make BlocksRenderer::createMesh return MeshData & make ChunksRenderer workers have standalone results

src/graphics/render/BlocksRenderer.cpp

@@ -531,7 +531,18 @@ void BlocksRenderer::build(const Chunk* chunk, const ChunksStorage* chunks) {
     render(voxels);
 }
 
-std::shared_ptr<Mesh> BlocksRenderer::createMesh() {
+MeshData BlocksRenderer::createMesh() {
+    const vattr attrs[]{ {3}, {2}, {1}, {0} };
+    return MeshData(
+        util::Buffer<float>(vertexBuffer.get(), vertexOffset), 
+        util::Buffer<int>(indexBuffer.get(), indexSize),
+        util::Buffer<vattr>({{3}, {2}, {1}, {0}})
+    );
+}
+
+std::shared_ptr<Mesh> BlocksRenderer::render(const Chunk* chunk, const ChunksStorage* chunks) {
+    build(chunk, chunks);
+
     const vattr attrs[]{ {3}, {2}, {1}, {0} };
     size_t vcount = vertexOffset / BlocksRenderer::VERTEX_SIZE;
     return std::make_shared<Mesh>(
@@ -539,11 +550,6 @@ std::shared_ptr<Mesh> BlocksRenderer::createMesh() {
     );
 }
 
-std::shared_ptr<Mesh> BlocksRenderer::render(const Chunk* chunk, const ChunksStorage* chunks) {
-    build(chunk, chunks);
-    return createMesh();
-}
-
 VoxelsVolume* BlocksRenderer::getVoxelsBuffer() const {
     return voxelsBuffer.get();
 }