299 lines
9.5 KiB
GLSL
299 lines
9.5 KiB
GLSL
#version 430 core
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uniform vec3 iResolution;
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uniform sampler2D iChannel1;
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uniform samplerCube iChannel0;
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uniform float time;
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//in float iDate;
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in vec4 bubblePosition;
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out vec4 fragColor;
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/*
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Fast Thin-Film Interference
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This is a performance-optimized version of my previous
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thin-film interference shader here: https://www.shadertoy.com/view/XddXRj
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This version also fixes a platform-specific bug and has
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a few other tweaks as well.
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Thin-film interference and chromatic dispersion are simulated at
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six different wavelengths and then downsampled to RGB.
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*/
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// To see just the reflection (no refraction/transmission) uncomment this next line:
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//#define REFLECTANCE_ONLY
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// performance and raymarching options
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#define INTERSECTION_PRECISION 0.01 // raymarcher intersection precision
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#define ITERATIONS 20 // max number of iterations
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#define AA_SAMPLES 1 // anti aliasing samples
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#define BOUND 6.0 // cube bounds check
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#define DIST_SCALE 0.9 // scaling factor for raymarching position update
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// optical properties
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#define DISPERSION 0.05 // dispersion amount
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#define IOR 0.9 // base IOR value specified as a ratio
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#define THICKNESS_SCALE 32.0 // film thickness scaling factor
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#define THICKNESS_CUBEMAP_SCALE 0.1 // film thickness cubemap scaling factor
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#define REFLECTANCE_SCALE 3.0 // reflectance scaling factor
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#define REFLECTANCE_GAMMA_SCALE 2.0 // reflectance gamma scaling factor
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#define FRESNEL_RATIO 0.7 // fresnel weight for reflectance
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#define SIGMOID_CONTRAST 8.0 // contrast enhancement
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#define TWO_PI 6.28318530718
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#define WAVELENGTHS 6 // number of wavelengths, not a free parameter
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// iq's cubemap function
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vec3 fancyCube( sampler2D sam, in vec3 d, in float s, in float b )
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{
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vec3 colx = textureLod( sam, 0.5 + s*d.yz/d.x, b ).xyz;
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vec3 coly = textureLod( sam, 0.5 + s*d.zx/d.y, b ).xyz;
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vec3 colz = textureLod( sam, 0.5 + s*d.xy/d.z, b ).xyz;
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vec3 n = d*d;
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return (colx*n.x + coly*n.y + colz*n.z)/(n.x+n.y+n.z);
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}
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// iq's 3D noise function
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float hash( float n ){
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return fract(sin(n)*43758.5453);
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}
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float noise( in vec3 x ) {
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vec3 p = floor(x);
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vec3 f = fract(x);
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f = f*f*(3.0-2.0*f);
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float n = p.x + p.y*57.0 + 113.0*p.z;
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return mix(mix(mix( hash(n+ 0.0), hash(n+ 1.0),f.x),
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mix( hash(n+ 57.0), hash(n+ 58.0),f.x),f.y),
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mix(mix( hash(n+113.0), hash(n+114.0),f.x),
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mix( hash(n+170.0), hash(n+171.0),f.x),f.y),f.z);
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}
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vec3 noise3(vec3 x) {
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return vec3( noise(x+vec3(123.456,.567,.37)),
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noise(x+vec3(.11,47.43,19.17)),
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noise(x) );
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}
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// a sphere with a little bit of warp
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float sdf( vec3 p ) {
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vec3 n = vec3(sin(time * 0.5), sin(time * 0.3), cos(time * 0.2));
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vec3 q = 0.1 * (noise3(p + n) - 0.5);
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return length(q + p) - 3.5;
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}
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vec3 fresnel( vec3 rd, vec3 norm, vec3 n2 ) {
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vec3 r0 = pow((1.0-n2)/(1.0+n2), vec3(2));
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return r0 + (1. - r0)*pow(clamp(1. + dot(rd, norm), 0.0, 1.0), 5.);
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}
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vec3 calcNormal( in vec3 pos ) {
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const float eps = INTERSECTION_PRECISION;
