# Solid Polygon Clipping Techniques

## Sutherland-Hodgeman Algorithm:

Compute each of the vertices against window edges. The inside
vertices are saved for clipping against next boundary; outside
vertices are discarded. There are four possible cases as we
process line segments.

### Processing line segments

Let S = previous point and P = new point

Look at three examplesof solid polygon clipping

So have procedure:

procedure SOLID_POLY (N: integer; X, Y: Points; FILL_COLOR: integer);

var
I : integer
X_OUT, Y_OUT : Points; array [1..2] of real
X_PDC, Y_PDC : PDC_Points; array [1..2] of integer
M : integer;

begin
POLYGON_CLIP (N, X, Y, M, X_OUT, Y_OUT);
for I := 1 to M do
PointViewingTransform(X_OUT[I], Y_OUT[I], X_PDC[I], Y_PDC[I]);
FILL_AREA_SOLID (N, FILL_COLOR, X_PDC, Y_PDC);
end;

Main Clipping Page

HyperGraph
Table of Contents.

HyperGraph Home
page.

Last changed May 13, 1998, G. Scott Owen, owen@siggraph.org