using System.Collections;
using System.Collections.Generic;
using UnityEngine;

namespace BF
{
	public class PostEffectVividBloom : AbsPostEffect
	{
		public static int FilterID = Shader.PropertyToID("_Filter");
		public static int IntensityID = Shader.PropertyToID("_Intensity");
		public static int SourceTexID = Shader.PropertyToID("_SourceTex");

		const int BoxDownPrefilterPass = 0;
		const int BoxDownPass = 1;
		const int BoxUpPass = 2;
		const int ApplyBloomPass = 3;

		Material vividBloomMat;

		RenderTexture[] textures = new RenderTexture[4];

		[Range(0, 3)]
		float intensity = 1;
		[Range(1, 4)]
		int iterations = 3;
		[Range(0, 10)]
		float threshold = 1;
		[Range(0, 1)]
		float softThreshold = 0.5f;

		public float Intensity { get { return intensity; } }
		public int Iterations { get { return iterations; } }
		public float Threshold { get { return threshold; } }
		public float SoftThreshold { get { return softThreshold; } }

        public void SetIntensity(float value)
        {
			intensity = value;
			RefreshIntensity();
		}

        public void SetIterations(int value)
        {
			iterations = value;
        }

        public void SetThreshold(float value)
        {
			threshold = value;
			RefreshFilter();
		}

        public void SetSoftThreshold(float value)
        {
			softThreshold = value;
			RefreshFilter();
		}

		public PostEffectVividBloom()
        {
			vividBloomMat = BFMain.Instance.RenderMgr.VividBloomMat;
			RefreshFilter();
			RefreshIntensity();
		}

        public void RefreshFilter()
        {
			var knee = threshold * softThreshold;
			Vector4 filter;
			filter.x = threshold;
			filter.y = filter.x - knee;
			filter.z = 2f * knee;
			filter.w = 0.25f / (knee + 0.00001f);
			vividBloomMat.SetVector(FilterID, filter);
		}

        public void RefreshIntensity()
        {
			vividBloomMat.SetFloat(IntensityID, intensity);
		}

		public override PostEffectContext OnRenderImage(PostEffectContext context)
        {
            var src = context.src;
            var dest = context.dest;

			int width = src.width / 2;
			int height = src.height / 2;
			var format = src.format;

			var currentDestination = textures[0] = RenderTexture.GetTemporary(width, height, 0, format);
			Graphics.Blit(src, currentDestination, vividBloomMat, BoxDownPrefilterPass);
			var currentSource = currentDestination;

			int i = 1;
			for (; i < iterations; i++)
			{
				width /= 2;
				height /= 2;
				if (height < 2)
				{
					break;
				}
				currentDestination = textures[i] = RenderTexture.GetTemporary(width, height, 0, format);
				Graphics.Blit(currentSource, currentDestination, vividBloomMat, BoxDownPass);
				currentSource = currentDestination;
			}

			for (i -= 2; i >= 0; i--)
			{
				currentDestination = textures[i];
				textures[i] = null;
				Graphics.Blit(currentSource, currentDestination, vividBloomMat, BoxUpPass);
				RenderTexture.ReleaseTemporary(currentSource);
				currentSource = currentDestination;
			}

			vividBloomMat.SetTexture(SourceTexID, src);
			Graphics.Blit(currentSource, dest, vividBloomMat, ApplyBloomPass);
			RenderTexture.ReleaseTemporary(currentSource);

            return context;
        }
    }
}