Programming and Graphics

214 Introduction to C++ Programming and Graphics

void drawshape(int fill)

{

polyfill(fill);

if (!fill)

for (int i=0; i<20; i++)

{

if (fill)

{

color(i+1);

}

makepoly();

move(xyz[ncon[i][0]-1][0], xyz[ncon[i][0]-1][1], xyz[ncon[i][0]-1][2]);

draw(xyz[ncon[i][1]-1][0], xyz[ncon[i][1]-1][1], xyz[ncon[i][1]-1][2]);

draw(xyz[ncon[i][2]-1][0], xyz[ncon[i][2]-1][1], xyz[ncon[i][2]-1][2]);

closepoly();

}

}

Figure 7.3.1(b) shows a snapshot of the animation. The code features the fol-
lowing implementations:

• A function is used to draw the icosahedron based on hard-coded data for
  the vertex coordinates and a connectivity table relating faces to vertices.


• When the “p” key is pressed, a postscript file of the current shape is
  produced.


• When the “x”, “y”, or “z” key is pressed, the icosahedron translates by a
  specified shift in the respective directions. When the “-” key is pressed,
  the direction of translation is reversed, and when the “+” key is pressed,
  the direction of translation is reinstated.


• When either the Escape or the “q” key is pressed, the execution termi-
  nates.

Problems

7.3.1. Modify the polygon animation code to implement a rotating regular

hexagon.

7.3.2. Modify the polygon animation code to insert a second rotating polygon.

7.3.3. Translate into C++ aVogledistribution animation code of your choice.