GLSL图形（一）

precision lowp float;

varying vec2 vUv;
void main(){
    gl_FragColor =vec4(vUv,0,1);
}

precision lowp float;
varying vec2 vUv;
void main(){
    gl_FragColor =vec4(vUv,1,1);
}

precision lowp float;
varying vec2 vUv;
void main(){
    float strength = vUv.x;
    gl_FragColor =vec4(strength,strength,strength,1);
}

precision lowp float;
varying vec2 vUv;
void main(){
    float strength = vUv.y;
    gl_FragColor =vec4(strength,strength,strength,1);
}

precision lowp float;
varying vec2 vUv;
void main(){
    float strength = 1.0-vUv.y;
    gl_FragColor =vec4(strength,strength,strength,1);
}

precision lowp float;
varying vec2 vUv;
void main(){
    //利用uv实现短范围内渐变
    float strength = vUv.y * 10.0;
    gl_FragColor =vec4(strength,strength,strength,1);
}

precision lowp float;
varying vec2 vUv;
void main(){
     //7利用通过取模达到反复效果
   float strength = mod(vUv.y * 10.0 , 1.0) ;
   gl_FragColor =vec4(strength,strength,strength,1);
}

precision lowp float;
varying vec2 vUv;
void main(){
     //8利用step(edge, x)如果x < edge，返回0.0，否则返回1.0
    float strength =  mod(vUv.y * 10.0 , 1.0) ;
    strength = step(0.5,strength);
    gl_FragColor =vec4(strength,strength,strength,1);
}

precision lowp float;
varying vec2 vUv;
void main(){
     //9利用step(edge, x)如果x < edge，返回0.0，否则返回1.0
    float strength =  mod(vUv.y * 10.0 , 1.0) ;
    strength = step(0.8,strength);
    gl_FragColor =vec4(strength,strength,strength,1);
}

precision lowp float;
varying vec2 vUv;
void main(){
    //10利用step(edge, x)如果x < edge，返回0.0，否则返回1.0
    float strength =  mod(vUv.x * 10.0 , 1.0) ;
    strength = step(0.8,strength);
    gl_FragColor =vec4(strength,strength,strength,1);
}

precision lowp float;
varying vec2 vUv;
void main(){
    // 11条纹相加
    float strength = step(0.8, mod(vUv.x * 10.0 , 1.0)) ;
    strength += step(0.8, mod(vUv.y * 10.0 , 1.0)) ;
     gl_FragColor =vec4(strength,strength,strength,1);
}

precision lowp float;
varying vec2 vUv;
void main(){
    // 12条纹相乘
    float strength = step(0.8, mod(vUv.x * 10.0 , 1.0)) ;
    strength *= step(0.8, mod(vUv.y * 10.0 , 1.0)) ;
     gl_FragColor =vec4(strength,strength,strength,1);
}

precision lowp float;
varying vec2 vUv;
void main(){
    // 13条纹相减
    float strength = step(0.8, mod(vUv.x * 10.0 , 1.0)) ;
    strength -= step(0.8, mod(vUv.y * 10.0 , 1.0)) ;
     gl_FragColor =vec4(strength,strength,strength,1);
}

precision lowp float;
varying vec2 vUv;
void main(){
     // 14方块图形
    float strength = step(0.2, mod(vUv.x * 10.0 , 1.0)) ;
    strength *= step(0.2, mod(vUv.y * 10.0 , 1.0)) ;
     gl_FragColor =vec4(strength,strength,strength,1);
}

precision lowp float;
uniform float uTime;
varying vec2 vUv;

void main(){
    float barX = step(0.4, mod((vUv.x+uTime*0.1) * 10.0 , 1.0))*step(0.8, mod(vUv.y * 10.0 , 1.0)) ;
    float barX = step(0.4, mod(vUv.x * 10.0 - 0.2 , 1.0))*step(0.8, mod(vUv.y * 10.0 , 1.0)) ;
    float barY = step(0.4, mod(vUv.y * 10.0 , 1.0))*step(0.8, mod(vUv.x * 10.0 , 1.0))  ;
    float strength = barX+barY;

    gl_FragColor =vec4(strength,strength,strength,1);
}

precision lowp float;
uniform float uTime;
varying vec2 vUv;
void main(){
    float barX = step(0.4, mod((vUv.x+uTime*0.1) * 10.0 , 1.0))*step(0.8, mod(vUv.y * 10.0 , 1.0)) ;
    float barX = step(0.4, mod(vUv.x * 10.0 - 0.2 , 1.0))*step(0.8, mod(vUv.y * 10.0 , 1.0)) ;
    float barY = step(0.4, mod(vUv.y * 10.0 , 1.0))*step(0.8, mod(vUv.x * 10.0 , 1.0))  ;
    float strength = barX+barY;

    gl_FragColor = vec4(vUv,1,strength);
}