NTA-UGC-NET 2021 Dec & 2022 June Paper-2

Hidden surface removal problem with minimal 3D pipeline can be solved with Window Clipping algorithm.
The z-buffer algorithm is the most widely used method for solving the hidden surface problem. It has the following major advantages over other hidden surface removal algorithms:
-No sorting is required. Models can be rendered in any order.
-No geometric intersection calculations are required. The algorithm produces the correct output even for intersecting or overlapping triangles.
-The algorithm is very simple to implement.

Disadvantages of the z-buffer algorithm include:
-A z-buffer requires a non-trivial amount of memory. For example, assuming each value in a z-buffer is a 32 bit floating point value, a rendered image that is 1024×768 pixels requires 3MB of memory to store its z-buffer.
-Every pixel of every primitive element must be rendered, even if many of them never write their color to the frame buffer.
-If two primitives are in exactly the same place in 3D space, as their positions are interpolated across their respective surfaces, the z values for each object will typically be different by a very small amount due to floating-point round-off errors. These small differences will alternate between primitives for adjacent pixels resulting in random and weird patterns in a rendering. This is called “z-fighting” and it can be avoided by never placing two primitives in the same location in 3D space.