mirror of
https://github.com/italicsjenga/slang-shaders.git
synced 2024-11-25 08:51:32 +11:00
339 lines
12 KiB
Plaintext
339 lines
12 KiB
Plaintext
#version 450
|
|
/*
|
|
Quasi Infinite Zoom Voronoi
|
|
---------------------------
|
|
|
|
The infinite zoom effect has been keeping me amused for years.
|
|
|
|
This one is based on something I wrote some time ago, but was inspired by Fabrice Neyret's
|
|
"Infinite Fall" shader. I've aired on the side of caution and called it "quasi infinite,"
|
|
just in case it doesn't adhere to his strict infinite zoom standards. :)
|
|
|
|
Seriously though, I put together a couple of overly optimized versions a couple of days ago,
|
|
just for fun, and Fabrice's comments were pretty helpful. I also liked the way he did the
|
|
layer rotation in his "Infinite Fall" version, so I'm using that. The rest is stock standard
|
|
infinite zoom stuff that has been around for years.
|
|
|
|
Most people like to use noise for this effect, so I figured I'd do something different
|
|
and use Voronoi. I've also bump mapped it, added specular highlights, etc. It was
|
|
tempting to add a heap of other things, but I wanted to keep the example relatively simple.
|
|
|
|
By the way, most of the code is basic bump mapping and lighting. The infinite zoom code
|
|
takes up just a small portion.
|
|
|
|
|
|
Fabrice Neyret's versions:
|
|
|
|
infinite fall - short
|
|
https://www.shadertoy.com/view/ltjXWW
|
|
|
|
infinite fall - FabriceNeyret2
|
|
https://www.shadertoy.com/view/4sl3RX
|
|
|
|
Other examples:
|
|
|
|
Fractal Noise - mu6k
|
|
https://www.shadertoy.com/view/Msf3Wr
|
|
|
|
Infinite Sierpinski - gleurop
|
|
https://www.shadertoy.com/view/MdfGR8
|
|
|
|
Infinite Zoom - fizzer
|
|
https://www.shadertoy.com/view/MlXGW7
|
|
|
|
Private link to a textured version of this.
|
|
Bumped Infinite Zoom Texture - Shane
|
|
https://www.shadertoy.com/view/Xl2XWw
|
|
*/
|
|
|
|
|
|
layout(std140, set = 0, binding = 0) uniform UBO
|
|
{
|
|
mat4 MVP;
|
|
vec4 OutputSize;
|
|
vec4 OriginalSize;
|
|
vec4 SourceSize;
|
|
uint FrameCount;
|
|
} global;
|
|
|
|
#pragma stage vertex
|
|
layout(location = 0) in vec4 Position;
|
|
layout(location = 1) in vec2 TexCoord;
|
|
layout(location = 0) out vec2 vTexCoord;
|
|
const vec2 madd = vec2(0.5, 0.5);
|
|
void main()
|
|
{
|
|
gl_Position = global.MVP * Position;
|
|
vTexCoord = gl_Position.xy;
|
|
}
|
|
|
|
#pragma stage fragment
|
|
layout(location = 0) in vec2 vTexCoord;
|
|
layout(location = 0) out vec4 FragColor;
|
|
float iGlobalTime = float(global.FrameCount)*0.025;
|
|
vec2 iResolution = global.OutputSize.xy;
|
|
|
|
vec2 hash22(vec2 p) {
|
|
|
|
// Faster, but doesn't disperse things quite as nicely. However, when framerate
|
|
// is an issue, and it often is, this is a good one to use. Basically, it's a tweaked
|
|
// amalgamation I put together, based on a couple of other random algorithms I've
|
|
// seen around... so use it with caution, because I make a tonne of mistakes. :)
|
|
float n = sin(dot(p, vec2(41, 289)));
|
|
return fract(vec2(262144, 32768)*n);
|
|
|
|
// Animated.
