The salient document on this subject is Humanae Vitae, an encyclical by Pope Paul VI issued in 1968. His argument on the subject is largely contained in the second section, entitled Doctrinal Principles. It makes reference to several passages from the Bible, as well as previous theologians--especially via the concept of natural law. There are 41 footnotes provided in the text including numerous biblical references, which would argue that Paul VI thought that your assertion that "[c]learly these came from church dictates rather than the bible since the bible has little to say on the matter" is false. Subsequent papal documents include Theology of the Body (a series of lectures given by John Paul II from 1979-1984, utilizing both theology and philosophy to form his argument) and Verititas Splendor from John Paul II in 1993. These two documents have extended arguments regarding the foundations of this doctrine, including copious footnotes.

Note: I will not debate the merits of the Church's arguments, as this is the wrong forum for such a discussion. I merely point out the existence of the most important documents on the subject to point out the history of the subject.

What I want to know what St. Augustine said about this, and if current opinion is based on anything attributed to him. He loved making rules for sex. Our Catholic School "sex ed" mentioned him a bit. The role of sex for reproduction in marriage and whatnot.