Function setupInstancedAttribute

src/index.js:329–339

* Set up instanced attribute

(attrib, size, stride, offset, divisor)

   * Set up instanced attribute
   */
  function setupInstancedAttribute(attrib, size, stride, offset, divisor) {
    if (attrib < 0) return
    gl.enableVertexAttribArray(attrib)
    gl.vertexAttribPointer(attrib, size, gl.FLOAT, false, stride, offset)

    if (webgl2) {
      gl.vertexAttribDivisor(attrib, divisor)
    } else if (instExt) {
      instExt.vertexAttribDivisorANGLE(attrib, divisor)
    }
  }

  /**
   * Draw instanced