function multiplyScalarAndAdd$1(out, a, b, scale) {
    out[0] = a[0] + b[0] * scale;
    out[1] = a[1] + b[1] * scale;
    out[2] = a[2] + b[2] * scale;
    out[3] = a[3] + b[3] * scale;
    out[4] = a[4] + b[4] * scale;
    out[5] = a[5] + b[5] * scale;
    out[6] = a[6] + b[6] * scale;
    out[7] = a[7] + b[7] * scale;
    out[8] = a[8] + b[8] * scale;
    return out;
  }
Adds two mat3's after multiplying each element of the second operand by a scalar value.

@param {mat3} out the receiving vector
@param {ReadonlyMat3} a the first operand
@param {ReadonlyMat3} b the second operand
@param {Number} scale the amount to scale b's elements by before adding
@returns {mat3} out