From 7e9c865bc248a996ba9a360eb1392d05aa8a2010 Mon Sep 17 00:00:00 2001
From: David Thompson <dthompson2@worcester.edu>
Date: Mon, 1 Aug 2022 16:03:25 -0400
Subject: math: matrix: Clean up matrix4-2d-transform! implementation.

---
 chickadee/math/matrix.scm | 72 +++++++++++++++++++++++------------------------
 1 file changed, 35 insertions(+), 37 deletions(-)

diff --git a/chickadee/math/matrix.scm b/chickadee/math/matrix.scm
index db05dd6..095699c 100644
--- a/chickadee/math/matrix.scm
+++ b/chickadee/math/matrix.scm
@@ -751,46 +751,44 @@ position EYE, with the top of the viewport facing UP."
     (matrix4-rotate-z! matrix angle)
     matrix))
 
-(define matrix4-2d-transform!
-  (let ((tmp (make-null-matrix4))
-        (offset (vec2 0.0 0.0))
-        (null-vec2 (vec2 0.0 0.0))
-        (default-scale (vec2 1.0 1.0)))
-    (lambda* (matrix
-              #:key
-              (origin null-vec2)
-              (position null-vec2)
-              (rotation 0.0)
-              (scale default-scale)
-              (shear null-vec2))
-      "Store in MATRIX the transformation described by POSITION, a 2D
+(define %null-vec2 (vec2 0.0 0.0))
+(define %default-scale (vec2 1.0 1.0))
+
+(define* (matrix4-2d-transform! matrix
+                                #:key
+                                (origin %null-vec2)
+                                (position %null-vec2)
+                                (rotation 0.0)
+                                (scale %default-scale)
+                                (shear %null-vec2))
+  "Store in MATRIX the transformation described by POSITION, a 2D
 vector or rect, ROTATION, a scalar representing a rotation about the Z
 axis, SCALE, a 2D vector, and SHEAR, a 2D vector.  The transformation
 happens with respect to ORIGIN, a 2D vector."
-      (let* ((bv (matrix4-bv matrix))
-             (x (vec2-x position))
-             (y (vec2-y position))
-             (ox (vec2-x origin))
-             (oy (vec2-y origin))
-             (sx (vec2-x scale))
-             (sy (vec2-y scale))
-             (kx (vec2-x shear))
-             (ky (vec2-y shear))
-             (c (cos rotation))
-             (s (sin rotation))
-             (q (* c sx))
-             (r (+ (* s sx) (* c sy ky)))
-             (s (- (* c sx kx) (* s sy)))
-             (t (* c sy)))
-        (bytevector-fill! bv 0)
-        (f32vector-set! bv 10 1.0)
-        (f32vector-set! bv 15 1.0)
-        (f32vector-set! bv 0 q)
-        (f32vector-set! bv 1 r)
-        (f32vector-set! bv 4 s)
-        (f32vector-set! bv 5 t)
-        (f32vector-set! bv 12 (- x (* ox q) (* oy s)))
-        (f32vector-set! bv 13 (- y (* ox r) (* oy t)))))))
+  (let* ((bv (matrix4-bv matrix))
+         (x (vec2-x position))
+         (y (vec2-y position))
+         (ox (vec2-x origin))
+         (oy (vec2-y origin))
+         (sx (vec2-x scale))
+         (sy (vec2-y scale))
+         (kx (vec2-x shear))
+         (ky (vec2-y shear))
+         (c (cos rotation))
+         (s (sin rotation))
+         (q (* c sx))
+         (r (+ (* s sx) (* c sy ky)))
+         (s (- (* c sx kx) (* s sy)))
+         (t (* c sy)))
+    (bytevector-fill! bv 0)
+    (f32vector-set! bv 0 q)
+    (f32vector-set! bv 1 r)
+    (f32vector-set! bv 4 s)
+    (f32vector-set! bv 5 t)
+    (f32vector-set! bv 10 1.0)
+    (f32vector-set! bv 12 (- x (* ox q) (* oy s)))
+    (f32vector-set! bv 13 (- y (* ox r) (* oy t)))
+    (f32vector-set! bv 15 1.0)))
 
 (define-inlinable (matrix4-transform-x matrix x y)
   (let ((bv (matrix4-bv matrix)))
-- 
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