src/chunk: don't allocate empty ground/wall/scenery meshes

5 files changed, 26 insertions, 7 deletions

diff --git a/draw/ground.cpp b/draw/ground.cpp
index 515729b1..b049f96d 100644
--- a/draw/ground.cpp
+++ b/draw/ground.cpp
@@ -13,6 +13,8 @@ void ground_mesh::draw(tile_shader& shader, chunk& c)
 {
     constexpr int quad_index_count = 6;
     const auto [mesh_, ids, size] = c.ensure_ground_mesh();
+    if (size == 0)
+        return;
     struct {
         ground_atlas* atlas = nullptr; size_t pos = 0; } last;
     GL::MeshView mesh{mesh_};
diff --git a/draw/wall.cpp b/draw/wall.cpp
index 1c9c80cc..cbe90b23 100644
--- a/draw/wall.cpp
+++ b/draw/wall.cpp
@@ -16,6 +16,9 @@ wall_mesh::wall_mesh() = default;
 void wall_mesh::draw(tile_shader& shader, chunk& c)
 {
     const auto [mesh_, ids, size] = c.ensure_wall_mesh();
+    if (size == 0)
+        return;
+
     struct { wall_atlas* atlas = nullptr; size_t pos = 0; } last;
     GL::MeshView mesh{mesh_};
     [[maybe_unused]] size_t draw_count = 0;
diff --git a/src/chunk-render.cpp b/src/chunk-render.cpp
index 0cc88af2..0c5d5bc6 100644
--- a/src/chunk-render.cpp
+++ b/src/chunk-render.cpp
@@ -52,6 +52,12 @@ auto chunk::ensure_ground_mesh() noexcept -> ground_mesh_tuple
         if (_ground->atlases[i])
             _ground->indexes[count++] = uint8_t(i);
 
+    if (count == 0)
+    {
+        ground_mesh = GL::Mesh{NoCreate};
+        return { ground_mesh, {}, 0 };
+    }
+
     std::sort(_ground->indexes.begin(), _ground->indexes.begin() + count,
               [this](uint8_t a, uint8_t b) {
                   return _ground->atlases[a].get() < _ground->atlases[b].get();
diff --git a/src/chunk-scenery.cpp b/src/chunk-scenery.cpp
index 2e491d4d..4bf55312 100644
--- a/src/chunk-scenery.cpp
+++ b/src/chunk-scenery.cpp
@@ -177,13 +177,18 @@ auto chunk::ensure_scenery_mesh(scenery_scratch_buffers buffers) noexcept -> sce
             i++;
         }
 
-        GL::Mesh mesh{GL::MeshPrimitive::Triangles};
-        auto vert_view = ArrayView<const std::array<vertex, 4>>{scenery_vertexes, count};
-        auto index_view = ArrayView<const std::array<UnsignedShort, 6>>{scenery_indexes, count};
-        mesh.addVertexBuffer(GL::Buffer{vert_view}, 0, tile_shader::Position{}, tile_shader::TextureCoordinates{}, tile_shader::Depth{})
-            .setIndexBuffer(GL::Buffer{index_view}, 0, GL::MeshIndexType::UnsignedShort)
-            .setCount(int32_t(6 * count));
-        scenery_mesh = move(mesh);
+        if (count == 0)
+            scenery_mesh = GL::Mesh{NoCreate};
+        else
+        {
+            GL::Mesh mesh{GL::MeshPrimitive::Triangles};
+            auto vert_view = ArrayView<const std::array<vertex, 4>>{scenery_vertexes, count};
+            auto index_view = ArrayView<const std::array<UnsignedShort, 6>>{scenery_indexes, count};
+            mesh.addVertexBuffer(GL::Buffer{vert_view}, 0, tile_shader::Position{}, tile_shader::TextureCoordinates{}, tile_shader::Depth{})
+                .setIndexBuffer(GL::Buffer{index_view}, 0, GL::MeshIndexType::UnsignedShort)
+                .setCount(int32_t(6 * count));
+            scenery_mesh = move(mesh);
+        }
     }
 
     const auto size = _objects.size();
diff --git a/src/chunk-walls.cpp b/src/chunk-walls.cpp
index 9971bcde..efff51b8 100644
--- a/src/chunk-walls.cpp
+++ b/src/chunk-walls.cpp
@@ -323,6 +323,9 @@ GL::Mesh chunk::make_wall_mesh()
         }
     }
 
+    if (N == 0)
+        return GL::Mesh{NoCreate};
+
     ranges::sort(ranges::zip_view(vertexes.prefix(N),
                                   ArrayView{_walls->mesh_indexes.data(), N}),
                  [&A = _walls->atlases](const auto& a, const auto& b) {