ANURAG KUMAR

https://www.youtube.com/watch?v=vQuvl6tvUSA

Warnock's Algorithm (Area Subdivision Algorithm):- An interesting approach to the hidden-surface problem was developed by Warnock. He developed area subdivision algorithm which subdivides each area into four equal squares. At each stage in the recursive-subdivision process, the relationship between projection of each polygon and the area of interest is checked for four possible relationships: 1. Surrounding Polygon  - One that completely encloses the (shaded)area of interest (see Fig.h (a)) 2. Overlapping or Intersecting Polygon  - One that is partly inside and partly outside the area (see Fig. h (b)) 3. Inside or Contained Polygon  - One that is completely inside the area (see Fig. h (c)). 4. Outside or Disjoint Polygon  - One that is completely outside the area (see Fig. h (d)). After checking four relationships we can handle each relationship as follows: If all the polygons are disjoint from the area, then the background colour is displayed in the area. If there i...

ques10.com(Z-Buffer) Depth Buffer Method:- One of the simplest and commonly used image space approach to eliminate hidden surfaces is the Z-buffer or depth buffer algorithm. It is developed by Catmull. This algorithm compares surface depths at each pixel position on the projection plane. The surface depth is measured from the view plane along the z-axis of a viewing system. When object description is converted to projection co-ordinates (x, y, z), each pixel position on the view plane is specified by x and y coordinate, and z-value gives the depth information. Thus object depths can be compared by comparing the z- values. The Z-buffer algorithm is usually implemented in the normalized coordinates, so that z-values range from 0 at the back clipping plane to 1 at the front clipping plane. The implementation requites another buffer memory called Z-buffer along with the frame buffer memory required for raster display devices. A Z-buffer is used to store depth values for each (x, y) positio...