From 4e5b59b1e672667b7aa8793469ba2f937a9be198 Mon Sep 17 00:00:00 2001
From: David Thompson <dthompson2@worcester.edu>
Date: Wed, 16 Dec 2020 08:44:48 -0500
Subject: math: matrix: Add procedures to extract translation from 4x4 matrix.

---
 chickadee/math/matrix.scm | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/chickadee/math/matrix.scm b/chickadee/math/matrix.scm
index 4616643..0f1e523 100644
--- a/chickadee/math/matrix.scm
+++ b/chickadee/math/matrix.scm
@@ -66,7 +66,10 @@
             matrix4-2d-transform!
             matrix4-transform-x
             matrix4-transform-y
-            matrix4-transform!))
+            matrix4-transform!
+            matrix4-x
+            matrix4-y
+            matrix4-z))
 
 
 ;;;
@@ -707,3 +710,12 @@ happens with respect to ORIGIN, a 2D vector."
         (y (vec2-y v)))
     (set-vec2-x! v (matrix4-transform-x matrix x y))
     (set-vec2-y! v (matrix4-transform-y matrix x y))))
+
+(define-inlinable (matrix4-x matrix)
+  (matrix4-ref (matrix4-bv matrix) 3 0))
+
+(define-inlinable (matrix4-y matrix)
+  (matrix4-ref (matrix4-bv matrix) 3 1))
+
+(define-inlinable (matrix4-z matrix)
+  (matrix4-ref (matrix4-bv matrix) 3 2))
-- 
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