touchdesignershaderworkshopshader.glsl

// Example Pixel Shader

// uniform float exampleUniform;

out vec4 fragColor;

uniform float time;

float circ(vec2 p){
    return length(p) - .50;   
}

// Repeat in two dimensions
vec2 pMod2(inout vec2 p, vec2 size) {
    vec2 c = floor((p + size*0.5)/size);
    p = mod(p + size*0.5,size) - size*0.5;
    return c;
}

// http://www.iquilezles.org/www/articles/palettes/palettes.htm
// As t runs from 0 to 1 (our normalized palette index or domain), 
//the cosine oscilates c times with a phase of d. 
//The result is scaled and biased by a and b to meet the desired constrast and brightness.
vec3 cosPalette( float t, vec3 a, vec3 b, vec3 c, vec3 d )
{
    return a + b*cos( 6.28318*(c*t+d) );
}

float sdBox( in vec2 p, in vec2 b )
{
    vec2 d = abs(p)-b;
    return length(max(d,vec2(0))) + min(max(d.x,d.y),0.0);
}


void main()
{
    //gl_FragColor = vec4(black,1.0);
    
    // VEC review 
    // float v = 0.50;
    
    // vec2 v2 = vec2(0.2,0.4);
    
    // vec3 v3 = vec3(v2,0.3);
    
    // gl_FragColor = vec4(v3,v);
    
    // moving UV position
   // vec2 position = (uv() + 1.)/2.0 ;
    //gl_FragColor = vec4(position,0,1.);
    
    
    // distance metric
    vec2 position = vUV.st;
    position = position + vec2(sin(time),0);
    
    pMod2(position, vec2(1));
    
    float shape = circ( position * vec2(3.0));
    
    position = position + vec2(cos(time),0);
    
    float shape2 = sdBox(position, vec2(0.1));
    shape = min(shape,shape2);    
    
    //gl_FragColor = vec4(shape);
    
    vec3 col = cosPalette(0.5,vec3(0.1),vec3(0.3),vec3(1),vec3(time*0.01,time*0.1,time*.2));
    
   // gl_FragColor = vec4(col,1.0);
    // lighting: darken at the center
     col = vec3(shape) * col;
     //gl_FragColor = vec4(col,1.0);

   
   fragColor = TDOutputSwizzle(vec4(col,1.0));
}