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ressource:code:processing:shaders [2022/09/07 09:51] gweltaz [Ressources] |
ressource:code:processing:shaders [2022/09/07 11:00] gweltaz [Textures] |
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===== Textures ===== | ===== Textures ===== | ||
+ | Pour sampler un texel en GLSL (extraire la couleur d'une texture à un point donné), on utilise la fonction: | ||
+ | ''texture2D(sampler2D image, vec2 uv)'' \\ | ||
+ | Les coordonnes UV doivent être comprises entre 0.0 et 1.0 \\ | ||
+ | Elles pour origine le coin bas-gauche (0, 0) contrairement aux coordonnées d'écran, qui ont pour origine le coin haut-gauche. | ||
===== Fonctions utiles ===== | ===== Fonctions utiles ===== | ||
+ | |||
+ | === Couleur === | ||
+ | |||
+ | == Luminance == | ||
+ | <code glsl> | ||
+ | float luma(vec4 color) { | ||
+ | return dot(color.rgb, vec3(0.299, 0.587, 0.114)); | ||
+ | } | ||
+ | </code> | ||
+ | |||
+ | == Brightness == | ||
+ | <code glsl> | ||
+ | float brightness(vec4 color) { | ||
+ | return dot( color.rgb , vec3( 0.2126 , 0.7152 , 0.0722 )); | ||
+ | } | ||
+ | </code> | ||
+ | |||
+ | == HSB -> RGB == | ||
+ | <code glsl> | ||
+ | vec3 hsb2rgb( in vec3 c ){ | ||
+ | vec3 rgb = clamp(abs(mod(c.x*6.0+vec3(0.0,4.0,2.0), | ||
+ | 6.0)-3.0)-1.0, | ||
+ | 0.0, | ||
+ | 1.0 ); | ||
+ | rgb = rgb*rgb*(3.0-2.0*rgb); | ||
+ | return c.z * mix(vec3(1.0), rgb, c.y); | ||
+ | } | ||
+ | </code> | ||
+ | |||
+ | == RGB -> HSB == | ||
+ | <code glsl> | ||
+ | vec3 rgb2hsb( in 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); | ||
+ | } | ||
+ | </code> | ||
+ | === Random === | ||
+ | <code glsl> | ||
+ | float random2d(vec2 coord) | ||
+ | { | ||
+ | return fract(sin(dot(coord.xy, vec2(12.9898, 78.233))) * 43758.5453123); | ||
+ | } | ||
+ | </code> | ||
+ | |||
+ | === Noise === | ||
+ | == Gradient noise == | ||
+ | <code glsl> | ||
+ | // 2D Noise based on Morgan McGuire @morgan3d | ||
+ | // https://www.shadertoy.com/view/4dS3Wd | ||
+ | float noise (in vec2 coord) { | ||
+ | vec2 i = floor(coord); | ||
+ | vec2 f = fract(coord); | ||
+ | |||
+ | // Four corners in 2D of a tile | ||
+ | float a = random(i); | ||
+ | float b = random(i + vec2(1.0, 0.0)); | ||
+ | float c = random(i + vec2(0.0, 1.0)); | ||
+ | float d = random(i + vec2(1.0, 1.0)); | ||
+ | |||
+ | // Smooth Interpolation | ||
+ | |||
+ | // Cubic Hermite Curve. Same as SmoothStep() | ||
+ | vec2 u = f*f*(3.0-2.0*f); | ||
+ | // u = smoothstep(0.,1.,f); | ||
+ | |||
+ | // Mix 4 coorners percentages | ||
+ | return mix(a, b, u.x) + | ||
+ | (c - a)* u.y * (1.0 - u.x) + | ||
+ | (d - b) * u.x * u.y; | ||
+ | } | ||
+ | </code> | ||
+ | |||
+ | == Fractional Brownian Motion == | ||
+ | <code glsl> | ||
+ | float hash(vec2 coord) | ||
+ | { | ||
+ | return fract(sin(dot(coord.xy, vec2(12.9898, 78.233))) * 43758.5453123); | ||
+ | } | ||
+ | |||
+ | float noise(vec2 U) | ||
+ | { | ||
+ | vec2 id = floor(U); | ||
+ | U = fract(U); | ||
+ | U *= U * ( 3. - 2. * U ); | ||
+ | |||
+ | vec2 A = vec2( hash(id), hash(id + vec2(0,1)) ), | ||
