Direct Volume Rendering
A direct volume renderer requires every sample value to be mapped to opacity and a color. This is done with a "transfer function" which can be a simple ramp, a piecewise linear function or an arbitrary table. Once converted to an RGBA (for red, green, blue, alpha) value, the composed RGBA result is projected on corresponding pixel of the frame buffer. The way this is done depends on the rendering technique.
A combination of these techniques is possible. For instance, a shear warp implementation could use texturing hardware to draw the aligned slices in the off-screen buffer.
Read more about this topic: Volume Rendering
Famous quotes containing the words direct, volume and/or rendering:
“Forty years after a battle it is easy for a noncombatant to reason about how it ought to have been fought. It is another thing personally and under fire to have to direct the fighting while involved in the obscuring smoke of it.”
—Herman Melville (1819–1891)
“So it is with books, for the most part: they work no redemption on us. The bookseller might certainly know that his customers are in no respect better for the purchase and consumption of his wares. The volume is dear at a dollar, and after to reading to weariness the lettered backs, we leave the shop with a sigh, and learn, as I did without surprise of a surly bank director, that in bank parlors they estimate all stocks of this kind as rubbish.”
—Ralph Waldo Emerson (1803–1882)
“Americans are notorious for looking to their children for approval. How our children turn out and what they think of us has become the “final judgment” on our lives. . . . We imagine that the rising generation is rendering history’s verdict on us. We may resent children simply because we expect a harsh judgment from them.”
—C. John Sommerville (20th century)