Don't load font shaders upon importing (2d font) module.

* 2d/font.scm (font-shader): Set to #f initially.
  (enable-fonts): New procedure.

* examples/font.scm: Enable fonts.

2 files changed, 17 insertions, 10 deletions

diff --git a/2d/font.scm b/2d/font.scm
index 4e9d401..5cdc9cf 100644
--- a/2d/font.scm
+++ b/2d/font.scm
@@ -36,7 +36,8 @@
   #:use-module (2d vector2)
   #:use-module (2d window)
   #:use-module (2d wrappers gl)
-  #:export (load-font
+  #:export (enable-fonts
+            load-font
             load-default-font
             font?
             font-point-size
@@ -48,12 +49,23 @@
             label-color
             draw-label))
 
-(SDL:ttf-init)
-
 ;;;
 ;;; Font
 ;;;
 
+(define font-shader #f)
+
+(define (enable-fonts)
+  (SDL:ttf-init)
+  (set! font-shader
+        (make-shader-program
+         (load-vertex-shader
+          (string-append %pkgdatadir
+                         "/shaders/font-vertex.glsl"))
+         (load-fragment-shader
+          (string-append %pkgdatadir
+                         "/shaders/font-fragment.glsl")))))
+
 (define-record-type <font>
   (make-font ttf point-size)
   font?
@@ -131,13 +143,6 @@ white and ANCHOR with a default of 'top-left."
          (anchor (anchor-texture texture anchor)))
     (%make-label font text position anchor color texture vertices)))
 
-(define font-shader
-  (make-shader-program
-   (load-vertex-shader (string-append %pkgdatadir
-                                      "/shaders/font-vertex.glsl"))
-   (load-fragment-shader (string-append %pkgdatadir
-                                        "/shaders/font-fragment.glsl"))))
-
 (define (draw-label label)
   "Draw LABEL on the screen."
   (with-shader-program font-shader
diff --git a/examples/font.scm b/examples/font.scm
index a5167fa..a48bc37 100644
--- a/examples/font.scm
+++ b/examples/font.scm
@@ -27,6 +27,8 @@
 
 (load "common.scm")
 
+(enable-fonts)
+
 (define font (load-default-font 18))
 (define label
   (make-label font "The quick brown fox jumped over the lazy dog."