Friday, 14 August 2009

ExeSketch (and yes, I'm still alive)

In an intermission to the vapid vacuousness of a presumably perpetual hiatus, I write this posting to once again acknowledge my own failure to maintain any sort of consistency in update frequency, and simultaneously to reveal to you a new project which serves as a sort of culmination of the long period I have spent attempting to gain some basic understanding of the syntactical intricacies and idiosyncrasies of C++ (which I hitherto had only the most rudimentary of aptitudes at). This, I may add, has proved rather successful, as that language, which was once as alien to me as this slightly ridiculous writing style I've chosen to adopt today may seem to any sane person, now seems as natural as the aforementioned ludicrously lavish lexicon usage (which I must at this point apologise for) does to myself at this particular moment.

So, with one hundred and forty-one words wasted on wanton waffling, and this post's 'ramblings' tag quite successfully earned, the time has come for me t
o take the next logical step in post-writing and endow upon you, the reader, the purpose of the bandwidth this page consumes.

The process of ExeSket
ch's development began quite some time ago, at my discovery of Beziér curves. The Wikipedia page linked to by the end of the last sentence provides the best explanation I've yet read of how they work, and armed with the provided understanding I set about implementing them in Python, using Pygame (naturally). The result can be found here.

From there, I took the concept further and developed a small drawing application, CurveDraw. It used discrete Bézier curve objects, each of which was made up of a series of joined curves, which could be used to build up drawings. The program grew to incorporate linear transformations such as rotation, and it came to the point where the code represented a toy car modified to transport cities of people to the Moon - in essence, a mess of awkward modifications and additions. So, at the point where someone suggested adding different types of shapes, a concept unthinkable with the program's existing code base, I decided that the program would have to be coded anew with a full drawing program as the intention from the outset.

Such a program
would fail to take shape for some time, and in the intermittent weeks I set about learning how to *properly* code in C++ (split infinitives included at no extra charge). I commenced to swiftly seek out tutorials, which I went on to carefully follow until the time came when I was to gradually procure an appreciation for the language whose documentation I was to systematically peruse.

So, that done, I went on to learn OpenGL - a graphics library which turned out to be much simpler to use than I had previously anticipated. Within a relatively small period of time I had managed to create an only semi-glitchy camera lookaround demo, with various cubes spinning around in the sky (about their own individual axes, after a bit of fiddling!). And after deciding that I probably lacked the mathematical calibre needed to make a full 3D game engine with cutting-edge graphics and high-tech shaders, I thought I might as well have a go at 2d for a bit.

Which led me to ExeSketch. It seemed a
s good a time as any to write the fatalistic sequel to CurveDraw, and as good a way as any to test whether I actually knew enough C++ to do it properly. This particular project involved a large amount of planning (well, in comparison to the thirty-seconds-ish I've put into other coding projects in the past), and some of the largest compiler error outputs I've ever seen (I tried to compile it all before I had written the Vector2d class which I had promised the compiler, and it spent a good five minutes vomiting forth garbled attempts at explaining what was wrong). However, after a few weeks of coding I've finally managed to get a basic version of the program running.

The program works in two
modes: Object View, and Editing (as inspired by Blender 3D, a program which provided ideas for much of the user interface of CurveDraw). In object view, one can select objects and drag them around, (ultimately) add/delete objects, and possibly apply linear transformations (that's still waiting on implementation). In edit mode, you can drag the points which form whatever object you're editing - currently the only object implemented is a Rect, which has four corner points which can be dragged to resize it (you can also press F to toggle whether or not the rectangle is filled). Panning and zooming are done with the mouse: click-and-drag and middle-click-and-push-in-or-pull-out, respectively.

The current source code is available from, and requires OpenGL and GLUT to compile. According to a line-counter script I wrote, it's 1136 lines so far, which I believe is an ExeSoft record (fair enough, given that I've mainly used Python up until this point). More updates are to come (if all goes well), and I might post an explanation of how ExeSketch works in the near future; for now, however, I must take my leave. Ta-ra!

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