From 424353f5fedb4c2b1cd9e0c6621fbbf4b86a1b07 Mon Sep 17 00:00:00 2001
From: David Thompson <dthompson2@worcester.edu>
Date: Wed, 29 Oct 2014 21:50:54 -0400
Subject: render: Remove knowledge of cameras from renderer.

* sly/render/renderer.scm (renderer-cameras): Delete.
  (apply-render-op): Remove 'view' parameter.
  (make-renderer): Remove 'cameras' parameter.
  (render): Remove camera logic.
* sly/scene.scm (scene->render-list): Renamed.
  (scene->renderer): New procedure.  Return a renderer instead of a list
  of render ops.
  (draw-scene): New procedure.
---
 sly/render/renderer.scm | 24 ++++++++----------------
 sly/scene.scm           | 21 ++++++++++++++-------
 2 files changed, 22 insertions(+), 23 deletions(-)

diff --git a/sly/render/renderer.scm b/sly/render/renderer.scm
index 76cc4aa..d71b89a 100644
--- a/sly/render/renderer.scm
+++ b/sly/render/renderer.scm
@@ -33,14 +33,13 @@
   #:use-module (sly transform)
   #:use-module (sly math vector)
   #:use-module (sly render utils)
-  #:use-module (sly render camera)
   #:use-module (sly render vertex-array)
   #:export (make-render-op render-op?
             render-op-transform render-op-vertex-array
             render-op-texture render-op-shader
             render-op-blend-mode render-op-uniforms
             make-renderer renderer?
-            renderer-cameras renderer-ops
+            renderer-ops
             render))
 
 ;; Representation of a single OpenGL render call.
@@ -74,10 +73,9 @@ activated or not."
       (with-texture texture body ...)
       (begin body ...)))
 
-(define (apply-render-op view op)
-  "Render the contents of OP.  The transform of OP is multiplied by
-the VIEW transform before rendering and passed to the shader as the
-uniform variable 'mvp'."
+(define (apply-render-op op)
+  "Render OP by applying its texture, shader, vertex array, uniforms,
+blend mode, etc.."
   (match op
     (($ <render-op> transform vertex-array texture shader uniforms
                     blend-mode depth-test?)
@@ -93,7 +91,7 @@ uniform variable 'mvp'."
                    (match uniform
                      ((name value)
                       (uniform-set! shader name value))))
-                 `(("mvp" ,(transform* view transform))
+                 `(("mvp" ,transform)
                    ,@uniforms))
        (with-vertex-array vertex-array
          (with-texture-maybe texture
@@ -105,18 +103,12 @@ uniform variable 'mvp'."
        (gl-disable (enable-cap depth-test))))))
 
 (define-record-type <renderer>
-  (make-renderer cameras ops)
+  (make-renderer ops)
   renderer?
-  (cameras renderer-cameras)
   (ops renderer-ops))
 
 (define (render renderer)
   "Apply all of the render operations in RENDERER.  The render
 operations are applied once for each camera."
-  (define (render-with-camera camera)
-    (apply-viewport (camera-viewport camera))
-    (let ((view (transform* (camera-projection camera)
-                            (camera-location camera))))
-      (for-each (cut apply-render-op view <>)
-                (renderer-ops renderer))))
-  (for-each render-with-camera (renderer-cameras renderer)))
+  (for-each (cut apply-render-op <>)
+            (renderer-ops renderer)))
diff --git a/sly/scene.scm b/sly/scene.scm
index 8b58d10..e068e60 100644
--- a/sly/scene.scm
+++ b/sly/scene.scm
@@ -31,12 +31,13 @@
   #:use-module (sly transform)
   #:use-module (sly math vector)
   #:use-module (sly render utils)
+  #:use-module (sly render camera)
   #:use-module (sly render renderer)
   #:export (scene-node make-scene-node
             scene-node?
             scene-node-object scene-node-transform
             scene-node-visible? scene-node-children
-            scene->render-list))
+            draw-scene))
 
 (define-record-type <scene-node>
   (%make-scene-node object transform visible? children)
@@ -66,11 +67,10 @@ whether to draw the node and all of its children or not."
      (cons elem memo)))
    '() lst))
 
-(define (scene->render-list node)
-  "Traverse the scene graph defined by NODE and its children and
-return a list of the render operations needed to display the scene.
-Additionally, NODE or any of its children may be a signal to allow for
-dynamic changes to the scene."
+(define (scene->renderer node camera)
+  "Traverse the scene graph defined by NODE and its children, as seen
+by CAMERA, and return a list of the render operations needed to
+display the scene."
   (define (iter node parent-transform)
     (signal-let ((node node))
       (if (scene-node-visible? node)
@@ -83,4 +83,11 @@ dynamic changes to the scene."
                   (map (cut iter <> transform)
                        (scene-node-children node))))
           '())))
-  (flatten (iter node identity-transform)))
+  (let ((view (transform* (camera-projection camera)
+                          (camera-location camera))))
+    (make-renderer (flatten (iter node view)))))
+
+(define (draw-scene node camera)
+  "Draw the scene defined by NODE, as seen by CAMERA."
+  (apply-viewport (camera-viewport camera))
+  (render (scene->renderer node camera)))
-- 
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