|
|
//p = fract(vec2(262144, 32768)*n);
|
|
//return sin( p*6.2831853 + time )*0.5 + 0.5;
|
|
|
|
}
|
|
|
|
// One of many 2D Voronoi algorithms getting around, but all are based on IQ's
|
|
// original. I got bored and roughly explained it. It was a slow day. :) The
|
|
// explanations will be obvious to many, but not all.
|
|
float Voronoi(vec2 p)
|
|
{
|
|
// Partitioning the 2D space into repeat cells.
|
|
vec2 ip = floor(p); // Analogous to the cell's unique ID.
|
|
p = fract(p); // Fractional reference point within the cell.
|
|
|
|
// Set the minimum distance (squared distance, in this case, because it's
|
|
// faster) to a maximum of 1. Outliers could reach as high as 2 (sqrt(2)^2)
|
|
// but it's being capped to 1, because it covers a good portion of the range
|
|
// (basically an inscribed unit circle) and dispenses with the need to
|
|
// normalize the final result.
|
|
//
|
|
// If you're finding that your Voronoi patterns are a little too contrasty,
|
|
// you could raise "d" to something like "1.5." Just remember to divide
|
|
// the final result by the same amount.
|
|
float d = 1.;
|
|
|
|
// Put a "unique" random point in the cell (using the cell ID above), and it's 8
|
|
// neighbors (using their cell IDs), then check for the minimum squared distance
|
|
// between the current fractional cell point and these random points.
|
|
for (float i = -1.; i < 1.1; i++){
|
|
for (float j = -1.; j < 1.1; j++){
|
|
|
|
vec2 cellRef = vec2(i, j); // Base cell reference point.
|
|
|
|
vec2 offset = hash22(ip + cellRef); // 2D offset.
|
|
|
|
// Vector from the point in the cell to the offset point.
|
|
vec2 r = cellRef + offset - p;
|
|
float d2 = dot(r, r); // Squared length of the vector above.
|
|
|
|
d = min(d, d2); // If it's less than the previous minimum, store it.
|
|
}
|
|
}
|
|
|
|
// In this case, the distance is being returned, but the squared distance
|
|
// can be used too, if prefered.
|
|
return sqrt(d);
|
|
}
|
|
|
|
/*
|
|
// 2D 2nd-order Voronoi: Obviously, this is just a rehash of IQ's original. I've tidied
|
|
// up those if-statements. Since there's less writing, it should go faster. That's how
|
|
// it works, right? :)
|
|
//
|
|
float Voronoi2(vec2 p){
|
|
|
|
vec2 g = floor(p), o;
|
|
p -= g;// p = fract(p);
|
|
|
|
vec2 d = vec2(1); // 1.4, etc.
|
|
|
|
for(int y = -1; y <= 1; y++){
|
|
for(int x = -1; x <= 1; x++){
|
|
|
|
o = vec2(x, y);
|
|
o += hash22(g + o) - p;
|
|
|
|
float h = dot(o, o);
|
|
d.y = max(d.x, min(d.y, h));
|
|
d.x = min(d.x, h);
|
|
}
|
|
}
|
|
|
|
//return sqrt(d.y) - sqrt(d.x);
|
|
return (d.y - d.x); // etc.
|
|
}
|
|
*/
|
|
|
|
|
|
|
|
void mainImage( out vec4 fragColor, in vec2 fragCoord ){
|
|
|
|
// Screen coordinates.
|
|
vec2 uv = (fragCoord - iResolution.xy*.5)/iResolution.y;
|
|
|
|
// Variable setup, plus rotation.
|
|
float t = iGlobalTime, s, a, b, e;
|
|
|
|
|
|
// Rotation the canvas back and forth.
|
|
float th = sin(iGlobalTime*0.1)*sin(iGlobalTime*0.13)*4.;
|
|
float cs = cos(th), si = sin(th);
|
|
uv *= mat2(cs, -si, si, cs);
|
|
|
|
|
|
// Setup: I find 2D bump mapping more intuitive to pretend I'm raytracing, then lighting a bump mapped plane
|
|
// situated at the origin. Others may disagree. :)
|
|
vec3 sp = vec3(uv, 0); // Surface posion. Hit point, if you prefer. Essentially, a screen at the origin.
