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@prusnak
Last active March 22, 2022 00:20
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// constants
const float PI = 3.1415925654;
// colorspace conversion
vec3 rgb2hsv(vec3 c)
{
vec4 K = vec4(0.0, -1.0 / 3.0, 2.0 / 3.0, -1.0);
vec4 p = mix(vec4(c.bg, K.wz), vec4(c.gb, K.xy), step(c.b, c.g));
vec4 q = mix(vec4(p.xyw, c.r), vec4(c.r, p.yzx), step(p.x, c.r));
float d = q.x - min(q.w, q.y);
float e = 1.0e-10;
return vec3(abs(q.z + (q.w - q.y) / (6.0 * d + e)), d / (q.x + e), q.x);
}
vec3 hsv2rgb(vec3 c)
{
vec4 K = vec4(1.0, 2.0 / 3.0, 1.0 / 3.0, 3.0);
vec3 p = abs(fract(c.xxx + K.xyz) * 6.0 - K.www);
return c.z * mix(K.xxx, clamp(p - K.xxx, 0.0, 1.0), c.y);
}
// misc functions
float random (in vec2 _st, float seed) {
return fract(sin(seed + dot(_st.xy,vec2(12.9898, 78.233))) * 43758.5453123);
}
// shapes
float sdCircle(vec2 p, float r)
{
return length(p) - r;
}
float sdPentagon(vec2 p, float r)
{
const vec3 k = vec3(0.809016994,0.587785252,0.726542528);
p.x = abs(p.x);
p -= 2.0*min(dot(vec2(-k.x,k.y),p),0.0)*vec2(-k.x,k.y);
p -= 2.0*min(dot(vec2( k.x,k.y),p),0.0)*vec2( k.x,k.y);
return length(p-vec2(clamp(p.x,-r*k.z,r*k.z),r))*sign(p.y-r);
}
float sdBox(vec2 p, vec2 b)
{
vec2 d = abs(p)-b;
return length(max(d,vec2(0))) + min(max(d.x,d.y),0.0);
}
// 2d operations
void pRotate(inout vec2 p, float a) {
p = cos(a)*p + sin(a)*vec2(p.y, -p.x);
}
float pPolar(inout vec2 p, float repetitions) {
float angle = 2*PI/repetitions;
float a = atan(p.y, p.x) + angle/2.;
float r = length(p);
float c = floor(a/angle);
a = mod(a,angle) - angle/2.;
p = vec2(cos(a), sin(a))*r;
if (abs(c) >= (repetitions/2)) c = abs(c);
return c;
}
// 3d operations
mat4 rotationX(in float angle) {
return mat4( 1.0, 0, 0, 0,
0, cos(angle), -sin(angle), 0,
0, sin(angle), cos(angle), 0,
0, 0, 0, 1);
}
mat4 rotationY(in float angle) {
return mat4( cos(angle), 0, sin(angle), 0,
0, 1.0, 0, 0,
-sin(angle), 0, cos(angle), 0,
0, 0, 0, 1);
}
mat4 rotationZ(in float angle) {
return mat4( cos(angle), -sin(angle), 0, 0,
sin(angle), cos(angle), 0, 0,
0, 0, 1, 0,
0, 0, 0, 1);
}
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