Correct sub-pixel font rendering with OpenGL

Uses the GL_ARB_blend_func_extended to get single-pass, per-channel
alpha blending. gl_generator is now used instead of gl to enable the
extension.

The background color is removed since that presumably needs to run in a
separate pass.

1 files changed, 17 insertions, 0 deletions

diff --git a/build.rs b/build.rs
new file mode 100644
index 00000000..c63f7964
--- /dev/null
+++ b/build.rs
@@ -0,0 +1,17 @@
+extern crate gl_generator;
+
+use gl_generator::{Registry, Api, Profile, Fallbacks, GlobalGenerator};
+use std::env;
+use std::fs::File;
+use std::path::Path;
+
+fn main() {
+    let dest = env::var("OUT_DIR").unwrap();
+    let mut file = File::create(&Path::new(&dest).join("gl_bindings.rs")).unwrap();
+
+    Registry::new(Api::Gl, (4, 5), Profile::Core, Fallbacks::All, [
+            "GL_ARB_blend_func_extended"
+        ])
+        .write_bindings(GlobalGenerator, &mut file)
+        .unwrap();
+}