Ravines.cpp

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// Ravines.cpp
 
// Implements the cStructGenRavines class representing the ravine structure generator
 
#include "Globals.h"
#include "Ravines.h"
 
 
 
 
static const int NUM_RAVINE_POINTS = 4;
 
 
 
 
 
struct cRavDefPoint
{
    int m_BlockX;
    int m_BlockZ;
    int m_Radius;
    int m_Top;
    int m_Bottom;
 
    cRavDefPoint(int a_BlockX, int a_BlockZ, int a_Radius, int a_Top, int a_Bottom) :
        m_BlockX(a_BlockX),
        m_BlockZ(a_BlockZ),
        m_Radius(a_Radius),
        m_Top   (a_Top),
        m_Bottom(a_Bottom)
    {
    }
} ;
 
using cRavDefPoints = std::vector<cRavDefPoint>;
 
 
 
 
 
class cStructGenRavines::cRavine:
    public cGridStructGen::cStructure
{
    using Super = cGridStructGen::cStructure;
 
    cRavDefPoints m_Points;
 
 
    void GenerateBaseDefPoints(int a_BlockX, int a_BlockZ, int a_Size, cNoise & a_Noise);
 
    void RefineDefPoints(const cRavDefPoints & a_Src, cRavDefPoints & a_Dst);
 
    void Smooth(void);
 
    void FinishLinear(void);
 
public:
 
    cRavine(int a_GridX, int a_GridZ, int a_OriginX, int a_OriginZ, int a_Size, cNoise & a_Noise);
 
    #ifndef NDEBUG
    AString ExportAsSVG(int a_Color, int a_OffsetX = 0, int a_OffsetZ = 0) const;
    #endif  // !NDEBUG
 
protected:
    // cGridStructGen::cStructure overrides:
    virtual void DrawIntoChunk(cChunkDesc & a_ChunkDesc) override;
} ;
 
 
 
 
 
// cStructGenRavines:
 
cStructGenRavines::cStructGenRavines(int a_Seed, int a_Size) :
    Super(a_Seed, a_Size, a_Size, a_Size, a_Size, a_Size * 2, a_Size * 2, 100),
    m_Size(a_Size)
{
}
 
 
 
 
 
cGridStructGen::cStructurePtr cStructGenRavines::CreateStructure(int a_GridX, int a_GridZ, int a_OriginX, int a_OriginZ)
{
    return cStructurePtr(new cRavine(a_GridX, a_GridZ, a_OriginX, a_OriginZ, m_Size, m_Noise));
}
 
 
 
 
 
// cStructGenRavines::cRavine
 
cStructGenRavines::cRavine::cRavine(int a_GridX, int a_GridZ, int a_OriginX, int a_OriginZ, int a_Size, cNoise & a_Noise) :
    Super(a_GridX, a_GridZ, a_OriginX, a_OriginZ)
{
    // Calculate the ravine shape-defining points:
    GenerateBaseDefPoints(a_OriginX, a_OriginZ, a_Size, a_Noise);
 
    // Smooth the ravine. Two passes are needed:
    Smooth();
    Smooth();
 
    // Linearly interpolate the neighbors so that they're close enough together:
    FinishLinear();
}
 
 
 
 
 
void cStructGenRavines::cRavine::GenerateBaseDefPoints(int a_BlockX, int a_BlockZ, int a_Size, cNoise & a_Noise)
{
    // Modify the size slightly to have different-sized ravines (1 / 2 to 1 / 1 of a_Size):
    a_Size = (512 + ((a_Noise.IntNoise3DInt(19 * a_BlockX, 11 * a_BlockZ, a_BlockX + a_BlockZ) / 17) % 512)) * a_Size / 1024;
 
    // The complete offset of the ravine from its cellpoint, up to 2 * a_Size in each direction
    int OffsetX = (((a_Noise.IntNoise3DInt(50 * a_BlockX, 30 * a_BlockZ, 0)    / 9) % (2 * a_Size)) + ((a_Noise.IntNoise3DInt(30 * a_BlockX, 50 * a_BlockZ, 1000) / 7) % (2 * a_Size)) - 2 * a_Size) / 2;
    int OffsetZ = (((a_Noise.IntNoise3DInt(50 * a_BlockX, 30 * a_BlockZ, 2000) / 7) % (2 * a_Size)) + ((a_Noise.IntNoise3DInt(30 * a_BlockX, 50 * a_BlockZ, 3000) / 9) % (2 * a_Size)) - 2 * a_Size) / 2;
    int CenterX = a_BlockX + OffsetX;
    int CenterZ = a_BlockZ + OffsetZ;
 
