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/**
* Film grain & scanlines shader
*
* - ported from HLSL to WebGL / GLSL
* https://web.archive.org/web/20210226214859/http://www.truevision3d.com/forums/showcase/staticnoise_colorblackwhite_scanline_shaders-t18698.0.html
*
* Screen Space Static Postprocessor
*
* Produces an analogue noise overlay similar to a film grain / TV static
*
* Original implementation and noise algorithm
* Pat 'Hawthorne' Shearon
*
* Optimized scanlines + noise version with intensity scaling
* Georg 'Leviathan' Steinrohder
*
* This version is provided under a Creative Commons Attribution 3.0 License
* http://creativecommons.org/licenses/by/3.0/
*/
const FilmShader = {
uniforms: {
'tDiffuse': { value: null },
'time': { value: 0.0 },
'nIntensity': { value: 0.5 },
'sIntensity': { value: 0.05 },
'sCount': { value: 4096 },
'grayscale': { value: 1 }
},
vertexShader: /* glsl */`
varying vec2 vUv;
void main() {
vUv = uv;
gl_Position = projectionMatrix * modelViewMatrix * vec4( position, 1.0 );
}`,
fragmentShader: /* glsl */`
#include <common>
// control parameter
uniform float time;
uniform bool grayscale;
// noise effect intensity value (0 = no effect, 1 = full effect)
uniform float nIntensity;
// scanlines effect intensity value (0 = no effect, 1 = full effect)
uniform float sIntensity;
// scanlines effect count value (0 = no effect, 4096 = full effect)
uniform float sCount;
uniform sampler2D tDiffuse;
varying vec2 vUv;
void main() {
// sample the source
vec4 cTextureScreen = texture2D( tDiffuse, vUv );
// make some noise
float dx = rand( vUv + time );
// add noise
vec3 cResult = cTextureScreen.rgb + cTextureScreen.rgb * clamp( 0.1 + dx, 0.0, 1.0 );
// get us a sine and cosine
vec2 sc = vec2( sin( vUv.y * sCount ), cos( vUv.y * sCount ) );
// add scanlines
cResult += cTextureScreen.rgb * vec3( sc.x, sc.y, sc.x ) * sIntensity;
// interpolate between source and result by intensity
cResult = cTextureScreen.rgb + clamp( nIntensity, 0.0,1.0 ) * ( cResult - cTextureScreen.rgb );
// convert to grayscale if desired
if( grayscale ) {
cResult = vec3( cResult.r * 0.3 + cResult.g * 0.59 + cResult.b * 0.11 );
}
gl_FragColor = vec4( cResult, cTextureScreen.a );
}`,
};
export { FilmShader };