using UnityEngine;
using System.Collections;


[ExecuteInEditMode]
[RequireComponent (typeof(Camera))]
[AddComponentMenu ("Image Effects/Blur/Blur (Optimized)")]
class BlurOptimized : PostEffectsBase
{

	[Range(0, 2)]
	public int downsample = 1;

	public enum BlurType {
		StandardGauss = 0,
		SgxGauss = 1,
	}

	[Range(0.0f, 10.0f)]
	public float blurSize = 3.0f;
	
	[Range(1, 4)]
	public int blurIterations = 2;

	public BlurType blurType= BlurType.StandardGauss;

	public Shader blurShader = null;
	private Material blurMaterial = null;


    public override bool CheckResources (){	
		 CheckSupport (false);	
	
		blurMaterial = CheckShaderAndCreateMaterial (blurShader, blurMaterial);
		
		if(!isSupported)
			ReportAutoDisable ();
		return isSupported;				
	}

	void OnDisable (){
		if(blurMaterial)
			DestroyImmediate (blurMaterial);
	}
	
	void OnRenderImage ( RenderTexture source ,   RenderTexture destination  ){	
		if(CheckResources() == false) {
			Graphics.Blit (source, destination);
			return;
		}

		float widthMod = 1.0f / (1.0f * (1<<downsample));

		blurMaterial.SetVector ("_Parameter", new Vector4 (blurSize * widthMod, -blurSize * widthMod, 0.0f, 0.0f));
		source.filterMode = FilterMode.Bilinear;

		int rtW = source.width >> downsample;
		int rtH = source.height >> downsample;

		// downsample
		RenderTexture rt = RenderTexture.GetTemporary (rtW, rtH, 0, source.format);

		rt.filterMode = FilterMode.Bilinear;
		Graphics.Blit (source, rt, blurMaterial, 0);

		var passOffs= blurType == BlurType.StandardGauss ? 0 : 2;
		
		for(int i = 0; i < blurIterations; i++) {
			float iterationOffs = (i*1.0f);
			blurMaterial.SetVector ("_Parameter", new Vector4 (blurSize * widthMod + iterationOffs, -blurSize * widthMod - iterationOffs, 0.0f, 0.0f));

			// vertical blur
			RenderTexture rt2 = RenderTexture.GetTemporary (rtW, rtH, 0, source.format);
			rt2.filterMode = FilterMode.Bilinear;
			Graphics.Blit (rt, rt2, blurMaterial, 1 + passOffs);
			RenderTexture.ReleaseTemporary (rt);
			rt = rt2;

			// horizontal blur
			rt2 = RenderTexture.GetTemporary (rtW, rtH, 0, source.format);
			rt2.filterMode = FilterMode.Bilinear;
			Graphics.Blit (rt, rt2, blurMaterial, 2 + passOffs);
			RenderTexture.ReleaseTemporary (rt);
			rt = rt2;
		}
		
		Graphics.Blit (rt, destination);

		RenderTexture.ReleaseTemporary (rt);
	}	
}