+ | B = vec2( hash(id + vec2(1,0)), hash(id + vec2(1,1)) ), | ||
+ | C = mix( A, B, U.x); | ||
+ | |||
+ | return mix( C.x, C.y, U.y ); | ||
+ | } | ||
+ | |||
+ | /** | ||
+ | fBM stands for Fractional Brownian Motion | ||
+ | https://iquilezles.org/articles/fbm/ | ||
+ | Set octave to 8 for a detailed noise | ||
+ | A value of 1.0 for H is good | ||
+ | */ | ||
+ | float fbm(vec2 x, float H, int octave) | ||
+ | { | ||
+ | float G = exp2(-H); | ||
+ | float f = 1.0; | ||
+ | float a = 1.0; | ||
+ | float t = 0.0; | ||
+ | for( int i=0; i<octave; i++ ) | ||
+ | { | ||
+ | t += a*noise(f*x); | ||
+ | f *= 2.0; | ||
+ | a *= G; | ||
+ | } | ||
+ | return t; | ||
+ | } | ||
+ | </code> | ||
+ | |||
+ | == Simplex noise == | ||
+ | <code glsl> | ||
+ | // | ||
+ | // Description : GLSL 2D simplex noise function | ||
+ | // Author : Ian McEwan, Ashima Arts | ||
+ | // Maintainer : ijm | ||
+ | // Lastmod : 20110822 (ijm) | ||
+ | // License : | ||
+ | // Copyright (C) 2011 Ashima Arts. All rights reserved. | ||
+ | // Distributed under the MIT License. See LICENSE file. | ||
+ | // https://github.com/ashima/webgl-noise | ||
+ | // | ||
+ | |||
+ | // Some useful functions | ||
+ | vec3 mod289(vec3 x) { return x - floor(x * (1.0 / 289.0)) * 289.0; } | ||
+ | vec2 mod289(vec2 x) { return x - floor(x * (1.0 / 289.0)) * 289.0; } | ||
+ | vec3 permute(vec3 x) { return mod289(((x*34.0)+1.0)*x); } | ||
+ | |||
+ | float snoise(vec2 v) { | ||
+ | |||
+ | // Precompute values for skewed triangular grid | ||
+ | const vec4 C = vec4(0.211324865405187, | ||
+ | // (3.0-sqrt(3.0))/6.0 | ||
+ | 0.366025403784439, | ||
+ | // 0.5*(sqrt(3.0)-1.0) | ||
+ | -0.577350269189626, | ||
+ | // -1.0 + 2.0 * C.x | ||
+ | 0.024390243902439); | ||
+ | // 1.0 / 41.0 | ||
+ | |||
+ | // First corner (x0) | ||
+ | vec2 i = floor(v + dot(v, C.yy)); | ||
+ | vec2 x0 = v - i + dot(i, C.xx); | ||
+ | |||
+ | // Other two corners (x1, x2) | ||
+ | vec2 i1 = vec2(0.0); | ||
+ | i1 = (x0.x > x0.y)? vec2(1.0, 0.0):vec2(0.0, 1.0); | ||
+ | vec2 x1 = x0.xy + C.xx - i1; | ||
+ | vec2 x2 = x0.xy + C.zz; | ||
+ | |||
+ | // Do some permutations to avoid | ||
+ | // truncation effects in permutation | ||
+ | i = mod289(i); | ||
+ | vec3 p = permute( | ||
+ | permute( i.y + vec3(0.0, i1.y, 1.0)) | ||
+ | + i.x + vec3(0.0, i1.x, 1.0 )); | ||
+ | |||
+ | vec3 m = max(0.5 - vec3( | ||
+ | dot(x0,x0), | ||
+ | dot(x1,x1), | ||
+ | dot(x2,x2) | ||
+ | ), 0.0); | ||
+ | |||
+ | m = m*m ; | ||
+ | m = m*m ; | ||
+ | |||
+ | // Gradients: | ||
+ | // 41 pts uniformly over a line, mapped onto a diamond | ||
+ | // The ring size 17*17 = 289 is close to a multiple | ||
+ | // of 41 (41*7 = 287) | ||
+ | |||
+ | vec3 x = 2.0 * fract(p * C.www) - 1.0; | ||
+ | vec3 h = abs(x) - 0.5; | ||
+ | vec3 ox = floor(x + 0.5); | ||
+ | vec3 a0 = x - ox; | ||
+ | |||
+ | // Normalise gradients implicitly by scaling m | ||
+ | // Approximation of: m *= inversesqrt(a0*a0 + h*h); | ||
+ | m *= 1.79284291400159 - 0.85373472095314 * (a0*a0+h*h); | ||
+ | |||
+ | // Compute final noise value at P | ||
