Question

In Sutherland-Hodgman algorithm for polygon clipping, assume P (present
point) lies inside the window and S (previous point) lies outside the window.
Then, while processing through that window boundary, we should
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Answer 1

Answer:

==>> It is performed by processing the boundary of polygon against each window corner or edge. First of all entire polygon is clipped against one edge, then resulting polygon is considered, then the polygon is considered against the second edge, so on for all four edges.

→ Four possible situations while processing

• the first vertex is an outside the window, the second vertex is inside the window. Then second vertex is added to the output list. The point of intersection of window boundary and polygon side (edge) is also added to the output line.
• If both vertexes are inside window boundary. Then only second vertex is added to the output list.
• If the first vertex is inside the window and second is an outside window. The edge which intersects with window is added to output list.
• If both vertices are the outside window, then nothing is added to output list.