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Issue 17.2 ('Barchart API')
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FEATURE

Rotating a Cube

Rotating a 3D Wireframe Cube on a Canvas

Issue: 17.2 (March/April 2019)
Author: Eugene Dakin
Author Bio: Eugene works as a Senior Oilfield Technical Specialist. He has university degrees in the disciplines of Engineering, Chemistry, Biology, Business, and a Ph.D. in Chemical Engineering. He is the author of dozens of books on Xojo available on the xdevlibrary.com website.
Article Description: No description available.
Article Length (in bytes): 14,146
Starting Page Number: 44
Article Number: 17207
Resource File(s):

Download Icon project17207.zip Updated: 2019-03-04 09:41:38

Related Link(s): None

Excerpt of article text...

Our project for today is to create a program to display a spinning 3-dimensional wireframe cube on a 2-dimensional Xojo canvas. This works on Windows, Mac, and Linux systems and works in 32-bit and 64-bit modes. The program uses Xojo native code so that the same code-base can be used on any supported operating system.

When you start the program and a Canvas is loaded, lines are drawn in a cube form, and the cube rotates (see Figure 1).

How It Works

Basically, our window has a canvas, and 12 lines are drawn. Dimensions are changed in a timer with every call and the new line coordinates are recalculated and drawn (see Figure 2).

Before the lines are drawn, there is the ability to change the spin-rate for the xy, xz, and yz axis. To centre the cube there are x-axis offset and y-axis offset values from the upper and left part of the canvas. Also, a scale factor is available to increase or decrease the size of the cube.

To make the cube spin faster, either change all of the xyR, xzR, and yzR values to a higher number such as 3.14/90 or change the timer period to a value lower than 20. There is a limit on many computers where the lowest limit seems to be near about 15 milliseconds or so.

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