/*
   render/draw.cc
   This file is part of the Osirion project and is distributed under
   the terms and conditions of the GNU General Public License version 2
*/

#include <sstream>
#include <iomanip>

#include "core/application.h"
#include "core/entity.h"
#include "core/entityglobe.h"
#include "core/gameinterface.h"
#include "core/range.h"

#include "math/functions.h"

#include "model/fragment.h"
#include "model/material.h"
#include "model/model.h"

#include "render/debugdrawer.h"
#include "render/draw.h"
#include "render/dust.h"
#include "render/light.h"
#include "render/lightenvironment.h"
#include "render/render.h"
#include "render/textures.h"
#include "render/gl.h"

namespace render
{

size_t Stats::tris = 0;
size_t Stats::quads = 0;
size_t Stats::fragments = 0;

void Stats::clear()
{
	tris = 0;
	quads = 0;
	fragments = 0;
}

math::Vector3f v0(1, -1, 1);
math::Vector3f v1(1,  1, 1);
math::Vector3f v2(-1,  1,  1);
math::Vector3f v3(-1, -1,  1);

math::Vector3f v4(1, -1, -1);
math::Vector3f v5(1,  1, -1);
math::Vector3f v6(-1,  1,  -1);
math::Vector3f v7(-1, -1,  -1);

core::Zone *zone = 0;

bool draw_particles = true;
bool draw_lights = true;

typedef std::map<float, core::EntityGlobe *> Globes;
Globes globes_list;

LightEnvironment lightenv_zone;

/* ---- Prepare the renderer state --------------------------------- */

void pass_prepare(float seconds)
{
	using namespace model;
	
	// render settings for this pass_prepare
	draw_lights = true;
	if (r_lights && (r_lights->value() <= 0.0f)) {
		draw_lights = false;
	}
	
	draw_particles = true;
	if (r_particles && (r_particles->value() <= 0.0f)) {
		draw_particles = false;
	}
	
	// initialize lights
	lightenv_zone.clear();

	// clear current list of globes
	globes_list.clear();

	// zone ambient light
	GLfloat zone_ambient[4];
	for (size_t i = 0; i < 3; i++) {
		zone_ambient[i] = core::localplayer()->zone()->ambient_color()[i];
	}
	zone_ambient[3] = 1.0f;
	gl::lightmodel(GL_LIGHT_MODEL_AMBIENT, zone_ambient);

	// zone light sources
	for (core::Zone::Content::iterator it = zone->content().begin(); it != zone->content().end(); it++) {
		core::Entity *entity = (*it);

		if (!ext_render(entity)) {
			new RenderExt(entity);
		}
		entity->extension((size_t) core::Extension::Render)->frame(seconds);

		// globes
		if (entity->type() == core::Entity::Globe) {
			core::EntityGlobe *globe = static_cast<core::EntityGlobe *>(entity);

			// add the globe to the globes list
			if (globe->visible() && !ext_render(globe)->behind()) {
				globes_list[ext_render(globe)->distance()] = globe;
			}

			// add zone lights
			if (globe->has_flag(core::Entity::Bright)) {
				float zone_light_brightness = math::max(globe->color().r, math::max(globe->color().g, globe->color().b));
				Light *zone_light = new Light(globe->location(), globe->color());
				zone_light->set_attenuation(zone_light_brightness * 1.5f, zone_light_brightness * 0.00001f, zone_light_brightness * 0.000000001f);
				lightenv_zone.add(zone_light);
			}

		} else {
			// this reloads entity models if required by r_restart
			if (!entity->model() && entity->modelname().size()) {
				entity->set_model(model::Model::load(entity->modelname()));
			}
		}
	}
	
	// zone lights are draw in world space coordinates
	lightenv_zone.draw();
	lightenv_zone.enable();
}

/* ----- Skybox ---------------------------------------------------- */
/*
* To use quake3 skyboxes:
* 	switch left and right images
* 	rotate top image 90 degrees clockwise
* 	rotate bottom image 90 degrees counter-clockwise
*  
*/
void draw_pass_sky()
{
	if (!(r_sky && r_sky->value()))
		return;

	if (!core::localplayer()->zone())
		return;

	if (core::localplayer()->zone()->sky().size()) {
		Textures::load_cubemap("textures/sky/" + core::localplayer()->zone()->sky());
	} else {
		return;
	}

	gl::enable(GL_TEXTURE_CUBE_MAP);
	
	gl::push();
	gl::translate(Camera::eye());

	gl::color(1.0f, 1.0f, 1.0f, 1.0f);
	
	const float r = 128.0f;

	gl::begin((r_wireframe && r_wireframe->value()) ? gl::LineLoop : gl::Quads);
	
	// front
	gl::texcoord(1, 1, 1); gl::vertex(r, r, r);
	gl::texcoord(1, -1, 1); gl::vertex(r, -r, r);
	gl::texcoord(1, -1, -1); gl::vertex(r, -r, -r);
	gl::texcoord(1, 1, -1); gl::vertex(r, r, -r);
	
	// right
	gl::texcoord(1, -1, 1); gl::vertex(r, -r, r);
	gl::texcoord(-1, -1, 1); gl::vertex(-r, -r, r);
	gl::texcoord(-1, -1, -1); gl::vertex(-r, -r, -r);
	gl::texcoord(1, -1, -1); gl::vertex(r, -r, -r);
	
	// back
	gl::texcoord(-1, -1, 1); gl::vertex(-r, -r, r);
	gl::texcoord(-1, 1, 1); gl::vertex(-r, r, r);
	gl::texcoord(-1, 1, -1); gl::vertex(-r, r, -r);
	gl::texcoord(-1, -1, -1); gl::vertex(-r, -r, -r);
	
