Practical Algorithms for 3D Computer Graphics, 2nd Edition

4.2. Hidden surface drawing and rasteriz a tio n 107

While repeating for all polygons k add the following:

{

Set flag

repeat for all vertices i of polygo n k {

let (X, Y ) be projected coordinates of vertex i

i f X ≥ 0 and X < X

max

{\

clear the flag and jump to next polygon

}

i f Y ≥ 0 and Y < Y

max

{

clear the flag and jump to next polygon

}

}

if the flag is set cull the polygon

}

Listing 4.5: Amendments to the Z buffer algorithm to cull polygons which lie outside

the field of view.

Check scanlin e, i, to see if it is inside the raster.

i f i < 0 or i ≥ Y

max

skip to next scanline

On scanline i polygon k spans pixels x

1

to x

2

.

Before setting p ixel values apply limits to ...