Week 3 HW

For this week, I expanded upon my week 2 shader by adding noise and distorting it.

ripple

I first started by adding noise to the colour of my circles, and I experimented with the effects using different values would give me. I also applied noise to the entire canvas by using st.x, distorting the entire sketch.

 


#ifdef GL_ES
precision mediump float;
#endif

uniform vec2 u_resolution;
uniform vec2 u_mouse;
uniform float u_time;

vec2 createGrid( in vec2 st, in vec2 grid, out vec2 indices ){

// multiply by the number of cells
// [0,1] range => [0,10] (for example)
st *= grid;

// get the cell indices
// for example, in a grid of 10x10:
// 0, 1, 2, 3, 4, 5, 6, 7, 8, 9
indices = floor(st);

// use fract to get the fractional amount of st
// 9.5 => 0.5
// shows the xy coordinate in each cell
st = fract(st);

return st;
}

float drawCircle (vec2 st, vec2 pos, float size){
float result = distance (st, pos);
result=1.-step(size,result);


return result;
}

float random (vec2 st) {
return fract(sin(dot(st.xy,
vec2(12.9898,78.233)))*
43758.5453123);
}
vec3 permute(vec3 x) { return mod(((x*34.0)+1.0)*x, 289.0); }

float snoise(vec2 v){
const vec4 C = vec4(0.211324865405187, 0.366025403784439,
-0.577350269189626, 0.024390243902439);
vec2 i = floor(v + dot(v, C.yy) );
vec2 x0 = v - i + dot(i, C.xx);
vec2 i1;
i1 = (x0.x > x0.y) ? vec2(1.0, 0.0) : vec2(0.0, 1.0);
vec4 x12 = x0.xyxy + C.xxzz;
x12.xy -= i1;
i = mod(i, 289.0);
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(x12.xy,x12.xy),
dot(x12.zw,x12.zw)), 0.0);
m = m*m ;
m = m*m ;
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;
m *= 1.79284291400159 - 0.85373472095314 * ( a0*a0 + h*h );
vec3 g;
g.x = a0.x * x0.x + h.x * x0.y;
g.yz = a0.yz * x12.xz + h.yz * x12.yw;
return 130.0 * dot(m, g);
}

void main() {

vec2 st = gl_FragCoord.xy/u_resolution.xy;
st.x *= u_resolution.x/u_resolution.y;

st.x += snoise(st*0.4);
// good practice to take a copy of the original st
// before you change it
vec2 st0 = st;

vec2 indices;

// This divides the result of the sin function, changing the final size of the circle
float size = 3.;

// This changes the period of the sin function, changing the speed at which the circles animate
float speed = 3.;

vec3 color;

color.r = snoise(st*2. + vec2(0., u_time*.5)) * 0.5+0.5;
color.g = snoise(st*2. + vec2(100., u_time*.5)) * 0.5+0.5;
color.b = snoise(st*2. + vec2(200., u_time*.5)) * 0.5+0.5;
// Create grid for circles
st = createGrid( st, vec2(5., 5.), indices);

// Set bg colour
// Change the colour and sin function of each column
if(indices.x == 0.){
float r = drawCircle(st, vec2(0.5), sin(u_time*speed)/size);
vec3 circleC;

circleC.r = snoise(st*2. + vec2(0., u_time*2.)) * 0.5+0.5;
circleC.g = snoise(st*2. + vec2(100., u_time*2.)) * 0.5+0.5;
circleC.b = snoise(st*2. + vec2(200., u_time*2.)) * 0.5+0.5;
color = mix( color, circleC, r);

}else if(indices.x == 1.){
float r = drawCircle(st, vec2(0.5), sin(u_time*speed+1.)/size);
vec3 circleC;

circleC.r = snoise(st*2. + vec2(0., u_time*2.)) * 0.5+0.5;
circleC.g = snoise(st*2. + vec2(100., u_time*2.)) * 0.5+0.5;
circleC.b = snoise(st*2. + vec2(200., u_time*2.)) * 0.5+0.5;
color = mix( color, circleC, r);
}
else if(indices.x == 2.){
float r = drawCircle(st, vec2(0.5), sin(u_time*speed+2.)/size);
vec3 circleC;

circleC.r = snoise(st*2. + vec2(0., u_time*2.)) * 0.5+0.5;
circleC.g = snoise(st*2. + vec2(100., u_time*2.)) * 0.5+0.5;
circleC.b = snoise(st*2. + vec2(200., u_time*2.)) * 0.5+0.5;
color = mix( color, circleC, r);
}
else if(indices.x == 3.){
float r = drawCircle(st, vec2(0.5), sin(u_time*speed+3.)/size);
vec3 circleC;

circleC.r = snoise(st*2. + vec2(0., u_time*2.)) * 0.5+0.5;
circleC.g = snoise(st*2. + vec2(100., u_time*2.)) * 0.5+0.5;
circleC.b = snoise(st*2. + vec2(200., u_time*2.)) * 0.5+0.5;
color = mix( color, circleC, r);
}
else if(indices.x == 4.){
float r = drawCircle(st, vec2(0.5), sin(u_time*speed+4.)/size);
vec3 circleC;

circleC.r = snoise(st*2. + vec2(0., u_time*2.)) * 0.5+0.5;
circleC.g = snoise(st*2. + vec2(100., u_time*2.)) * 0.5+0.5;
circleC.b = snoise(st*2. + vec2(200., u_time*2.)) * 0.5+0.5;
color = mix( color, circleC, r);
}

gl_FragColor = vec4(color,1.0);
}

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