tchayen

const vertex = `
  attribute vec2 a_position;
  attribute vec3 a_barycentric;
  uniform mat3 u_matrix;
  varying vec3 vbc;

  void main() {
    vbc = a_barycentric;
    gl_Position = vec4((u_matrix * vec3(a_position, 1)).xy, 0, 1);
  }`