    // Get the base angle in which the ravine "axis" goes:
    float Angle = static_cast<float>((static_cast<float>((a_Noise.IntNoise3DInt(20 * a_BlockX, 70 * a_BlockZ, 6000) / 9) % 16384)) / 16384.0 * M_PI);
    float xc = sinf(Angle);
    float zc = cosf(Angle);
 
    // Calculate the definition points and radii:
    int MaxRadius = static_cast<int>(sqrt(12.0 + ((a_Noise.IntNoise2DInt(61 * a_BlockX, 97 * a_BlockZ) / 13) % a_Size) / 16));
    int Top       = 32 + ((a_Noise.IntNoise2DInt(13 * a_BlockX, 17 * a_BlockZ) / 23) % 32);
    int Bottom    = 5 + ((a_Noise.IntNoise2DInt(17 * a_BlockX, 29 * a_BlockZ) / 13) % 32);
    int Mid = (Top + Bottom) / 2;
    int DefinitionPointX = CenterX - static_cast<int>(xc * a_Size / 2);
    int DefinitionPointZ = CenterZ - static_cast<int>(zc * a_Size / 2);
    m_Points.emplace_back(DefinitionPointX, DefinitionPointZ, 0, (Mid + Top) / 2, (Mid + Bottom) / 2);
    for (int i = 1; i < NUM_RAVINE_POINTS - 1; i++)
    {
        int LineX = CenterX + static_cast<int>(xc * a_Size * (i - NUM_RAVINE_POINTS / 2) / NUM_RAVINE_POINTS);
        int LineZ = CenterZ + static_cast<int>(zc * a_Size * (i - NUM_RAVINE_POINTS / 2) / NUM_RAVINE_POINTS);
        // Amplitude is the amount of blocks that this point is away from the ravine "axis"
        int Amplitude = (a_Noise.IntNoise3DInt(70 * a_BlockX, 20 * a_BlockZ + 31 * i, 10000 * i) / 9) % a_Size;
        Amplitude = Amplitude / 4 - a_Size / 8;  // Amplitude is in interval [-a_Size / 4, a_Size / 4]
        int PointX = LineX + static_cast<int>(zc * Amplitude);
        int PointZ = LineZ - static_cast<int>(xc * Amplitude);
        int Radius = MaxRadius - abs(i - NUM_RAVINE_POINTS / 2);  // TODO: better radius function
        int ThisTop    = Top    + ((a_Noise.IntNoise3DInt(7 *  a_BlockX, 19 * a_BlockZ, i * 31) / 13) % 8) - 4;
        int ThisBottom = Bottom + ((a_Noise.IntNoise3DInt(19 * a_BlockX, 7 *  a_BlockZ, i * 31) / 13) % 8) - 4;
        m_Points.emplace_back(PointX, PointZ, Radius, ThisTop, ThisBottom);
    }  // for i - m_Points[]
    DefinitionPointX = CenterX + static_cast<int>(xc * a_Size / 2);
    DefinitionPointZ = CenterZ + static_cast<int>(zc * a_Size / 2);
    m_Points.emplace_back(DefinitionPointX, DefinitionPointZ, 0, Mid, Mid);
}
 
 
 
 
 
void cStructGenRavines::cRavine::RefineDefPoints(const cRavDefPoints & a_Src, cRavDefPoints & a_Dst)
{
    if (a_Src.size() < 2)
    {
        // No midpoints, nothing to refine
        return;
    }
 
    // Smoothing: for each line segment, add points on its 1 / 4 lengths
    size_t Num = a_Src.size() - 2;  // this many intermediary points
    a_Dst.clear();
    a_Dst.reserve(Num * 2 + 2);
    cRavDefPoints::const_iterator itr = a_Src.begin() + 1;
    const cRavDefPoint & Source = a_Src.front();
    a_Dst.push_back(Source);
    int PrevX = Source.m_BlockX;
    int PrevZ = Source.m_BlockZ;
    int PrevR = Source.m_Radius;
    int PrevT = Source.m_Top;
    int PrevB = Source.m_Bottom;
    for (size_t i = 0; i <= Num; ++i, ++itr)
    {
        int dx = itr->m_BlockX - PrevX;
        int dz = itr->m_BlockZ - PrevZ;
        if (abs(dx) + abs(dz) < 4)
        {
            // Too short a segment to smooth-subdivide into quarters
            continue;
        }
        int dr = itr->m_Radius - PrevR;
        int dt = itr->m_Top    - PrevT;
        int db = itr->m_Bottom - PrevB;
        int Rad1 = std::max(PrevR + 1 * dr / 4, 1);
        int Rad2 = std::max(PrevR + 3 * dr / 4, 1);
        a_Dst.emplace_back(PrevX + 1 * dx / 4, PrevZ + 1 * dz / 4, Rad1, PrevT + 1 * dt / 4, PrevB + 1 * db / 4);
        a_Dst.emplace_back(PrevX + 3 * dx / 4, PrevZ + 3 * dz / 4, Rad2, PrevT + 3 * dt / 4, PrevB + 3 * db / 4);
        PrevX = itr->m_BlockX;
        PrevZ = itr->m_BlockZ;
        PrevR = itr->m_Radius;
        PrevT = itr->m_Top;
        PrevB = itr->m_Bottom;
    }
    a_Dst.push_back(a_Src.back());
}
 
