Function CalculateHeightmapRange

Source/Engine/Terrain/TerrainPatch.cpp:273–317

}

void CalculateHeightmapRange(Terrain* terrain, TerrainDataUpdateInfo& info, const float* heightmap, float chunkOffsets[Terrain::ChunksCount], float chunkHeights[Terrain::ChunksCount])
{
    PROFILE_CPU_NAMED("Terrain.CalculateRange");

    // Note: terrain heightmap doesn't store raw height values but normalized into per-patch dimensions (height = normHeight * chunkPatch + patchOffset)

    float minPatchHeight = MAX_float;
    float maxPatchHeight = MIN_float;

    for (int32 chunkIndex = 0; chunkIndex < Terrain::ChunksCount; chunkIndex++)
    {
        const int32 chunkX = (chunkIndex % Terrain::ChunksCountEdge) * info.ChunkSize;
        const int32 chunkZ = (chunkIndex / Terrain::ChunksCountEdge) * info.ChunkSize;

        float minHeight = MAX_float;
        float maxHeight = MIN_float;

        for (int32 z = 0; z < info.VertexCountEdge; z++)
        {
            const int32 sz = (chunkZ + z) * info.HeightmapSize;
            for (int32 x = 0; x < info.VertexCountEdge; x++)
            {
                const int32 sx = chunkX + x;
                const float height = heightmap[sz + sx];

                minHeight = Math::Min(minHeight, height);
                maxHeight = Math::Max(maxHeight, height);
            }
        }

        chunkOffsets[chunkIndex] = minHeight;
        chunkHeights[chunkIndex] = Math::Max(maxHeight - minHeight, 1.0f);

        minPatchHeight = Math::Min(minPatchHeight, minHeight);
        maxPatchHeight = Math::Max(maxPatchHeight, maxHeight);
    }

    // Align the patch heightmap range error to reduce artifacts on patch edges (each patch has own height range)
    const double error = 1.0 / MAX_uint16;
    minPatchHeight = AlignHeight(minPatchHeight - error, error);
    maxPatchHeight = AlignHeight(maxPatchHeight + error, error);

    info.PatchOffset = minPatchHeight;
    info.PatchHeight = Math::Max(maxPatchHeight - minPatchHeight, 1.0f);
}

void UpdateHeightMap(const TerrainDataUpdateInfo& info, const float* heightmap, const Int2& modifiedOffset, const Int2& modifiedSize, const byte* data)
{