From b73a3c677171a13bdd7b0044071601647bfbfe67 Mon Sep 17 00:00:00 2001
From: Dan Goodliffe <dan.goodliffe@octal.co.uk>
Date: Tue, 10 Mar 2026 09:40:37 +0000
Subject: Refactor glMappedBufferWriter into a DSA wrapper for std::span

---
 lib/glMappedBufferSpan.h | 51 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 51 insertions(+)
 create mode 100644 lib/glMappedBufferSpan.h

(limited to 'lib/glMappedBufferSpan.h')

diff --git a/lib/glMappedBufferSpan.h b/lib/glMappedBufferSpan.h
new file mode 100644
index 0000000..d30c911
--- /dev/null
+++ b/lib/glMappedBufferSpan.h
@@ -0,0 +1,51 @@
+#pragma once
+
+#include "special_members.h"
+#include <cstddef>
+#include <glad/gl.h>
+#include <span>
+#include <utility>
+
+template<typename T> class glMappedBufferSpan : public std::span<T> {
+public:
+	glMappedBufferSpan(GLuint buffer, size_t count, GLenum access, bool reinit) :
+		std::span<T> {[&]() {
+						  if (reinit) {
+							  glNamedBufferData(
+									  buffer, static_cast<GLsizeiptr>(sizeof(T) * count), nullptr, GL_DYNAMIC_DRAW);
+						  }
+						  return static_cast<T *>(glMapNamedBuffer(buffer, access));
+					  }(),
+				count},
+		buffer {buffer}
+	{
+	}
+
+	~glMappedBufferSpan()
+	{
+		if (buffer) {
+			glUnmapNamedBuffer(buffer);
+		}
+	}
+
+	glMappedBufferSpan(glMappedBufferSpan && other) noexcept :
+		std::span<T> {other}, buffer {std::exchange(other.buffer, 0)}
+	{
+	}
+
+	glMappedBufferSpan &
+	operator=(glMappedBufferSpan && other) noexcept
+	{
+		std::span<T>::span = other;
+		if (buffer) {
+			glUnmapBuffer(buffer);
+		}
+		buffer = std::exchange(other.buffer, 0);
+		return *this;
+	}
+
+	NO_COPY(glMappedBufferSpan);
+
+private:
+	GLuint buffer;
+};
-- 
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