fix: standardize vertex attribute ordering

examples/game_of_life.ml

@@ -60,6 +60,7 @@ module Grid = struct
     t.cells <- new_cells
 
   let update_vm t vertex_mesh =
+    (* TODO: only add visible faces/vertices. *)
     let open Graphics in
     let data = ref [] in
     for x = 0 to t.dimension - 1 do
@@ -70,12 +71,11 @@ module Grid = struct
             let cube = Primitive.Cuboid.create () in
             let rec shift = function
               | [] -> []
-              | nx :: ny :: nz :: px :: py :: pz :: rest ->
-                  nx :: ny :: nz
-                  :: (px +. float_of_int x -. (float_of_int t.dimension /. 2.))
+              | px :: py :: pz :: nx :: ny :: nz :: rest ->
+                  (px +. float_of_int x -. (float_of_int t.dimension /. 2.))
                   :: (py +. float_of_int y -. (float_of_int t.dimension /. 2.))
                   :: (pz +. float_of_int z -. (float_of_int t.dimension /. 2.))
-                  :: shift rest
+                  :: nx :: ny :: nz :: shift rest
               | _ -> failwith "Invalid list"
             in
             data := shift cube @ !data
@@ -167,4 +167,3 @@ let () =
   in
 
   App.run app
-

lib/graphics/mesh3d.ml

@@ -51,8 +51,7 @@ let rec install t =
             let stride = Vertex_mesh.vertex_size mesh * size_of_float in
             let offset = ref 0 in
             Vertex_mesh.attributes mesh
-            |> Hashtbl.to_seq |> List.of_seq
-            |> List.sort (fun (index1, _) (index2, _) -> compare index2 index1)
+            |> Hashtbl.to_seq |> List.of_seq |> List.sort compare
             |> List.iter (fun (index, size) ->
                    Gl.enable_vertex_attrib_array index;
                    Gl.vertex_attrib_pointer index size Gl.float false stride

lib/graphics/primitive/cuboid.ml

@@ -3,20 +3,20 @@ open Util
 type config = { param1 : int; half_size : Math.Vec3.t; data : float list ref }
 
 let add_tile c topl topr botl botr =
-  let add v = add_vec3 c.data v in
-  add topl;
-  add Math.Vec3.(normalize (cross (botl - topl) (botr - topl)));
-  add botl;
-  add Math.Vec3.(normalize (cross (botr - botl) (topl - botl)));
-  add botr;
-  add Math.Vec3.(normalize (cross (topl - botr) (botl - botr)));
+  let prepend v = prepend_vec3 c.data v in
+  prepend Math.Vec3.(normalize (cross (botl - topl) (botr - topl)));
+  prepend topl;
+  prepend Math.Vec3.(normalize (cross (botr - botl) (topl - botl)));
+  prepend botl;
+  prepend Math.Vec3.(normalize (cross (topl - botr) (botl - botr)));
+  prepend botr;
 
-  add topl;
-  add Math.Vec3.(normalize (cross (botr - topl) (topr - topl)));
-  add botr;
-  add Math.Vec3.(normalize (cross (topr - botr) (topl - botr)));
-  add topr;
-  add Math.Vec3.(normalize (cross (topl - topr) (botr - topr)))
+  prepend Math.Vec3.(normalize (cross (botr - topl) (topr - topl)));
+  prepend topl;
+  prepend Math.Vec3.(normalize (cross (topr - botr) (topl - botr)));
+  prepend botr;
+  prepend Math.Vec3.(normalize (cross (topl - topr) (botr - topr)));
+  prepend topr
 
 let add_face c botl topl topr =
   let size = 1. /. float_of_int c.param1 in

lib/graphics/primitive/sphere.ml

@@ -8,17 +8,17 @@ type config = {
 }
 
 let add_tile c tl tr bl br =
-  let add v =
-    add_vec3 c.data v;
-    add_vec3 c.data (Math.Vec3.normalize v)
+  let prepend v =
+    prepend_vec3 c.data (Math.Vec3.normalize v);
+    prepend_vec3 c.data v
   in
-  add tl;
-  add bl;
-  add br;
+  prepend tl;
+  prepend bl;
+  prepend br;
 
-  add tl;
-  add br;
-  add tr
+  prepend tl;
+  prepend br;
+  prepend tr
 
 let add_wedge c theta theta' =
   let step = Float.pi /. float_of_int c.param1 in

lib/graphics/util.ml

@@ -55,6 +55,6 @@ let check_gl_error () =
   done;
   if !errored then failwith "shortcircuit in print_gl_error"
 
-let add_vec3 l v =
+let prepend_vec3 l v =
   let x, y, z = Math.Vec3.to_tuple v in
   l := x :: y :: z :: !l

lib/graphics/util.mli

@@ -23,4 +23,4 @@ val load_uniform1i : int -> int -> string -> unit
 val load_uniform1f : float -> int -> string -> unit
 val load_uniform3fv : Math.Vec3.t -> int -> string -> unit
 val check_gl_error : unit -> unit
-val add_vec3 : float list ref -> Math.Vec3.t -> unit
+val prepend_vec3 : float list ref -> Math.Vec3.t -> unit