	// left
	gl::texcoord(-1, 1, 1); gl::vertex(-r, r, r);
	gl::texcoord(1, 1, 1); gl::vertex(r, r, r);
	gl::texcoord(1, 1, -1); gl::vertex(r, r, -r);	
	gl::texcoord(-1, 1, -1); gl::vertex(-r, r, -r);
	
	// up
	gl::texcoord(-1, 1, 1); gl::vertex(-r, r, r);
	gl::texcoord(-1, -1, 1); gl::vertex(-r, -r, r);
	gl::texcoord(1, -1, 1); gl::vertex(r, -r, r);
	gl::texcoord(1, 1, 1); gl::vertex(r, r, r);
	
	// down
	gl::texcoord(1, 1, -1); gl::vertex(r, r, -r);
	gl::texcoord(1, -1, -1); gl::vertex(r, -r, -r);
	gl::texcoord(-1, -1, -1); gl::vertex(-r, -r, -r);
	gl::texcoord(-1, 1, -1); gl::vertex(-r, r, -r);

	gl::end();

	gl::disable(GL_TEXTURE_CUBE_MAP);
	
	gl::pop();
	
	Stats::quads += 6;
}

/* ---- Draw a wireframe box --------------------------------------- */

void draw_box(const math::Vector3f & minbox, const math::Vector3f & maxbox)
{
	// top
	gl::begin(gl::LineLoop);
	gl::vertex(maxbox.x(), maxbox.y(), maxbox.z());
	gl::vertex(minbox.x(), maxbox.y(), maxbox.z());
	gl::vertex(minbox.x(), minbox.y(), maxbox.z());
	gl::vertex(maxbox.x(), minbox.y(), maxbox.z());
	gl::end();

	// bottom
	gl::begin(gl::LineLoop);
	gl::vertex(maxbox.x(), maxbox.y(), minbox.z());
	gl::vertex(minbox.x(), maxbox.y(), minbox.z());
	gl::vertex(minbox.x(), minbox.y(), minbox.z());
	gl::vertex(maxbox.x(), minbox.y(), minbox.z());
	gl::end();

	// body
	gl::begin(gl::Lines);
	gl::vertex(maxbox.x(), maxbox.y(), maxbox.z());
	gl::vertex(maxbox.x(), maxbox.y(), minbox.z());
	gl::vertex(minbox.x(), maxbox.y(), maxbox.z());
	gl::vertex(minbox.x(), maxbox.y(), minbox.z());
	gl::vertex(minbox.x(), minbox.y(), maxbox.z());
	gl::vertex(minbox.x(), minbox.y(), minbox.z());
	gl::vertex(maxbox.x(), minbox.y(), maxbox.z());
	gl::vertex(maxbox.x(), minbox.y(), minbox.z());
	gl::end();
}
 
/* ---- Globes ----------------------------------------------------- */

void draw_sphere(const math::Color & color, float radius)
{
	gl::scale(radius, radius, radius);
	gl::color(color);

	size_t index = 0;
	size_t count = (model::SPHERESEGMENTS) * 2;

	// draw body
	for (int j = 0; j < (model::SPHERESEGMENTS - 1) / 2; j++) {
		glDrawArrays(gl::QuadStrip, index, count);
		index += count;
		Stats::quads += count / 2 - 1;
	}
}

void draw_globe_corona(const math::Vector3f location, const math::Color & color, const float radius, const size_t corona_id) 
{
	// draw the globe's corona
	if (corona_id) {
		math::Vector3f v = location - Camera::eye();
		v.normalize();
		float a = dotproduct(v, Camera::axis().forward());
		if (a > 0.1f) {
			gl::enable(GL_BLEND);
			gl::disable(GL_DEPTH_TEST);
			gl::depthmask(GL_FALSE);	// disable depth buffer writes
			gl::enable(GL_TEXTURE_2D);
			
			Textures::bind(corona_id);

			math::Color drawcolor(color);
			drawcolor.a = a - 0.1f;

			gl::color(drawcolor);
			
			gl::begin(gl::Quads);
			gl::texcoord(0, 1);
			gl::vertex((Camera::axis().up() - Camera::axis().left()) * radius * 4.0f);
			gl::texcoord(0, 0);
			gl::vertex((Camera::axis().up() + Camera::axis().left()) * radius * 4.0f);
			gl::texcoord(1, 0);
			gl::vertex((Camera::axis().up() * -1 + Camera::axis().left()) * radius * 4.0f);
			gl::texcoord(1, 1);
			gl::vertex((Camera::axis().up() * -1 - Camera::axis().left()) * radius * 4.0f);
			gl::end();

			Stats::quads++;
			
			gl::disable(GL_TEXTURE_2D);
			gl::enable(GL_DEPTH_TEST);
			gl::depthmask(GL_TRUE);	// enable depth buffer writes
			gl::disable(GL_BLEND);
		}
	}	
}

void draw_globe_rings(const math::Color & color, const size_t rings_id)
{
	gl::color(color);
	
	gl::enable(GL_BLEND);
	//gl::disable(GL_CULL_FACE);
	gl::depthmask(GL_FALSE);	// disable depth buffer writes
	
	Textures::bind(rings_id);
	
	gl::begin(gl::Quads);
	
	// top
	gl::normal(0.0f, 0.0f, 1.0f);
	gl::texcoord(0, 0);
	gl::vertex(-2.0f, -2.0f, 0.0f);
	
	gl::normal(0.0f, 0.0f, 1.0f);
	gl::texcoord(1, 0);
	gl::vertex(2.0f, -2.0f, 0.0f);
	
	gl::normal(0.0f, 0.0f, 1.0f);
	gl::texcoord(1, 1);
	gl::vertex(2.0f, 2.0f, 0.0f);
	
	gl::normal(0.0f, 0.0f, 1.0f);
	gl::texcoord(0, 1);
	gl::vertex(-2.0f, 2.0f, 0.0f);
	
