cone of light

cone_of_light.glsl

// https://shadertoy.com


// tweak the frequency and let the magic happen dawg

#define FREQUENCY 333.
#define THICKNESS 0.004
#define Y_SHIFT 0.5
#define AMPLITUDE 0.2
#define SPEED 1.

#define PI 3.141592653589793
#define BLACK vec3(0.,0.,0.)
#define RED   vec3(1.,0.,0.)
#define GREEN vec3(0.,1.,0.)
#define BLUE  vec3(0.,0.,1.)

vec3 drawSine(vec2 uv, vec3 color, float phase) {
    float sine = sin(uv.y * FREQUENCY + iTime * SPEED + phase) * AMPLITUDE + Y_SHIFT;
    
    bool isSineUpper = uv.x <= (sine + THICKNESS) ; 
    bool isSineLower = uv.x >= (sine - THICKNESS);
    
    if (isSineUpper && isSineLower) {
        return color;
    } else {
        return BLACK;
    }
}

void mainImage( out vec4 fragColor, in vec2 fragCoord )
{
    vec2 uv = fragCoord/iResolution.xy;
    vec3 col;
        
    vec3 t = vec3(iTime);
    col += drawSine(uv, RED ,  0.);
    col += drawSine(uv, GREEN,  2./3. * PI);
    col += drawSine(uv, BLUE,  4./3. * PI);   

    fragColor = vec4(col,1.0);
}