FloodyFluidSimulator.cpp

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// FloodyFluidSimulator.cpp

// Interfaces to the cFloodyFluidSimulator that represents a fluid simulator that tries to flood everything :)
// https://forum.cuberite.org/thread-565.html

#include "Globals.h"

#include "FloodyFluidSimulator.h"
#include "../World.h"
#include "../Chunk.h"
#include "../BlockArea.h"
#include "../Blocks/BlockHandler.h"
#include "../BlockInServerPluginInterface.h"
#include "../Blocks/ChunkInterface.h"





// Enable or disable detailed logging
#if 0
    #define FLUID_FLOG FLOGD
#else
    #define FLUID_FLOG(...)
#endif





cFloodyFluidSimulator::cFloodyFluidSimulator(
    cWorld & a_World,
    BLOCKTYPE a_Fluid,
    BLOCKTYPE a_StationaryFluid,
    NIBBLETYPE a_Falloff,
    int a_TickDelay,
    int a_NumNeighborsForSource
) :
    super(a_World, a_Fluid, a_StationaryFluid, a_TickDelay),
    m_Falloff(a_Falloff),
    m_NumNeighborsForSource(a_NumNeighborsForSource)
{
}





void cFloodyFluidSimulator::SimulateBlock(cChunk * a_Chunk, int a_RelX, int a_RelY, int a_RelZ)
{
    FLUID_FLOG("Simulating block {0}: block {1}, meta {2}",
        a_Chunk->PositionToWorldPosition(a_RelX, a_RelY, a_RelZ),
        a_Chunk->GetBlock(a_RelX, a_RelY, a_RelZ),
        a_Chunk->GetMeta(a_RelX, a_RelY, a_RelZ)
    );

    BLOCKTYPE MyBlock; NIBBLETYPE MyMeta;
    a_Chunk->GetBlockTypeMeta(a_RelX, a_RelY, a_RelZ, MyBlock, MyMeta);

    if (!IsAnyFluidBlock(MyBlock))
    {
        // Can happen - if a block is scheduled for simulating and gets replaced in the meantime.
        FLUID_FLOG("  BadBlockType exit");
        return;
    }

    // When in contact with water, lava should harden
    if (HardenBlock(a_Chunk, {a_RelX, a_RelY, a_RelZ}, MyBlock, MyMeta))
    {
        // Block was changed, bail out
        return;
    }

    if (MyMeta != 0)
    {
        // Source blocks aren't checked for tributaries, others are.
        if (CheckTributaries(a_Chunk, a_RelX, a_RelY, a_RelZ, MyMeta))
        {
            // Has no tributary, has been decreased (in CheckTributaries()),
            // no more processing needed (neighbors have been scheduled by the decrease)
            FLUID_FLOG("  CheckTributaries exit");
            return;
        }
    }

    // New meta for the spreading to neighbors:
    // If this is a source block or was falling, the new meta is just the falloff
    // Otherwise it is the current meta plus falloff (may be larger than max height, will be checked later)
    NIBBLETYPE NewMeta = ((MyMeta == 0) || ((MyMeta & 0x08) != 0)) ? m_Falloff : (MyMeta + m_Falloff);
    if (a_RelY > 0)
    {
        bool SpreadFurther = true;
        BLOCKTYPE Below = a_Chunk->GetBlock(a_RelX, a_RelY - 1, a_RelZ);
        if (IsPassableForFluid(Below) || IsBlockLava(Below) || IsBlockWater(Below))
        {
            // Spread only down, possibly washing away what's there or turning lava to stone / cobble / obsidian:
            SpreadToNeighbor(a_Chunk, a_RelX, a_RelY - 1, a_RelZ, 8);

            // Source blocks spread both downwards and sideways
            if (MyMeta != 0)
            {
                SpreadFurther = false;
            }
        }
        // Spread to the neighbors:
        if (SpreadFurther && (NewMeta < 8))
        {
            SpreadXZ(a_Chunk, a_RelX, a_RelY, a_RelZ, NewMeta);
        }

        // If source creation is on, check for it here:
        if (
            (m_NumNeighborsForSource > 0) &&    // Source creation is on
            (MyMeta == m_Falloff) &&            // Only exactly one block away from a source (fast bail-out)
            (
                !IsPassableForFluid(Below) ||  // Only exactly 1 block deep
                (Below == m_StationaryFluidBlock)  // Or a source block underneath
            ) &&
            CheckNeighborsForSource(a_Chunk, a_RelX, a_RelY, a_RelZ)  // Did we create a source?
        )
        {
            // We created a source, no more spreading is to be done now
            // Also has been re-scheduled for ticking in the next wave, so no marking is needed
            return;
        }
    }