	//bottom		
	gl::normal(0.0f, 0.0f, -1.0f);
	gl::texcoord(0, 1);
	gl::vertex(-2.0f, 2.0f, 0.0f);	
	
	gl::normal(0.0f, 0.0f, -1.0f);
	gl::texcoord(1, 1);
	gl::vertex(2.0f, 2.0f, 0.0f);

	gl::normal(0.0f, 0.0f, -1.0f);
	gl::texcoord(1, 0);
	gl::vertex(2.0f, -2.0f, 0.0f);

	gl::normal(0.0f, 0.0f, -1.0f);
	gl::texcoord(0, 0);
	gl::vertex(-2.0f, -2.0f, 0.0f);
	
	gl::end();
	
	gl::depthmask(GL_TRUE);	// enable depth buffer writes
	
	//gl::enable(GL_CULL_FACE);
	gl::disable(GL_BLEND);
	
	Stats::quads += 2;
}

void draw_pass_globes()
{
	// FIXME is this ever reset ?
	GLfloat globe_specular[] = { 0.25f, 0.25f, 0.25f, 1.0f };
	gl::material(GL_FRONT, GL_SPECULAR, globe_specular);

	// Globes have to be rendered distance sorted, closest last.
	// Globes behind farplane are rescaled and repositioned.
	for (Globes::reverse_iterator rit = globes_list.rbegin(); rit != globes_list.rend(); rit++) {
		const core::EntityGlobe *globe = (*rit).second;
		
		math::Vector3f location(globe->location());	
		float radius = globe->radius();
		
		if (ext_render(globe)->distance() > (FARPLANE - globe->radius())) {
			// globe is behind the far plane, make a fake size calculation
			location = Camera::eye() + (location - Camera::eye()) * ((FARPLANE - globe->radius()) / ext_render(globe)->distance());
			radius  *= (FARPLANE - globe->radius()) / (ext_render(globe)->distance());

			gl::depthmask(GL_FALSE);

			lightenv_zone.draw(location - globe->location());
		}
				
		gl::push();
		gl::translate(location);
		
		if (globe->has_flag(core::Entity::Bright)) { 
			gl::disable(GL_LIGHTING);
			if (globe->corona_id()) {
				// draw globe corona
				// corona is rendered in camera space
				draw_globe_corona(location, globe->color(), radius, globe->corona_id());
			}
		}
		
		if (globe->texture_id()) {
			// textured globe
			Textures::bind(globe->texture_id());
			gl::enable(GL_TEXTURE_2D);
		}
		
		gl::multmatrix(globe->axis());
		if (globe->rotationspeed()) {
			float angle = math::degrees360f(core::application()->time() * globe->rotationspeed());
			gl::rotate(angle, math::Vector3f::Zaxis());
		}
		
		draw_sphere(globe->color(), radius);
		
		if (globe->rings_id()) {	
			if (!globe->texture_id()) {
				gl::enable(GL_TEXTURE_2D);
			}			
			draw_globe_rings(globe->color(), globe->rings_id());
		}

		gl::pop();
		
		if (globe->texture_id() || globe->rings_id()) {
			gl::disable(GL_TEXTURE_2D);
		}
		
		if (globe->has_flag(core::Entity::Bright)) { 
			gl::enable(GL_LIGHTING);
		}
		
		if (ext_render(globe)->distance() > (FARPLANE - globe->radius())) {
			gl::depthmask(GL_TRUE);
			lightenv_zone.draw();
		}
	}
}

/* ---- Default entities ------------------------------------------ */

void draw_entity_sphere(const core::Entity* entity)
{
	draw_sphere(entity->color(), entity->radius());
}

void draw_entity_cube(const core::Entity* entity)
{
	const float radius = entity->radius();

	gl::scale(radius, radius, radius);

	gl::color(entity->color());
	gl::begin(gl::Quads);

	// top
	gl::normal(0, 0, 1);
	gl::vertex(v0);
	gl::vertex(v1);
	gl::vertex(v2);
	gl::vertex(v3);

	// bottom
	gl::normal(0, 0, -1);
	gl::vertex(v7);
	gl::vertex(v6);
	gl::vertex(v5);
	gl::vertex(v4);

	// sides
	gl::normal(1, 0, 0);
	gl::vertex(v1);
	gl::vertex(v0);
	gl::vertex(v4);
	gl::vertex(v5);

	gl::normal(-1, 0, 0);
	gl::vertex(v3);
	gl::vertex(v2);
	gl::vertex(v6);
	gl::vertex(v7);

	gl::normal(0, 1, 0);
	gl::vertex(v2);
	gl::vertex(v1);
	gl::vertex(v5);
	gl::vertex(v6);

	gl::normal(0, -1, 0);
	gl::vertex(v0);
	gl::vertex(v3);
	gl::vertex(v7);
	gl::vertex(v4);

	gl::end();
}

void draw_entity_diamond(const core::Entity* entity)
{
	const float radius = entity->radius() / 2.0f;

	/* ---- draw axis lines ---- */
	gl::color(entity->color_second());
	gl::begin(gl::Lines);

	gl::vertex(1.25f * radius, 0, 0);
	gl::vertex(2* radius, 0, 0);

	gl::vertex(0, 1.25f * radius, 0);
	gl::vertex(0, 2* radius, 0);

	gl::vertex(0, 0, 1.25f * radius);
	gl::vertex(0, 0, 2 * radius);

	gl::vertex(-1.25f * radius, 0, 0);
	gl::vertex(-2 * radius, 0, 0);

	gl::vertex(0, -1.25f * radius, 0);
	gl::vertex(0, -2 * radius, 0);

	gl::vertex(0, 0, -1.25f * radius);
	gl::vertex(0, 0, -2 * radius);

	gl::end();

