using System;

using OpenTK.Graphics.OpenGL;

namespace org.nhengine.graphics
{
	public class GlobalDefaults
	{
		private static GlobalDefaults _instance = new GlobalDefaults();
		public static GlobalDefaults instance(){
			return _instance;
		}

		private Shader defVertexShader,
					defFragmentShader;
		private ShaderProgram
					defShaderProgram;

		private GLSceneOrientation activeScene;

		private GlobalDefaults(){

			Console.WriteLine("GlobalDefaults: Shader Version: {0}", GL.GetString(StringName.ShadingLanguageVersion));

			defVertexShader = new Shader(OpenTK.Graphics.OpenGL.ShaderType.VertexShader, defVertexShaderSource);
			defFragmentShader = new Shader(OpenTK.Graphics.OpenGL.ShaderType.FragmentShader, defFragmentShaderSource);

			defShaderProgram = new ShaderProgram(defVertexShader, defFragmentShader);

			activeScene = new GLSceneOrientation();
		}

		public ShaderProgram DefaultShaderProgram {
			get { return this.defShaderProgram;}
		}

		public Shader DefaultVertexShader
		{
			get { return defVertexShader; }
		}

		public Shader DefaultFragmentShader
		{
			get { return defFragmentShader; }
		}

		public GLSceneOrientation ActiveScene {
			get { return this.activeScene; }
			set { this.activeScene = value; }
		}


private string defVertexShaderSource = @"#version 330
  
in vec3 iv_position;
in vec4 iv_color;
in vec3 iv_normal;
in vec2 iv_uv;

uniform mat4 mObject;
uniform mat4 mCamera;
uniform mat4 mObjectCamera;
uniform mat4 mObjectCameraIT;
uniform mat4 mProjection;
uniform mat4 mScene;

out vec4 color;
out vec3 norm;
out vec2 uv;

void main()
{
			gl_Position = mScene * vec4( iv_position, 1 );
	
			norm	= normalize( ( mObjectCameraIT * vec4( iv_normal, 1 ) ).xyz );
	vec3 	camray	= normalize( -gl_Position.xyz );

	float	cosTheta = dot( norm , camray );
	
	float	visibility = 1.0;
	if (cosTheta < 0){
	}
	color = vec4( iv_color.xyz * (0.5 + (0.5 * cosTheta * cosTheta)), visibility );
}

";
		
private string defFragmentShaderSource = @"#version 330

in vec4 color;
in vec3 norm;
in vec2 uv;

out vec4 _color;

void main()
{
    _color = color;
}

";


	}

}