Processing: Creative Coding and Computational Art

coordinates of the line. For example, to draw a 2D line across the screen, you pass the initial
point’s coordinate, (x1, y1), and the endpoint’s coordinate, (x2, y2), to the line(x1,
y1, x2, y2) function. Figure 6-21 shows the output.
size(500, 300);
background(255);
line(0, height/2, width, height/2);
Figure 6-21. Drawing a 2D line with Processing’s line()
function
If you were using one of the 3D rendering options (P3D or OPENGL), you could pass in a
third coordinate, referencing the z-axis. If you run the next example, you’ll notice that the
line doesn’t appear to reach the end of the display, as it did in the last example. This
is because the line is stretching back 300 pixels into virtual space, and the P3D renderer is
simulating perspective, which causes things to converge and decrease in scale (visually of
course) as they recede into space (see Figure 6-22).
size(500, 300, P3D);
background(255);
// line(x1, y1, z1, x2, y2, z2);
line(0, height/2, 0, width, height/2, -300);
Figure 6-22. Drawing a 3D line with Processing’s line()
function
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