Week 04

// Author:Qinxinrui Zhu
// Title:Color Harmony

#ifdef GL_ES
precision mediump float;
#endif

#define PI 3.14159265359
#define Orange vec3(1.,0.427,0.)
#define Purple vec3(0.141,0.,0.275)
#define Green vec3(0.0,1.0,0.0)
#define White vec3(1.0)


uniform vec2 u_resolution;
uniform vec2 u_mouse;
uniform float u_time;
//rotate the canvas
 mat2 rotate2d(float angle){
     return
         mat2(
         cos (angle), - sin(angle),
         sin(angle), - cos(angle)

     );
 }

  //Create many small square bars to divide the canvas by x-axis
float create_blind(float start, float blind_width,float direction){
    return -1.0*(step(start, direction) - smoothstep(start + blind_width, start + blind_width+0.05,direction) - 1.0);

}


void main() {
    vec2 st = gl_FragCoord.xy/u_resolution.xy;
float blind_width =0.15;
    //rotate our st make the animation move in the opposite direction
    st.x -= 1.0;
    st = rotate2d(PI)*st;


    // canvas color
    vec3 lights = mix(Purple, Orange,st.x);
    lights = mix(lights,Green,sin(20.0*u_time)*1.0-st.x);

    //Animated values
    //Use abs() to keep the motion in a range with a spacing of 0.15 for each frame
    float Animated_blind_width = blind_width - abs(blind_width*sin(1.5*u_time));

    //Parameters and position of each small bar
    float blind0 = create_blind(0.00,Animated_blind_width,st.x);
    float blind1 = create_blind(0.15,Animated_blind_width,st.x);
    float blind2 = create_blind(0.30,Animated_blind_width,st.x);
    float blind3 = create_blind(0.45,Animated_blind_width,st.x);
    float blind4 = create_blind(0.60,Animated_blind_width,st.x);
    float blind5 = create_blind(0.75,Animated_blind_width,st.x);
    float blind6 = create_blind(0.90,Animated_blind_width,st.x);



    vec3 allblinds  = White * blind0 * blind1 * blind2 * blind3 * blind4 * blind5 * blind6;

    gl_FragColor = vec4(allblinds*lights,1.0);
}