The Book of Shaders —— 形状

原文地址The Book of Shaders: Shapeshttps://thebookofshaders.com/07/?lan=ch

 乱做一个：应用造型函数和绘图形状

#ifdef GL_ES
precision mediump float;
#endif

#ifdef GL_ES
precision mediump float;
#endif

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

void main(){
    vec2 st = gl_FragCoord.xy/u_resolution.xy;
    vec3 color = vec3(0.716,0.885,0.649);
    vec3 color2 = vec3(0.516,0.614,0.885);
    float r = sin(u_time) * cos(u_time);

    // bottom-left
    vec2 bl = step(0.4+r,st);
    float pct = bl.x;
      
    vec2 b3 = step(0.4-r,1.0-st);
    pct *= b3.x ;
    
    vec2 b4 = step(0.4+r,st);
    float pct2 = b4.y;
    
    vec2 b5 = step(0.4-r,1.0-st);
    pct2 *= b5.y;
  
    // top-right
     //vec2 tr = step(vec2(0.1),1.0-st);
     //pct *= tr.x * tr.y;

    color += vec3(pct+pct2);

    gl_FragColor = vec4(color,1.0);
}