From dda297a7dfb9a39eedcd668ffdb395e7e90abd34 Mon Sep 17 00:00:00 2001
From: David Thompson <dthompson2@worcester.edu>
Date: Thu, 23 Oct 2014 18:46:17 -0400
Subject: Move rotate procedure to transform module.

* sly/quaternion.scm (rotate): Remove.
* sly/transform.scm (rotate): New procedure.
---
 sly/quaternion.scm | 21 +--------------------
 sly/transform.scm  | 20 +++++++++++++++++++-
 2 files changed, 20 insertions(+), 21 deletions(-)

diff --git a/sly/quaternion.scm b/sly/quaternion.scm
index fe5cce9..48ebba4 100644
--- a/sly/quaternion.scm
+++ b/sly/quaternion.scm
@@ -26,7 +26,6 @@
   #:use-module (srfi srfi-1)
   #:use-module (srfi srfi-9)
   #:use-module (sly math)
-  #:use-module (sly transform)
   #:use-module (sly math vector)
   #:export (<quaternion> make-quaternion quaternion
             quaternion?
@@ -34,8 +33,7 @@
             identity-quaternion null-quaternion
             quaternion* quaternion-slerp
             quaternion-magnitude quaternion-normalize
-            vector->quaternion quaternion->vector
-            rotate))
+            vector->quaternion quaternion->vector))
 
 (define-record-type <quaternion>
   (%make-quaternion w x y z)
@@ -112,20 +110,3 @@ Q2 and blending factor DELTA."
   (match-lambda
     (($ <vector4> x y z w)
      (make-quaternion x y z w))))
-
-(define rotate
-  (match-lambda
-   (($ <quaternion> w x y z)
-    (make-transform
-     (- 1 (* 2 (square y)) (* 2 (square z)))
-     (- (* 2 x y) (* 2 w z))
-     (+ (* 2 x z) (* 2 w y))
-     0
-     (+ (* 2 x y) (* 2 w z))
-     (- 1 (* 2 (square x)) (* 2 (square z)))
-     (- (* 2 y z) (* 2 w x))
-     0
-     (- (* 2 x z) (* 2 w y))
-     (+ (* 2 y z) (* 2 w x))
-     (- 1 (* 2 (square x)) (* 2 (square y)))
-     0 0 0 0 1))))
diff --git a/sly/transform.scm b/sly/transform.scm
index 95324ed..205ecbe 100644
--- a/sly/transform.scm
+++ b/sly/transform.scm
@@ -28,11 +28,12 @@
   #:use-module (srfi srfi-42)
   #:use-module (sly math)
   #:use-module (sly math vector)
+  #:use-module (sly quaternion)
   #:export (make-transform null-transform identity-transform
             transform? transform-matrix
             transpose transform-vector2
             transform+ transform*
-            scale translate rotate-x rotate-y rotate-z
+            scale translate rotate-x rotate-y rotate-z rotate
             orthographic-projection perspective-projection
             look-at))
 
@@ -184,6 +185,23 @@ identity-transform if called without any arguments."
                   0           0               1 0
                   0           0               0 1))
 
+(define rotate
+  (match-lambda
+   (($ <quaternion> w x y z)
+    (make-transform
+     (- 1 (* 2 (square y)) (* 2 (square z)))
+     (- (* 2 x y) (* 2 w z))
+     (+ (* 2 x z) (* 2 w y))
+     0
+     (+ (* 2 x y) (* 2 w z))
+     (- 1 (* 2 (square x)) (* 2 (square z)))
+     (- (* 2 y z) (* 2 w x))
+     0
+     (- (* 2 x z) (* 2 w y))
+     (+ (* 2 y z) (* 2 w x))
+     (- 1 (* 2 (square x)) (* 2 (square y)))
+     0 0 0 0 1))))
+
 (define (orthographic-projection left right top bottom near far)
   "Return a new transform that represents an orthographic projection
 for the vertical clipping plane LEFT and RIGHT, the horizontal
-- 
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