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

#include "render/camera.h"
#include "render/sky.h"
#include "render/textures.h"

namespace render 
{
	
size_t Sky::sky_texture_up = 0;
size_t Sky::sky_texture_down = 0;
size_t Sky::sky_texture_left = 0;
size_t Sky::sky_texture_right = 0;
size_t Sky::sky_texture_front = 0;
size_t Sky::sky_texture_back = 0;

std::string  Sky::sky_name;

void Sky::draw(const std::string & name)
{
	if (sky_name.compare(name) != 0) {
		unload();
	}
	
	if (!sky_name.size()) {
		
		if (name.size()) {
			const std::string basename("textures/sky/" + name);
			
			sky_texture_up = Textures::load(basename + "_up");
			sky_texture_down = Textures::load(basename + "_down");
			sky_texture_left = Textures::load(basename + "_left");
			sky_texture_right = Textures::load(basename + "_right");
			sky_texture_front = Textures::load(basename + "_front");
			sky_texture_back = Textures::load(basename + "_back");
		}
		sky_name.assign(name);
	}

	/*
	 * NOTE
	 *  for quake3 skyboxes: the _left texture is actually the right side  of the skybox
	 */
	gl::push();
	gl::translate(Camera::eye());
	gl::enable(GL_TEXTURE_2D);
	gl::color(1.0f, 1.0f, 1.0f, 1.0f);
	
	// front
	Textures::bind(sky_texture_front);
	gl::begin(gl::Quads);
	gl::texcoord(0, 0); gl::vertex(1, 1, 1);
	gl::texcoord(1, 0); gl::vertex(1, -1, 1);
	gl::texcoord(1, 1); gl::vertex(1, -1, -1);
	gl::texcoord(0, 1); gl::vertex(1, 1, -1);	
	gl::end();
	
	// right
	Textures::bind(sky_texture_right);
	gl::begin(gl::Quads);
	gl::texcoord(0, 0); gl::vertex(1, -1, 1);
	gl::texcoord(1, 0); gl::vertex(-1, -1, 1);
	gl::texcoord(1, 1); gl::vertex(-1, -1, -1);
	gl::texcoord(0, 1); gl::vertex(1, -1, -1);
	gl::end();
	
	// back
	Textures::bind(sky_texture_back);
	gl::begin(gl::Quads);
	gl::texcoord(0, 0); gl::vertex(-1, -1, 1);
	gl::texcoord(1, 0); gl::vertex(-1, 1, 1);
	gl::texcoord(1, 1); gl::vertex(-1, 1, -1);
	gl::texcoord(0, 1); gl::vertex(-1, -1, -1);
	gl::end();
	
	// left
	Textures::bind(sky_texture_left);
	gl::begin(gl::Quads);
	gl::texcoord(0, 0); gl::vertex(-1, 1, 1);
	gl::texcoord(1, 0); gl::vertex(1, 1, 1);
	gl::texcoord(1, 1); gl::vertex(1, 1, -1);	
	gl::texcoord(0, 1); gl::vertex(-1, 1, -1);
	gl::end();
	
	// up
	Textures::bind(sky_texture_up);
	gl::begin(gl::Quads);
	gl::texcoord(0, 0); gl::vertex(-1, 1, 1);
	gl::texcoord(1, 0); gl::vertex(-1, -1, 1);
	gl::texcoord(1, 1); gl::vertex(1, -1, 1);
	gl::texcoord(0, 1); gl::vertex(1, 1, 1);
	gl::end();
	
	// down
	Textures::bind(sky_texture_down);
	gl::begin(gl::Quads);
	gl::texcoord(0, 0); gl::vertex(1, 1, -1);
	gl::texcoord(1, 0); gl::vertex(1, -1, -1);
	gl::texcoord(1, 1); gl::vertex(-1, -1, -1);
	gl::texcoord(0, 1); gl::vertex(-1, 1, -1);
	gl::end();

	gl::pop();
	
	gl::disable(GL_TEXTURE_2D);
}

void Sky::unload()
{
	if (sky_texture_up) {
		Textures::unload(sky_texture_up);
		sky_texture_up = 0;
	}
	
	if (sky_texture_down) {
		Textures::unload(sky_texture_down);
		sky_texture_down = 0;
	}
	
	if (sky_texture_left) {
		Textures::unload(sky_texture_left);
		sky_texture_left = 0;
	}
	
	if (sky_texture_right) {
		Textures::unload(sky_texture_right);
		sky_texture_right = 0;
	}
	
	if (sky_texture_front) {
		Textures::unload(sky_texture_front);
		sky_texture_front = 0;
	}
	
	if (sky_texture_back) {
		Textures::unload(sky_texture_back);
		sky_texture_back = 0;
	}
	
	sky_name.clear();
}

} // namespace render