From 35fe2265e5a2732796bfe905ca7fcaf480adcb27 Mon Sep 17 00:00:00 2001
From: David Thompson <dthompson2@worcester.edu>
Date: Tue, 7 Sep 2021 18:27:34 -0400
Subject: graphics: shader: Add support for 3x3 matrices.

---
 chickadee/graphics/shader.scm | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/chickadee/graphics/shader.scm b/chickadee/graphics/shader.scm
index 08e8672..7def1f2 100644
--- a/chickadee/graphics/shader.scm
+++ b/chickadee/graphics/shader.scm
@@ -45,6 +45,7 @@
             float-vec2
             float-vec3
             float-vec4
+            mat3
             mat4
             sampler-2d
             sampler-cube
@@ -214,6 +215,18 @@
   #:setter gl-uniform4fv
   #:null (make-null-rect))
 
+(define-shader-primitive-type mat3
+  #:name 'mat3
+  #:size (* 3 3 4) ; 3 rows x 3 columns x 4 byte floats
+  #:validator matrix3?
+  #:serializer
+  (let ((matrix3-bv (@@ (chickadee math matrix) matrix3-bv)))
+    (lambda (bv i m)
+      (bytevector-copy! (matrix3-bv m) 0 bv i (* 3 3 4))))
+  #:setter (lambda (location count ptr)
+             (gl-uniform-matrix3fv location count #f ptr))
+  #:null (make-identity-matrix3))
+
 (define-shader-primitive-type mat4
   #:name 'mat4
   #:size 64 ; 4 rows x 4 columns = 16 floats x 4 bytes each = 64 bytes
@@ -588,6 +601,7 @@ them into a GPU shader program."
      ((= type (version-2-0 float-vec2)) float-vec2)
      ((= type (version-2-0 float-vec3)) float-vec3)
      ((= type (version-2-0 float-vec4)) float-vec4)
+     ((= type (version-2-0 float-mat3)) mat3)
      ((= type (version-2-0 float-mat4)) mat4)
      ((= type (version-2-0 sampler-2d)) sampler-2d)
      ((= type (version-2-0 sampler-cube)) sampler-cube)
-- 
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