384 lines
12 KiB
GLSL
384 lines
12 KiB
GLSL
/* BTW: You can use ANY function as the noise/plasma function
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* It just needs to return a float in the range 0.0 - 17.0
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* But shouldn't return 0.0 or 17.0 (they're exclusive bounds).
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* View this shader on shadertoy: https://www.shadertoy.com/view/t3tSRj#
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*/
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// TODO: go through all my TODO items
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/* ==== Text Colouring ==== */
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#define PHOSPHOR_COL vec4(1, 1., 1., 1.)
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#define BG_COL vec4(0.2, 0.0, 0.2, 0.)
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/* ======= Text Size ======= */
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#define FONT_SIZE vec2(10.,20.)
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#define ROWCOLS vec2(80., 24.)
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/* === Text Bloom Effect === */
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#define WIDTH 1.2
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#define HEIGHT 0.7
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#define SMOOTH 0.004
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/* ====== Smoke Noise ====== */
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const int noiseSwirlSteps = 0;
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const float noiseSwirlValue = 1.;
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const float noiseSwirlStepValue = noiseSwirlValue / float(noiseSwirlSteps);
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const float noiseScale = 1.0;
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const float noiseTimeScale = 0.1;
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precision highp float;
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// ===================================================================
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// Library Functions
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//
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inline float rand(vec2 co){
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return fract(sin(dot(co.xy ,vec2(12.9898,78.233))) * 43758.5453);
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}
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inline float quantise(float val, float n) {
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return clamp(floor(val * n), 0.0, n) / n;
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}
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inline float roundSquare(vec2 p, vec2 b, float r) {
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return length(max(abs(p)-b,0.0))-r;
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}
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// standard roundSquare
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inline float stdRS(vec2 uv, float r) {
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return roundSquare(uv - 0.5, vec2(WIDTH, HEIGHT) + r, 0.05);
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}
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// ===================================================================
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// Description : Array and textureless GLSL 2D/3D/4D simplex
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// noise functions.
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// Author : Ian McEwan, Ashima Arts.
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// Maintainer : ijm
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// Lastmod : 20110822 (ijm)
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// License : Copyright (C) 2011 Ashima Arts. All rights reserved.
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// Distributed under the MIT License. See LICENSE file.
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// https://github.com/ashima/webgl-noise
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//
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inline vec3 mod289(vec3 x) {
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return x - floor(x * (1.0 / 289.0)) * 289.0;
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}
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inline vec4 mod289(vec4 x) {
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return x - floor(x * (1.0 / 289.0)) * 289.0;
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}
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inline vec4 permute(vec4 x) {
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return mod289(((x*34.0)+1.0)*x);
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}
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inline vec4 taylorInvSqrt(vec4 r) {
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return 1.79284291400159 - 0.85373472095314 * r;
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}
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float simplex(vec3 v) {
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const vec2 C = vec2(1.0/6.0, 1.0/3.0) ;
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const vec4 D = vec4(0.0, 0.5, 1.0, 2.0);
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// First corner
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vec3 i = floor(v + dot(v, C.yyy) );
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vec3 x0 = v - i + dot(i, C.xxx) ;
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// Other corners
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vec3 g = step(x0.yzx, x0.xyz);
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vec3 l = 1.0 - g;
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vec3 i1 = min( g.xyz, l.zxy );
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vec3 i2 = max( g.xyz, l.zxy );
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vec3 x1 = x0 - i1 + C.xxx;
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vec3 x2 = x0 - i2 + C.yyy;
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vec3 x3 = x0 - D.yyy;
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// Permutations
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i = mod289(i);
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vec4 p = permute( permute( permute(
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i.z + vec4(0.0, i1.z, i2.z, 1.0 ))
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+ i.y + vec4(0.0, i1.y, i2.y, 1.0 ))
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+ i.x + vec4(0.0, i1.x, i2.x, 1.0 ));
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// Gradients: 7x7 points over a square, mapped onto an octahedron.
