Grid Warp.fs

Code

uniform float level;
uniform float radius;
uniform vec2 center;
uniform vec4 bgColor;
uniform vec4 lineColor;
uniform int majorDivisions;
uniform int minorHDivisions;
uniform int minorVDivisions;
uniform float majorDivisionLineWidth;
uniform int square;
precision mediump float;
/*{
    "CATEGORIES": [
        "Geometry"
    ],
    "CREDIT": "by VIDVOX",
    "INPUTS": [
        {
            "DEFAULT": -0.5,
            "MAX": 1,
            "MIN": -1,
            "NAME": "level",
            "TYPE": "float"
        },
        {
            "DEFAULT": 0.25,
            "MAX": 1,
            "MIN": 0,
            "NAME": "radius",
            "TYPE": "float"
        },
        {
            "DEFAULT": [
                0.5,
                0.5
            ],
            "MAX": [
                1,
                1
            ],
            "MIN": [
                0,
                0
            ],
            "NAME": "center",
            "TYPE": "point2D"
        },
        {
            "DEFAULT": [
                0,
                0,
                0,
                0
            ],
            "NAME": "bgColor",
            "TYPE": "color"
        },
        {
            "DEFAULT": [
                0.9436030983924866,
                0.5601619482040405,
                0,
                1
            ],
            "NAME": "lineColor",
            "TYPE": "color"
        },
        {
            "DEFAULT": 6,
            "LABELS": [
                "0",
                "1",
                "2",
                "3",
                "4",
                "5",
                "6",
                "7",
                "8",
                "9",
                "10",
                "11",
                "12",
                "13",
                "14",
                "15",
                "16"
            ],
            "NAME": "majorDivisions",
            "TYPE": "long",
            "VALUES": [
                0,
                1,
                2,
                3,
                4,
                5,
                6,
                7,
                8,
                9,
                10,
                11,
                12,
                13,
                14,
                15,
                16
            ]
        },
        {
            "DEFAULT": 2,
            "LABELS": [
                "0",
                "1",
                "2",
                "3",
                "4",
                "5",
                "6",
                "7",
                "8"
            ],
            "NAME": "minorHDivisions",
            "TYPE": "long",
            "VALUES": [
                0,
                1,
                2,
                3,
                4,
                5,
                6,
                7,
                8
            ]
        },
        {
            "DEFAULT": 1,
            "LABELS": [
                "0",
                "1",
                "2",
                "3",
                "4",
                "5",
                "6",
                "7",
                "8"
            ],
            "NAME": "minorVDivisions",
            "TYPE": "long",
            "VALUES": [
                0,
                1,
                2,
                3,
                4,
                5,
                6,
                7,
                8
            ]
        },
        {
            "DEFAULT": 3,
            "MAX": 5,
            "MIN": 1,
            "NAME": "majorDivisionLineWidth",
            "TYPE": "float"
        },
        {
            "DEFAULT": true,
            "NAME": "square",
            "TYPE": "bool"
        }
    ],
    "ISFVSN": "2"
}
*/

const float minorDivisionLineWidth = 1.0;
const float pi = 3.14159265359;

#ifndef GL_ES
float distance (vec2 center, vec2 pt)
{
	float tmp = pow(center.x-pt.x,2.0)+pow(center.y-pt.y,2.0);
	return pow(tmp,0.5);
}
#endif

void main() {
	vec2 uv = vec2((gl_FragCoord.xy / u_resolution.xy)[0],(gl_FragCoord.xy / u_resolution.xy)[1]);
	vec2 texSize = u_resolution;
	vec2 tc = uv * texSize;
	vec2 modifiedCenter = center * u_resolution;
	float r = distance(modifiedCenter, tc);
	float a = atan ((tc.y-modifiedCenter.y),(tc.x-modifiedCenter.x));
	float radius_sized = radius * length(u_resolution);
	vec4 inputPixelColor = bgColor;
	
	tc -= modifiedCenter;

	if (r < radius_sized) 	{
		float percent = 1.0-(radius_sized - r) / radius_sized;
		if (level>=0.0)	{
			percent = percent * percent;
			tc.x = r*pow(percent,level) * cos(a);
			tc.y = r*pow(percent,level) * sin(a);
		}
		else	{
			float adjustedLevel = level/2.0;
			tc.x = r*pow(percent,adjustedLevel) * cos(a);
			tc.y = r*pow(percent,adjustedLevel) * sin(a);		
		}
	}
	tc += modifiedCenter;
	
	vec2 loc = tc;
	vec2 divisionSize = (square) ? vec2(max(u_resolution.x,u_resolution.y)) : u_resolution;
	divisionSize = (divisionSize - majorDivisionLineWidth) / (1.0 + float(majorDivisions));
	vec2 modLoc = mod(loc,divisionSize);
	if ((modLoc.x < majorDivisionLineWidth)||(modLoc.y < majorDivisionLineWidth))	{
		inputPixelColor = lineColor;
	}
	if (minorHDivisions > 0)	{
		vec2	locDivisionSize = (divisionSize) / (1.0+float(minorHDivisions));
		modLoc = mod(loc,locDivisionSize);
		if (modLoc.x < minorDivisionLineWidth)	{
			inputPixelColor = lineColor;
		}
	}
	if (minorVDivisions > 0)	{
		vec2	locDivisionSize = (divisionSize) / (1.0+float(minorVDivisions));
		modLoc = mod(loc,locDivisionSize);
		if (modLoc.y < minorDivisionLineWidth)	{
			inputPixelColor = lineColor;
		}
	}
	
	gl_FragColor = inputPixelColor;
}