ChunkX, ChunkZ, *this); +} + + + + + +void cLineBlockTracer::FixStartAboveWorld(void) +{ + // We must set the start Y to less than cChunkDef::Height so that it is considered inside the world later on + // Therefore we use an EPS-offset from the height, as small as reasonably possible. + const double Height = (double)cChunkDef::Height - 0.00001; + CalcXZIntersection(Height, m_StartX, m_StartZ); + m_StartY = Height; +} + + + + + +void cLineBlockTracer::FixStartBelowWorld(void) +{ + CalcXZIntersection(0, m_StartX, m_StartZ); + m_StartY = 0; +} + + + + + +void cLineBlockTracer::CalcXZIntersection(double a_Y, double & a_IntersectX, double & a_IntersectZ) +{ + double Ratio = (m_StartY - a_Y) / (m_StartY - m_EndY); + a_IntersectX = m_StartX + (m_EndX - m_StartX) * Ratio; + a_IntersectZ = m_StartZ + (m_EndZ - m_StartZ) * Ratio; +} + + + + + +bool cLineBlockTracer::MoveToNextBlock(void) +{ + // Find out which of the current block's walls gets hit by the path: + static const double EPS = 0.00001; + double Coeff = 1; + enum eDirection + { + dirNONE, + dirX, + dirY, + dirZ, + } Direction = dirNONE; + if (abs(m_DiffX) > EPS) + { + double DestX = (m_DirX > 0) ? (m_CurrentX + 1) : m_CurrentX; + Coeff = (m_EndX - DestX) / m_DiffX; + Direction = dirX; + } + if (abs(m_DiffY) > EPS) + { + double DestY = (m_DirY > 0) ? (m_CurrentY + 1) : m_CurrentY; + double CoeffY = (DestY - m_StartY) / m_DiffY; + if (CoeffY < Coeff) + { + Coeff = CoeffY; + Direction = dirY; + } + } + if (abs(m_DiffZ) > EPS) + { + double DestZ = (m_DirZ > 0) ? (m_CurrentZ + 1) : m_CurrentZ; + double CoeffZ = (DestZ - m_StartZ) / m_DiffZ; + if (CoeffZ < Coeff) + { + Coeff = CoeffZ; + Direction = dirZ; + } + } + + // Based on the wall hit, adjust the current coords + switch (Direction) + { + case dirX: m_CurrentX += m_DirX; break; + case dirY: m_CurrentY += m_DirY; break; + case dirZ: m_CurrentZ += m_DirZ; break; + case dirNONE: return false; + } + return true; +} + + + + + +bool cLineBlockTracer::Item(cChunk * a_Chunk) +{ + ASSERT((m_CurrentY >= 0) && (m_CurrentY < cChunkDef::Height)); // This should be provided by FixStartAboveWorld() / FixStartBelowWorld() + + // This is the actual line tracing loop. + bool Finished = false; + while (true) + { + // Report the current block through the callbacks: + if (a_Chunk == NULL) + { + m_Callbacks->OnNoChunk(); + return false; + } + if (a_Chunk->IsValid()) + { + BLOCKTYPE BlockType; + NIBBLETYPE BlockMeta; + int RelX = FAST_FLOOR_DIV(m_CurrentX, cChunkDef::Width); + int RelZ = FAST_FLOOR_DIV(m_CurrentZ, cChunkDef::Width); + a_Chunk->GetBlockTypeMeta(RelX, m_CurrentY, RelZ, BlockType, BlockMeta); + if (m_Callbacks->OnNextBlock(m_CurrentX, m_CurrentY, m_CurrentZ, BlockType, BlockMeta)) + { + // The callback terminated the trace + return false; + } + } + else + { + if (m_Callbacks->OnNextBlockNoData(m_CurrentX, m_CurrentY, m_CurrentZ)) + { + // The callback terminated the trace + return false; + } + } + + // Move to next block + if (!MoveToNextBlock()) + { + // We've reached the end + m_Callbacks->OnNoMoreHits(); + return true; + } + + // Update the current chunk + if (a_Chunk != NULL) + { + a_Chunk = a_Chunk->GetNeighborChunk(m_CurrentX, m_CurrentZ); + } + + if ((m_CurrentY < 0) || (m_CurrentY >= cChunkDef::Height)) + { + // We've gone out of the world, that's the end of this trace + double IntersectX, IntersectZ; + CalcXZIntersection(m_CurrentY, IntersectX, IntersectZ); + if (m_Callbacks->OnOutOfWorld(IntersectX, m_CurrentY, IntersectZ)) + { + // The callback terminated the trace + return false; + } + m_Callbacks->OnNoMoreHits(); + return true; + } + } +} + + + + -- cgit v1.2.3