voxelforge/tests/testNetherGen.cpp

#include "testHarness.h"
#include "vf/NetherGen.h"

#include <map>
#include <set>

using namespace vf;

namespace {

std::map<Block, int> censusColumn(const World& world, int columnX, int columnZ, int ceilingY) {
    std::map<Block, int> tally;
    int ox = columnX * chunkSize;
    int oz = columnZ * chunkSize;
    for (int gx = ox; gx < ox + chunkSize; ++gx)
        for (int gz = oz; gz < oz + chunkSize; ++gz)
            for (int gy = 0; gy < ceilingY; ++gy)
                ++tally[world.blockAt(gx, gy, gz)];
    return tally;
}

int countOf(const std::map<Block, int>& tally, Block block) {
    auto it = tally.find(block);
    return it == tally.end() ? 0 : it->second;
}

int findColumnWithBiome(const NetherGenerator& generator, NetherBiome biome, int& outColumnX,
                        int& outColumnZ) {
    for (int columnX = -40; columnX <= 40; ++columnX) {
        for (int columnZ = -40; columnZ <= 40; ++columnZ) {
            int probeX = columnX * chunkSize + 8;
            int probeZ = columnZ * chunkSize + 8;
            if (generator.biomeAt(probeX, probeZ) != biome) continue;
            outColumnX = columnX;
            outColumnZ = columnZ;
            return 1;
        }
    }
    return 0;
}

} // namespace

VF_TEST(netherChunkGenerationRepeatsExactlyOnTheSameSeed) {
    NetherGenerator generator;
    Chunk first, second;
    generator.generateChunk(first, {2, 3, -4});
    generator.generateChunk(second, {2, 3, -4});
    CHECK(first.raw() == second.raw());

    Chunk elsewhere;
    generator.generateChunk(elsewhere, {2, 3, 5});
    CHECK(first.raw() != elsewhere.raw());

    NetherGenerator::Params other;
    other.seed = 9001u;
    NetherGenerator reseeded(other);

    World original, alternative;
    generator.generateColumn(original, 2, -4);
    reseeded.generateColumn(alternative, 2, -4);

    int differingChunks = 0;
    for (const auto& entry : original.allChunks()) {
        const Chunk* twin = alternative.chunkAt(entry.first);
        if (!twin || twin->raw() != entry.second->raw()) ++differingChunks;
    }
    CHECK(differingChunks > 0);
}

VF_TEST(netherColumnIsByteIdenticalAcrossTwoRuns) {
    NetherGenerator generator;
    World first, second;
    generator.generateColumn(first, -3, 6);
    generator.generateColumn(second, -3, 6);

    CHECK_EQ(first.chunkCount(), second.chunkCount());
    CHECK_EQ(first.chunkCount(), static_cast<std::size_t>(generator.stackChunkCount()));

    int mismatches = 0;
    for (const auto& entry : first.allChunks()) {
        const Chunk* twin = second.chunkAt(entry.first);
        if (!twin || twin->raw() != entry.second->raw()) ++mismatches;
    }
    CHECK_EQ(mismatches, 0);
}

VF_TEST(netherGenerationStaysInsideTheColumnItWasAskedFor) {
    NetherGenerator generator;
    World world;
    generator.generateColumn(world, 5, 7);

    int strays = 0;
    for (const auto& entry : world.allChunks())
        if (entry.first.x != 5 || entry.first.z != 7) ++strays;
    CHECK_EQ(strays, 0);
}

VF_TEST(netherIsSealedByBedrockAtTheFloorAndTheRoof) {
    NetherGenerator generator;
    const NetherGenerator::Params& params = generator.settings();
    World world;
    generator.generateColumn(world, 0, 0);

    int floorGaps = 0;
    int roofGaps = 0;
    for (int gx = 0; gx < chunkSize; ++gx) {
        for (int gz = 0; gz < chunkSize; ++gz) {
            if (world.blockAt(gx, params.floorY, gz) != Block::Bedrock) ++floorGaps;
            if (world.blockAt(gx, params.ceilingY - 1, gz) != Block::Bedrock) ++roofGaps;
        }
    }
    CHECK_EQ(floorGaps, 0);
    CHECK_EQ(roofGaps, 0);

    // The bands just inside those layers are ragged, not uniformly bedrock.
    int raggedFloor = 0;
    for (int gx = 0; gx < chunkSize; ++gx)
        for (int gz = 0; gz < chunkSize; ++gz)
            if (generator.isBedrock(gx, params.floorY + 2, gz)) ++raggedFloor;
    CHECK(raggedFloor > 0);
    CHECK(raggedFloor < chunkSize * chunkSize);
    CHECK(!generator.isBedrock(0, 60, 0));
}

VF_TEST(netherCavernSitsBetweenTheFloorAndTheRoofMass) {
    NetherGenerator generator;
    const NetherGenerator::Params& params = generator.settings();

    int drownedColumns = 0;
    int dryColumns = 0;
    for (int gx = -400; gx <= 400; gx += 37) {
        for (int gz = -400; gz <= 400; gz += 37) {
            NetherColumn column = generator.columnAt(gx, gz);
            CHECK(column.floorHeight > params.floorY);
            CHECK(column.ceilingHeight < params.ceilingY - 1);
            CHECK(column.cavernHeight() >= 9);
            CHECK_EQ(column.lavaLevel, params.lavaLevel);
            if (column.drowned) ++drownedColumns;
            else ++dryColumns;
        }
    }
    CHECK(drownedColumns > 0);
    CHECK(dryColumns > 0);
}

VF_TEST(netherLavaSeaLeavesNoAirBelowItsSurface) {
    NetherGenerator generator;
    const NetherGenerator::Params& params = generator.settings();

    int airBelowLava = 0;
    int lavaSamples = 0;
    for (int gx = -120; gx <= 120; gx += 11) {
        for (int gz = -120; gz <= 120; gz += 11) {
            NetherColumn column = generator.columnAt(gx, gz);
            for (int gy = params.floorY + 1; gy <= params.lavaLevel; ++gy) {
                Block block = generator.blockAt(column, gx, gy, gz);
                if (block == Block::Air) ++airBelowLava;
                if (block == Block::Lava) ++lavaSamples;
            }
        }
    }
    CHECK_EQ(airBelowLava, 0);
    CHECK(lavaSamples > 0);
}