diff --git a/src/chunk.zig b/src/chunk.zig
index 14ac883f..ef814bc3 100644
--- a/src/chunk.zig
+++ b/src/chunk.zig
@@ -704,8 +704,8 @@ pub const meshing = struct {
 				}
 				offset += neighborLen;
 			}
-			const fullBuffer = try main.stackAllocator.alloc(FaceData, len);
-			defer main.stackAllocator.free(fullBuffer);
+			const fullBuffer = try faceBuffer.allocateAndMapRange(len, &self.bufferAllocation);
+			defer faceBuffer.unmapRange(fullBuffer);
 			@memcpy(fullBuffer[0..self.coreLen], self.completeList[0..self.coreLen]);
 			var i: usize = self.coreLen;
 			for(0..6) |n| {
@@ -713,7 +713,6 @@ pub const meshing = struct {
 				i += list[n].len;
 			}
 			self.vertexCount = @intCast(6*fullBuffer.len);
-			try faceBuffer.uploadData(fullBuffer, &self.bufferAllocation); // TODO: Avoid the extra copy by writing to the memory-mapped buffer directly.
 			self.wasChanged = true;
 		}
 
diff --git a/src/graphics.zig b/src/graphics.zig
index 73eda01c..c2b6d7c7 100644
--- a/src/graphics.zig
+++ b/src/graphics.zig
@@ -1323,6 +1323,27 @@ pub fn LargeBuffer(comptime Entry: type) type {
 			try self.fencedFreeLists[self.activeFence].append(allocation);
 		}
 
+		/// Must unmap after use!
+		pub fn allocateAndMapRange(self: *Self, len: usize, allocation: *SubAllocation) ![]Entry {
+			try self.free(allocation.*);
+			if(len == 0) {
+				allocation.len = 0;
+				return &.{};
+			}
+			allocation.* = try self.alloc(@intCast(len));
+			c.glBindBuffer(c.GL_SHADER_STORAGE_BUFFER, self.ssbo.bufferID);
+			const ptr: [*]Entry = @ptrCast(@alignCast(
+				c.glMapBufferRange(c.GL_SHADER_STORAGE_BUFFER, allocation.start*@sizeOf(Entry), allocation.len*@sizeOf(Entry), c.GL_MAP_WRITE_BIT | c.GL_MAP_INVALIDATE_RANGE_BIT)
+			));
+			return ptr[0..len];
+		}
+
+		pub fn unmapRange(self: *Self, range: []Entry) void {
+			if(range.len == 0) return;
+			c.glBindBuffer(c.GL_SHADER_STORAGE_BUFFER, self.ssbo.bufferID);
+			std.debug.assert(c.glUnmapBuffer(c.GL_SHADER_STORAGE_BUFFER) == c.GL_TRUE);
+		}
+
 		pub fn uploadData(self: *Self, data: []Entry, allocation: *SubAllocation) !void {
 			try self.free(allocation.*);
 			if(data.len == 0) {