boilerplateCodeInISFEditor.glsl

/*{
	"DESCRIPTION": "",
	"CREDIT": "",
	"ISFVSN": "2",
	"CATEGORIES": [
		"XXX"
	],
	"INPUTS": [
		{
			"NAME": "inputImage",
			"TYPE": "image"
		},
		{
			"NAME": "boolInput",
			"TYPE": "bool",
			"DEFAULT": 1.0
		},
		{
			"NAME": "colorInput",
			"TYPE": "color",
			"DEFAULT": [
				0.0,
				0.0,
				1.0,
				1.0
			]
		},
		{
			"NAME": "flashInput",
			"TYPE": "event"
		},
		{
			"NAME": "floatInput",
			"TYPE": "float",
			"DEFAULT": 0.5,
			"MIN": 0.0,
			"MAX": 1.0
		},
		{
			"NAME": "longInputIsAPopUpButton",
			"TYPE": "long",
			"VALUES": [
				0,
				1,
				2
			],
			"LABELS": [
				"red",
				"green",
				"blue"
			],
			"DEFAULT": 1
		},
		{
			"NAME": "pointInput",
			"TYPE": "point2D",
			"DEFAULT": [
				0,
				0
			]
		}
	],
	"PASSES": [
		{
			"TARGET":"bufferVariableNameA",
			"WIDTH": "$WIDTH/16.0",
			"HEIGHT": "$HEIGHT/16.0"
		},
		{
			"DESCRIPTION": "this empty pass is rendered at the same rez as whatever you are running the ISF filter at- the previous step rendered an image at one-sixteenth the res, so this step ensures that the output is full-size"
		}
	]
	
}*/
// http://iquilezles.org/www/articles/distfunctions2d/distfunctions2d.htm
float equiTri(vec2 p){
    float side = sqrt(3.0);
    p.x = abs(p.x) - 1.0;
    p.y = p.y +1.0/side;
    if(p.x + side*p.y > 0.0){
        p = vec2(p.x - side*p.y, -side*p.x - p.y)/2.0;
    }
    p.x -= clamp(p.x,-2.0,0.0);
    return -length(p)*sign(p.y);
    
}

// http://www.iquilezles.org/www/articles/palettes/palettes.htm
// As t runs from 0 to 1 (our normalized palette index or domain), 
//the cosine oscilates c times with a phase of d. 
//The result is scaled and biased by a and b to meet the desired constrast and brightness.
vec3 cosPalette( float t, vec3 a, vec3 b, vec3 c, vec3 d )
{
    return a + b*cos( 6.28318*(c*t+d) );
}


void main()
{

    // distance metric
    vec2 uv = (isf_FragNormCoord * vec2(2)) -vec2(1);
    
    float shape = equiTri(uv * vec2(3.0));
    
    vec3 col = cosPalette(0.5,vec3(0.5),vec3(0.5),vec3(1),vec3(TIME*0.01,TIME*0.1,TIME*.2));
    
    // lighting: darken at the center
    col = vec3(shape) * col;
    
    // output: pixel color
    gl_FragColor = min(vec4( col.rgb, 1.0 ), vec4(0.8,0.8,0.8,1.0));

}