Weave.osl

// Making a simple Weave, can be used for carbon fiber, cloth, or similar
// Weave.osl, by Zap Andersson
// Modified: 2018-12-06
// Modified: 2021-02-22 by Saul Espinosa for Redshift 3D
// Copyright 2018 Autodesk Inc, All rights reserved. This file is licensed under Apache 2.0 license
//    https://github.com/ADN-DevTech/3dsMax-OSL-Shaders/blob/master/LICENSE.txt

shader Weave
	[[ string help="<font size=+1><b>Weave</b></font><br>A simple threaded weave shader. Can be used for everything from cloth to carbon fiber.", 
	   string label = "Weave",
	   string URL ="https://github.com/ADN-DevTech/3dsMax-OSL-Shaders" ]]
(
	point UVW = point(u,v,0),
	float Scale = 0.2,
	// Inputs
	color U_Color = 0.2 [[ string label = "U Color"]],
	color V_Color = 0.5 [[ string label = "V Color"]],
	
	float Width       = 0.5
		[[ float min = 0.0, float max = 1.0 ]],	
	float Roundness   = 1.0
		[[ float min = 0.0, float max = 1.0 ]],
	float RoundnessBump = 1.0
		[[ float min = 0.0, float max = 2.0 ]],	
	float RoundShadow   = 0.5
		[[ float min = 0.0, float max = 1.0 ]],
	float WeaveBump = 0.5
		[[ float min = 0.0, float max = 2.0 ]],	
	float WeaveShadow = 0.4
		[[ float min = 0.0, float max = 1.0 ]],	
	float Frizz       = 0.0
		[[ float min = 0.0, float max = 1.0 ]],	
	float FrizzBump   = 0.0
		[[ float min = 0.0, float max = 2.0 ]],	
	float FrizzScale  = 0.1
		[[ float min = 0.0, float max = 10.0 ]],
	float Bendyness       = 0.2
		[[ float min = 0.0, float max = 1.0 ]],	
	float BendynessScale  = 3.0
		[[ float min = 0.0, float max = 10.0 ]],
	float OpacityFade     = 0.0
		[[ float min = 0.0, float max = 1.0 ]],	
	

	// Outputs
	output color Col = 0.0,	
 	output float Bump = 0.5,
 	output float ThreadID = 0,
 	output float Opacity = 0.0,
)
{
	// Compute the scaled point
	point uvw = UVW / Scale;
	
	// Add frizz to the width
	float frizz = noise("perlin", uvw / FrizzScale) ;
	float w2  = Width + frizz * Frizz;
	float w   = w2 * 0.5;
	
	int uf = int(floor(uvw[0]));
	int vf = int(floor(uvw[1]));	
	
	// Compute an independent per-thread randomness for bending it
	float ubend = noise("perlin", uvw[1] / BendynessScale + uf) * Bendyness;
	float vbend = noise("perlin", uvw[0] / BendynessScale + vf) * Bendyness;
	
	// Compute the thread coordinates
	float sx = uvw[0] - uf + ubend;
	float sy = uvw[1] - vf + vbend;
	
	int onU = (sy > 0.5 - w && sy < 0.5 + w);
	int onV = (sx > 0.5 - w && sx < 0.5 + w);
	
	float uu = (sy - (0.5 - w)) / w2;
	float vv = (sx - (0.5 - w)) / w2;
	
	// Odd or even U / V ?
	int oddU = uf % 2;
	int oddV = vf % 2;

	// Are we on neither thread? Just return	
	if (onU == 0 && onV == 0) return;
	
	int U_on_top = (oddU ^ oddV) == 0;		

	// Both - disambiguate
	if (onU && onV)
	{
		onU = U_on_top;
		onV = onU == 0;
	}	
	
	// Return a random ID for each thread
	ThreadID = 1 + float((cellnoise(uf) * onV + cellnoise(vf) * onU) * 1024.0) + onU;

	// Which color to return?	
	if (onU)
		Col = U_Color;
	else
		Col = V_Color;

	// Compute the bump and fake "Shadowing"
	float r = Roundness; 	
	float weave = (onU) ? sin((uvw[0] + oddV) * M_PI) : sin((uvw[1] + oddU + 1.0) * M_PI);
	
	float ubulge = sin(uu * M_PI);
	float vbulge = sin(vv * M_PI);
	
	float bulge = pow((onU ? ubulge : vbulge), r);	
	
	Opacity = max(pow(ubulge, OpacityFade), pow(vbulge, OpacityFade));
	
	Bump = 0.2	 + weave * WeaveBump + bulge * RoundnessBump + frizz * FrizzBump;	
	Col *= mix(1.0, bulge, RoundShadow);
	Col *= mix(1.0, weave, WeaveShadow);	
}