	/* ---- draw rotating body lines ---- */
	float angle = (core::application()->time() + ext_render(entity)->fuzz()) * 45.0f;
	angle = angle - 360.0f * floorf(angle / 360.0f);
	gl::rotate(angle, math::Vector3f::Zaxis());

	if (r_wireframe->value() == 0.0f) {
		glPolygonMode(GL_FRONT, GL_LINE);
	}
	gl::color(entity->color());

	gl::begin(gl::TriangleFan);
	gl::normal(0, 0 , 1);
	gl::vertex(0, 0, radius);

	gl::normal(1, 0 , 0);
	gl::vertex(radius, 0.0f, 0.0f);
	gl::normal(0, 1, 0);
	gl::vertex(0.0f, radius, 0.0f);
	gl::normal(-1, 0 , 0);
	gl::vertex(-radius, 0.0f, 0.0f);
	gl::normal(0, -1, 0);
	gl::vertex(0.0f, -radius, 0.0f);
	gl::normal(1, 0 , 0);
	gl::vertex(radius, 0.0f, 0.0f);

	gl::end();

	gl::begin(gl::TriangleFan);
	gl::normal(0, 0 , -1);
	gl::vertex(0, 0, -radius);

	gl::normal(1, 0,  0);
	gl::vertex(radius, 0.0f, 0.0f);

	gl::normal(0, -1, 0);
	gl::vertex(0.0f, -radius, 0.0f);

	gl::normal(-1, 0 , 0);
	gl::vertex(-radius, 0.0f, 0.0f);

	gl::normal(0, 1, 0);
	gl::vertex(0.0f, radius, 0.0f);

	gl::normal(1, 0 , 0);
	gl::vertex(radius, 0.0f, 0.0f);

	gl::end();
	if (r_wireframe->value() == 0.0f) {
		glPolygonMode(GL_FRONT, GL_FILL);
	}
}

void draw_entity_axis(const core::Entity* entity)
{
	float r = entity->radius();

	gl::begin(gl::Lines);
	gl::color(entity->color_second());
	gl::vertex(r, 0.0f, 0.0f);
	gl::color(entity->color());
	gl::vertex(-r, 0.0f, 0.0f);

	gl::vertex(0.0f, r / 2, 0.0f);
	gl::vertex(0.0f, -r / 2, 0.0f);

	gl::vertex(0.0f, 0.0f, r);
	gl::vertex(0.0f, 0.0f, -r);
	gl::end();
}

void draw_pass_default()
{
	for (core::Zone::Content::iterator it = zone->content().begin(); it != zone->content().end(); ++it) {

		core::Entity *entity = (*it);
		if (!entity->model() && (entity->type() != core::Entity::Globe) && !entity->serverside() && !ext_render(entity)->behind()) {

			gl::push();
			gl::translate(entity->location());
			gl::multmatrix(entity->axis());

			if (entity->has_flag(core::Entity::Bright)) {
				gl::disable(GL_LIGHTING);
			}

			switch (entity->shape()) {
				case core::Entity::Sphere:
					draw_entity_sphere(entity);
					break;

				case core::Entity::Diamond:
					draw_entity_diamond(entity);
					break;

				case core::Entity::Axis:
					draw_entity_axis(entity);
					break;

				case core::Entity::Cube:

				default:
					draw_entity_cube(entity);
					break;
			}

			if (entity->has_flag(core::Entity::Bright)) {
				gl::enable(GL_LIGHTING);
			}

			gl::pop();
		}
	}
}

/* ---- Model Fragments -------------------------------------------- */

void draw_fragment_normals(const model::Fragment *fragment, bool draw_details)
{
	size_t index = fragment->index();
	size_t vertex_count = fragment->structural_size();
	if (draw_details)
		vertex_count += fragment->detail_size();

	gl::begin(gl::Lines);

	const float s = 0.05f;
	for (size_t i = 0; i < vertex_count; i++) {
		const float *n = &core::game()->vertexarray()->ptr()[(index+i) * 8 + 2];
		const float *v = &core::game()->vertexarray()->ptr()[(index+i) * 8 + 5];

		//gl::normal(-n[0], -n[1], -n[2]);
		gl::vertex(v[0], v[1], v[2]);

		//gl::normal(n[0], n[1], n[2]);
		gl::vertex(v[0] + n[0] * s, v[1] + n[1] * s, v[2] + n[2] * s);
	}
	gl::end();
}

void draw_fragment(const model::Fragment *fragment, bool draw_details)
{
	size_t index = fragment->index();

	size_t vertex_count = fragment->structural_size();
	if (draw_details)
		vertex_count += fragment->detail_size();

	switch (fragment->type()) {
		case model::Fragment::Triangles:
			glDrawArrays(gl::Triangles, index, vertex_count);
			Stats::tris += vertex_count / 3;
			break;

		case model::Fragment::Quads:
			glDrawArrays(gl::Quads, index, vertex_count);
			Stats::quads += vertex_count / 4;
			break;
	}

	if (r_normals->value()) {
		gl::begin(gl::Lines);

		gl::color(1.0f, 0.0f, 0.0f);
		const float s = 0.01f;
		
		for (size_t i = 0; i < vertex_count; i++) {
			
			const float *n = &core::game()->vertexarray()->ptr()[(index+i) * 8 + 2];
			const float *v = &core::game()->vertexarray()->ptr()[(index+i) * 8 + 5];

			gl::normal(-n[0], -n[1], -n[2]);
			gl::vertex(v[0], v[1], v[2]);

			gl::normal(n[0], n[1], n[2]);
			gl::vertex(v[0] + n[0] * s, v[1] + n[1] * s, v[2] + n[2] * s);
			