    // Mark as processed:
    a_Chunk->FastSetBlock(a_RelX, a_RelY, a_RelZ, m_StationaryFluidBlock, MyMeta);
}





void cFloodyFluidSimulator::SpreadXZ(cChunk * a_Chunk, int a_RelX, int a_RelY, int a_RelZ, NIBBLETYPE a_NewMeta)
{
    SpreadToNeighbor(a_Chunk, a_RelX - 1, a_RelY, a_RelZ,     a_NewMeta);
    SpreadToNeighbor(a_Chunk, a_RelX + 1, a_RelY, a_RelZ,     a_NewMeta);
    SpreadToNeighbor(a_Chunk, a_RelX,     a_RelY, a_RelZ - 1, a_NewMeta);
    SpreadToNeighbor(a_Chunk, a_RelX,     a_RelY, a_RelZ + 1, a_NewMeta);
}





bool cFloodyFluidSimulator::CheckTributaries(cChunk * a_Chunk, int a_RelX, int a_RelY, int a_RelZ, NIBBLETYPE a_MyMeta)
{
    // If we have a section above, check if there's fluid above this block that would feed it:
    if (a_RelY < cChunkDef::Height - 1)
    {
        if (IsAnyFluidBlock(a_Chunk->GetBlock(a_RelX, a_RelY + 1, a_RelZ)))
        {
            // This block is fed from above, no more processing needed
            FLUID_FLOG("  Fed from above");
            return false;
        }
    }

    // Not fed from above, check if there's a feed from the side (but not if it's a downward-flowing block):
    if (a_MyMeta != 8)
    {
        BLOCKTYPE BlockType;
        NIBBLETYPE BlockMeta;
        static const Vector3i Coords[] =
        {
            Vector3i( 1, 0,  0),
            Vector3i(-1, 0,  0),
            Vector3i( 0, 0,  1),
            Vector3i( 0, 0, -1),
        } ;
        for (size_t i = 0; i < ARRAYCOUNT(Coords); i++)
        {
            if (!a_Chunk->UnboundedRelGetBlock(a_RelX + Coords[i].x, a_RelY, a_RelZ + Coords[i].z, BlockType, BlockMeta))
            {
                continue;
            }
            if (IsAllowedBlock(BlockType) && IsHigherMeta(BlockMeta, a_MyMeta))
            {
                // This block is fed, no more processing needed
                FLUID_FLOG("  Fed from {0}, type {1}, meta {2}",
                    a_Chunk->PositionToWorldPosition(a_RelX+ Coords[i].x, a_RelY, a_RelZ + Coords[i].z),
                    BlockType, BlockMeta
                );
                return false;
            }
        }  // for i - Coords[]
    }  // if not fed from above

    // Block is not fed, decrease by m_Falloff levels:
    if (a_MyMeta >= 8)
    {
        FLUID_FLOG("  Not fed and downwards, turning into non-downwards meta {0}", m_Falloff);
        a_Chunk->SetBlock({a_RelX, a_RelY, a_RelZ}, m_StationaryFluidBlock, m_Falloff);
    }
    else
    {
        a_MyMeta += m_Falloff;
        if (a_MyMeta < 8)
        {
            FLUID_FLOG("  Not fed, decreasing from {0} to {1}", a_MyMeta - m_Falloff, a_MyMeta);
            a_Chunk->SetBlock({a_RelX, a_RelY, a_RelZ}, m_StationaryFluidBlock, a_MyMeta);
        }
        else
        {
            FLUID_FLOG("  Not fed, meta {0}, erasing altogether", a_MyMeta);
            a_Chunk->SetBlock({a_RelX, a_RelY, a_RelZ}, E_BLOCK_AIR, 0);
        }
    }
    return true;
}





void cFloodyFluidSimulator::SpreadToNeighbor(cChunk * a_NearChunk, int a_RelX, int a_RelY, int a_RelZ, NIBBLETYPE a_NewMeta)
{
    ASSERT(a_NewMeta <= 8);  // Invalid meta values
    ASSERT(a_NewMeta > 0);  // Source blocks aren't spread

    Vector3i relPos(a_RelX, a_RelY, a_RelZ);
    a_NearChunk = a_NearChunk->GetRelNeighborChunkAdjustCoords(relPos);
    if ((a_NearChunk == nullptr) || (!a_NearChunk->IsValid()))
    {
        // Chunk not available
        return;
    }

    const auto absPos = a_NearChunk->RelativeToAbsolute(relPos);
    BLOCKTYPE BlockType;
    NIBBLETYPE BlockMeta;
    a_NearChunk->GetBlockTypeMeta(relPos, BlockType, BlockMeta);

    if (IsAllowedBlock(BlockType))
    {
        if ((BlockMeta == a_NewMeta) || IsHigherMeta(BlockMeta, a_NewMeta))
        {
            // Don't spread there, there's already a higher or same level there
            return;
        }
    }

