initial sprite batch implementation & testbed

Sources/Voxelotl/Renderer/Metal/RendererDynamicMesh.swift

@@ -0,0 +1,70 @@
+import Metal
+
+public struct RendererDynamicMesh<VertexType: Vertex, IndexType: UnsignedInteger> {
+  private weak var _renderer: Renderer!
+  internal let _vertBufs: [MTLBuffer], _idxBufs: [MTLBuffer]
+  private var _numVertices: Int = 0, _numIndices: Int = 0
+
+  public let vertexCapacity: Int, indexCapacity: Int
+  public var vertexCount: Int { self._numVertices }
+  public var indexCount: Int { self._numIndices }
+
+  init(renderer: Renderer, _ vertBufs: [MTLBuffer], _ idxBufs: [MTLBuffer]) {
+    self._renderer = renderer
+    self._vertBufs = vertBufs
+    self._idxBufs = idxBufs
+    self.vertexCapacity = self._vertBufs.map { $0.length }.min()! / MemoryLayout<VertexType>.stride
+    self.indexCapacity = self._idxBufs.map { $0.length }.min()! / MemoryLayout<IndexType>.stride
+  }
+
+  public mutating func clear() {
+    self._numVertices = 0
+    self._numIndices = 0
+  }
+
+
+  public mutating func insert(vertices: [VertexType]) {
+    self.insert(vertices: vertices[...])
+  }
+
+  public mutating func insert(vertices: ArraySlice<VertexType>) {
+    assert(self._numVertices + vertices.count < self.vertexCapacity)
+
+    let vertexBuffer: MTLBuffer = self._vertBufs[self._renderer.currentFrame]
+    vertexBuffer.contents().withMemoryRebound(to: VertexType.self, capacity: self.vertexCapacity) { vertexData in
+      for i in 0..<vertices.count {
+        vertexData[self._numVertices + i] = vertices[i]
+      }
+    }
+
+#if os(macOS)
+    if self._renderer.isManagedStorage {
+      let stride = MemoryLayout<VertexType>.stride
+      vertexBuffer.didModifyRange(stride * self._numVertices..<stride * vertices.count)
+    }
+#endif
+
+    self._numVertices += vertices.count
+  }
+
+  public mutating func insert(indices: [IndexType], baseVertex: Int = 0) {
+    assert(self._numIndices + indices.count < self.indexCapacity)
+
+    let indexBuffer: MTLBuffer = self._idxBufs[self._renderer.currentFrame]
+    let base = IndexType(baseVertex)
+    indexBuffer.contents().withMemoryRebound(to: IndexType.self, capacity: self.indexCapacity) { indexData in
+      for i in 0..<indices.count {
+        indexData[self._numIndices + i] = base + indices[i]
+      }
+    }
+
+#if os(macOS)
+    if self._renderer.isManagedStorage {
+      let stride = MemoryLayout<VertexType>.stride
+      indexBuffer.didModifyRange(stride * self._numIndices..<stride * indices.count)
+    }
+#endif
+
+    self._numIndices += indices.count
+  }
+}