render: shader: Fix bug where default values for local fields didn't work.

1 files changed, 18 insertions, 8 deletions

diff --git a/chickadee/render/shader.scm b/chickadee/render/shader.scm
index 1f97a0d..050a81c 100644
--- a/chickadee/render/shader.scm
+++ b/chickadee/render/shader.scm
@@ -279,13 +279,17 @@
 (define (shader-struct-default vtable field)
   (match (assq-ref (shader-struct-fields vtable) field)
     ((_ type size)
-     (let ((default (if (eq? (struct-vtable type) <shader-struct>)
-                        (apply make-struct/no-tail type
-                               (map (match-lambda
-                                      ((sub-field _ _ _)
-                                       (shader-struct-default type sub-field)))
-                                    (shader-struct-fields type)))
-                        (shader-primitive-type-null type))))
+     (let ((default (cond
+                     ((eq? type local-field)
+                      #f)
+                     ((eq? (struct-vtable type) <shader-struct>)
+                      (apply make-struct/no-tail type
+                             (map (match-lambda
+                                    ((sub-field _ _ _)
+                                     (shader-struct-default type sub-field)))
+                                  (shader-struct-fields type))))
+                     (else
+                      (shader-primitive-type-null type)))))
        (if (= size 1)
            default
            (make-vector size default))))))
@@ -749,7 +753,13 @@ shader program."
       (if (shader-struct? value)
           (uniform-namespace-for-each
            (lambda (key uniform)
-             (traverse uniform (shader-struct-ref value key)))
+             ;; Samplers are opaque types and you cannot pass them
+             ;; into the shader as uniform values like you can with
+             ;; most other values.  In the case of samplers, they are
+             ;; mapped to OpenGL's "texture units", so we need to
+             ;; ignore them here.
+             (unless (eq? (uniform-type uniform) sampler-2d)
+               (traverse uniform (shader-struct-ref value key))))
            uniform)
           (error "expected shader struct" x)))
      ;; A nested array namespace indicates that this must be an array