		}
		gl::end();
	}

	Stats::fragments++;
}

void draw_model_fragments(model::Model *model,
			  const math::Color & color_primary, const math::Color & color_secondary,
			  const float enginetime, const bool detail, const bool power, const float thrust)
{
	State::set_color(color_primary);
	State::set_color_second(color_secondary);
	State::set_color_engine(model->enginecolor() * thrust);
	State::set_power(power);
			
	for (model::Model::Groups::const_iterator git = model->groups().begin(); git != model->groups().end(); git++) {

		const model::FragmentGroup *group = (*git);
		gl::push();

		gl::translate(group->location());
		gl::multmatrix(group->axis());
		const float s = group->scale();
		if (s)
			gl::scale(s, s, s);
		
		if (group->type() == model::FragmentGroup::Rotate) {
			const float rotation_angle = math::degrees360f((group->engine() ? enginetime : core::game()->time()) * group->speed());
			gl::rotate(-rotation_angle, group->movement());
			
		} else if (group->type() == model::FragmentGroup::Move ) {
			
			const float freq = group->speed() / group->distance(); 
			math::Vector3f translation(group->movement() * group->distance());
			translation *= sinf((group->engine() ? enginetime : core::game()->time()) * M_PI * freq) * 0.5f + 0.5f;
			gl::translate(translation);
		}

		for (model::FragmentGroup::Fragments::const_iterator fit = group->fragments().begin(); fit != group->fragments().end(); fit++) {

			const model::Fragment *fragment = (*fit);
			
			for (model::Material::Layers::const_iterator lit = fragment->material()->layers().begin(); lit != fragment->material()->layers().end(); ++lit) {
				State::use_material_layer(fragment->material(), (*lit));
				draw_fragment(fragment, detail);
				State::reset();
			}
			
			if (r_normals->value()) {
				// force reset of material settings for the next fragment
				State::reset();
				gl::color(0.75f, 0.0f, 0.0f);
				draw_fragment_normals(fragment, detail);
				State::reset();
			}
		}

		gl::pop();
	}
}

// draw entity axis
void draw_model_axis(const core::Entity *entity)
{
	// axis
	const float r = entity->model()->radius() * 1.5f;

	gl::begin(gl::Lines);

	gl::color(entity->color());

	gl::vertex(-r, 0.0f, 0.0f);
	gl::vertex(r, 0.0f, 0.0f);

	gl::vertex(0.0f, -r, 0.0f);
	gl::vertex(0.0f, r, 0.0f);

	gl::vertex(0.0f, 0.0f, -r);
	gl::vertex(0.0f, 0.0f, r);

	const math::Axis worldaxis(entity->axis().transpose());

	gl::color(1.0f, 0.0f, 0.0f);

	gl::vertex(worldaxis.forward() * -1 * r);
	gl::vertex(worldaxis.forward() * r);

	gl::vertex(worldaxis.left() * -1 * r);
	gl::vertex(worldaxis.left() * r);

	gl::vertex(worldaxis.up() * -1 * r);
	gl::vertex(worldaxis.up() * r);

	gl::end();
}

void draw_pass_model_fragments()
{
	/*
	 * 	FIXME
	 * 	fragmentgroups with movement tied to engine activity can not be synchronized with server-side collision
	 * 
	 * 	For moving and rotating fragmentgroups, the enginetime must match
	 * 	the time used by core:: to calculate the rotation or movement 
	 * 	of the asssociated collision models.
	 * 	Currently, enginetime is client-side only, and there is no way
	 * 	to sync core and render movement of fragmentgroups without sacrificing
	 * 	the functionality of the FragmentGroup::engine() flag. 
	 */
	for (core::Zone::Content::iterator it = zone->content().begin(); it != zone->content().end(); it++) {
		core::Entity *entity = (*it);

		if (entity->model() && ext_render(entity)->visible() && !ext_render(entity)->behind()) {
			gl::push();
			gl::translate(entity->location());
			gl::multmatrix(entity->axis());
			
			const float modelscale = entity->radius() / entity->model()->radius();
			gl::scale(modelscale, modelscale, modelscale);

			draw_model_fragments(
				entity->model(),
				entity->color(), 
				entity->color_second(), 
				ext_render(entity)->enginetime(), 
				ext_render(entity)->detailvisible(), 
				ext_render(entity)->power(), 
				ext_render(entity)->thrust()
			);

			if (r_slots && r_slots->value()) {
				draw_slots(entity);
			}
			
			if (r_bbox->value()) {
				gl::disable(GL_DEPTH_TEST);
				gl::color(entity->color().r * 0.5f, entity->color().g * 0.5f, entity->color().b * 0.5f, 0.25f);
				draw_box(entity->model()->box().min(), entity->model()->box().max());
				
				gl::enable(GL_DEPTH_TEST);
				gl::color(entity->color());
				draw_box(entity->model()->box().min(), entity->model()->box().max());
			}

			if (r_axis->value()) {
				draw_model_axis(entity);
			}
			
			gl::pop();
		}
	}
}

/* ---- Model FX --------------------------------------------------- */

void draw_model_lights(model::Model *model, const float scale,
	const math::Vector3f & entity_location, const math::Axis & entity_axis,
	const math::Color & entity_color, const math::Color & entity_color_second, const float thrust, const float fuzz)
{
	float t = 0.0f;
	float a = 0.0f;
	float light_size = 0.0f;

	math::Vector3f location;
	math::Vector3f offset;
	math::Color color;
	math::Axis flare_axis;

	// disable culling by default
	gl::disable(GL_CULL_FACE);
	model::Cull current_cull = model::CullNone;
	
	size_t current_texture = Textures::bind("textures/fx/flare00");
	
	gl::begin(gl::Quads);