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const vec3 v1 = vec3( 1.0,-1.0,-1.0);
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const vec3 v2 = vec3(-1.0,-1.0, 1.0);
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const vec3 v3 = vec3(-1.0, 1.0,-1.0);
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const vec3 v4 = vec3( 1.0, 1.0, 1.0);
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return normalize( v1*sdf( pos + v1*eps ) +
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v2*sdf( pos + v2*eps ) +
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v3*sdf( pos + v3*eps ) +
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v4*sdf( pos + v4*eps ) );
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}
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#define GAMMA_CURVE 50.0
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#define GAMMA_SCALE 4.5
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vec3 filmic_gamma(vec3 x) {
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return log(GAMMA_CURVE * x + 1.0) / GAMMA_SCALE;
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}
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vec3 filmic_gamma_inverse(vec3 y) {
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return (1.0 / GAMMA_CURVE) * (exp(GAMMA_SCALE * y) - 1.0);
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}
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// sample weights for the cubemap given a wavelength i
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// room for improvement in this function
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#define GREEN_WEIGHT 2.8
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vec3 texCubeSampleWeights(float i) {
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vec3 w = vec3((1.0 - i) * (1.0 - i), GREEN_WEIGHT * i * (1.0 - i), i * i);
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return w / dot(w, vec3(1.0));
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}
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vec3 sampleCubeMap(vec3 i, vec3 rd) {
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vec3 col = textureLod(iChannel0, rd * vec3(1.0,-1.0,1.0), 0.0).xyz;
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return vec3(
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dot(texCubeSampleWeights(i.x), col),
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dot(texCubeSampleWeights(i.y), col),
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dot(texCubeSampleWeights(i.z), col)
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);
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}
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vec3 sampleCubeMap(vec3 i, vec3 rd0, vec3 rd1, vec3 rd2) {
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vec3 col0 = textureLod(iChannel0, rd0 * vec3(1.0,-1.0,1.0), 0.0).xyz;
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vec3 col1 = textureLod(iChannel0, rd1 * vec3(1.0,-1.0,1.0), 0.0).xyz;
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vec3 col2 = textureLod(iChannel0, rd2 * vec3(1.0,-1.0,1.0), 0.0).xyz;
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return vec3(
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dot(texCubeSampleWeights(i.x), col0),
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dot(texCubeSampleWeights(i.y), col1),
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dot(texCubeSampleWeights(i.z), col2)
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);
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}
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vec3 sampleWeights(float i) {
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return vec3((1.0 - i) * (1.0 - i), GREEN_WEIGHT * i * (1.0 - i), i * i);
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}
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vec3 resample(vec3 wl0, vec3 wl1, vec3 i0, vec3 i1) {
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vec3 w0 = sampleWeights(wl0.x);
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vec3 w1 = sampleWeights(wl0.y);
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vec3 w2 = sampleWeights(wl0.z);
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vec3 w3 = sampleWeights(wl1.x);
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vec3 w4 = sampleWeights(wl1.y);
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vec3 w5 = sampleWeights(wl1.z);
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return i0.x * w0 + i0.y * w1 + i0.z * w2
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+ i1.x * w3 + i1.y * w4 + i1.z * w5;
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}
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// downsample to RGB
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vec3 resampleColor(vec3[WAVELENGTHS] rds, vec3 refl0, vec3 refl1, vec3 wl0, vec3 wl1) {
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#ifdef REFLECTANCE_ONLY
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vec3 intensity0 = refl0;
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vec3 intensity1 = refl1;
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#else
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vec3 cube0 = sampleCubeMap(wl0, rds[0], rds[1], rds[2]);
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vec3 cube1 = sampleCubeMap(wl1, rds[3], rds[4], rds[5]);
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vec3 intensity0 = filmic_gamma_inverse(cube0) + refl0;
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vec3 intensity1 = filmic_gamma_inverse(cube1) + refl1;
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#endif
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vec3 col = resample(wl0, wl1, intensity0, intensity1);
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return 1.4 * filmic_gamma(col / float(WAVELENGTHS));
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}
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vec3 resampleColorSimple(vec3 rd, vec3 wl0, vec3 wl1) {
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vec3 cube0 = sampleCubeMap(wl0, rd);
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vec3 cube1 = sampleCubeMap(wl1, rd);
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vec3 intensity0 = filmic_gamma_inverse(cube0);
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vec3 intensity1 = filmic_gamma_inverse(cube1);
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vec3 col = resample(wl0, wl1, intensity0, intensity1);
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return 1.4 * filmic_gamma(col / float(WAVELENGTHS));
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}
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// compute the wavelength/IOR curve values.
