Fix after hardware node coloring (#5114)

src/mapblock_mesh.cpp

@@ -1090,10 +1090,10 @@ MapBlockMesh::MapBlockMesh(MeshMakeData *data, v3s16 camera_offset):
 				brightness of vertices 1 and 3 differ less than
 				the brightness of vertices 0 and 2.
 			*/
-			if (abs(f.vertices[0].Color.getAverage()
-					- f.vertices[2].Color.getAverage())
-					> abs(f.vertices[1].Color.getAverage()
-					- f.vertices[3].Color.getAverage()))
+			if (abs(f.vertices[0].Color.getLuminance()
+					- f.vertices[2].Color.getLuminance())
+					> abs(f.vertices[1].Color.getLuminance()
+					- f.vertices[3].Color.getLuminance()))
 				indices_p = indices_alternate;
 
 			collector.append(f.tile, f.vertices, 4, indices_p, 6);

src/particles.h

@@ -32,8 +32,8 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 struct ClientEvent;
 class ParticleManager;
 class ClientEnvironment;
-class MapNode;
-class ContentFeatures;
+struct MapNode;
+struct ContentFeatures;
 
 class Particle : public scene::ISceneNode
 {