1 files changed, 107 insertions, 0 deletions
diff --git a/opengl-bindings/build.rs b/opengl-bindings/build.rs
new file mode 100644
index 0000000..060472c
--- /dev/null
+++ b/opengl-bindings/build.rs
@@ -0,0 +1,107 @@
+use std::collections::HashSet;
+use std::env;
+use std::fs::File;
+use std::path::{Path, PathBuf};
+
+use anyhow::anyhow;
+use gl_generator::{Api, Fallbacks, Profile, Registry, StructGenerator};
+
+fn main() -> Result<(), anyhow::Error>
+{
+    println!("cargo::rerun-if-changed=build.rs");
+    println!("cargo::rerun-if-changed=Cargo.toml");
+
+    let dest = env::var("OUT_DIR")?;
+
+    let mut file = File::create(Path::new(&dest).join("bindings.rs"))?;
+
+    let mut registry = Registry::new(Api::Gl, (4, 6), Profile::Core, Fallbacks::All, []);
+
+    let mut build_metadata = get_build_metadata()?;
+
+    filter_gl_commands(&mut registry, &mut build_metadata)?;
+
+    registry.write_bindings(StructGenerator, &mut file)?;
+
+    Ok(())
+}
+
+fn filter_gl_commands(
+    registry: &mut Registry,
+    build_metadata: &mut BuildMetadata,
+) -> Result<(), anyhow::Error>
+{
+    registry
+        .cmds
+        .retain(|command| build_metadata.gl_commands.remove(&command.proto.ident));
+
+    if !build_metadata.gl_commands.is_empty() {
+        return Err(anyhow!(
+            "Invalid GL commands: [{}]",
+            build_metadata
+                .gl_commands
+                .iter()
+                .cloned()
+                .collect::<Vec<_>>()
+                .join(", ")
+        ));
+    }
+
+    Ok(())
+}
+
+fn get_build_metadata() -> Result<BuildMetadata, anyhow::Error>
+{
+    let manifest_path = PathBuf::from(std::env::var("CARGO_MANIFEST_PATH")?);
+
+    let manifest = std::fs::read_to_string(manifest_path)?.parse::<toml::Table>()?;
+
+    let package = match manifest
+        .get("package")
+        .ok_or_else(|| anyhow!("Manifest does not have a package table"))?
+    {
+        toml::Value::Table(package) => Ok(package),
+        _ => Err(anyhow!("Manifest package must be a table")),
+    }?;
+
+    let metadata = match package
+        .get("metadata")
+        .ok_or_else(|| anyhow!("Manifest does not have a package.metadata table"))?
+    {
+        toml::Value::Table(metadata) => Ok(metadata),
+        _ => Err(anyhow!("Manifest package.metadata must be a table")),
+    }?;
+
+    let build_metadata = match metadata
+        .get("build")
+        .ok_or_else(|| anyhow!("Manifest does not have a package.metadata.build table"))?
+    {
+        toml::Value::Table(build_metadata) => Ok(build_metadata),
+        _ => Err(anyhow!("Manifest package.metadata.build must be a table")),
+    }?;
+
+    let gl_command_values = match build_metadata.get("gl_commands").ok_or_else(|| {
+        anyhow!("Manifest does not have a package.metadata.build.gl_commands array")
+    })? {
+        toml::Value::Array(gl_commands) => Ok(gl_commands),
+        _ => Err(anyhow!(
+            "Manifest package.metadata.build.gl_commands must be a array"
+        )),
+    }?;
+
+    let gl_commands = gl_command_values
+        .iter()
+        .map(|gl_command_val| match gl_command_val {
+            toml::Value::String(gl_command) => Ok(gl_command.clone()),
+            _ => Err(anyhow!("GL command must be a string")),
+        })
+        .collect::<Result<HashSet<_>, _>>()?;
+
+    Ok(BuildMetadata { gl_commands })
+}
+
+#[derive(Debug)]
+struct BuildMetadata
+{
+    gl_commands: HashSet<String>,
+}