plumpmath / practice

Practice Programming

Every day I will do a small 30ish minute programming practice session. These are meant to be thrown away when I am done and just to work on skills that help me when programming in the large. Use of libraries or prebuilt scaffolding are permitted so I can focus on specific problems rather than boilerplate.

Skills I wish to get better at.

• System level programming in c.
• Multithreaded programming
• Graphics programming.
• Algorithms and data structures.
• Implementing things from papers.
• Simulation code, physics stuff.
• Data viz.
• Maybe some audo stuff.

Practice Log

• #####2015-01-04: Threaded Work Queue.

  Problem: Build a multithreaded circular work queue using processor atomics.

  Time: 37 minutes

  I managed to get a little linear single producer multiple consumer work queue up and running in half an hour. I didn't get to making it a ring buffer. It could be cool to try and build on this to implement different concurrency patterns but I don't know if that is against the rules or not. I feel like 30 minutes isn't much time and it takes about 30 mins to type out all the boilerplate to do this. We'll see though, maybe it's just because I'm rusty. Felt overall like a good first day.

• #####2015-01-05: OpenGL Cube.

  Problem: Get a cube up on the screen with opengl.

  Time: 1 hour 21 minutes

  This took me a lot longer than I expected. Getting the shader code up and running was pretty easy, that was mostly a copy paste job of the code to handle errors. Then I had the cube vertices and the shader code ready to go but what took the longest is the math for the perspective transform. I tried for awhile to do it from scratch but ended up just copying in some code I already had to do it which also used a bunch of custom types. I would like to do this again with either a good math library that I decide I can use for practices like this or do it really from scratch and actually understand the math involved. I also ran into some problems with my lib segfaulting. I solved those by trying to link it int directly to the platform to get some errors saying functions were not defined. This is because those were copy paste functions that were decalred as inline because it was copied from a cpp project. Another error I ran into and couldn't figure out for awhile is that I wasn't calling glUseProgram on my shader program so nothing was happening. Opengl gives you no feedback and that took forever to figure out because afaik there's no easy way to debug opengl. Opengl kinda really sucks because of the no debugging thing, hopefully more practice will make it a lot less tedious though.

• #####2015-01-08: Compress Image.

  Problem: Load a pixel art screenshot and compress it to just be 1 pixel per logical pixel.

  Time: 1 hour 20 minutes

  This one is directly related to a side project where I want to write a program that plays the binding of isaac. Later practices might be about image recognition but this one is just to load a file and compress it. It didn't take too long to read and write the image thanks to stb_image. Most of the work was just getting the compression math right, I knew that this image was compressed by 3 so I just hardcoded that, in my real app that might not be the case.