CppEdition

CppEdition is a C++ library that mimics the biome and feature generation of Minecraft Java Edition.

This project is a clone of the following C library made by Cubitect : https://github.com/Cubitect/cubiomes. My goal was to convert it to a C++ lib in order to enhance my C++ skills and use it for future applications.

It's intended as a powerful tool to create custom seed-finding apps and large-scale map viewers with minimal memory usage.

Usage exemples (main.cpp)

-> Check the biome at a block position

#include "generator.h"
#include <cstdio>

int main()
{
    // Set up a biome generator that reflects the biome generation of
    // Minecraft 1.18.
    Generator g;
    setupGenerator(&g, MC_1_18, 0);

    // Seeds are internally represented as unsigned 64-bit integers.
    uint64_t seed;
    for (seed = 0; ; seed++)
    {
        // Apply the seed to the generator for the Overworld dimension.
        applySeed(&g, DIM_OVERWORLD, seed);

        // To get the biome at a single block position, we can use getBiomeAt().
        int scale = 1; // scale=1: block coordinates, scale=4: biome coordinates
        int x = 0, y = 63, z = 0;
        int biomeID = getBiomeAt(&g, scale, x, y, z);
        if (biomeID == mushroom_fields)
        {
            printf("Seed %" PRId64 " has a Mushroom Fields biome at block position (%d, %d).\n", (int64_t) seed, x, z);
            break;
        }
    }

    return 0;
}

-> Generate an image of the world

#include "generator.h"
#include "util.h"

int main()
{
    Generator g;
    setupGenerator(&g, MC_1_18, LARGE_BIOMES);

    uint64_t seed = 123LL;
    applySeed(&g, DIM_OVERWORLD, seed);

    Range r;
    // 1:16, a.k.a. horizontal chunk scaling
    r.scale = 16;
    // Define the position and size for a horizontal area:
    r.x = -60, r.z = -60;   // position (x,z)
    r.sx = 120, r.sz = 120; // size (width,height)
    // Set the vertical range as a plane near sea level at scale 1:4.
    r.y = 15, r.sy = 1;

    // Allocate the necessary cache for this range.
    int *biomeIds = allocCache(&g, r);

    // Generate the area inside biomeIds, indexed as:
    // biomeIds[i_y*r.sx*r.sz + i_z*r.sx + i_x]
    // where (i_x, i_y, i_z) is a position relative to the range cuboid.
    genBiomes(&g, biomeIds, r);

    // Map the biomes to an image buffer, with 4 pixels per biome cell.
    int pix4cell = 4;
    int imgWidth = pix4cell*r.sx, imgHeight = pix4cell*r.sz;
    unsigned char biomeColors[256][3];
    initBiomeColors(biomeColors);
    unsigned char *rgb = (unsigned char *) std::malloc(3*imgWidth*imgHeight);
    biomesToImage(rgb, biomeColors, biomeIds, r.sx, r.sz, pix4cell, 2);

    // Save the RGB buffer to a PPM image file.
    savePPM("map.ppm", rgb, imgWidth, imgHeight);

    // Clean up.
    std::free(biomeIds);
    std::free(rgb);

    return 0;
}

-> Find a seed with a given structure at the origin chunk

#include "finders.h"
#include <cstdio>

int main()
{
    int structType = Outpost;
    int mc = MC_1_18;

    Generator g;
    setupGenerator(&g, mc, 0);

    uint64_t lower48;
    for (lower48 = 0; ; lower48++)
    {
        // The structure position depends only on the region coordinates and
        // the lower 48-bits of the world seed.
        Pos p;
        if (!getStructurePos(structType, mc, lower48, 0, 0, &p))
            continue;

        // Look for a seed with the structure at the origin chunk.
        if (p.x >= 16 || p.z >= 16)
            continue;

        // Look for a full 64-bit seed with viable biomes.
        uint64_t upper16;
        for (upper16 = 0; upper16 < 0x10000; upper16++)
        {
            uint64_t seed = lower48 | (upper16 << 48);
            applySeed(&g, DIM_OVERWORLD, seed);
            if (isViableStructurePos(structType, &g, p.x, p.z, 0))
            {
                printf("Seed %" PRId64 " has a Pillager Outpost at (%d, %d).\n",
                    (int64_t) seed, p.x, p.z);
                return 0;
            }
        }
    }
}