using UnityEngine;
using System.Collections;


[ExecuteInEditMode]
[RequireComponent (typeof(Camera))]
class PostEffectsHelper : MonoBehaviour 
{	
	void OnRenderImage ( RenderTexture source ,   RenderTexture destination  )
    {
		Debug.Log("OnRenderImage in Helper called ...");
	}
	
	static void DrawLowLevelPlaneAlignedWithCamera (
		 float dist ,
		  RenderTexture source ,   RenderTexture dest , 
		  Material material , 
		  Camera cameraForProjectionMatrix   )
    {
        // Make the destination texture the target for all rendering
        RenderTexture.active = dest;
        // Assign the source texture to a property from a shader
        material.SetTexture("_MainTex", source);
        bool  invertY = true; // source.texelSize.y < 0.0ff;
        // Set up the simple Matrix
        GL.PushMatrix();
        GL.LoadIdentity();	
        GL.LoadProjectionMatrix(cameraForProjectionMatrix.projectionMatrix);
        
        float fovYHalfRad = cameraForProjectionMatrix.fieldOfView * 0.5f * Mathf.Deg2Rad;
        float cotangent = Mathf.Cos(fovYHalfRad) / Mathf.Sin(fovYHalfRad);
        float asp = cameraForProjectionMatrix.aspect;
        
        float x1 = asp/-cotangent;
        float x2 = asp/cotangent;
        float y1 = 1.0f/-cotangent;
        float y2 = 1.0f/cotangent;
        
        float sc = 1.0f; // magic constant (for now)
        
        x1 *= dist * sc;
        x2 *= dist * sc;
        y1 *= dist * sc;
        y2 *= dist * sc;
                
        float z1 = -dist;
        
        for (int i = 0; i < material.passCount; i++)
        {
            material.SetPass(i);

	        GL.Begin(GL.QUADS);
	        float y1_; float y2_;
	        if (invertY)
	        {
	            y1_ = 1.0f; y2_ = 0.0f;
	        }
	        else
	        {
	            y1_ = 0.0f; y2_ = 1.0f;
	        }
	        GL.TexCoord2(0.0f, y1_); GL.Vertex3(x1, y1, z1);
	        GL.TexCoord2(1.0f, y1_); GL.Vertex3(x2, y1, z1);
	        GL.TexCoord2(1.0f, y2_); GL.Vertex3(x2, y2, z1);
	        GL.TexCoord2(0.0f, y2_); GL.Vertex3(x1, y2, z1);
	        GL.End();	
        }	
        
        GL.PopMatrix();        
	}
	
	static void DrawBorder (
		 RenderTexture dest , 
		  Material material   ){
		float x1;	
		float x2;
		float y1;
		float y2;		
		
		RenderTexture.active = dest;
        bool  invertY = true; // source.texelSize.y < 0.0ff;
        // Set up the simple Matrix
        GL.PushMatrix();
        GL.LoadOrtho();		
        
        for (int i = 0; i < material.passCount; i++)
        {
            material.SetPass(i);
	        
	        float y1_; float y2_;
	        if (invertY)
	        {
	            y1_ = 1.0f; y2_ = 0.0f;
	        }
	        else
	        {
	            y1_ = 0.0f; y2_ = 1.0f;
	        }
	        	        
	        // left	        
	        x1 = 0.0f;
	        x2 = 0.0f + 1.0f/(dest.width*1.0f);
	        y1 = 0.0f;
	        y2 = 1.0f;
	        GL.Begin(GL.QUADS);
	        
	        GL.TexCoord2(0.0f, y1_); GL.Vertex3(x1, y1, 0.1f);
	        GL.TexCoord2(1.0f, y1_); GL.Vertex3(x2, y1, 0.1f);
	        GL.TexCoord2(1.0f, y2_); GL.Vertex3(x2, y2, 0.1f);
	        GL.TexCoord2(0.0f, y2_); GL.Vertex3(x1, y2, 0.1f);
	
	        // right
	        x1 = 1.0f - 1.0f/(dest.width*1.0f);
	        x2 = 1.0f;
	        y1 = 0.0f;
	        y2 = 1.0f;

	        GL.TexCoord2(0.0f, y1_); GL.Vertex3(x1, y1, 0.1f);
	        GL.TexCoord2(1.0f, y1_); GL.Vertex3(x2, y1, 0.1f);
	        GL.TexCoord2(1.0f, y2_); GL.Vertex3(x2, y2, 0.1f);
	        GL.TexCoord2(0.0f, y2_); GL.Vertex3(x1, y2, 0.1f);	        
	
	        // top
	        x1 = 0.0f;
	        x2 = 1.0f;
	        y1 = 0.0f;
	        y2 = 0.0f + 1.0f/(dest.height*1.0f);

	        GL.TexCoord2(0.0f, y1_); GL.Vertex3(x1, y1, 0.1f);
	        GL.TexCoord2(1.0f, y1_); GL.Vertex3(x2, y1, 0.1f);
	        GL.TexCoord2(1.0f, y2_); GL.Vertex3(x2, y2, 0.1f);
	        GL.TexCoord2(0.0f, y2_); GL.Vertex3(x1, y2, 0.1f);
	        
	        // bottom
	        x1 = 0.0f;
	        x2 = 1.0f;
	        y1 = 1.0f - 1.0f/(dest.height*1.0f);
	        y2 = 1.0f;

	        GL.TexCoord2(0.0f, y1_); GL.Vertex3(x1, y1, 0.1f);
	        GL.TexCoord2(1.0f, y1_); GL.Vertex3(x2, y1, 0.1f);
	        GL.TexCoord2(1.0f, y2_); GL.Vertex3(x2, y2, 0.1f);
	        GL.TexCoord2(0.0f, y2_); GL.Vertex3(x1, y2, 0.1f);	
	                	              
	        GL.End();	
        }	
        
        GL.PopMatrix();
	}
	
	static void DrawLowLevelQuad (  float x1 ,   float x2 ,   float y1 ,   float y2 ,   RenderTexture source ,   RenderTexture dest ,   Material material   ){
        // Make the destination texture the target for all rendering
        RenderTexture.active = dest;
        // Assign the source texture to a property from a shader
        material.SetTexture("_MainTex", source);
        bool  invertY = true; // source.texelSize.y < 0.0ff;
        // Set up the simple Matrix
        GL.PushMatrix();
        GL.LoadOrtho();

        for (int i = 0; i < material.passCount; i++)
        {
            material.SetPass(i);

	        GL.Begin(GL.QUADS);
	        float y1_; float y2_;
	        if (invertY)
	        {
	            y1_ = 1.0f; y2_ = 0.0f;
	        }
	        else
	        {
	            y1_ = 0.0f; y2_ = 1.0f;
	        }
	        GL.TexCoord2(0.0f, y1_); GL.Vertex3(x1, y1, 0.1f);
	        GL.TexCoord2(1.0f, y1_); GL.Vertex3(x2, y1, 0.1f);
	        GL.TexCoord2(1.0f, y2_); GL.Vertex3(x2, y2, 0.1f);
	        GL.TexCoord2(0.0f, y2_); GL.Vertex3(x1, y2, 0.1f);
	        GL.End();	
        }	
        
        GL.PopMatrix();
	}
}