|
|
vec3 ro = vec3(0, 0, -1); // Camera position, ray origin, etc.
|
|
vec3 rd = normalize(sp-ro); // Unit direction vector. From the origin to the screen plane.
|
|
vec3 lp = vec3(cos(iGlobalTime)*0.375, sin(iGlobalTime)*0.1, -1.); // Light position - Back from the screen.
|
|
|
|
|
|
// The number of layers. More gives you a more continous blend, but is obviously slower.
|
|
// If you change the layer number, you'll proably have to tweak the "gFreq" value.
|
|
const float L = 8.;
|
|
// Global layer frequency, or global zoom, if you prefer.
|
|
const float gFreq = 0.5;
|
|
float sum = 0.; // Amplitude sum, of sorts.
|
|
|
|
|
|
// Setting up the layer rotation matrix, used to rotate each layer.
|
|
// Not completely necessary, but it helps mix things up. It's standard practice, but
|
|
// this one is based on Fabrice's example.
|
|
th = 3.14159265*0.7071/L;
|
|
cs = cos(th), si = sin(th);
|
|
mat2 M = mat2(cs, -si, si, cs);
|
|
|
|
|
|
// The overall scene color. Initiated to zero.
|
|
vec3 col = vec3(0);
|
|
|
|
|
|
|
|
|
|
// Setting up the bump mapping variables and initiating them to zero.
|
|
// f - Function value
|
|
// fx - Change in "f" in in the X-direction.
|
|
// fy - Change in "f" in in the Y-direction.
|
|
float f=0., fx=0., fy=0.;
|
|
vec2 eps = vec2(4./iResolution.y, 0.);
|
|
|
|
// I've had to off-center this just a little to avoid an annoying white speck right
|
|
// in the middle of the canvas. If anyone knows how to get rid of it, I'm all ears. :)
|
|
vec2 offs = vec2(0.1);
|
|
|
|
|
|
// Infinite Zoom.
|
|
//
|
|
// The first three lines are a little difficult to explain without describing what infinite
|
|
// zooming is in the first place. A lot of it is analogous to fBm. Sum a bunch of increasing
|
|
// frequencies with decreasing amplitudes.
|
|
//
|
|
// Anyway, the effect is nothing more than a series of layers being expanded from an initial
|
|
// size to a final size, then being snapped back to its original size to repeat the process
|
|
// again. However, each layer is doing it at diffent incremental stages in time, which tricks
|
|
// the brain into believing the process is continuous. If you wish to spoil the illusion,
|
|
// simply reduce the layer count. If you wish to completely ruin the effect, set it to one.
|
|
|
|
// Infinite zoom loop.
|
|
for (float i = 0.; i<L; i++){
|
|
|
|
// Fractional time component. Obviously, incremented by "1./L" and ranging from
|
|
// zero to one, whist on a repeat cycle.
|
|
s = fract((i - t*2.)/L);
|
|
|
|
// Using the fractional time component to determine the layer frequency. It increases
|
|
// with time, then snaps back to one in a cyclic fashion.
|
|
// Note that exp2(t) is just another way to write pow(2., s). The latter is more
|
|
// intuitive, but slower... Well, I assume it is.
|
|
e = exp2(s*L)*gFreq; // Range (approx): [ 1, pow(2., L)*gFreq ]
|
|
|
|
// Layer ampltude component. Inversely propotional to the frequency, which makes sense.
|
|
// Because the layers are finite, you need to smoothly interpolate between them,
|
|
// and the "cos" setup below is just one of many ways to do it.
|
|
a = (1.-cos(s*6.283))/e; // Smooth transition.
|
|
//a = (1. - abs(s-.5)*2.)/e; // Alternative linear fade. Not as smooth, or accurate.