	// draw model lights
	for (model::Model::Lights::iterator lit = model->lights().begin(); lit != model->lights().end(); lit++) {
		model::Light *light = (*lit);

		// engine activated lights
		if (light->engine()) {
			if (thrust < 0.001f) {
				continue;	// next light
			}
		}

		// strobe frequency
		if (light->strobe()) {
			t = (core::application()->time() + fuzz - light->offset()) * light->frequency();
			if ((t - floorf(t)) > light->time()) {
				continue;	// next light
			}
		}
		
		// entity color overrides light color
		// light color overrides engine color
		if (light->entity()) {
			if (light->entity_second()) {
				// entity tertiary color
				for (size_t i = 0; i < 3; i++) {
					color[i] = (entity_color[i] + entity_color_second[i]) / 2;
				}
			} else {
				// entity primary color
				color.assign(entity_color);
			}
			
		} else if (light->entity_second()) {
			// entity secondary color
			color.assign(entity_color_second);
			
		} else if (light->has_color()) {
			// light color
			color.assign(light->color());
			
		} else if (light->engine()) {
			// FIXME engine_color or thrust_activated
			color.assign(model->enginecolor());
			
		} else {
			color.assign(light->color());
			
		}

		// default alpha is 0.8, engine flag alters alpha
		a = 0.8f;
		if (light->engine()) {
			a *= thrust;
		}
		color.a = a;

		location.assign(entity_location + (entity_axis * light->location()) * scale);
		light_size = light->radius() * scale;

		// track OpenGL state changes
		if (current_texture != light->texture()) {
			gl::end();
			current_texture = Textures::bind(light->texture());
			gl::begin(gl::Quads);
		}

		// draw the quad
		
		// FIXME add random per-light rotation
		gl::color(color);

		gl::texcoord(1, 0);
		gl::vertex(location + (Camera::axis().up() - Camera::axis().left()) * light_size);
		gl::texcoord(0, 0);
		gl::vertex(location + (Camera::axis().up() + Camera::axis().left()) * light_size);
		gl::texcoord(0, 1);
		gl::vertex(location + (Camera::axis().up() * -1 + Camera::axis().left()) * light_size);
		gl::texcoord(1, 1);
		gl::vertex(location + (Camera::axis().up() * -1 - Camera::axis().left()) * light_size);
		Stats::quads++;

	}

	// draw flares
	for (model::Model::Flares::iterator flit = model->flares().begin(); flit != model->flares().end(); flit++) {
		model::Flare *flare = (*flit);

		// engine activated flares
		if (flare->engine()) {
			if (thrust < 0.001f) {
				continue;	// next flare
			}
		}

		// strobe frequency
		if (flare->strobe()) {
			t = (core::application()->time() + fuzz - flare->offset()) * flare->frequency();
			if ((t - floorf(t)) > flare->time()) {
				continue;	// next flare
			}
		}

		// calulcate viewing angle factor
		flare_axis.assign(entity_axis * flare->axis());
		a = math::absf(dotproduct(flare_axis.forward(), Camera::axis().forward()));
		if (a < 0.001f) {
			continue;	// next flare
		}

		// entity color overrides flare color
		// flare color overrides engine color
		if (flare->entity()) {
			if (flare->entity_second()) {
				// entity tertiary color
				for (size_t i = 0; i < 3; i++) {
					color[i] = (entity_color[i] + entity_color_second[i]) / 2;
				}
			} else {
				// entity primary color
				color.assign(entity_color);
			}
			
		} else if (flare->entity_second()) {
			// entity secondary color
			color.assign(entity_color_second);
			
		} else if (flare->has_color()) {
			// flare color
			color.assign(flare->color());
			
		} else if (flare->engine()) {
			// FIXME engine_color or thrust_activated
			color.assign(model->enginecolor());
			
		} else {
			color.assign(flare->color());
			
		}

		// default alpha is 0.8, engine flag alters alpha
		// alpha decreases with viewing angle
		a *= 0.8f;
		if (flare->engine()) {
			a *= thrust;
		}
		color.a = a;

		location.assign(entity_location + (entity_axis * flare->location()) * scale);
		light_size = flare->radius() * scale;

		// track OpenGL state changes
		if ((current_cull != flare->cull()) || (current_texture != flare->texture())) {
			gl::end();

			if (current_texture != flare->texture()) {
				current_texture = Textures::bind(flare->texture());
			}

			if (current_cull != flare->cull()) {
				if (flare->cull() == model::CullNone) {
					gl::disable(GL_CULL_FACE);
					current_cull = model::CullNone;
				} else {
					if (current_cull == model::CullNone) {
						gl::enable(GL_CULL_FACE);
					}

					if (flare->cull() == model::CullBack) {
						gl::cullface(GL_BACK);
						current_cull = model::CullBack;
					} else {
						gl::cullface(GL_FRONT);
						current_cull = model::CullFront;
					}
				}
			}

			gl::begin(gl::Quads);
		}

		// draw the quad
		gl::color(color);

		gl::texcoord(1, 0);
		gl::vertex(location + (flare_axis.up() + flare_axis.left()) * light_size);
		gl::texcoord(0, 0);
		gl::vertex(location + (flare_axis.up() - flare_axis.left()) * light_size);
		gl::texcoord(0, 1);
		gl::vertex(location + (flare_axis.up() * -1 - flare_axis.left()) * light_size);
		gl::texcoord(1, 1);
		gl::vertex(location + (flare_axis.up() * -1 + flare_axis.left()) * light_size);

