Method DrawSetup

Source/Engine/Terrain/Terrain.cpp:556–615

}

bool Terrain::DrawSetup(RenderContext& renderContext)
{
    // Special drawing modes
    const DrawPass drawModes = DrawModes & renderContext.View.Pass;
    if (drawModes == DrawPass::GlobalSDF)
    {
        const float chunkScale = 0.25f / (TERRAIN_UNITS_PER_VERTEX * (float)_chunkSize); // Patch heightfield is divided into 4x4 chunks
        for (const TerrainPatch* patch : _patches)
        {
            if (!patch->Heightmap)
                continue;
            GPUTexture* heightfield = patch->Heightmap->GetTexture();
            float size = (float)heightfield->Width();
            Float4 localToUV;
            localToUV.X = localToUV.Y = chunkScale * (size - 1) / size; // Skip the last edge texel
            localToUV.Z = localToUV.W = 0.5f / size; // Include half-texel offset
            Transform patchTransform;
            patchTransform.Translation = patch->_offset + Vector3(0, patch->_yOffset, 0);
            patchTransform.Orientation = Quaternion::Identity;
            patchTransform.Scale = Float3(1.0f, patch->_yHeight, 1.0f);
            patchTransform = _transform.LocalToWorld(patchTransform);
            GlobalSignDistanceFieldPass::Instance()->RasterizeHeightfield(this, heightfield, patchTransform, patch->_bounds, localToUV);
        }
        return true;
    }
    if (drawModes == DrawPass::GlobalSurfaceAtlas)
    {
        for (TerrainPatch* patch : _patches)
        {
            if (!patch->Heightmap)
                continue;
            Matrix localToWorld, worldToLocal;
            BoundingSphere chunkSphere;
            BoundingBox localBounds;
            for (int32 chunkIndex = 0; chunkIndex < Terrain::ChunksCount; chunkIndex++)
            {
                TerrainChunk* chunk = &patch->Chunks[chunkIndex];
                chunk->GetTransform().GetWorld(localToWorld); // TODO: large-worlds
                Matrix::Invert(localToWorld, worldToLocal);
                BoundingBox::Transform(chunk->GetBounds(), worldToLocal, localBounds);
                BoundingSphere::FromBox(chunk->GetBounds(), chunkSphere);
                GlobalSurfaceAtlasPass::Instance()->RasterizeActor(this, chunk, chunkSphere, chunk->GetTransform(), localBounds, 1 << 2, false);
            }
        }
        return true;
    }

    // Reset cached LOD for chunks (prevent LOD transition from invisible chunks)
    for (int32 patchIndex = 0; patchIndex < _patches.Count(); patchIndex++)
    {
        const auto patch = _patches[patchIndex];
        for (int32 chunkIndex = 0; chunkIndex < Terrain::ChunksCount; chunkIndex++)
        {
            auto chunk = &patch->Chunks[chunkIndex];
            chunk->_cachedDrawLOD = 0;
        }
    }