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@beesandbombs
Created September 5, 2018 22:57
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star torus
// "star torus" by davey
int[][] result;
float t, c;
float ease(float p) {
return 3*p*p - 2*p*p*p;
}
float ease(float p, float g) {
if (p < 0.5)
return 0.5 * pow(2*p, g);
else
return 1 - 0.5 * pow(2*(1 - p), g);
}
float mn = .5*sqrt(3), ia = atan(sqrt(.5));
void push() {
pushMatrix();
pushStyle();
}
void pop() {
popStyle();
popMatrix();
}
float c01(float g) {
return constrain(g, 0, 1);
}
void draw() {
if (!recording) {
t = mouseX*1.0/width;
c = mouseY*1.0/height;
if (mousePressed)
println(c);
draw_();
} else {
for (int i=0; i<width*height; i++)
for (int a=0; a<3; a++)
result[i][a] = 0;
c = 0;
for (int sa=0; sa<samplesPerFrame; sa++) {
t = map(frameCount-1 + sa*shutterAngle/samplesPerFrame, 0, numFrames, 0, 1);
draw_();
loadPixels();
for (int i=0; i<pixels.length; i++) {
result[i][0] += pixels[i] >> 16 & 0xff;
result[i][1] += pixels[i] >> 8 & 0xff;
result[i][2] += pixels[i] & 0xff;
}
}
loadPixels();
for (int i=0; i<pixels.length; i++)
pixels[i] = 0xff << 24 |
int(result[i][0]*1.0/samplesPerFrame) << 16 |
int(result[i][1]*1.0/samplesPerFrame) << 8 |
int(result[i][2]*1.0/samplesPerFrame);
updatePixels();
saveFrame("f###.gif");
if (frameCount==numFrames)
exit();
}
}
//////////////////////////////////////////////////////////////////////////////
int samplesPerFrame = 4;
int numFrames = 280;
float shutterAngle = 1;
boolean recording = false;
void setup() {
size(800, 800, P3D);
pixelDensity(recording ? 1 : 2);
smooth(8);
result = new int[width*height][3];
noStroke();
}
float x, y, z;
int nStars = 180, starSpeed = 12;
int m = 5, n = 3; // coprime for single knot!
float depth;
float r = 80, th;
float starRad, starSize = 15;
float zMax = r*3;
void star() {
beginShape();
for (int j=0; j<8; j++) {
starRad = j%2==0?starSize:starSize*.175;
vertex(starRad*cos(TWO_PI*j/8), starRad*sin(TWO_PI*j/8));
}
endShape();
}
void draw_() {
background(0);
push();
translate(width/2, height/2);
rotateY(-TWO_PI*t);
for (int i=0; i<nStars; i++) {
th = TWO_PI*(i+starSpeed*t)/nStars;
x = r*(2+cos(n*th))*cos(m*th); // https://en.wikipedia.org/wiki/Torus_knot
y = r*(2+cos(n*th))*sin(m*th);
z = -r*sin(n*th);
depth = map(modelZ(x, y, z), -zMax, zMax, -.5, 2);
depth = sq(c01(depth));
push();
translate(x, y, z);
rotateY(TWO_PI*t);
fill(255*depth);
star();
pop();
}
pop();
}
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