// Copyright (C) 2011 Kornel Kisielewicz
// This file is part of NV Libraries.
// For conditions of distribution and use, see copyright notice in nv.hh

#include "nv/gfx/keyframed_mesh.hh"

#include <glm/gtc/matrix_access.hpp>
#include <glm/gtx/matrix_interpolation.hpp>
#include "nv/interface/context.hh"
#include "nv/interface/device.hh"


#include "nv/logging.hh"

using namespace nv;

keyframed_mesh::keyframed_mesh( context* a_context, mesh_data* a_data )
	: animated_mesh( a_context )
	, m_data( a_data )
	, m_start_frame( false )
	, m_stop_frame( false )
	, m_last_frame( 0 )
	, m_next_frame( 0 )
	, m_time( 0 )
	, m_fps( 0 )
	, m_interpolation( 0.0f )
	, m_looping( false )
	, m_active( false )
{
	m_va = m_context->get_device()->create_vertex_array();
}

size_t keyframed_mesh::get_max_frames() const
{
	return m_data->get_frame_count();
}

transform keyframed_mesh::get_tag( const std::string& tag ) const
{
	const std::vector< transform >& transforms = m_data->get_tag_map().at( tag );
	return interpolate( transforms[ m_last_frame ], transforms[ m_next_frame ], m_interpolation );
}

void keyframed_mesh::setup_animation( uint32 start, uint32 count, uint32 fps, bool loop )
{
	m_start_frame   = start;
	m_stop_frame    = start+count-1;
	m_looping       = loop;
	m_fps           = fps;
	m_active        = count > 1;
	m_time          = 0;
	m_last_frame    = start;
	m_next_frame    = (count > 1 ? start + 1 : start );
	m_interpolation = 0.0f;
}

void nv::keyframed_mesh::set_frame( uint32 frame )
{
	m_last_frame    = frame;
	m_next_frame    = frame;
	m_active        = false;
	m_interpolation = 0.0f;
}

void keyframed_mesh::update( uint32 ms )
{
	if ( m_active )
	{
		m_time += ms;
		uint32 f_diff = (m_stop_frame - m_start_frame);
		float f_time  = 1000 / (float)m_fps;
		float f_max   = ( m_looping ? ( f_diff + 1 ) : f_diff ) * f_time;
		float f_pos   = m_time / f_time;

		m_last_frame    = (uint32)glm::floor( f_pos ) + m_start_frame;
		m_next_frame    = m_last_frame + 1;
		if ( m_next_frame > m_stop_frame )
		{
			m_next_frame = m_start_frame;
		}

		if ( m_time >= f_max )
		{
			if ( m_looping )
			{
				uint32 left = m_time - static_cast< uint32 >( f_max );
				m_time = 0;
				update( left );
			}
			else
			{
				m_active     = false;
				m_last_frame = m_stop_frame;
				m_next_frame = m_stop_frame;
			}
		}
		m_interpolation = f_pos - glm::floor( f_pos );
	}
}

void nv::keyframed_mesh::update( program* a_program )
{
	a_program->set_opt_uniform( "nv_interpolate", m_interpolation );
}

nv::keyframed_mesh::~keyframed_mesh()
{
	delete m_va;
}

void nv::keyframed_mesh::run_animation( animation_entry* a_anim )
{
	keyframed_animation_entry * anim = down_cast<keyframed_animation_entry>(a_anim);
	setup_animation( anim->m_start, anim->m_frames, anim->m_fps, anim->m_looping );
}

keyframed_mesh_gpu::keyframed_mesh_gpu( context* a_context, mesh_data* a_data, program* a_program )
	: keyframed_mesh( a_context, a_data )
	, m_loc_next_position( 0 )
	, m_loc_next_normal( 0 )
	, m_gpu_last_frame( 0xFFFFFFFF )
	, m_gpu_next_frame( 0xFFFFFFFF )
{
	nv::vertex_buffer* vb;
	m_loc_next_position = a_program->get_attribute( "nv_next_position" )->get_location();
	m_loc_next_normal   = a_program->get_attribute( "nv_next_normal" )->get_location();

	vb = m_context->get_device()->create_vertex_buffer( nv::STATIC_DRAW, m_data->get_vertex_count() * sizeof( nv::vec3 ) * m_data->get_frame_count(), (void*)m_data->get_positions().data() );
	m_va->add_vertex_buffer( m_loc_next_position, vb, nv::FLOAT, 3, 0, 0, false );
	m_va->add_vertex_buffer( nv::POSITION, vb, nv::FLOAT, 3 );

