[gtk+/gtk-3-22] demo: Fix the GLES fragment shader for GLArea

[Emmanuele Bassi <ebassi src gnome org>]

commit da43bfd2727e6ef6546ae8796668ec3adcd5340c
Author: Emmanuele Bassi <ebassi gnome org>
Date:   Wed Dec 14 18:36:18 2016 +0000

    demo: Fix the GLES fragment shader for GLArea
    
    We have a couple of syntax errors, like 'f' modifier for floating point
    values.

 demos/gtk-demo/glarea-gles.fs.glsl |    6 +++---
 1 files changed, 3 insertions(+), 3 deletions(-)
---
diff --git a/demos/gtk-demo/glarea-gles.fs.glsl b/demos/gtk-demo/glarea-gles.fs.glsl
index 39f7143..1bfe643 100644
--- a/demos/gtk-demo/glarea-gles.fs.glsl
+++ b/demos/gtk-demo/glarea-gles.fs.glsl
@@ -1,7 +1,7 @@
-precision highp float;
+precision mediump float;
 
 void main() {
-  float lerpVal = gl_FragCoord.y / 500.0f;
+  float lerpVal = gl_FragCoord.y / 500.0;
 
-  gl_FragColor = mix(vec4(1.0f, 0.85f, 0.35f, 1.0f), vec4(0.2f, 0.2f, 0.2f, 1.0f), lerpVal);
+  gl_FragColor = mix(vec4(1.0, 0.85, 0.35, 1.0), vec4(0.2, 0.2, 0.2, 1.0), lerpVal);
 }