Sketch is a small application to test primitive drawing algorithms in OpenGL.
Sketch uses a simplified UI consisting of keyboard commands. Press the H
key at any time to toggle a dropdown menu showing each of the commands.
+---------------------+
| H - Toggle Help |
+---------------------+
| L - Line |
| O - Circle |
| S - Curve |
| C - Clock |
| P - Control Points |
| U - Undo |
| X - Clear |
| Q - Quit |
+---------------------+
The first four commands switch the Sketch's drawing state. The current state is displayed in brackets in the bottom left corner of the screen along with the coordinates of the mouse pointer.
The P command shows the control points for any Bezier curves on screen.
The last thre commands do almost exactly what a reasonable person would expect,
except that Undo is drawing state sensitive. For example, in the Line
state, only lines are removed (in the reverse order that they were drawn).
In the Line, Circle, and Clock states, the user clicks the left mouse
button down to indicate a starting point, drags the pointer to an end point,
and releases the left mouse button. While the left mouse button is held down, a
temporary primitive will "rubber-band" beteen the start and end points.
In the Curve state, the user indicates four control points using a full click
and release. A line is drawn between each point until the fourth point is drawn
and a Bezier curve is generated.
Christopher D. Parks (chris.parks@uky.edu)
hosted on github