precision mediump float;

#endif

​

uniform vec2 u_resolution;

​

float rectShape(vec2 position, vec2 scale){

  scale = vec2(0.5) - scale * 0.5;

  vec2 shaper = vec2(step(scale.x, position.x), step(scale.y, position.y));

  shaper *= vec2(step(scale.x, 1.0 - position.x), step(scale.y, 1.0 - position.y));

  return shaper.x * shaper.y;

}

​

mat2 rotate(float angle){

  return mat2(cos(angle), sin(angle), sin(angle), cos(angle));

}

​

void main() {

  vec2 coord = gl_FragCoord.xy/u_resolution.xy;

  vec3 color = vec3(0.0);

​

  coord -= vec2(0.5);

  coord = rotate(0.4) * coord;

  coord += vec2(0.5);

  color += vec3(rectShape(coord, vec2(0.3, 0.3)));

  gl_FragColor = vec4(color, 1.0);

}