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// The ring size 17*17 = 289 is close to a multiple of 49 (49*6 = 294)
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float n_ = 0.142857142857; // 1.0/7.0
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vec3 ns = n_ * D.wyz - D.xzx;
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vec4 j = p - 49.0 * floor(p * ns.z * ns.z); // mod(p,7*7)
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vec4 x_ = floor(j * ns.z);
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vec4 y_ = floor(j - 7.0 * x_ ); // mod(j,N)
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vec4 x = x_ *ns.x + ns.yyyy;
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vec4 y = y_ *ns.x + ns.yyyy;
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vec4 h = 1.0 - abs(x) - abs(y);
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vec4 b0 = vec4( x.xy, y.xy );
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vec4 b1 = vec4( x.zw, y.zw );
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vec4 s0 = floor(b0)*2.0 + 1.0;
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vec4 s1 = floor(b1)*2.0 + 1.0;
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vec4 sh = -step(h, vec4(0.0));
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vec4 a0 = b0.xzyw + s0.xzyw*sh.xxyy ;
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vec4 a1 = b1.xzyw + s1.xzyw*sh.zzww ;
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vec3 p0 = vec3(a0.xy,h.x);
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vec3 p1 = vec3(a0.zw,h.y);
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vec3 p2 = vec3(a1.xy,h.z);
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vec3 p3 = vec3(a1.zw,h.w);
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//Normalise gradients
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vec4 norm = taylorInvSqrt(vec4(dot(p0,p0), dot(p1,p1), dot(p2, p2), dot(p3,p3)));
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p0 *= norm.x;
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p1 *= norm.y;
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p2 *= norm.z;
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p3 *= norm.w;
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// Mix final noise value
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vec4 m = max(0.6 - vec4(dot(x0,x0), dot(x1,x1), dot(x2,x2), dot(x3,x3)), 0.0);
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m = m * m;
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return 42.0 * dot( m*m, vec4( dot(p0,x0), dot(p1,x1), dot(p2,x2), dot(p3,x3) ) );
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}
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// ===================================================================
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// VT220 Font Rendering
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// Author/Source : https://www.shadertoy.com/view/llSXDV
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//
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#define l(y,a,b) roundLine(p, vec2(float(a), float(y)), vec2(float(b), float(y)))
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float roundLine(vec2 p, vec2 a, vec2 b) {
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b -= a + vec2(1.0,0.);
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p -= a;
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float f = length(p-clamp(dot(p,b)/dot(b,b),0.0,1.0)*b);
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if (iResolution.y < 320.) // attempt to get rid of aliasing on small resolution
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return smoothstep(1.0, 0.9, f);
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else if (iResolution.y < 720.)
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return smoothstep(0.75, 0.5, f);
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else
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return smoothstep(1., 0., f);
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}
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float vt220Font(vec2 p, float c) {
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if (c < 1.) return 0.;
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if (p.y > 16.) {
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if (c > 2.) return 0.0;
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if (c > 1.) return l(17,1,9);
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}
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if (p.y > 14.) {
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if (c > 16.) return l(15,3,8);
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if (c > 15.) return l(15,1,8);
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if (c > 14.) return l(15,1,3)+ l(15,7,9);
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if (c > 13.) return l(15,2,8);
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if (c > 12.) return l(15,1,9);
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if (c > 11.) return l(15,2,8);
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if (c > 10.) return l(15,1,3)+ l(15,6,8);
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if (c > 9.) return l(15,4,6);
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if (c > 8.) return l(15,2,4)+ l(15,5,7);
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if (c > 7.) return l(15,2,8);
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if (c > 6.) return l(15,2,8);
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if (c > 5.) return l(15,2,8);
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if (c > 4.) return l(15,2,9);
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if (c > 3.) return l(15,1,8);
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if (c > 2.) return l(15,2,9);
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}
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if (p.y > 12.) {
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if (c > 16.) return l(13,2,4)+ l(13,7,9);
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if (c > 15.) return l(13,2,4)+ l(13,7,9);
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if (c > 14.) return l(13,1,3)+ l(13,7,9);
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if (c > 13.) return l(13,1,3)+ l(13,7,9);
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if (c > 12.) return l(13,1,3);
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if (c > 11.) return l(13,4,6);
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if (c > 10.) return l(13,2,4)+ l(13,5,9);
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if (c > 9.) return l(13,2,8);
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if (c > 8.) return l(13,2,4)+ l(13,5,7);
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if (c > 7.) return l(13,1,3)+ l(13,7,9);
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if (c > 6.) return l(13,1,3)+ l(13,7,9);
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if (c > 5.) return l(13,1,3)+ l(13,7,9);
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if (c > 4.) return l(13,1,3)+ l(15,2,9);
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if (c > 3.) return l(13,1,4)+ l(13,7,9);
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if (c > 2.) return l(13,1,3)+ l(13,6,9);
