140 lines
4.5 KiB
Plaintext
140 lines
4.5 KiB
Plaintext
{
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"name": "curve",
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"node_position": {
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"x": 0,
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"y": 0
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},
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"parameters": {
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"ax": -0.4,
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"ay": -0.3,
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"bx": 0,
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"by": 0.5,
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"cx": 0.4,
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"cy": -0.3,
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"repeat": 1,
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"width": 0.05
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},
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"shader_model": {
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"code": "vec2 $(name_uv)_bezier = sdBezier($uv, vec2($ax+0.5, $ay+0.5), vec2($bx+0.5, $by+0.5), vec2($cx+0.5, $cy+0.5));\nvec2 $(name_uv)_uv = vec2($(name_uv)_bezier.x, $(name_uv)_bezier.y/$width+0.5);\nvec2 $(name_uv)_uvtest = step(vec2(0.5), abs($(name_uv)_uv-vec2(0.5)));\n$(name_uv)_uv = mix(vec2(fract($repeat*$(name_uv)_uv.x), $(name_uv)_uv.y), vec2(0.0), max($(name_uv)_uvtest.x, $(name_uv)_uvtest.y));\n",
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"global": "float cross2( in vec2 a, in vec2 b ) { return a.x*b.y - a.y*b.x; }\n\n// signed distance to a quadratic bezier\nvec2 sdBezier( in vec2 pos, in vec2 A, in vec2 B, in vec2 C ) { \n vec2 a = B - A;\n vec2 b = A - 2.0*B + C;\n vec2 c = a * 2.0;\n vec2 d = A - pos;\n\n float kk = 1.0/dot(b,b);\n float kx = kk * dot(a,b);\n float ky = kk * (2.0*dot(a,a)+dot(d,b))/3.0;\n float kz = kk * dot(d,a); \n\n float res = 0.0;\n float sgn = 0.0;\n\n float p = ky - kx*kx;\n float p3 = p*p*p;\n float q = kx*(2.0*kx*kx - 3.0*ky) + kz;\n float h = q*q + 4.0*p3;\n\tfloat rvx;\n\n if( h>=0.0 ) { // 1 root\n h = sqrt(h);\n vec2 x = (vec2(h,-h)-q)/2.0;\n vec2 uv = sign(x)*pow(abs(x), vec2(1.0/3.0));\n\t\trvx = uv.x+uv.y-kx;\n float t = clamp(rvx, 0.0, 1.0);\n vec2 q2 = d+(c+b*t)*t;\n res = dot(q2, q2);\n \tsgn = cross2(c+2.0*b*t, q2);\n } else { // 3 roots\n float z = sqrt(-p);\n float v = acos(q/(p*z*2.0))/3.0;\n float m = cos(v);\n float n = sin(v)*1.732050808;\n vec3 t = clamp(vec3(m+m,-n-m,n-m)*z-kx, 0.0, 1.0);\n vec2 qx=d+(c+b*t.x)*t.x; float dx=dot(qx, qx), sx = cross2(c+2.0*b*t.x,qx);\n vec2 qy=d+(c+b*t.y)*t.y; float dy=dot(qy, qy), sy = cross2(c+2.0*b*t.y,qy);\n if( dx<dy ) { res=dx; sgn=sx; rvx = t.x; } else { res=dy; sgn=sy; rvx = t.y; }\n }\n \n return vec2(rvx, sqrt(res)*sign(sgn));\n}\n",
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"inputs": [
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{
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"default": "vec4(vec3(step(abs($uv.y-0.5), 0.4999)), 1.0)",
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"label": "",
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"longdesc": "Input pattern to be drawn along the curve",
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"name": "in",
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"shortdesc": "Pattern",
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"type": "rgba"
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}
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],
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"instance": "",
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"name": "Curve",
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"outputs": [
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{
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"longdesc": "An image showing the specified curve",
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"rgba": "$in($(name_uv)_uv)",
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"shortdesc": "Output",
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"type": "rgba"
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}
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],
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"parameters": [
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{
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"control": "P1.x",
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"default": -0.3,
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"label": "AX",
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"longdesc": "Position on X axis of the first control point",
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"max": 0.5,
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"min": -0.5,
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"name": "ax",
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"shortdesc": "A.x",
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"step": 0.01,
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"type": "float"
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},
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{
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"control": "P1.y",
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"default": -0.1,
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"label": "AY",
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"longdesc": "Position on Y axis of the first control point",
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"max": 0.5,
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"min": -0.5,
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"name": "ay",
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"shortdesc": "A.y",
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"step": 0.01,
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"type": "float"
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},
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{
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"control": "P3.x",
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"default": -0,
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"label": "BX",
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"longdesc": "Position on X axis of the second control point",
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"max": 0.5,
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"min": -0.5,
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"name": "bx",
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"shortdesc": "B.x",
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"step": 0.01,
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"type": "float"
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},
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{
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"control": "P3.y",
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"default": 0.2,
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"label": "BY",
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"longdesc": "Position on Y axis of the second control point",
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"max": 0.5,
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"min": -0.5,
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"name": "by",
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"shortdesc": "B.y",
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"step": 0.01,
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"type": "float"
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},
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{
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"control": "P2.x",
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"default": 0.3,
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"label": "CX",
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"longdesc": "Position on X axis of the third control point",
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"max": 0.5,
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"min": -0.5,
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"name": "cx",
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"shortdesc": "C.x",
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"step": 0.01,
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"type": "float"
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},
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{
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"control": "P2.y",
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"default": -0.1,
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"label": "CY",
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"longdesc": "Position on Y axis of the third control point",
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"max": 0.5,
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"min": -0.5,
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"name": "cy",
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"shortdesc": "C.y",
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"step": 0.01,
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"type": "float"
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},
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{
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"control": "None",
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"default": 0.1,
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"label": "Width",
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"longdesc": "Width of the curve pattern",
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"max": 0.5,
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"min": 0,
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"name": "width",
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"shortdesc": "Width",
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"step": 0.01,
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"type": "float"
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},
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{
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"control": "None",
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"default": 1,
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"label": "Repeat",
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"longdesc": "Number of repetitions of the input pattern",
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"max": 16,
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"min": 1,
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"name": "repeat",
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"shortdesc": "Repeat",
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"step": 1,
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"type": "float"
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}
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]
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},
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"type": "shader"
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} |