		Stats::quads++;
	}

	gl::end();
	
	gl::cullface(GL_BACK);
	gl::enable(GL_CULL_FACE);
}

void draw_pass_model_fx(float elapsed)
{
	// enable texturing
	gl::enable(GL_TEXTURE_2D);

	for (core::Zone::Content::iterator it = zone->content().begin(); it != zone->content().end(); it++) {
		core::Entity *entity = (*it);
	
		if (entity->model() && ext_render(entity)->detailvisible()) {
			
			// draw lights and flares
			if (ext_render(entity)->power() && draw_lights) {
				const float modelscale = entity->radius() / entity->model()->radius();
				
				draw_model_lights(entity->model(), modelscale, 
						  entity->location(), entity->axis(),
						  entity->color(), entity->color_second(),
						  ext_render(entity)->thrust(), ext_render(entity)->fuzz()
				);
			}
		
			// draw particle systems
			if (draw_particles && ext_render(entity)->particles().size()) {

				for (RenderExt::ParticleSystems::iterator it = ext_render(entity)->particles().begin(); it != ext_render(entity)->particles().end(); ++it) {
					(*it)->draw(elapsed);
				}
			}		
		}
	}

	// restore the default depth buffer comparison function
	gl::depthfunc(GL_LEQUAL);
	
	gl::disable(GL_TEXTURE_2D);
	gl::cullface(GL_BACK);
	gl::enable(GL_CULL_FACE);
}

void draw_pass_model_radius()
{
	for (core::Zone::Content::iterator it = zone->content().begin(); it != zone->content().end(); it++) {
		core::Entity *entity = (*it);

		if (entity->model() && ext_render(entity)->visible()) {
			gl::push();
			gl::translate(entity->location());
			math::Color color = entity->color();
			color.a = 0.25f;
			draw_sphere(color, entity->radius());
			gl::pop();
		}
	}

}

void draw_pass_spacegrid()
{
	if (!(r_grid && r_grid->value()))
		return;

	int gridsize = 32;
	float s = 1.0f / gridsize;
	float z = -4.0f;

	float dx =  Camera::target().x() - floorf(Camera::target().x());
	float dy =  Camera::target().y() - floorf(Camera::target().y());

	gl::push();
	gl::translate(Camera::target());
	gl::color(0, 0, 1.0f);
	gl::normal(0, 0, 1.0f);

	gl::begin(gl::Lines);

	for (int i = -gridsize; i <= gridsize; i++) {
		gl::color(0, 0, 0, 0);
		gl::vertex(i - dx, -gridsize - dy, z);
		gl::color(0, 0, (gridsize - abs(i))*s, (gridsize - abs(i))*s);
		gl::vertex(i - dx, -dy, z);
		gl::vertex(i - dx, -dy , z);
		gl::color(0, 0, 0, 0);
		gl::vertex(i - dx, gridsize - dy, z);

		gl::vertex(-gridsize - dx, i - dy, z);
		gl::color(0, 0, (gridsize - abs(i))*s, (gridsize - abs(i))*s);
		gl::vertex(-dx, i - dy, z);
		gl::vertex(-dx, i - dy, z);
		gl::color(0, 0, 0, 0);
		gl::vertex(gridsize - dx, i - dy, z);
	}
	gl::end();

	gl::pop();
}

/* ----- Main draw routine ----------------------------------------- */

void draw(float seconds)
{
	zone = core::localplayer()->zone();

	// calculate client state
	pass_prepare(seconds);

	gl::disable(GL_DEPTH_TEST);	// disable depth testing
	gl::depthmask(GL_FALSE);	// disable depth buffer writing

	gl::polygonmode(GL_FRONT, GL_FILL);
	
	draw_pass_sky();		// draw the skybox

	gl::depthmask(GL_TRUE);		// enable writing to the depth buffer
	gl::depthfunc(GL_LEQUAL);	// default depth buffer comparison function
	gl::enable(GL_DEPTH_TEST);	// enable depth testing
	gl::enable(GL_CULL_FACE);	// enable culling
	gl::enable(GL_COLOR_MATERIAL);	// enable color tracking
	
	// enable wireframe mode if requested
	if (r_wireframe && r_wireframe->value()) {
		glPolygonMode(GL_FRONT, GL_LINE);
	}

	// check if the vertexarray needs re-uploading
	// set vertex array pointers
	if (State::has_vbo()) {
		gl::bindbuffer(GL_ARRAY_BUFFER, State::vbo());
		
		if (core::game()->vertexarray()->dirty()) {
			gl::bufferdata(GL_ARRAY_BUFFER, sizeof(float) * core::game()->vertexarray()->index(), core::game()->vertexarray()->ptr(), GL_STATIC_DRAW);
			core::game()->vertexarray()->set_dirty(false);
			
		}
		// Interleaved format is GL_T2F_N3F_V3F
		
		// void glTexCoordPointer(GLint size, GLenum type, GLsizei stride, const GLvoid *ptr )
		gl::texcoordpointer(2, GL_FLOAT, 8 * sizeof(GLfloat), 0);
		// void glNormalPointer(GLenum type, GLsizei stride, const GLvoid *ptr)
		gl::normalpointer(GL_FLOAT, 8 * sizeof(GLfloat), (void*) (2 * sizeof(GLfloat)));
		// void glVertexPointer(GLint size, GLenum type, GLsizei stride, const GLvoid *ptr)
		gl::vertexpointer(3, GL_FLOAT, 8 * sizeof(GLfloat), (void*) (5 * sizeof(GLfloat)));
		
	} else {
		gl::interleavedarrays(GL_T2F_N3F_V3F, 0, core::game()->vertexarray()->ptr());
	}
	
	// enable vertex arrays
	gl::enableclientstate(GL_TEXTURE_COORD_ARRAY);
	gl::enableclientstate(GL_NORMAL_ARRAY);
	gl::enableclientstate(GL_VERTEX_ARRAY);

