From 5e5920afad058cbb7a179b2be92271f1603da9e1 Mon Sep 17 00:00:00 2001
From: David Thompson <dthompson2@worcester.edu>
Date: Tue, 30 Sep 2014 08:05:58 -0400
Subject: scene: Remove messy interpolation/caching for now.

* sly/game.scm (run-game-loop): Remove scene updating step.
* sly/scene.scm (scene-node-prev-position,
  set-scene-node-prev-position!, scene-node-prev-scale,
  set-scene-node-prev-scale!, scene-node-prev-rotation,
  set-scene-node-prev-rotation!, scene-node-transform,
  set-scene-node-transform!, scene-node-dirty?, update-scene-node,
  recompute-transform!): Delete procedures.
  (make-scene-node): Remove transform caching.
  (draw-scene-node): Re-calculate transforms every frame.
---
 sly/game.scm  |  4 ----
 sly/scene.scm | 68 ++++++++++-------------------------------------------------
 2 files changed, 11 insertions(+), 61 deletions(-)

diff --git a/sly/game.scm b/sly/game.scm
index 67398de..729c586 100644
--- a/sly/game.scm
+++ b/sly/game.scm
@@ -99,10 +99,6 @@ unused accumulator time."
         (cond ((>= ticks max-ticks-per-frame)
                lag)
               ((>= lag tick-interval)
-               (signal-let ((scene scene))
-                 (if (list? scene)
-                     (for-each (cut update-scene <>) scene)
-                     (update-scene scene)))
                (tick-agenda!)
                (iter (- lag tick-interval) (1+ ticks)))
               (else
diff --git a/sly/scene.scm b/sly/scene.scm
index e3f00c3..bb748ca 100644
--- a/sly/scene.scm
+++ b/sly/scene.scm
@@ -47,10 +47,6 @@
   (position scene-node-position)
   (scale scene-node-scale)
   (rotation scene-node-rotation)
-  (prev-position scene-node-prev-position set-scene-node-prev-position!)
-  (prev-scale scene-node-prev-scale set-scene-node-prev-scale!)
-  (prev-rotation scene-node-prev-rotation set-scene-node-prev-rotation!)
-  (transform scene-node-transform set-scene-node-transform!)
   (uniforms scene-node-uniforms)
   (children scene-node-children))
 
@@ -61,75 +57,33 @@
                            (uniforms '())
                            (children '())
                            #:allow-other-keys)
-  (let ((node (%make-scene-node position scale rotation uniforms children)))
-    (update-scene-node node)
-    (recompute-transform! node 0)
-    node))
+  (%make-scene-node position scale rotation uniforms children))
 
 (define-syntax-rule (scene-node (field val) ...)
   (apply make-scene-node
          (append (list (symbol->keyword 'field) val) ...)))
 
-(define (scene-node-dirty? node)
-  (define (different? a b)
-    (not (equal? (a node) (b node))))
-
-  (or (different? scene-node-position scene-node-prev-position)
-      (different? scene-node-scale scene-node-prev-scale)
-      (different? scene-node-rotation scene-node-prev-rotation)))
-
-(define (scene-root . children)
-  (make-scene-node #:children children))
-
-(define (update-scene-node node)
-  (signal-let ((node node))
-    (when (scene-node? node)
-      (signal-let ((position (scene-node-position node))
-                   (scale (scene-node-scale node))
-                   (rotation (scene-node-rotation node))
-                   (children (scene-node-children node)))
-        (set-scene-node-prev-position! node position)
-        (set-scene-node-prev-scale! node scale)
-        (set-scene-node-prev-rotation! node rotation)
-        (for-each update-scene-node children)))))
-
 (define (interpolate current prev alpha)
   (if (or (not prev)
           (equal? current prev))
       current
       (vector-interpolate prev current alpha)))
 
-(define (recompute-transform! node alpha)
-  (signal-let ((position (scene-node-position node))
-               (%scale (scene-node-scale node))
-               (rotation (scene-node-rotation node)))
-    (let ((t (transform*
-              (translate
-               (interpolate position
-                            (scene-node-prev-position node)
-                            alpha))
-              (quaternion->transform
-               (quaternion-slerp rotation
-                                 (scene-node-prev-rotation node)
-                                 alpha))
-              (scale (interpolate %scale
-                                  (scene-node-prev-scale node)
-                                  alpha)))))
-      (set-scene-node-transform! node t)
-      t)))
-
 (define* (draw-scene-node node alpha transform #:optional (uniforms '()))
   (signal-let ((node node))
     (if (mesh? node)
         (draw-mesh node `(("mvp" ,transform)
                           ,@uniforms))
-        (let ((transform
-               (transform* transform
-                           (if (scene-node-dirty? node)
-                               (recompute-transform! node alpha)
-                               (scene-node-transform node)))))
-          (signal-let ((children (scene-node-children node)))
-            (for-each (cut draw-scene-node <> alpha transform
+        (signal-let ((children (scene-node-children node))
+                     (position (scene-node-position node))
+                     (%scale (scene-node-scale node))
+                     (rotation (scene-node-rotation node)))
+          (let ((node-transform (transform*
+                                 (translate position)
+                                 (scale %scale)
+                                 (quaternion->transform rotation))))
+            (for-each (cut draw-scene-node <> alpha
+                           (transform* transform node-transform)
                            (scene-node-uniforms node))
                       children))))))
 
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