	vb = m_context->get_device()->create_vertex_buffer( nv::STATIC_DRAW, m_data->get_vertex_count() * sizeof( nv::vec3 ) * m_data->get_frame_count(), (void*)m_data->get_normals().data() );
	m_va->add_vertex_buffer( m_loc_next_normal, vb, nv::FLOAT, 3, 0, 0, false );
	m_va->add_vertex_buffer( nv::NORMAL, vb, nv::FLOAT, 3 );

	vb = m_context->get_device()->create_vertex_buffer( nv::STATIC_DRAW, m_data->get_vertex_count() * sizeof( nv::vec2 ), (void*)m_data->get_texcoords().data() );
	m_va->add_vertex_buffer( nv::slot::TEXCOORD, vb, nv::FLOAT, 2 );
	nv::index_buffer* ib = m_context->get_device()->create_index_buffer( nv::STATIC_DRAW, m_data->get_index_count() * sizeof( nv::uint32 ), (void*)m_data->get_indices().data() );
	m_va->set_index_buffer( ib, nv::UINT, true );
}

void nv::keyframed_mesh_gpu::update( uint32 ms )
{
	keyframed_mesh::update( ms );

	size_t vtx_count = m_data->get_vertex_count();
	if ( m_gpu_last_frame != m_last_frame )
	{
		m_va->update_vertex_buffer( slot::POSITION, m_last_frame * vtx_count * sizeof( nv::vec3 ) );
		m_va->update_vertex_buffer( slot::NORMAL,   m_last_frame * vtx_count * sizeof( nv::vec3 ) );
		m_gpu_last_frame = m_last_frame;
	}
	if ( m_gpu_next_frame != m_next_frame )
	{
		m_va->update_vertex_buffer( m_loc_next_position, m_next_frame * vtx_count * sizeof( nv::vec3 ) );
		m_va->update_vertex_buffer( m_loc_next_normal,   m_next_frame * vtx_count * sizeof( nv::vec3 ) );
		m_gpu_next_frame = m_next_frame;
	}
}


nv::keyframed_mesh_cpu::keyframed_mesh_cpu( context* a_context, mesh_data* a_data )
	: keyframed_mesh( a_context, a_data )
{
	m_vb_position = m_context->get_device()->create_vertex_buffer( nv::STATIC_DRAW, m_data->get_vertex_count() * sizeof( nv::vec3 ), (void*)m_data->get_position_frame(0) );
	m_va->add_vertex_buffer( nv::slot::POSITION, m_vb_position, nv::FLOAT, 3 );

	m_vb_normal   = m_context->get_device()->create_vertex_buffer( nv::STATIC_DRAW, m_data->get_vertex_count() * sizeof( nv::vec3 ), (void*)m_data->get_normal_frame(0) );
	m_va->add_vertex_buffer( nv::slot::NORMAL, m_vb_normal, nv::FLOAT, 3 );

	nv::vertex_buffer* vb;
	vb = m_context->get_device()->create_vertex_buffer( nv::STATIC_DRAW, m_data->get_vertex_count() * sizeof( nv::vec2 ), (void*)m_data->get_texcoords().data() );
	m_va->add_vertex_buffer( nv::slot::TEXCOORD, vb, nv::FLOAT, 2 );

	nv::index_buffer* ib = m_context->get_device()->create_index_buffer( nv::STATIC_DRAW, m_data->get_index_count() * sizeof( nv::uint32 ), (void*)m_data->get_indices().data() );
	m_va->set_index_buffer( ib, nv::UINT, true );

	m_position.resize( m_data->get_vertex_count() );
	m_normal.resize( m_data->get_vertex_count() );
}

void nv::keyframed_mesh_cpu::update( uint32 ms )
{
	keyframed_mesh::update( ms );

	size_t vtx_count = m_data->get_vertex_count();
	const vec3* prev_position = m_data->get_position_frame( m_last_frame );
	const vec3* next_position = m_data->get_position_frame( m_next_frame );
	const vec3* prev_normal   = m_data->get_normal_frame( m_last_frame );
	const vec3* next_normal   = m_data->get_normal_frame( m_next_frame );

	for ( size_t i = 0; i < vtx_count; ++i )
	{
		m_position[i] = glm::mix( prev_position[i], next_position[i], m_interpolation );
		m_normal[i]   = glm::mix( prev_normal[i],   next_normal[i],   m_interpolation );
	}

	m_vb_position->bind();
	m_vb_position->update( m_position.data(), 0, vtx_count * sizeof( nv::vec3 ) );
	m_vb_position->unbind();

	m_vb_normal->bind();
	m_vb_normal->update( m_normal.data(), 0, vtx_count * sizeof( nv::vec3 ) );
	m_vb_normal->unbind();
}