From 61bd98f6a85626e49518591cccfc1e31d11a0367 Mon Sep 17 00:00:00 2001
From: DialecticalMaterialist
 <170803884+DialecticalMaterialist@users.noreply.github.com>
Date: Sun, 3 Aug 2025 20:22:38 +0200
Subject: [PATCH] Fix bufferStorage

The current packed struct is wrong, it was implemented in the order
which the flags are described in the OpenGL Spec. This is not how the
bits are laid out in memory though, in fact if you were to write true to
map_write with this implementation it would through a GL_INVALID_VALUE
error since the function does not allow setting any bits besides the
defined ones. This commit fixes the bitfield to have the correct order
and padding aswell as providing their offsets as a comment and a small
description of what each flag does.
---
 src/wrapper.zig | 39 ++++++++++++++++++++++++++++++---------
 1 file changed, 30 insertions(+), 9 deletions(-)

diff --git a/src/wrapper.zig b/src/wrapper.zig
index 528a0df..7bb8783 100644
--- a/src/wrapper.zig
+++ b/src/wrapper.zig
@@ -5227,15 +5227,36 @@ pub fn Wrap(comptime bindings: anytype) type {
         pub const QUERY_RESULT_NO_WAIT = bindings.QUERY_RESULT_NO_WAIT;
         pub const MIRROR_CLAMP_TO_EDGE = bindings.MIRROR_CLAMP_TO_EDGE;
 
-        pub fn bufferStorage(target: BufferTarget, size: usize, data: ?[]const u8, flags: packed struct(Bitfield) {
-            dynamic_storage: bool = false,
-            map_read: bool = false,
-            map_write: bool = false,
-            map_persistent: bool = false,
-            map_coherent: bool = false,
-            client_storage: bool = false,
-            __unused: u26 = 0,
-        }) void {
+        pub fn bufferStorage(
+            target: BufferTarget,
+            size: usize,
+            data: ?[]const u8,
+            flags: packed struct(Bitfield) {
+                ///Enables reading via buffer mapping; read mapping fails otherwise.
+                map_read: bool = false, //0x1
+
+                ///Enables write mapping; write mapping fails otherwise.
+                map_write: bool = false, //0x2
+
+                /// DO NOT WRITE
+                pad1: u4 = 0,
+
+                ///Permits buffer operations while mapped; otherwise, such operations fail.
+                map_persistent: bool = false, //0x40
+
+                ///Makes persistent accesses coherent without barriers; barriers required otherwise.
+                map_coherent: bool = false, //0x80
+
+                ///Permits glNamedBufferSubData updates; calls fail otherwise.
+                dynamic_storage: bool = false, //0x100
+
+                ///Hints storage should use client memory.
+                client_storage: bool = false, //0x200
+
+                /// DO NOT WRITE
+                pad2: u22 = 0,
+            },
+        ) void {
             bindings.bufferStorage(
                 @intFromEnum(target),
                 @as(Sizeiptr, @bitCast(size)),