#define TEXTURE_SIZE	256

float4 scurve(float4 v)
{
	return v * v * (3 - 2 * v);
}



float noise4(in float4 vec, uniform samplerRECT p, uniform samplerRECT g)
{
	float4 b0, b1, r0, r1;
	float4 u, v, u0, v0, u1, v1;

	r0 = modf(vec, b0);
	b1 = b0 + 1;
	r1 = r0 - 1;
	//b0 = fmod(b0, (TEXTURE_SIZE).xxxx);	// we could avoid these
	//b1 = fmod(b1, (TEXTURE_SIZE).xxxx);	// if rectangular textures could use GL_REPEAT mode

	// our textures are actually 1d so we don't care about the second coordinate
	/*
	half i0 = h1texRECT(p, b0.xx);
	half i1 = h1texRECT(p, b1.xx);

	half i00 = h1texRECT(p, i0.xx + b0.yy);
	half i10 = h1texRECT(p, i1.xx + b0.yy);
	half i01 = h1texRECT(p, i0.xx + b1.yy);
	half i11 = h1texRECT(p, i1.xx + b1.yy);

	half i000 = h1texRECT(p, i00.xx + b0.zz);
	half i100 = h1texRECT(p, i10.xx + b0.zz);
	half i010 = h1texRECT(p, i01.xx + b0.zz);
	half i110 = h1texRECT(p, i11.xx + b0.zz);
	half i001 = h1texRECT(p, i00.xx + b1.zz);
	half i101 = h1texRECT(p, i10.xx + b1.zz);
	half i011 = h1texRECT(p, i01.xx + b1.zz);
	half i111 = h1texRECT(p, i11.xx + b1.zz);
	*/

	float i0 = texRECT(p, b0.xx);
	float i1 = texRECT(p, b1.xx);

	float i00 = texRECT(p, i0.xx + b0.yy);
	float i10 = texRECT(p, i1.xx + b0.yy);
	float i01 = texRECT(p, i0.xx + b1.yy);
	float i11 = texRECT(p, i1.xx + b1.yy);

	float i000 = texRECT(p, i00.xx + b0.zz);
	float i100 = texRECT(p, i10.xx + b0.zz);
	float i010 = texRECT(p, i01.xx + b0.zz);
	float i110 = texRECT(p, i11.xx + b0.zz);
	float i001 = texRECT(p, i00.xx + b1.zz);
	float i101 = texRECT(p, i10.xx + b1.zz);
	float i011 = texRECT(p, i01.xx + b1.zz);
	float i111 = texRECT(p, i11.xx + b1.zz);

	// sample 16 neighbors and calculate 16 dot-products

	// sample at x = 0

	/*
	u0.x = dot(f4texRECT(g, i000.xx + b0.ww), r0);
	u0.y = dot(f4texRECT(g, i010.xx + b0.ww), fixed4(0, 1, 0, 0) > 0 ? r1 : r0);
	u0.z = dot(f4texRECT(g, i000.xx + b1.ww), fixed4(0, 0, 0, 1) > 0 ? r1 : r0);
	u0.w = dot(f4texRECT(g, i010.xx + b1.ww), fixed4(0, 1, 0, 1) > 0 ? r1 : r0);

	v0.x = dot(f4texRECT(g, i001.xx + b0.ww), fixed4(0, 0, 1, 0) > 0 ? r1 : r0);
	v0.y = dot(f4texRECT(g, i011.xx + b0.ww), fixed4(0, 1, 1, 0) > 0 ? r1 : r0);
	v0.z = dot(f4texRECT(g, i001.xx + b1.ww), fixed4(0, 0, 1, 1) > 0 ? r1 : r0);
	v0.w = dot(f4texRECT(g, i011.xx + b1.ww), fixed4(0, 1, 1, 1) > 0 ? r1 : r0);

	// sample at x = 1

	u1.x = dot(f4texRECT(g, i100.xx + b0.ww), fixed4(1, 0, 0, 0) > 0 ? r1 : r0);
	u1.y = dot(f4texRECT(g, i110.xx + b0.ww), fixed4(1, 1, 0, 0) > 0 ? r1 : r0);
	u1.z = dot(f4texRECT(g, i100.xx + b1.ww), fixed4(1, 0, 0, 1) > 0 ? r1 : r0);
	u1.w = dot(f4texRECT(g, i110.xx + b1.ww), fixed4(1, 1, 0, 1) > 0 ? r1 : r0);

	v1.x = dot(f4texRECT(g, i101.xx + b0.ww), fixed4(1, 0, 1, 0) > 0 ? r1 : r0);
	v1.y = dot(f4texRECT(g, i111.xx + b0.ww), fixed4(1, 1, 1, 0) > 0 ? r1 : r0);
	v1.z = dot(f4texRECT(g, i101.xx + b1.ww), fixed4(1, 0, 1, 1) > 0 ? r1 : r0);
	v1.w = dot(f4texRECT(g, i111.xx + b1.ww), r1);
	*/


	u0.x = dot(texRECT(g, i000.xx + b0.ww), r0);
	u0.y = dot(texRECT(g, i010.xx + b0.ww), float4(0, 1, 0, 0) > 0 ? r1 : r0);
	u0.z = dot(texRECT(g, i000.xx + b1.ww), float4(0, 0, 0, 1) > 0 ? r1 : r0);
	u0.w = dot(texRECT(g, i010.xx + b1.ww), float4(0, 1, 0, 1) > 0 ? r1 : r0);

