// Colorful FX - Unity Asset
// Copyright (c) 2015 - Thomas Hourdel
// http://www.thomashourdel.com

#include "UnityCG.cginc"
#include "./Colorful.cginc"

sampler2D _MainTex;
half4 _Params; // x: speed, y: intensity, z: maxDisplace, w: yuv offset

inline float offset(float x, float levels)
{
	return floor(x * levels) / levels;
}

inline float2 offset(float2 x, float levels)
{
	return floor(x * levels) / levels;
}

half4 frag_tearing(v2f_img i) : SV_Target
{
	float time = mod(_Time.y * _Params.x, 32.0);
	float change = simpleNoise(offset(i.uv.yy, 16.0) + 150.0 * offset(time, 4.0));

	float t = 5.0 * offset(time, 16.0 * change);
	float vt = 0.5 * simpleNoise(offset(i.uv.yy + t, 11.0));
	vt += 0.5 * simpleNoise(offset(i.uv.yy + t, 7.0));
	vt = vt * 2.0 - 1.0;
	vt = sign(vt) * saturate((abs(vt) - (1.0 - _Params.y)) / _Params.y);

	half2 texcoords = i.uv;
	texcoords = saturate(texcoords + half2(_Params.z * vt, 0.0));

	#ifdef ALLOW_FLIPPING
	half tt = offset(time, 8.0);
	half rnd = simpleNoise(half2(tt, tt));
	texcoords.y = (rnd > lerp(1.0, 0.975, _Params.y)) ? 1.0 - texcoords.y : texcoords.y;
	#endif

	half3 color = tex2D(_MainTex, texcoords).rgb;

	#ifdef YUV_COLOR_BLEEDING
	half3 yuv = RGBtoYUV(color);
	yuv.y /= 1.0 - 3.0 * abs(vt) * saturate(_Params.w - vt);
	yuv.z += 0.125 * vt * saturate(vt - _Params.w);
	return half4(YUVtoRGB(yuv), 1.0);
	#else
	return half4(color, 1.0);
	#endif
}