demo: Add GLES support to the GtkGLArea demo

We need new shaders, and we need to select the correct shader when
building the program we use to render the triangle.

1 files changed, 7 insertions, 0 deletions

diff --git a/demos/gtk-demo/glarea-gles.fs.glsl b/demos/gtk-demo/glarea-gles.fs.glsl
new file mode 100644
index 0000000000..39f7143960
--- /dev/null
+++ b/demos/gtk-demo/glarea-gles.fs.glsl
@@ -0,0 +1,7 @@
+precision highp float;
+
+void main() {
+  float lerpVal = gl_FragCoord.y / 500.0f;
+
+  gl_FragColor = mix(vec4(1.0f, 0.85f, 0.35f, 1.0f), vec4(0.2f, 0.2f, 0.2f, 1.0f), lerpVal);
+}