	v0.x = dot(texRECT(g, i001.xx + b0.ww), float4(0, 0, 1, 0) > 0 ? r1 : r0);
	v0.y = dot(texRECT(g, i011.xx + b0.ww), float4(0, 1, 1, 0) > 0 ? r1 : r0);
	v0.z = dot(texRECT(g, i001.xx + b1.ww), float4(0, 0, 1, 1) > 0 ? r1 : r0);
	v0.w = dot(texRECT(g, i011.xx + b1.ww), float4(0, 1, 1, 1) > 0 ? r1 : r0);

	// sample at x = 1

	u1.x = dot(texRECT(g, i100.xx + b0.ww), float4(1, 0, 0, 0) > 0 ? r1 : r0);
	u1.y = dot(texRECT(g, i110.xx + b0.ww), float4(1, 1, 0, 0) > 0 ? r1 : r0);
	u1.z = dot(texRECT(g, i100.xx + b1.ww), float4(1, 0, 0, 1) > 0 ? r1 : r0);
	u1.w = dot(texRECT(g, i110.xx + b1.ww), float4(1, 1, 0, 1) > 0 ? r1 : r0);

	v1.x = dot(texRECT(g, i101.xx + b0.ww), float4(1, 0, 1, 0) > 0 ? r1 : r0);
	v1.y = dot(texRECT(g, i111.xx + b0.ww), float4(1, 1, 1, 0) > 0 ? r1 : r0);
	v1.z = dot(texRECT(g, i101.xx + b1.ww), float4(1, 0, 1, 1) > 0 ? r1 : r0);
	v1.w = dot(texRECT(g, i111.xx + b1.ww), r1);
	// now, perform quadro-cubic interpolation between these 16 noise samples

	float4 s = scurve(r0);

	// interpolation in 4d-space requires 15 1d interpolations,
	// but thanks to parallel nature of lerp instruction and some swizzling
	// we can do the same with only 5 lerp instructions

	// lerp between two pairs of 8 values along x axis

	u = lerp(u0, u1, s.x);
	v = lerp(v0, v1, s.x);

	// lerp between two pairs of 4 values (resulted from the previous lerp) along z axis

	u = lerp(u, v, s.z);

	// now, lerp between two pairs of 2 values along y axis

	float2 a = lerp(u.xz, u.yw, s.y);

	// finally, lerp along w axis

	return abs(lerp(a.x, a.y, s.w));
}



float turbulence4(in float4 vec, uniform samplerRECT perm, uniform samplerRECT grad)
{
	float n;
	

	n = noise4(vec, perm, grad);
	// + 0.5x * noise4(vec * 2.0h, p, g) + 0.25x * noise4(vec * 4.0h, p, g) + 0.125x * noise4(vec * 8.0h, p, g) + 0.0625x * noise4(vec * 16.0h, p, g);
	//n = 0.0f;
	return n;
	
}



fragout main( in float4 pos : POSITION,
	     	in float3 col : COLOR0,
             	in float4 u : TEXCOORD0,
             	in float ypos : TEXCOORD1,
	     	//in float clip0 : CLP0,
             	//in float clip1 : CLP1,
             	//in float clip2 : CLP2,
             	//in float clip3 : CLP3,
             	//in float clip4 : CLP4,
	     	//in float clip5 : CLP5,
	    	// uniform samplerRECT perm,	
	     	// permutations texture
	     	uniform samplerRECT perm: TEXUNIT0,
	     	// uniform samplerRECT grad,	
	     	// random gradient 4d vectors texture
	     	uniform samplerRECT grad: TEXUNIT2,
	     	// uniform sampler2D firetex,	
	     	// color texture
	     	uniform sampler2D firetex : TEXUNIT4,
	     	// turbulance scale
	     	uniform float turb_scale
	     	//out fragout outval
	     	)
{
	fragout outval;

	float2 uv = u.xz - 0.5x;
	uv += uv;
	uv *= uv;

	float4 v = u;
	v.y += ypos;

	uv.x = sqrt(uv.x + uv.y);	// radial mapping

	//new code
	//float tur_res = turbulence4(v * 1.5x,permutation,gradient);
	//tur_res = tur_res.x + 0.5x*turbulence4(v * 3.0x,permutation,gradient);
	//tur_res = tur_res.x + 0.25x*turbulence4(v * 6.0x,permutation,gradient);
	//tur_res = tur_res.x + 0.125x*turbulence4(v * 12.0x,permutation,gradient);
	//tur_res = tur_res.x + 0.0625x*turbulence4(v * 24.0x,permutation,gradient);
	//tur_res = turb_scale.x * tur_res.x;
	//uv.y = u.y + sqrt(u.y) * tur_res.x;

	//turbulence4(v * 1.5x, perm, grad);
	uv.y = u.y + sqrt(u.y) * turb_scale * turbulence4(v, perm, grad);
	//perturb texture coordinates with turbulence() function
	//uv.y = u.y;

	outval.col.rgb = x3tex2D(firetex, uv);
	
	return outval;
}