Method Draw

Source/Engine/Terrain/TerrainChunk.cpp:85–142

}

void TerrainChunk::Draw(const RenderContext& renderContext) const
{
    const int32 lod = _cachedDrawLOD;
    const int32 minLod = Math::Max(lod + 1, 0);
    const int32 chunkSize = _patch->_terrain->GetChunkSize();

    // Setup draw call
    DrawCall drawCall;
    if (TerrainManager::GetChunkGeometry(drawCall, chunkSize, lod))
        return;
    if (!_neighbors[0])
        const_cast<TerrainChunk*>(this)->CacheNeighbors();
    drawCall.InstanceCount = 1;
    drawCall.Material = _cachedDrawMaterial;
    renderContext.View.GetWorldMatrix(_transform, drawCall.World);
    drawCall.ObjectPosition = drawCall.World.GetTranslation();
    drawCall.ObjectRadius = (float)_sphere.Radius;
    drawCall.Terrain.Patch = _patch;
    drawCall.Terrain.HeightmapUVScaleBias = _heightmapUVScaleBias;
    drawCall.Terrain.OffsetUV = Vector2((float)(_patch->_x * Terrain::ChunksCountEdge + _x), (float)(_patch->_z * Terrain::ChunksCountEdge + _z));
    drawCall.Terrain.CurrentLOD = (float)lod;
    drawCall.Terrain.ChunkSizeNextLOD = (float)(((chunkSize + 1) >> (lod + 1)) - 1);
    drawCall.Terrain.TerrainChunkSizeLOD0 = TERRAIN_UNITS_PER_VERTEX * chunkSize;
    // TODO: try using SIMD clamping for 4 chunks at once
    drawCall.Terrain.NeighborLOD.X = (float)Math::Clamp<int32>(_neighbors[0]->_cachedDrawLOD, lod, minLod);
    drawCall.Terrain.NeighborLOD.Y = (float)Math::Clamp<int32>(_neighbors[1]->_cachedDrawLOD, lod, minLod);
    drawCall.Terrain.NeighborLOD.Z = (float)Math::Clamp<int32>(_neighbors[2]->_cachedDrawLOD, lod, minLod);
    drawCall.Terrain.NeighborLOD.W = (float)Math::Clamp<int32>(_neighbors[3]->_cachedDrawLOD, lod, minLod);
    const auto scene = _patch->_terrain->GetScene();
    const auto flags = _patch->_terrain->_staticFlags;
    if ((flags & StaticFlags::Lightmap) != StaticFlags::None && scene)
    {
        drawCall.Terrain.Lightmap = scene->LightmapsData.GetReadyLightmap(Lightmap.TextureIndex);
        drawCall.Terrain.LightmapUVsArea = Lightmap.UVsArea;
    }
    else
    {
        drawCall.Terrain.Lightmap = nullptr;
        drawCall.Terrain.LightmapUVsArea = Rectangle::Empty;
    }
    drawCall.PerInstanceRandom = _perInstanceRandom;
    drawCall.SetStencilValue(_patch->_terrain->GetLayer());
#if USE_EDITOR
    if (renderContext.View.Mode == ViewMode::LightmapUVsDensity)
        drawCall.Surface.LODDitherFactor = 1.0f; // See LightmapUVsDensityMaterialShader
#endif

    // Add half-texel offset for heightmap sampling in vertex shader
    //const float lodHeightmapSize = Math::Max(1, drawCall.TerrainData.Heightmap->Width() >> lod);
    //const float halfTexelOffset = 0.5f / lodHeightmapSize;
    //drawCall.TerrainData.HeightmapUVScaleBias.Z += halfTexelOffset;
    //drawCall.TerrainData.HeightmapUVScaleBias.W += halfTexelOffset;

    // Submit draw call
    const DrawPass drawModes = _patch->_terrain->DrawModes & renderContext.View.Pass & drawCall.Material->GetDrawModes();
    if (drawModes != DrawPass::None)
        renderContext.List->AddDrawCall(renderContext, drawModes, flags, drawCall, true);
}