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}
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if (p.y > 10.) {
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if (c > 16.) return l(11,1,3);
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if (c > 15.) return l(11,2,4)+ l(11,7,9);
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if (c > 14.) return l(11,1,9);
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if (c > 13.) return l(11,7,9);
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if (c > 12.) return l(11,2,5);
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if (c > 11.) return l(11,4,6);
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if (c > 10.) return l(11,3,5)+ l(11,6,8);
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if (c > 9.) return l(11,4,6)+ l(11,7,9);
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if (c > 8.) return l(11,1,8);
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if (c > 7.) return l(11,1,3)+ l(11,7,9);
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if (c > 6.) return l(11,1,3)+ l(11,7,9);
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if (c > 5.) return l(11,1,3)+ l(11,7,9);
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if (c > 4.) return l(11,1,3);
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if (c > 3.) return l(11,1,3)+ l(11,7,9);
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if (c > 2.) return l(11,2,9);
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}
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if (p.y > 8.) {
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if (c > 16.) return l(9,1,3);
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if (c > 15.) return l(9,2,8);
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if (c > 14.) return l(9,1,3)+ l(9,7,9);
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if (c > 13.) return l(9,4,8);
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if (c > 12.) return l(9,4,8);
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if (c > 11.) return l(9,4,6);
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if (c > 10.) return l(9,4,6);
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if (c > 9.) return l(9,2,8);
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if (c > 8.) return l(9,2,4)+ l(9,5,7);
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if (c > 7.) return l(9,1,3)+ l(9,7,9);
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if (c > 6.) return l(9,1,3)+ l(9,7,9);
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if (c > 5.) return l(9,1,3)+ l(9,7,9);
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if (c > 4.) return l(9,1,3)+ l(9,7,9);
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if (c > 3.) return l(9,1,4)+ l(9,7,9);
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if (c > 2.) return l(9,7,9);
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}
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if (p.y > 6.) {
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if (c > 16.) return l(7,1,3);
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if (c > 15.) return l(7,2,4)+ l(7,7,9);
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if (c > 14.) return l(7,2,4)+ l(7,6,8);
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if (c > 13.) return l(7,5,7);
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if (c > 12.) return l(7,7,9);
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if (c > 11.) return l(7,2,6);
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if (c > 10.) return l(7,2,4)+ l(7,5,7);
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if (c > 9.) return l(7,1,3)+ l(7,4,6);
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if (c > 8.) return l(7,1,8);
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if (c > 7.) return l(7,2,8);
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if (c > 6.) return l(7,2,8);
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if (c > 5.) return l(7,2,8);
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if (c > 4.) return l(7,2,8);
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if (c > 3.) return l(7,1,8);
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if (c > 2.) return l(7,2,8);
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}
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if (p.y > 4.) {
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if (c > 16.) return l(5,2,4)+ l(5,7,9);
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if (c > 15.) return l(5,2,4)+ l(5,7,9);
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if (c > 14.) return l(5,3,7);
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if (c > 13.) return l(5,6,8);
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if (c > 12.) return l(5,1,3)+ l(5,7,9);
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if (c > 11.) return l(5,3,6);
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if (c > 10.) return l(5,1,5)+ l(5,6,8);
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if (c > 9.) return l(5,2,8);
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if (c > 8.) return l(5,2,4)+ l(5,5,7);
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if (c > 7.) return 0.;
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if (c > 6.) return 0.;
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if (c > 5.) return 0.;
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if (c > 4.) return 0.;
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if (c > 3.) return l(5,1,3);
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if (c > 2.) return 0.;
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}
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if (p.y > 2.) {
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if (c > 16.) return l(3,3,8);
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if (c > 15.) return l(3,1,8);
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if (c > 14.) return l(3,4,6);
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if (c > 13.) return l(3,1,9);
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if (c > 12.) return l(3,2,8);
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if (c > 11.) return l(3,4,6);
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if (c > 10.) return l(3,2,4)+ l(3,7,9);
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if (c > 9.) return l(3,4,6);
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if (c > 8.) return l(3,2,4)+ l(3,5,7);
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if (c > 7.) return l(3,2,4)+ l(3,6,8);
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if (c > 6.) return l(3,1,3)+ l(3,4,7);
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if (c > 5.) return l(3,2,4)+ l(3,6,8);
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if (c > 4.) return 0.;
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if (c > 3.) return l(3,1,3);
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if (c > 2.) return 0.;
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}
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else {
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if (c > 7.) return 0.;
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if (c > 6.) return l(1,2,5)+ l(1,6,8);
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}