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vec3 iorCurve(vec3 x) {
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return x;
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}
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vec3 attenuation(float filmThickness, vec3 wavelengths, vec3 normal, vec3 rd) {
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return 0.5 + 0.5 * cos(((THICKNESS_SCALE * filmThickness)/(wavelengths + 1.0)) * dot(normal, rd));
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}
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vec3 contrast(vec3 x) {
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return 1.0 / (1.0 + exp(-SIGMOID_CONTRAST * (x - 0.5)));
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}
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void doCamera( out vec3 camPos, out vec3 camTar, in float time, in vec4 m ) {
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camTar = vec3(0.0,0.0,0.0);
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if (max(m.z, m.w) <= 0.0) {
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float an = 1.5 + sin(time * 0.05) * 4.0;
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camPos = vec3(6.5*sin(an), 0.0 ,6.5*cos(an));
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} else {
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float an = 10.0 * m.x - 5.0;
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camPos = vec3(6.5*sin(an),10.0 * m.y - 5.0,6.5*cos(an));
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}
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}
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mat3 calcLookAtMatrix( in vec3 ro, in vec3 ta, in float roll )
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{
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vec3 ww = normalize( ta - ro );
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vec3 uu = normalize( cross(ww,vec3(sin(roll),cos(roll),0.0) ) );
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vec3 vv = normalize( cross(uu,ww));
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return mat3( uu, vv, ww );
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}
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void main()
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{
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vec2 p = (-iResolution.xy + 2.0*gl_FragCoord.xy)/iResolution.y;
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//vec4 m = vec4(iMouse.xy/iResolution.xy, iMouse.zw);
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// camera movement
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//vec3 ro, ta;
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//doCamera( ro, ta, iTime, m );
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float dh = (0.666 / iResolution.y);
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const float rads = TWO_PI / float(AA_SAMPLES);
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vec3 col = vec3(0.0);
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vec3 wavelengths0 = vec3(1.0, 0.8, 0.6);
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vec3 wavelengths1 = vec3(0.4, 0.2, 0.0);
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vec3 iors0 = IOR + iorCurve(wavelengths0) * DISPERSION;
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vec3 iors1 = IOR + iorCurve(wavelengths1) * DISPERSION;
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vec3 rds[WAVELENGTHS];
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for (int samp = 0; samp < AA_SAMPLES; samp++) {
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vec2 dxy = dh * vec2(cos(float(samp) * rads), sin(float(samp) * rads));
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vec3 rd = normalize(vec3(p.xy + dxy, 0.2)); // 1.5 is the lens length
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vec3 pos = vec3(-bubblePosition.z, -bubblePosition.y, bubblePosition.x);
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bool hit = false;
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for (int j = 0; j < ITERATIONS; j++) {
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float t = DIST_SCALE * sdf(pos);
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pos += t * rd;
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hit = t < INTERSECTION_PRECISION;
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if ( clamp(pos, -BOUND, BOUND) != pos || hit ) {
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break;
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}
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}
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if (hit) {
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vec3 normal = calcNormal(pos);
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float filmThickness = fancyCube( iChannel1, normal, THICKNESS_CUBEMAP_SCALE, 0.0 ).x + 0.1;
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vec3 att0 = attenuation(filmThickness, wavelengths0, normal, rd);
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vec3 att1 = attenuation(filmThickness, wavelengths1, normal, rd);
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vec3 f0 = (1.0 - FRESNEL_RATIO) + FRESNEL_RATIO * fresnel(rd, normal, 1.0 / iors0);
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vec3 f1 = (1.0 - FRESNEL_RATIO) + FRESNEL_RATIO * fresnel(rd, normal, 1.0 / iors1);
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vec3 rrd = reflect(rd, normal);
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vec3 cube0 = REFLECTANCE_GAMMA_SCALE * att0 * sampleCubeMap(wavelengths0, rrd);
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vec3 cube1 = REFLECTANCE_GAMMA_SCALE * att1 * sampleCubeMap(wavelengths1, rrd);
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vec3 refl0 = REFLECTANCE_SCALE * filmic_gamma_inverse(mix(vec3(0), cube0, f0));
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vec3 refl1 = REFLECTANCE_SCALE * filmic_gamma_inverse(mix(vec3(0), cube1, f1));
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rds[0] = refract(rd, normal, iors0.x);
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rds[1] = refract(rd, normal, iors0.y);
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rds[2] = refract(rd, normal, iors0.z);
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rds[3] = refract(rd, normal, iors1.x);
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rds[4] = refract(rd, normal, iors1.y);
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rds[5] = refract(rd, normal, iors1.z);
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col += resampleColor(rds, refl0, refl1, wavelengths0, wavelengths1);
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} else {
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col += resampleColorSimple(rd, wavelengths0, wavelengths1);
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}
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}
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col /= float(AA_SAMPLES);
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fragColor = vec4( contrast(col), 1.0 );
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} |