/*
Danger from the Deep - Open source submarine simulation
Copyright (C) 2003-2006  Thorsten Jordan, Luis Barrancos and others.

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*/

// Vertex Buffer Object
// (C)+(W) by Thorsten Jordan. See LICENSE

#include "vertexbufferobject.h"
#include "system.h"
#include "oglext/OglExt.h"
#include <stdexcept>


vertexbufferobject::vertexbufferobject(bool indexbuffer)
	: id(0), size(0), mapped(false),
	  target(indexbuffer ? GL_ELEMENT_ARRAY_BUFFER_ARB : GL_ARRAY_BUFFER_ARB)
{
	if (!sys().extension_supported("GL_ARB_vertex_buffer_object"))
		throw std::runtime_error("vertex buffer objects are not supported!");
	glGenBuffersARB(1, &id);
}



vertexbufferobject::~vertexbufferobject()
{
	if (mapped)
		unmap();
	glDeleteBuffersARB(1, &id);
}



void vertexbufferobject::init_data(unsigned size_, const void* data, int usage)
{
	size = size_;
	bind();
	glBufferDataARB(target, size, data, usage);
	unbind();
}



void vertexbufferobject::init_sub_data(unsigned offset, unsigned subsize, const void* data)
{
	bind();
	glBufferSubDataARB(target, offset, subsize, data);
	unbind();
}



void vertexbufferobject::bind() const
{
	glBindBufferARB(target, id);
}



void vertexbufferobject::unbind() const
{
	glBindBufferARB(target, 0);
}



void* vertexbufferobject::map(int access)
{
	if (mapped)
		throw std::runtime_error("vertex buffer object mapped twice");
	bind();
	void* addr = glMapBufferARB(target, access);
	if (addr == 0)
		throw std::runtime_error("vertex buffer object mapping failed");
	mapped = true;
	return addr;
}



void vertexbufferobject::unmap()
{
	if (!mapped)
		throw std::runtime_error("vertex buffer object not mapped before unmap()");
	mapped = false;
	bind();
	if (glUnmapBufferARB(target) != GL_TRUE) {
		sys().add_console("failed to unmap Vertex Buffer object, data invalid");
	}
}