From da9b8716264f62316aabddb2d390d5a43a563df9 Mon Sep 17 00:00:00 2001
From: rexy712 <rexy712@protonmail.com>
Date: Tue, 18 Jan 2022 15:28:10 -0800
Subject: [PATCH] Add ability to buffer data to the middle of a vbo

---
 include/graphics/vbo.hpp |  1 +
 src/graphics/vbo.cpp     | 13 +++++++++++++
 2 files changed, 14 insertions(+)

diff --git a/include/graphics/vbo.hpp b/include/graphics/vbo.hpp
index 31f3f2a..b049fbe 100644
--- a/include/graphics/vbo.hpp
+++ b/include/graphics/vbo.hpp
@@ -70,6 +70,7 @@ namespace gfx{
 		bool bind(gl_buffer_manager& b)const;
 		//add data to the end of this buffer (starts loading at data+get_size())
 		bool buffer(const void* data, size_t datasize);
+		bool buffer(const void* data, size_t datasize, size_t start);
 		//change capacity of buffer
 		bool resize(size_t newcap);
 
diff --git a/src/graphics/vbo.cpp b/src/graphics/vbo.cpp
index 084ad4b..83d5b56 100644
--- a/src/graphics/vbo.cpp
+++ b/src/graphics/vbo.cpp
@@ -75,6 +75,19 @@ namespace gfx{
 		m_buffer_size += datasize;
 		return true;
 	}
+	bool vbo::buffer(const void* data, size_t datasize, size_t start){
+		const size_t capacity = get_cap();
+		const size_t space_from_end = capacity - start;
+		if(datasize > space_from_end){
+			const size_t difference = datasize - space_from_end;
+			if(!resize(rexy::max(difference, capacity * 2))){
+				return false;
+			}
+		}
+		glNamedBufferSubData(m_buffer, start, datasize, data);
+		m_buffer_size = rexy::max(m_buffer_size, datasize + start);
+		return true;
+	}
 	bool vbo::resize(size_t newsize){
 		vbo tmp(newsize, get_usage());
 		if(!copy_buffer(tmp, *this))