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return 0.0;
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}
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// ===================================================================
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// Noise Generation Algorithms
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// textLines(...) is for simulating the writing of random characters in line formats
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// https://www.shadertoy.com/view/llSXDV (same author as VT220 font rendering)
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//
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// smokeNoise(...) is for the main noise generation algorithm (very tunable)
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// https://www.shadertoy.com/view/MsdGWn
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//
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float textLines(vec2 uvG)
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{
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float wt = 5. * (iTime + 0.5*sin(iTime*1.4) + 0.2*sin(iTime*2.9)); // wobbly time
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vec2 uvGt = uvG + vec2(0., floor(wt));
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float ll = rand(vec2(uvGt.y, - 1.)) * ROWCOLS.x; // line length
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if (uvG.y > ROWCOLS.y - 2.){
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if (ceil(uvG.x) == floor(min(ll, fract(wt)*ROWCOLS.x)))
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return 2.;
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if (ceil(uvG.x) > floor(min(ll, fract(wt)*ROWCOLS.x)))
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return 0.;
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}
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if (uvGt.x > 5. && rand(uvGt) < .075)
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return 0.;
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if (max(5., uvGt.x) > ll)
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return 0.;
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return rand(uvGt)*15. + 2.;
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}
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inline float fbm3(vec3 v) {
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float result = simplex(v);
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result += simplex(v * 2.) / 2.;
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result += simplex(v * 4.) / 4.;
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result /= (1. + 1./2. + 1./4.);
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return result;
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}
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inline float fbm5(vec3 v) {
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float result = simplex(v);
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result += simplex(v * 2.) / 2.;
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result += simplex(v * 4.) / 4.;
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result += simplex(v * 8.) / 8.;
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result += simplex(v * 16.) / 16.;
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result /= (1. + 1./2. + 1./4. + 1./8. + 1./16.);
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return result;
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}
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float smokeNoise(vec3 v) {
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// make it curl
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for (int i=0; i<noiseSwirlSteps; i++) {
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v.xy += vec2(fbm3(v), fbm3(vec3(v.xy, v.z + 1000.))) * noiseSwirlStepValue;
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}
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// normalize
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return fbm5(v) / 2. + 0.5;
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}
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// ===================================================================
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// Graphical Styling / Effects
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//
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inline float bloom(vec2 uv2) {
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// TODO
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c += (textureLod(iChannel0, uvC, 3.) +
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textureLod(iChannel0, uvC, 4.) +
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textureLod(iChannel0, uvC, 5.))
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* smoothstep(0., -SMOOTH*20., stdRS(uvC, -0.02)) * 0.5;
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}
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void mainImage( out vec4 fragColor, in vec2 fragCoord )
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{
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vec2 uv = vec2(fragCoord.x, iResolution.y - fragCoord.y);
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vec2 uvT = ROWCOLS * FONT_SIZE * uv / iResolution.xy;
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vec2 uvG = floor(ROWCOLS * uv / iResolution.xy);
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vec2 uvC = fragCoord/iResolution.xy;
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vec2 uvNoise = fragCoord.xy / iResolution.xy;
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uvNoise = ceil(uvNoise * ROWCOLS) / ROWCOLS;
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float val;
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if (iTime < 2.0)
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val = textLines(uvG);
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else if (iTime < 2.3)
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val = rand(uvG * iTime) * 17.;
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else {
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float noise = smokeNoise(vec3(uvNoise * noiseScale, iTime * noiseTimeScale));
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// Noise is fed through a sigmoid function, then quantised to integer range 0-17
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val = (exp(noise) / 2.71828); // increase contrast (normalised 0.0 - 1.0)
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val = 1.0 / val;
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val *= 1.0 / (1.0 + exp(-val)) - 0.5; // subtraction value is tunable (range 0.0 - 0.5)
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val *= quantise(val, 17.0); // quantise by 17 then normalise back to 0.0 - 1.0
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val = pow(18.0, val) - 1.0; // TODO: try changing 18.0 to 200.0 and you'll notice some pretty changes :)
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}
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fragColor = vt220Font(uvT - uvG * FONT_SIZE, val) * PHOSPHOR_COL + BG_COL;
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}
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