Working base for a full feature GPU-based CA runner in javascript

cellular-automata.glsl

# original : https://www.shadertoy.com/view/Xd33WS

int getNeighbourhoodMoore1 (vec2 relativePos) {
    int u = 0;
    u+=int(texture2D(iChannel0,(relativePos+vec2(-1.0,-1.0))/iResolution.xy).x); 
    u+=int(texture2D(iChannel0,(relativePos+vec2( 0.0,-1.0))/iResolution.xy).x); 
	u+=int(texture2D(iChannel0,(relativePos+vec2( 1.0,-1.0))/iResolution.xy).x); 
  	u+=int(texture2D(iChannel0,(relativePos+vec2(-1.0, 0.0))/iResolution.xy).x); 
  	u+=int(texture2D(iChannel0,(relativePos+vec2( 1.0, 0.0))/iResolution.xy).x); 
	u+=int(texture2D(iChannel0,(relativePos+vec2(-1.0, 1.0))/iResolution.xy).x); 
    u+=int(texture2D(iChannel0,(relativePos+vec2( 0.0, 1.0))/iResolution.xy).x); 
    u+=int(texture2D(iChannel0,(relativePos+vec2( 1.0, 1.0))/iResolution.xy).x);
    
    return u;
}

int getNeighbourhoodVonNeumann1 (vec2 relativePos) {
    int u = 0;
    u+=int(texture2D(iChannel0,(relativePos+vec2( 0.0,-1.0))/iResolution.xy).x); 
  	u+=int(texture2D(iChannel0,(relativePos+vec2(-1.0, 0.0))/iResolution.xy).x); 
  	u+=int(texture2D(iChannel0,(relativePos+vec2( 1.0, 0.0))/iResolution.xy).x); 
    u+=int(texture2D(iChannel0,(relativePos+vec2( 0.0, 1.0))/iResolution.xy).x);
    
    return u;
}

int getNeighbourhoodVonNeumann2 (vec2 relativePos) {
    int u = 0;
    u+=int(texture2D(iChannel0,(relativePos+vec2(-1.0,-1.0))/iResolution.xy).x); 
    u+=int(texture2D(iChannel0,(relativePos+vec2( 0.0,-1.0))/iResolution.xy).x); 
	u+=int(texture2D(iChannel0,(relativePos+vec2( 1.0,-1.0))/iResolution.xy).x); 
  	u+=int(texture2D(iChannel0,(relativePos+vec2(-1.0, 0.0))/iResolution.xy).x); 
  	u+=int(texture2D(iChannel0,(relativePos+vec2( 1.0, 0.0))/iResolution.xy).x); 
	u+=int(texture2D(iChannel0,(relativePos+vec2(-1.0, 1.0))/iResolution.xy).x); 
    u+=int(texture2D(iChannel0,(relativePos+vec2( 0.0, 1.0))/iResolution.xy).x); 
    u+=int(texture2D(iChannel0,(relativePos+vec2( 1.0, 1.0))/iResolution.xy).x);
    
    u+=int(texture2D(iChannel0,(relativePos+vec2( 0.0,-2.0))/iResolution.xy).x); 
  	u+=int(texture2D(iChannel0,(relativePos+vec2(-2.0, 0.0))/iResolution.xy).x); 
  	u+=int(texture2D(iChannel0,(relativePos+vec2( 2.0, 0.0))/iResolution.xy).x); 
    u+=int(texture2D(iChannel0,(relativePos+vec2( 0.0, 2.0))/iResolution.xy).x);
    
    return u;
}

bool isBirth(int v) {
    return (v == 4);
}

bool isSurvival(int v) {
    return (v == 2 || v== 3 || v == 5);
}

void mainImage( out vec4 fragColor, in vec2 fragCoord )
{
    if((iFrame==0)||(length(iMouse.xy-fragCoord))<5.0)
    {
        fragColor.x=(fract(dot(sin(fragCoord*vec2(157.1,113.7)),
                               vec2(353.17+iGlobalTime,383.093-iGlobalTime)))>0.33)?0.0:1.0;
    }
    else
    {
        fragColor=texture2D(iChannel0, fragCoord/iResolution.xy); 
		int v = getNeighbourhoodVonNeumann2(fragCoord);
        
        if(isBirth(v)) {
            fragColor.x=1.0;
        } else if(fragColor.x > 0.5 && isSurvival(v)) {
			fragColor.x=1.0;
        } else {
            fragColor.x=0.0;
        }
    }
}