|
|
//a = (1. - abs(s-.5)*2.); a *= a*(3.-2.*a)/e; // Smooth linear fade, if so desired.
|
|
|
|
|
|
// Accumulating each layer.
|
|
|
|
// I had to have a bit of a think as to how to bump map this. Normally, you'd write a function
|
|
// then call it three times, but that'd be too expensive, so it's all being done simultaneously.
|
|
//
|
|
// Either way, it's still pretty simple. In addition to accumulating the pixel value, accumulate
|
|
// sample values just to the left of it and above. The X-gradient and Y-gradient can then be
|
|
// determined outside the loop.
|
|
//
|
|
f += Voronoi(M*sp.xy*e + offs) * a; // Sample value multiplied by the amplitude.
|
|
fx += Voronoi(M*(sp.xy-eps.xy)*e + offs) * a; // Same for the nearby sample in the X-direction.
|
|
fy += Voronoi(M*(sp.xy-eps.yx)*e + offs) * a; // Same for the nearby sample in the Y-direction.
|
|
|
|
// Sum each amplitude. Used to normalize the results once the loop is complete.
|
|
sum += a;
|
|
|
|
// Rotating each successive layer is pretty standard, but this is the way Fabrice does
|
|
// it.
|
|
M *= M;
|
|
|
|
}
|
|
|
|
// I doubt it'd happen, but just in case sum is zero.
|
|
sum = max(sum, 0.001);
|
|
|
|
// Normalizing the three Voronoi samples.
|
|
f /= sum;
|
|
fx /= sum;
|
|
fy /= sum;
|
|
|
|
|
|
// Common bump mapping stuff.
|
|
float bumpFactor = 0.2;
|
|
// Using the above to determine the dx and dy function gradients.
|
|
fx = (fx-f)/eps.x; // Change in X
|
|
fy = (fy-f)/eps.x; // Change in Y.
|
|
// Using the gradient vector, "vec3(fx, fy, 0)," to perturb the XY plane normal ",vec3(0, 0, -1)."
|
|
vec3 n = normalize( vec3(0, 0, -1) + vec3(fx, fy, 0)*bumpFactor );
|
|
|
|
|
|
|
|
|
|
// Determine the light direction vector, calculate its distance, then normalize it.
|
|
vec3 ld = lp - sp;
|
|
float lDist = max(length(ld), 0.001);
|
|
ld /= lDist;
|
|
|
|
|
|
|
|
// Light attenuation.
|
|
float atten = 1.25/(1. + lDist*0.15 + lDist*lDist*0.15);
|
|
//float atten = min(1./(dist*dist*2.), 1.);
|
|
|
|
|
|
// Diffuse value.
|
|
float diff = max(dot(n, ld), 0.);
|
|
// Enhancing the diffuse value a bit. Made up.
|
|
diff = pow(diff, 2.)*0.66 + pow(diff, 4.)*0.34;
|
|
// Specular highlighting.
|
|
float spec = pow(max(dot( reflect(-ld, n), -rd), 0.), 16.);
|
|
|
|
|
|
// Using the infinite Voronoi value to produce a purplish color.
|
|
vec3 objCol = vec3(f*f, pow(f, 5.)*0.05, f*f*0.36);
|
|
// Blood... ruby red.
|
|
//vec3 objCol = vec3(f*f, pow(f, 16.), pow(f, 8.)*.5);
|
|
|
|
|
|
// Using the values above to produce the final color.
|
|
col = (objCol * (diff + .5) + vec3(.4, .6, 1.)*spec*1.5) * atten;
|
|
|
|
|
|
// Done.
|
|
fragColor = vec4(sqrt(min(col, 1.)), 1.);
|
|
}
|
|
|
|
|
|
void main(void)
|
|
{
|
|
//just some shit to wrap shadertoy's stuff
|
|
vec2 FragCoord = vTexCoord.xy*global.OutputSize.xy;
|
|
FragCoord.y = -FragCoord.y;
|
|
mainImage(FragColor,FragCoord);
|
|
}
|