Simple 3D drawing

For simple 3D drawing in openFrameworks, follow these steps:

1. Add the ofEnableDepthTest() function call in the beginning of the testApp::draw() function to enable z-buffering. If you omit it, all the graphics objects will be rendered without respect to their z coordinate in correspondence with the graphical primitives' rendering order.

2. Draw primitives as follows:

   • The ofLine( x1, y1, z1, x2, y2, z2 ) function draws a line segment between points (x1, y1, z1) and (x2, y2, z2). There is an overloaded version of the function, ofLine( p1, p2 ), where p1 and p2 have type ofPoint. Use the ofSetColor() and ofSetLineWidth() functions to adjust its rendering properties of color and line width.

     Note

     In Chapter 2, Drawing in 2D, we used the ofPoint class to represent 2D points using its fields x and y. Actually, ofPoint has a third field z, which, by default, is equal to zero. So ofPoint can represent points in 3D. Just declare ofPoint p and work with values p.x, p.y, and p.z.

   • The ofTriangle...