Fundamentally, rendering is a process that takes as its input a set of objects and produces as its output an array of pixels. One way or another, rendering involves considering how each object contributes to each pixel; it can be organized in two general ways. In object-order rendering, each object is considered in turn, and for each object all the pixels that it influences are found and updated. In image-order rendering, each pixel is considered in turn, and for each pixel all the objects that influence it are found and the pixel value is computed. You can think of the difference in terms of the nesting of loops: in image-order rendering the “for each pixel” loop i...
for each object, calculate how it appears after affected by all other objects
Share this highlighthttp://www.safaribooksonline.com/a/fundamentals-of-computer/9536155/