	State::set_normalize(true);

	gl::enable(GL_LIGHTING);	// enable lighting

	draw_pass_globes();		// draw globes

	draw_pass_default();		// draw entities without model

	draw_pass_model_fragments();

	gl::disable(GL_LIGHTING);	// disable lighting

	State::set_normalize(false);

	gl::enable(GL_BLEND);
	gl::depthmask(GL_FALSE);	// disable depth buffer writing

	draw_pass_spacegrid();		// draw the blue spacegrid

	if (!core::localplayer()->view()) {
		math::Color dust_color(core::localplayer()->zone()->ambient_color());
		float s = math::max(math::max(dust_color[0], dust_color[1]), dust_color[2]);
		dust_color *= 0.8f / s;
		Dust::draw(dust_color);	// draw spacedust
	}

	// draw entity lights, flares and particles
	if (draw_lights || draw_particles) {

		draw_pass_model_fx(seconds);
		
	}

	// draw entity radius globe
	if (r_radius && r_radius->value()) {

		if (r_normalize && r_normalize->value()) {
			// enable full normalization
			gl::enable(GL_NORMALIZE);
		} else {
			// enable rescaling of normals
			gl::enable(GL_RESCALE_NORMAL);
		}

		gl::enable(GL_LIGHTING);

		draw_pass_model_radius();

		gl::disable(GL_LIGHTING);

		if (r_normalize && r_normalize->value()) {
			// disable full normalization
			gl::disable(GL_NORMALIZE);
		} else {
			// disable resaling of normals
			gl::disable(GL_RESCALE_NORMAL);
		}
	}

	gl::disableclientstate(GL_VERTEX_ARRAY);
	gl::disableclientstate(GL_NORMAL_ARRAY);
	gl::disableclientstate(GL_TEXTURE_COORD_ARRAY);

	// draw physics
	if (r_physics && r_physics->value()) {
		if (zone->physics()) {
			if (!zone->physics()->getDebugDrawer())
				zone->physics()->setDebugDrawer(&bullet_debugdrawer);
			
			// draw physics bodies in red
			gl::color(1.0f, 0.0f, 0.0f, 1.0f);
			gl::begin(gl::Lines);
			zone->physics()->debugDrawWorld();
			gl::end();
		}
	}

	gl::depthmask(GL_TRUE);		// enable depth buffer writing
	gl::disable(GL_DEPTH_TEST);	// disable depth buffer testing	
	gl::disable(GL_CULL_FACE);	// disable culling

	// GL_BLEND and GL_COLOR_MATERIAL must be enabled for the GUI
	//gl::disable(GL_COLOR_MATERIAL);	// disable color tracking
	
	// clear current zone light environment
	lightenv_zone.disable();
	lightenv_zone.clear();

	// clear current list of globes
	globes_list.clear();
}

// draw model slots: weapon slots and docking ports
void draw_slots(const core::Entity *entity)
{
	if (!entity->model()) {
		return;
	}
	
	if (entity->model()->docks().size()) {
		
		// draw docks: pass 1 - background with GL_DEPTH_TEST disabled
		gl::disable(GL_DEPTH_TEST);
		gl::color(0.0f, 0.5f, 0.5f, 0.25f);
		
		for (model::Model::Docks::iterator dit = entity->model()->docks().begin(); dit != entity->model()->docks().end(); dit++) {
			model::Dock *dock = (*dit);
			math::Vector3f maxbox(dock->location());
			math::Vector3f minbox(dock->location());

			for (size_t i = 0; i < 3; i++) {
				maxbox[i] += 0.025;
				minbox[i] -= 0.025;
			}

			draw_box(minbox, maxbox);
		}
		
		// draw docks: pass 2 - highlight with GL_DEPTH_TEST enabled
		gl::enable(GL_DEPTH_TEST);
		gl::color(0.0f, 1.0f, 1.0f, 1.0f);
		
		for (model::Model::Docks::iterator dit = entity->model()->docks().begin(); dit != entity->model()->docks().end(); dit++) {
			model::Dock *dock = (*dit);
			math::Vector3f maxbox(dock->location());
			math::Vector3f minbox(dock->location());

			for (size_t i = 0; i < 3; i++) {
				maxbox[i] += 0.025;
				minbox[i] -= 0.025;
			}

			draw_box(minbox, maxbox);
		}
	}
	
	if (entity->slots()) {

		// draw weapon slots: pass 1 - background with GL_DEPTH_TEST disabled
		gl::disable(GL_DEPTH_TEST);
		gl::color(0.5f, 0.0f, 0.0f, 0.25f);
		
		for(core::Slots::iterator it = entity->slots()->begin(); it != entity->slots()->end(); ++it) {
			core::Slot *slot = (*it);
			
			math::Vector3f maxbox(slot->location());
			math::Vector3f minbox(slot->location());

			for (size_t i = 0; i < 3; i++) {
				maxbox[i] += 0.025;
				minbox[i] -= 0.025;
			}

			draw_box(minbox, maxbox);
		}
		
		// draw weapon slots: pass 2 - highlight with GL_DEPTH_TEST enabled
		gl::enable(GL_DEPTH_TEST);
		gl::color(1.0f, 0.0f, 0.0f);
		
		for(core::Slots::iterator it = entity->slots()->begin(); it != entity->slots()->end(); ++it) {
			core::Slot *slot = (*it);
			
			math::Vector3f maxbox(slot->location());
			math::Vector3f minbox(slot->location());

			for (size_t i = 0; i < 3; i++) {
				maxbox[i] += 0.025;
				minbox[i] -= 0.025;
			}

			draw_box(minbox, maxbox);
		}
	}

	gl::enable(GL_DEPTH_TEST);
}

}