/* Copyright 2005 Nicholas Bishop
 * 
 * This file is part of SharpConstruct.
 *
 * SharpConstruct 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.
 *
 * SharpConstruct 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 SharpConstruct; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA */

#include "Mesh.h"
#include "Output3D.hh"
#include "OglExt.h"

#include <iostream>

using SharpConstruct::Buffer;
using SharpConstruct::VBO;

Buffer::Buffer( const unsigned type )
: index_( 0 ), type_( type ),
  count_( 0 ), dsize_( 0 )
{}

Buffer::~Buffer()
{
	glDeleteBuffersARB( 1, &index_ );
}

void Buffer::Create()
{
	if( index_ == 0 )
		glGenBuffersARB( 1, &index_ );
}

void Buffer::Initialize( const unsigned count,
			 const unsigned dsize,
			 const unsigned hint )
{
	count_ = count;
	dsize_ = dsize;
	glBufferDataARB( type_, count_ * dsize_, 0, hint );
}

void Buffer::Initialize( const unsigned count,
			 const unsigned dsize,
			 const unsigned hint,
			 const void* data )
{
	count_ = count;
	dsize_ = dsize;
	glBufferDataARB( type_, count_ * dsize_, data, hint );
}

void Buffer::Bind() const
{
	glBindBufferARB( type_, index_ );
}

unsigned Buffer::Count() const
{
	return count_;
}

VBO::VBO()
: vert_norm_color_( GL_ARRAY_BUFFER_ARB ),
  triangle_( GL_ELEMENT_ARRAY_BUFFER_ARB ),
  quad_( GL_ELEMENT_ARRAY_BUFFER_ARB )
{
	glEnableClientState( GL_VERTEX_ARRAY );
	glEnableClientState( GL_NORMAL_ARRAY );
	glEnableClientState( GL_COLOR_ARRAY );

	vert_norm_color_.Create();
	triangle_.Create();
	quad_.Create();
}

bool VBO::IsSupported()
{
	return glexExtensionsSupported( "GL_ARB_vertex_buffer_object" );
}

void VBO::Set( const Mesh& mesh, const bool vn,
	       const bool c, const bool p )
{
	if( p )
	{
		set_vert_norm_color_( mesh, true, true );
		set_polygons_( mesh );
	}
	else if( vn || c )
		set_vert_norm_color_( mesh, vn, c );
}

void VBO::set_vert_norm_color_( const Mesh& mesh,
				bool vn, bool c )
{
	using SharpConstruct::Optimized::Point3D;

	vert_norm_color_.Bind();
	
	const unsigned count( mesh.VisibleElements().Vertices );

	if( vert_norm_color_.Count() != count * 3 )
	{
		vert_norm_color_.Initialize( count * 3, sizeof( Point3D ),
				       GL_STREAM_DRAW_ARB );
		vn = true;
		c = true;
	}
	
	if( vn )
	{
		// Load vertex locations...
		glBufferSubDataARB( GL_ARRAY_BUFFER_ARB, 0,
				    count * sizeof( Point3D ),
				    &mesh.VertexLocations()[ 0 ] );
		glVertexPointer( 3, GL_FLOAT, sizeof( Point3D ), 0 );
		
		// Load vertex normals...
		glBufferSubDataARB( GL_ARRAY_BUFFER_ARB,
				    count * sizeof( Point3D ),
				    count * sizeof( Point3D ),
				    &mesh.VertexNormals()[ 0 ] );
		glNormalPointer( GL_FLOAT, sizeof( Point3D ),
				 ( ( char* )NULL +
				   ( count * sizeof( Point3D ) ) ) );
	}

	if( c )
	{
		// Load vertex colors...
		glBufferSubDataARB( GL_ARRAY_BUFFER_ARB,
				    count * 2 * sizeof( Point3D ),
				    count * sizeof( Color ),
				    &mesh.VertexColors()[ 0 ] );
		glColorPointer( 3, GL_FLOAT, sizeof( Color ),
				 ( ( char* )NULL +
				   ( count * 2 * sizeof( Point3D ) ) ) );
	}
}

void VBO::set_polygons_( const Mesh& mesh )
{
	triangle_.Bind();
	triangle_.Initialize( mesh.VisibleElements().Triangles,
			     sizeof( Triangle ), GL_STATIC_DRAW_ARB,
			     &mesh.Triangles()[ 0 ] );

	quad_.Bind();
	quad_.Initialize( mesh.VisibleElements().Quads,
			  sizeof( Quad ), GL_STATIC_DRAW_ARB,
			  &mesh.Quads()[ 0 ] );
}

void VBO::Draw() const
{
	vert_norm_color_.Bind();

	triangle_.Bind();
	glDrawElements( GL_TRIANGLES, triangle_.Count() * 3,
			GL_UNSIGNED_INT, 0 );
	
	quad_.Bind();
	glDrawElements( GL_QUADS, quad_.Count() * 4,
			GL_UNSIGNED_INT, 0 );

	//glDrawArrays( GL_POINTS, 0, vert_norm_color_.Count() / 3 );
}