From 97d708c04eb36e14597b2485251a32e3ce3cca63 Mon Sep 17 00:00:00 2001
From: milo <iitalics@gmail.com>
Date: Mon, 5 Feb 2024 16:44:36 -0500
Subject: [PATCH] N2.Trans storage optimization

---
 src/n2/render.ml |  6 ++----
 src/n2/trans.ml  | 37 +++++++++++++------------------------
 src/n2/types.ml  |  4 ++++
 3 files changed, 19 insertions(+), 28 deletions(-)

diff --git a/src/n2/render.ml b/src/n2/render.ml
index bde9dcf..b68486b 100644
--- a/src/n2/render.ml
+++ b/src/n2/render.ml
@@ -26,8 +26,7 @@ module Sprite = struct
     Entity.Map.set map en cv;
     Stack.push ord
       (fun ren ->
-         let tf = Trans.world en in
-         Renderer.draw_sprites ren ~tf ~tint:cv.tint
+         Renderer.draw_sprites ren ~tf:en.tf ~tint:cv.tint
            cv.sprite_map cv.sprites)
 
   let clear en =
@@ -57,8 +56,7 @@ module Label = struct
     Entity.Map.set map en cv;
     Stack.push ord
       (fun ren ->
-         let tf = Trans.world en in
-         Renderer.draw_text ren ~tf ~fg:cv.fg
+         Renderer.draw_text ren ~tf:en.tf ~fg:cv.fg
            cv.font cv.glyphs)
 
   let set_text en text =
diff --git a/src/n2/trans.ml b/src/n2/trans.ml
index 3acbf54..4606e04 100644
--- a/src/n2/trans.ml
+++ b/src/n2/trans.ml
@@ -3,40 +3,29 @@ open Types
     
 (* include (val Ohlog.sublogs Import.logger "Trans") *)
 
-type cv = {
+type rel = {
   model : mat2a;
   world : mat2a;
-  parent : mat2a option;
+  parent : mat2a;
 }
 
 let map = Entity.Map.make ()
 let ord = Stack.make ()
 
-let model en = (Entity.Map.get map en).model
-let world en = (Entity.Map.get map en).world
+let model en = Entity.Map.get map en
+let[@inline] world en = en.tf
 
 let init ?parent child =
-  let model = Mat2A.make () in
-  let cv = match parent with
-    | Some parent -> {
-        model;
-        world = Mat2A.make ();
-        parent = Some (world parent);
-      }
-    | None -> {
-        model;
-        world = model;
-        parent = None;
-      }
-  in
-  Entity.Map.set map child cv;
-  Stack.push ord child
+  match parent with
+  | Some parent ->
+    let rel = { model = mat2a (); world = child.tf; parent = parent.tf } in
+    Stack.push ord rel;
+    Entity.Map.set map child rel.model
+  | None ->
+    Entity.Map.set map child child.tf
 
-let update en =
-  let cv = Entity.Map.get map en in
-  match cv.parent with
-  | None -> ((* world == parent *))
-  | Some parent -> Mat2A.multiply cv.world parent cv.model
+let update rel =
+  Mat2A.multiply rel.world rel.parent rel.model
 
 let update_transforms () =
   Stack.iter update ord
diff --git a/src/n2/types.ml b/src/n2/types.ml
index 51b7aa8..cce7a7e 100644
--- a/src/n2/types.ml
+++ b/src/n2/types.ml
@@ -5,6 +5,8 @@ open! Import
 type en = {
   name : string option;
   id : int;
+  (* OPTIMIZATION: since all entities have a transform, store it directly *)
+  tf : mat2a;
 }
 
 module Entity = struct
@@ -13,9 +15,11 @@ module Entity = struct
 
   let make ?name () =
     let id = !_next_id in
+    let tf = mat2a () in
     incr _next_id; {
       name;
       id;
+      tf;
     }
 
   let pp ppf en =