+ | vec3 g = vec3(0.0); | ||
+ | g.x = a0.x * x0.x + h.x * x0.y; | ||
+ | g.yz = a0.yz * vec2(x1.x,x2.x) + h.yz * vec2(x1.y,x2.y); | ||
+ | return 130.0 * dot(m, g); | ||
+ | } | ||
+ | </code> | ||
+ | |||
+ | === Rotations === | ||
+ | == 2D == | ||
+ | <code glsl> | ||
+ | mat2 rotation2d(float a) { | ||
+ | float c=cos(a); | ||
+ | float s=sin(a); | ||
+ | return mat2(c,-s,s,c); | ||
+ | } | ||
+ | |||
+ | vec2 rotate(vec2 v, float angle) { | ||
+ | return rotation2d(angle) * v; | ||
+ | } | ||
+ | </code> | ||
+ | |||
+ | == 3D == | ||
+ | <code glsl> | ||
+ | mat4 rotation3d(vec3 axis, float angle) { | ||
+ | axis = normalize(axis); | ||
+ | float s = sin(angle); | ||
+ | float c = cos(angle); | ||
+ | float oc = 1.0 - c; | ||
+ | |||
+ | return mat4( | ||
+ | oc * axis.x * axis.x + c, oc * axis.x * axis.y - axis.z * s, oc * axis.z * axis.x + axis.y * s, 0.0, | ||
+ | oc * axis.x * axis.y + axis.z * s, oc * axis.y * axis.y + c, oc * axis.y * axis.z - axis.x * s, 0.0, | ||
+ | oc * axis.z * axis.x - axis.y * s, oc * axis.y * axis.z + axis.x * s, oc * axis.z * axis.z + c, 0.0, | ||
+ | 0.0, 0.0, 0.0, 1.0 | ||
+ | ); | ||
+ | } | ||
+ | |||
+ | vec3 rotate(vec3 v, vec3 axis, float angle) { | ||
+ | return (rotation3d(axis, angle) * vec4(v, 1.0)).xyz; | ||
+ | } | ||
+ | </code> | ||
=== Flou Gaussien === | === Flou Gaussien === | ||
Ligne 83: | Ligne 322: | ||
A exécuter en deux passes : horizontale et verticale \\ | A exécuter en deux passes : horizontale et verticale \\ | ||
- | <code glsl> | + | <code glsl> |
- | uniform float offset[3] = float[](0.0, 1.3846153846, 3.2307692308); | + | |
- | uniform float weight[3] = float[](0.2270270270, 0.3162162162, 0.0702702703); | + | |
- | + | ||
vec4 blur(sampler2D image, vec2 uv, vec2 resolution, vec2 direction) { | vec4 blur(sampler2D image, vec2 uv, vec2 resolution, vec2 direction) { | ||
- | vec4 color = texture2D(image, uv / resolution) * weight[0]; | + | const float offset[3] = float[](0.0, 1.3846153846, 3.2307692308); |
+ | const float weight[3] = float[](0.2270270270, 0.3162162162, 0.0702702703); | ||
+ | |||
+ | vec4 colorOut = texture2D(image, uv / resolution) * weight[0]; | ||
for (int i=1; i<3; i++) { | for (int i=1; i<3; i++) { | ||
- | color += texture2D(image, (uv + direction * offset[i]) / resolution) * weight[i]; | + | vec3 color = texture2D(image, (uv + direction * offset[i]) / resolution); |
- | color += texture2D(image, (uv - direction * offset[i]) / resolution) * weight[i]; | + | color += texture2D(image, (uv - direction * offset[i]) / resolution); |
+ | colorOut += color * weight[i]; | ||
} | } | ||
- | return color; | + | return colorOut; |
} | } | ||
</code> | </code> | ||
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===== Librairies Processing ===== | ===== Librairies Processing ===== | ||
Quelques librairies externes pour l'utilisation de shaders dans Processing : | Quelques librairies externes pour l'utilisation de shaders dans Processing : | ||
- | * PixelFlow | + | * https://github.com/diwi/PixelFlow |
===== Ressources ===== | ===== Ressources ===== |