using UnityEngine;
using System.Collections;


[ExecuteInEditMode]
[RequireComponent (typeof(Camera))]
[AddComponentMenu ("Image Effects/Edge Detection/Crease Shading")]
class CreaseShading : PostEffectsBase {
	public float intensity = 0.5f;
	public int softness = 1;
	public float spread = 1.0f;
	
	public Shader blurShader = null;
	private Material blurMaterial = null;	
	
	public Shader depthFetchShader = null;
	private Material depthFetchMaterial = null;
	
	public Shader creaseApplyShader = null;
	private Material creaseApplyMaterial = null;


    public override bool CheckResources (){	
		 CheckSupport (true);
		
		blurMaterial = CheckShaderAndCreateMaterial (blurShader, blurMaterial);
		depthFetchMaterial = CheckShaderAndCreateMaterial (depthFetchShader, depthFetchMaterial);
		creaseApplyMaterial = CheckShaderAndCreateMaterial (creaseApplyShader, creaseApplyMaterial);
		
		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;
		
		float widthOverHeight = (1.0f * rtW) / (1.0f * rtH);
		float oneOverBaseSize = 1.0f / 512.0f;		

		RenderTexture hrTex = RenderTexture.GetTemporary (rtW, rtH, 0); 
		RenderTexture lrTex1 = RenderTexture.GetTemporary (rtW/2, rtH/2, 0); 
		
		Graphics.Blit (source,hrTex, depthFetchMaterial);
		Graphics.Blit (hrTex, lrTex1);
		
		for(int i = 0; i < softness; i++) {
			RenderTexture lrTex2 = RenderTexture.GetTemporary (rtW/2, rtH/2, 0);
			blurMaterial.SetVector ("offsets", new Vector4 (0.0f, spread * oneOverBaseSize, 0.0f, 0.0f));
			Graphics.Blit (lrTex1, lrTex2, blurMaterial);
			RenderTexture.ReleaseTemporary (lrTex1);
			lrTex1 = lrTex2;

			lrTex2 = RenderTexture.GetTemporary (rtW/2, rtH/2, 0);
			blurMaterial.SetVector ("offsets", new Vector4 (spread * oneOverBaseSize / widthOverHeight,  0.0f, 0.0f, 0.0f));		
			Graphics.Blit (lrTex1, lrTex2, blurMaterial);
			RenderTexture.ReleaseTemporary (lrTex1);
			lrTex1 = lrTex2;
		}
		
		creaseApplyMaterial.SetTexture ("_HrDepthTex", hrTex);
		creaseApplyMaterial.SetTexture ("_LrDepthTex", lrTex1);
		creaseApplyMaterial.SetFloat ("intensity", intensity);
		Graphics.Blit (source,destination, creaseApplyMaterial);

		RenderTexture.ReleaseTemporary (hrTex);
		RenderTexture.ReleaseTemporary (lrTex1);
	}	
}