From 91322da5b1b940a7f6e620b388aec5d5d7a0e670 Mon Sep 17 00:00:00 2001
From: tali <iitalics@gmail.com>
Date: Mon, 15 Jan 2024 17:39:09 -0500
Subject: [PATCH] ECS WIP: transform tree

---
 src/adam/adam.ml |  2 +-
 src/dune         |  1 +
 src/main.ml      | 50 ++++++++++++++++++++++--
 src/n2/dune      |  7 ++++
 src/n2/n2.ml     | 98 ++++++++++++++++++++++++++++++++++++++++++++++++
 5 files changed, 153 insertions(+), 5 deletions(-)
 create mode 100644 src/n2/dune
 create mode 100644 src/n2/n2.ml

diff --git a/src/adam/adam.ml b/src/adam/adam.ml
index 0a8cb58..dd43851 100644
--- a/src/adam/adam.ml
+++ b/src/adam/adam.ml
@@ -109,7 +109,6 @@ module Mat2A = struct
       dst.a5 <- src.a5;
     end
 
-  (*
   let[@inline] mul (lhs : t) (rhs : t) : unit =
     let { a0; a1; a2; a3; a4; a5 } = lhs in
     begin
@@ -121,6 +120,7 @@ module Mat2A = struct
       lhs.a5 <- (a3 * rhs.a2) + (a4 * rhs.a5) + a5;
     end
 
+  (*
   let[@inline] tra (dst : t) ~(tx : float) ~(ty : float) =
     begin
       dst.a2 <- (dst.a0 * tx) + (dst.a1 * ty) + dst.a2;
diff --git a/src/dune b/src/dune
index 0f23324..fde31ef 100644
--- a/src/dune
+++ b/src/dune
@@ -5,5 +5,6 @@
  (libraries
    adam
    s2
+   n2
 
    ohlog))
diff --git a/src/main.ml b/src/main.ml
index f6dfef1..fd06135 100644
--- a/src/main.ml
+++ b/src/main.ml
@@ -1,8 +1,24 @@
-open S2
 open Adam
+open S2
+open N2
+
 include (val Ohlog.logs "Main")
 
 let main () =
+  let tfs = Transform.make () in
+
+  let a = Transform.add tfs in
+  let b = Transform.add tfs ~parent:a in
+  let c = Transform.add tfs ~parent:a in
+
+  let square = aabb (-50.0) (-50.0) 50.0 50.0 in
+
+  Mat2A.set (Transform.model b)
+    ~tx:(-5.0) ~ty:(-5.0) ~sx:1.0 ~sy:1.0;
+
+  Mat2A.set (Transform.model c)
+    ~tx:(+5.0) ~ty:(+5.0) ~sx:1.0 ~sy:1.0;
+
   debug (fun m -> m "initializing");
   let window = Window.make ~title:"GEOMETRA" in
   info (fun m -> m "window initialized");
@@ -10,14 +26,40 @@ let main () =
   info (fun m -> m "renderer initialized");
   let render () =
     begin
-      (* let time = Sdl.get_ticks () |> Int32.to_int in *)
+      (* Update *)
+
+      let time = Sdl.get_ticks () |> Int32.to_int in
+      let tx =
+        Float_infix.(
+          Float.sin (flt time / 1000.0 * 2.0) * 300.0
+          + 512.0
+        )
+      in
+      let ty = 400.0 in
+
+      Mat2A.set (Transform.model a)
+        ~tx ~ty ~sx:1.0 ~sy:1.0;
+
+      Transform.update tfs;
+
+      (* Render *)
+
       Renderer.pre_draw ren;
       Renderer.clear ren (rgb24 0x000000);
+
       Renderer.draw_rect ren
-        ~tf:(mat2a 100.0 50.0 1.0 1.0)
-        ~bb:(aabb (-5.0) (-10.0) 50.0 200.0)
+        ~tf:(Transform.world b)
+        ~bb:square
         ~fill:(rgb24 0xff0000);
+
+      Renderer.draw_rect ren
+        ~tf:(Transform.world c)
+        ~bb:square
+        ~fill:(rgb24 0x0055ff);
+
       Renderer.post_draw ren;
+
+      Gc.major ();
     end
   in
   Window.event_loop window ~render;
diff --git a/src/n2/dune b/src/n2/dune
new file mode 100644
index 0000000..29133e3
--- /dev/null
+++ b/src/n2/dune
@@ -0,0 +1,7 @@
+(library
+ (name n2)
+ (package geometra)
+ (libraries
+   adam
+   s2
+   ohlog))
diff --git a/src/n2/n2.ml b/src/n2/n2.ml
new file mode 100644
index 0000000..fb2cb39
--- /dev/null
+++ b/src/n2/n2.ml
@@ -0,0 +1,98 @@
+open Adam
+
+include (val Ohlog.logs "N2")
+
+module Transform = struct
+  type t = {
+    mutable buffer : node array;
+    mutable size : int;
+  }
+
+  and node =
+    | Null
+    | Node of {
+        idx : int;
+        parent : node;
+        model_tf : mat2a;
+        world_tf : mat2a;
+      }
+
+  let make () = {
+    buffer = Array.make 64 Null;
+    size = 0;
+  }
+
+  let push t n =
+    let buf = t.buffer in
+    let cap = Array.length buf in
+    if t.size >= cap then
+      t.buffer <-
+        Array.init (cap * 2)
+          (fun i -> if i < cap then buf.(i) else Null);
+    t.buffer.(t.size) <- n;
+    t.size <- t.size + 1
+
+  let add ?(parent = Null) t =
+    let model_tf = mat2a 0.0 0.0 1.0 1.0 in
+    let world_tf = mat2a 0.0 0.0 1.0 1.0 in
+    let node =
+      Node {
+        idx = t.size;
+        parent;
+        model_tf;
+        world_tf;
+      }
+    in
+    push t node;
+    node
+
+  let update t =
+    let buf = t.buffer in
+    for i = 0 to t.size - 1 do
+      match buf.(i) with
+      | Null -> ()
+      | Node n ->
+        match n.parent with
+        | Null ->
+          Mat2A.copy n.world_tf ~src:n.model_tf
+        | Node p ->
+          Mat2A.copy n.world_tf ~src:p.world_tf;
+          Mat2A.mul n.world_tf n.model_tf;
+    done
+
+  let world = function
+    | Null -> invalid_arg "null"
+    | Node n -> n.world_tf
+
+  let model = function
+    | Null -> invalid_arg "null"
+    | Node n -> n.model_tf
+end
+
+(*
+module Entity = struct
+  include (val Ohlog.sublogs logger "Entity")
+
+  type t = {
+    name : string option;
+    id : int;
+  }
+
+  let _next_id = ref (-1)
+
+  let make ?name () = {
+    name;
+    id = (incr _next_id; !_next_id);
+  }
+
+  let pp ppf t =
+    Format.fprintf ppf "<%s@%d>"
+      (Option.value t.name ~default:"")
+      t.id
+
+  let make ?name () =
+    let ent = make ?name () in
+    trace (fun m -> m "new entity %a" pp ent);
+    ent
+end
+*)