 
 
 
 
void cStructGenRavines::cRavine::Smooth(void)
{
    cRavDefPoints Pts;
    RefineDefPoints(m_Points, Pts);  // Refine m_Points -> Pts
    RefineDefPoints(Pts, m_Points);  // Refine Pts -> m_Points
}
 
 
 
 
 
void cStructGenRavines::cRavine::FinishLinear(void)
{
    // For each segment, use Bresenham's line algorithm to draw a "line" of defpoints
    // _X 2012_07_20: I tried modifying this algorithm to produce "thick" lines (only one coord change per point)
    //   But the results were about the same as the original, so I disposed of it again - no need to use twice the count of points
 
    cRavDefPoints Pts;
    std::swap(Pts, m_Points);
 
    m_Points.reserve(Pts.size() * 3);
    int PrevX = Pts.front().m_BlockX;
    int PrevZ = Pts.front().m_BlockZ;
    for (cRavDefPoints::const_iterator itr = Pts.begin() + 1, end = Pts.end(); itr != end; ++itr)
    {
        int x1 = itr->m_BlockX;
        int z1 = itr->m_BlockZ;
        int dx = abs(x1 - PrevX);
        int dz = abs(z1 - PrevZ);
        int sx = (PrevX < x1) ? 1 : -1;
        int sz = (PrevZ < z1) ? 1 : -1;
        int err = dx - dz;
        int R = itr->m_Radius;
        int T = itr->m_Top;
        int B = itr->m_Bottom;
        for (;;)
        {
            m_Points.emplace_back(PrevX, PrevZ, R, T, B);
            if ((PrevX == x1) && (PrevZ == z1))
            {
                break;
            }
            int e2 = 2 * err;
            if (e2 > -dz)
            {
                err -= dz;
                PrevX += sx;
            }
            if (e2 < dx)
            {
                err += dx;
                PrevZ += sz;
            }
        }  // while (true)
    }  // for itr
}
 
 
 
 
 
#ifndef NDEBUG
AString cStructGenRavines::cRavine::ExportAsSVG(int a_Color, int a_OffsetX, int a_OffsetZ) const
{
    auto SVG = fmt::format(FMT_STRING("<path style=\"fill:none;stroke:#{:06x};stroke-width:1px;\"\nd=\""), a_Color);
    char Prefix = 'M';  // The first point needs "M" prefix, all the others need "L"
    for (cRavDefPoints::const_iterator itr = m_Points.begin(); itr != m_Points.end(); ++itr)
    {
        SVG.append(fmt::format(FMT_STRING("{} {}, {} "), Prefix, a_OffsetX + itr->m_BlockX, a_OffsetZ + itr->m_BlockZ));
        Prefix = 'L';
    }
    SVG.append("\"/>\n");
 
    // Base point highlight:
    SVG.append(fmt::format(FMT_STRING("<path style=\"fill:none;stroke:#ff0000;stroke-width:1px;\"\nd=\"M {}, {} L {}, {}\"/>\n"),
        a_OffsetX + m_OriginX - 5, a_OffsetZ + m_OriginZ, a_OffsetX + m_OriginX + 5, a_OffsetZ + m_OriginZ
    ));
    SVG.append(fmt::format(FMT_STRING("<path style=\"fill:none;stroke:#ff0000;stroke-width:1px;\"\nd=\"M {}, {} L {}, {}\"/>\n"),
        a_OffsetX + m_OriginX, a_OffsetZ + m_OriginZ - 5, a_OffsetX + m_OriginX, a_OffsetZ + m_OriginZ + 5
    ));
 