    // Check water - lava interaction:
    if (m_FluidBlock == E_BLOCK_LAVA)
    {
        if (IsBlockWater(BlockType))
        {
            // Lava flowing into water, change to stone / cobblestone based on direction:
            BLOCKTYPE NewBlock = (a_NewMeta == 8) ? E_BLOCK_STONE : E_BLOCK_COBBLESTONE;
            FLUID_FLOG("  Lava flowing into water, turning water at rel {0} into {1}",
                relPos, ItemTypeToString(NewBlock)
            );
            a_NearChunk->SetBlock(relPos, NewBlock, 0);

            m_World.BroadcastSoundEffect(
                "block.lava.extinguish",
                absPos,
                0.5f,
                1.5f
            );
            return;
        }
    }
    else if (m_FluidBlock == E_BLOCK_WATER)
    {
        if (IsBlockLava(BlockType))
        {
            // Water flowing into lava, change to cobblestone / obsidian based on dest block:
            BLOCKTYPE NewBlock = (BlockMeta == 0) ? E_BLOCK_OBSIDIAN : E_BLOCK_COBBLESTONE;
            FLUID_FLOG("  Water flowing into lava, turning lava at rel {0} into {1}",
                relPos, ItemTypeToString(NewBlock)
            );
            a_NearChunk->SetBlock(relPos, NewBlock, 0);

            m_World.BroadcastSoundEffect(
                "block.lava.extinguish",
                absPos,
                0.5f,
                1.5f
            );
            return;
        }
    }
    else
    {
        ASSERT(!"Unknown fluid!");
    }

    if (!IsPassableForFluid(BlockType))
    {
        // Can't spread there
        return;
    }

    // Wash away the block there, if possible:
    if (CanWashAway(BlockType))
    {
        cBlockHandler * Handler = BlockHandler(BlockType);
        if (Handler->DoesDropOnUnsuitable())
        {
            m_World.DropBlockAsPickups(absPos, nullptr, nullptr);
        }
    }  // if (CanWashAway)

    // Spread:
    FLUID_FLOG("  Spreading to {0} with meta {1}", absPos, a_NewMeta);
    a_NearChunk->SetBlock(relPos, m_FluidBlock, a_NewMeta);
    m_World.GetSimulatorManager()->WakeUp(absPos, a_NearChunk);

    HardenBlock(a_NearChunk, relPos, m_FluidBlock, a_NewMeta);
}





bool cFloodyFluidSimulator::CheckNeighborsForSource(cChunk * a_Chunk, int a_RelX, int a_RelY, int a_RelZ)
{
    FLUID_FLOG("  Checking neighbors for source creation");

    static const Vector3i NeighborCoords[] =
    {
        Vector3i(-1, 0,  0),
        Vector3i( 1, 0,  0),
        Vector3i( 0, 0, -1),
        Vector3i( 0, 0,  1),
    } ;

    int NumNeeded = m_NumNeighborsForSource;
    for (size_t i = 0; i < ARRAYCOUNT(NeighborCoords); i++)
    {
        int x = a_RelX + NeighborCoords[i].x;
        int y = a_RelY + NeighborCoords[i].y;
        int z = a_RelZ + NeighborCoords[i].z;
        BLOCKTYPE BlockType;
        NIBBLETYPE BlockMeta;
        if (!a_Chunk->UnboundedRelGetBlock(x, y, z, BlockType, BlockMeta))
        {
            // Neighbor not available, skip it
            continue;
        }
        // FLUID_FLOG("   Neighbor at {0}: {1}", Vector3i{x, y, z}, ItemToFullString(cItem(BlockType, 1, BlockMeta)));
        if ((BlockMeta == 0) && IsAnyFluidBlock(BlockType))
        {
            NumNeeded--;
            // FLUID_FLOG("    Found a neighbor source at {0}, NumNeeded := {1}", Vector3i{x, y, z}, NumNeeded);
            if (NumNeeded == 0)
            {
                // Found enough, turn into a source and bail out
                // FLUID_FLOG("    Found enough neighbor sources, turning into a source");
                a_Chunk->SetBlock({a_RelX, a_RelY, a_RelZ}, m_FluidBlock, 0);
                return true;
            }
        }
    }
    // FLUID_FLOG("    Not enough neighbors for turning into a source, NumNeeded = {0}", NumNeeded);
    return false;
}





bool cFloodyFluidSimulator::HardenBlock(cChunk * a_Chunk, Vector3i a_RelPos, BLOCKTYPE a_BlockType, NIBBLETYPE a_Meta)
{
    ASSERT(cChunkDef::IsValidRelPos(a_RelPos));

    // Only lava blocks can harden
    if (!IsBlockLava(a_BlockType))
    {
        return false;
    }

    bool ShouldHarden = false;

    BLOCKTYPE BlockType;
    NIBBLETYPE BlockMeta;
    static const Vector3i neighborOffsets[] =
    {
        Vector3i( 1, 0,  0),
        Vector3i(-1, 0,  0),
        Vector3i( 0, 0,  1),
        Vector3i( 0, 0, -1),
    };
    for (const auto & ofs: neighborOffsets)
    {
        if (!a_Chunk->UnboundedRelGetBlock(a_RelPos + ofs, BlockType, BlockMeta))
        {
            continue;
        }
        if (IsBlockWater(BlockType))
        {
            ShouldHarden = true;
        }
    }  // for i - Coords[]

    if (ShouldHarden)
    {
        if (a_Meta == 0)
        {
            // Source lava block
            a_Chunk->SetBlock(a_RelPos, E_BLOCK_OBSIDIAN, 0);
            return true;
        }
        // Ignore last lava level
        else if (a_Meta <= 4)
        {
            a_Chunk->SetBlock(a_RelPos, E_BLOCK_COBBLESTONE, 0);
            return true;
        }
    }

    return false;
}