1 files changed, 161 insertions, 0 deletions
diff --git a/opengl-bindings/src/debug.rs b/opengl-bindings/src/debug.rs
new file mode 100644
index 0000000..a9369a4
--- /dev/null
+++ b/opengl-bindings/src/debug.rs
@@ -0,0 +1,161 @@
+use std::ffi::c_void;
+use std::io::{stderr, Write};
+use std::mem::transmute;
+use std::panic::catch_unwind;
+
+use util_macros::FromRepr;
+
+use crate::CurrentContextWithFns;
+
+pub fn set_debug_message_callback(
+    current_context: &CurrentContextWithFns<'_>,
+    cb: MessageCallback,
+)
+{
+    unsafe {
+        current_context
+            .fns()
+            .DebugMessageCallback(Some(debug_message_cb), cb as *mut c_void);
+    }
+}
+
+/// Sets debug message parameters.
+///
+/// # Errors
+/// Returns `Err` if `ids` contains too many ids.
+pub fn set_debug_message_control(
+    current_context: &CurrentContextWithFns<'_>,
+    source: Option<MessageSource>,
+    ty: Option<MessageType>,
+    severity: Option<MessageSeverity>,
+    ids: &[u32],
+    ids_action: MessageIdsAction,
+) -> Result<(), SetDebugMessageControlError>
+{
+    let ids_len: crate::sys::types::GLsizei =
+        ids.len()
+            .try_into()
+            .map_err(|_| SetDebugMessageControlError::TooManyIds {
+                id_cnt: ids.len(),
+                max_id_cnt: crate::sys::types::GLsizei::MAX as usize,
+            })?;
+
+    unsafe {
+        current_context.fns().DebugMessageControl(
+            source.map_or(crate::sys::DONT_CARE, |source| source as u32),
+            ty.map_or(crate::sys::DONT_CARE, |ty| ty as u32),
+            severity.map_or(crate::sys::DONT_CARE, |severity| severity as u32),
+            ids_len,
+            ids.as_ptr(),
+            ids_action as u8,
+        );
+    }
+
+    Ok(())
+}
+
+#[derive(Debug, thiserror::Error)]
+pub enum SetDebugMessageControlError
+{
+    #[error("Too many ids provided ({id_cnt}). Must be < {max_id_cnt}")]
+    TooManyIds
+    {
+        id_cnt: usize, max_id_cnt: usize
+    },
+}
+
+pub type MessageCallback = fn(
+    source: MessageSource,
+    ty: MessageType,
+    id: u32,
+    severity: MessageSeverity,
+    message: &str,
+);
+
+#[derive(Debug, Clone, Copy)]
+#[repr(u8)] // GLboolean = u8
+pub enum MessageIdsAction
+{
+    Enable = crate::sys::TRUE,
+    Disable = crate::sys::FALSE,
+}
+
+#[derive(Debug, Clone, Copy, FromRepr)]
+#[repr(u32)] // GLenum = u32
+pub enum MessageSource
+{
+    Api = crate::sys::DEBUG_SOURCE_API,
+    WindowSystem = crate::sys::DEBUG_SOURCE_WINDOW_SYSTEM,
+    ShaderCompiler = crate::sys::DEBUG_SOURCE_SHADER_COMPILER,
+    ThirdParty = crate::sys::DEBUG_SOURCE_THIRD_PARTY,
+    Application = crate::sys::DEBUG_SOURCE_APPLICATION,
+    Other = crate::sys::DEBUG_SOURCE_OTHER,
+}
+
+#[derive(Debug, Clone, Copy, FromRepr)]
+#[repr(u32)] // GLenum = u32
+pub enum MessageType
+{
+    DeprecatedBehavior = crate::sys::DEBUG_TYPE_DEPRECATED_BEHAVIOR,
+    Error = crate::sys::DEBUG_TYPE_ERROR,
+    Marker = crate::sys::DEBUG_TYPE_MARKER,
+    Other = crate::sys::DEBUG_TYPE_OTHER,
+    Performance = crate::sys::DEBUG_TYPE_PERFORMANCE,
+    PopGroup = crate::sys::DEBUG_TYPE_POP_GROUP,
+    PushGroup = crate::sys::DEBUG_TYPE_PUSH_GROUP,
+    Portability = crate::sys::DEBUG_TYPE_PORTABILITY,
+    UndefinedBehavior = crate::sys::DEBUG_TYPE_UNDEFINED_BEHAVIOR,
+}
+
+#[derive(Debug, Clone, Copy, FromRepr)]
+#[repr(u32)] // GLenum = u32
+pub enum MessageSeverity
+{
+    High = crate::sys::DEBUG_SEVERITY_HIGH,
+    Medium = crate::sys::DEBUG_SEVERITY_MEDIUM,
+    Low = crate::sys::DEBUG_SEVERITY_LOW,
+    Notification = crate::sys::DEBUG_SEVERITY_NOTIFICATION,
+}
+
+extern "system" fn debug_message_cb(
+    source: crate::sys::types::GLenum,
+    ty: crate::sys::types::GLenum,
+    id: crate::sys::types::GLuint,
+    severity: crate::sys::types::GLenum,
+    message_length: crate::sys::types::GLsizei,
+    message: *const crate::sys::types::GLchar,
+    user_cb: *mut c_void,
+)
+{
+    let user_cb = unsafe { transmute::<*mut c_void, MessageCallback>(user_cb) };
+
+    let Ok(msg_length) = usize::try_from(message_length) else {
+        return;
+    };
+
+    // Unwinds are catched because unwinding from Rust code into foreign code is UB.
+    let res = catch_unwind(|| {
+        let msg_source = MessageSource::from_repr(source).unwrap();
+        let msg_type = MessageType::from_repr(ty).unwrap();
+        let msg_severity = MessageSeverity::from_repr(severity).unwrap();
+
+        // SAFETY: The received message should be a valid ASCII string
+        let message = unsafe {
+            std::str::from_utf8_unchecked(std::slice::from_raw_parts(
+                message.cast(),
+                msg_length,
+            ))
+        };
+
+        user_cb(msg_source, msg_type, id, msg_severity, message);
+    });
+
+    if res.is_err() {
+        // eprintln is not used since it can panic and unwinds are unwanted because
+        // unwinding from Rust code into foreign code is UB.
+        stderr()
+            .write_all(b"ERROR: Panic in debug message callback")
+            .ok();
+        println!();
+    }
+}