using UnityEngine;
using System.Collections;

[ExecuteInEditMode]
[RequireComponent(typeof(Camera))]
[AddComponentMenu("Image Effects/Color Adjustments/Contrast Enhance (Unsharp Mask)")]
class ContrastEnhance : PostEffectsBase {
	public float intensity = 0.5f;
	public float threshhold = 0.0f;
	
	private Material separableBlurMaterial;
	private Material contrastCompositeMaterial;
	
	public float blurSpread = 1.0f;
	
	public Shader separableBlurShader = null;
	public Shader contrastCompositeShader = null;


    public override bool CheckResources (){	
		 CheckSupport (false);
		
		contrastCompositeMaterial = CheckShaderAndCreateMaterial (contrastCompositeShader, contrastCompositeMaterial);
		separableBlurMaterial = CheckShaderAndCreateMaterial (separableBlurShader, separableBlurMaterial);
		
		if(!isSupported)
			ReportAutoDisable ();
		return isSupported;		
	}
	
	void OnRenderImage ( RenderTexture source ,   RenderTexture destination  ){	
		if(CheckResources()==false) {
			Graphics.Blit (source, destination);
			return;
		}

		int rtW = source.width;
		int rtH = source.height;
				
		RenderTexture color2 = RenderTexture.GetTemporary (rtW/2, rtH/2, 0);	
			
		// downsample

		Graphics.Blit (source, color2);
		RenderTexture color4a = RenderTexture.GetTemporary (rtW/4, rtH/4, 0);
		Graphics.Blit (color2, color4a); 
		RenderTexture.ReleaseTemporary (color2);
	
		// blur
		
		separableBlurMaterial.SetVector ("offsets", new Vector4 (0.0f, (blurSpread * 1.0f) / color4a.height, 0.0f, 0.0f));	
		RenderTexture color4b = RenderTexture.GetTemporary (rtW/4, rtH/4, 0);
		Graphics.Blit (color4a, color4b, separableBlurMaterial);
		RenderTexture.ReleaseTemporary (color4a);

		separableBlurMaterial.SetVector ("offsets", new Vector4 ((blurSpread * 1.0f) / color4a.width, 0.0f, 0.0f, 0.0f));	
		color4a = RenderTexture.GetTemporary (rtW/4, rtH/4, 0);
		Graphics.Blit (color4b, color4a, separableBlurMaterial); 
		RenderTexture.ReleaseTemporary (color4b);
	
		// composite

		contrastCompositeMaterial.SetTexture ("_MainTexBlurred", color4a);
		contrastCompositeMaterial.SetFloat ("intensity", intensity);
		contrastCompositeMaterial.SetFloat ("threshhold", threshhold);
		Graphics.Blit (source, destination, contrastCompositeMaterial); 
		
		RenderTexture.ReleaseTemporary (color4a);
	}
}