    // A gray line from the base point to the first point of the ravine, for identification:
    SVG.append(fmt::format(FMT_STRING("<path style=\"fill:none;stroke:#cfcfcf;stroke-width:1px;\"\nd=\"M {}, {} L {}, {}\"/>\n"),
        a_OffsetX + m_OriginX, a_OffsetZ + m_OriginZ, a_OffsetX + m_Points.front().m_BlockX, a_OffsetZ + m_Points.front().m_BlockZ
    ));
 
    // Offset guides:
    if (a_OffsetX > 0)
    {
        SVG.append(fmt::format(FMT_STRING("<path style=\"fill:none;stroke:#0000ff;stroke-width:1px;\"\nd=\"M {}, 0 L {}, 1024\"/>\n"),
            a_OffsetX, a_OffsetX
        ));
    }
    if (a_OffsetZ > 0)
    {
        SVG.append(fmt::format(FMT_STRING("<path style=\"fill:none;stroke:#0000ff;stroke-width:1px;\"\nd=\"M 0, {} L 1024, {}\"/>\n"),
            a_OffsetZ, a_OffsetZ
        ));
    }
    return SVG;
}
#endif  // !NDEBUG
 
 
 
 
 
void cStructGenRavines::cRavine::DrawIntoChunk(cChunkDesc & a_ChunkDesc)
{
    int BlockStartX = a_ChunkDesc.GetChunkX() * cChunkDef::Width;
    int BlockStartZ = a_ChunkDesc.GetChunkZ() * cChunkDef::Width;
    int BlockEndX = BlockStartX + cChunkDef::Width;
    int BlockEndZ = BlockStartZ + cChunkDef::Width;
    for (cRavDefPoints::const_iterator itr = m_Points.begin(), end = m_Points.end(); itr != end; ++itr)
    {
        if (
            (itr->m_BlockX + itr->m_Radius < BlockStartX) ||
            (itr->m_BlockX - itr->m_Radius > BlockEndX) ||
            (itr->m_BlockZ + itr->m_Radius < BlockStartZ) ||
            (itr->m_BlockZ - itr->m_Radius > BlockEndZ)
        )
        {
            // Cannot intersect, bail out early
            continue;
        }
 
        // Carve out a cylinder around the xz point, m_Radius in diameter, from Bottom to Top:
        int RadiusSq = itr->m_Radius * itr->m_Radius;  // instead of doing sqrt for each distance, we do sqr of the radius
        int DifX = BlockStartX - itr->m_BlockX;  // substitution for faster calc
        int DifZ = BlockStartZ - itr->m_BlockZ;  // substitution for faster calc
        for (int x = 0; x < cChunkDef::Width; x++) for (int z = 0; z < cChunkDef::Width; z++)
        {
            #ifndef NDEBUG
            // DEBUG: Make the ravine shapepoints visible on a single layer (so that we can see with Minutor what's going on)
            if ((DifX + x == 0) && (DifZ + z == 0))
            {
                a_ChunkDesc.SetBlockType(x, 4, z, E_BLOCK_LAPIS_ORE);
            }
            #endif  // !NDEBUG
 
            int DistSq = (DifX + x) * (DifX + x) + (DifZ + z) * (DifZ + z);
            if (DistSq <= RadiusSq)
            {
                int Top = std::min(itr->m_Top, static_cast<int>(cChunkDef::Height));  // Stupid gcc needs int cast
                for (int y = std::max(itr->m_Bottom, 1); y <= Top; y++)
                {
                    switch (a_ChunkDesc.GetBlockType(x, y, z))
                    {
                        // Only carve out these specific block types
                        case E_BLOCK_DIRT:
                        case E_BLOCK_GRASS:
                        case E_BLOCK_STONE:
                        case E_BLOCK_COBBLESTONE:
                        case E_BLOCK_GRAVEL:
                        case E_BLOCK_SAND:
                        case E_BLOCK_SANDSTONE:
                        case E_BLOCK_NETHERRACK:
                        case E_BLOCK_COAL_ORE:
                        case E_BLOCK_IRON_ORE:
                        case E_BLOCK_GOLD_ORE:
                        case E_BLOCK_DIAMOND_ORE:
                        case E_BLOCK_REDSTONE_ORE:
                        case E_BLOCK_REDSTONE_ORE_GLOWING:
                        {
                            a_ChunkDesc.SetBlockType(x, y, z, E_BLOCK_AIR);
                            break;
                        }
                        default: break;
                    }
                }
            }
        }  // for x, z - a_BlockTypes
    }  // for itr - m_Points[]
}