Beautiful and unique snowflakes

So last time, I had managed to add some code to create a height-map from a simplex noise function, using the space coordinates as input and getting a pseudo-random number between -1 and 1 as the output. For now I'm just coloring the vertices, black for lowest value and white for highest, but eventually I'd use the values to distort the sphere.

The only problem was that the noise function used a shuffled array to create the pattern of noise, so in order to create new patterns I had to reshuffle that array. Reshuffling the array presented a few problems, mostly caused by my reliance on the STL's rand() function, which is really quite terrible. As a result I had to search for a better function that could do the job I needed.

I eventually found an excellent paper on pseudo random number generators, by David Jones. I settled for the JLKISS64 generator, and after altering it to fit the framework I managed to create multiple height maps on demand. The problem, then, was how to display them.

Currently, my method for displaying models is to create a Vertex Buffer Array for each model, and a custom transform for each object. The different spheres where really all the same array with different matrices applied. But the height map was created as an additional coloring at each vertex, meaning I had to create new Arrays that still used the same buffers for vertex position, normal and color, but different heights.

This was fairly straightforward, thankfully. Essentially, the process involved the same steps as creating a vertex array from scratch, but skipping the buffer step, since the information had already been loaded to the video card.

In short order I had the new code running, and the space that was once filled with the same patterned spheres now had unique marbles floating all about.

Next up, I'm going to be trying to get text into the program, create a console of sorts.

Tearing my hair out

Ok, I fixed the issue I was having. I'm not really sure what the issue was, but it appears to be gone after a few modifications to the offending code. I can't really say I'm happy about the outcome. I haven't really changed anything fundamental, and I don't even know what the problem was in the first place.

Since I'm sure you're riveted to your seats, wondering what the bug was, I'll tell you. Maybe you can tell me what the cause was. When I changed the path of the program, it crashed. That is, the compiled program would work in the directory I compiled it to, no issues. But change the name of the directory the executable was in, or copy the directory to a different location (keeping the relative paths of the resources intact) and it would fail. Madness.

I did do a couple of things in the program that weren't very nice. I had a nested for loop and I needed to keep track of how many times I run the inner loop, so I declared a variable outside of the loop and incremented it inside the loop, as an index into a dynamically allocated array, then used it again outside after increasing it a couple of times.

The big change I did was not to use it outside the loop. My best guess is I was incrementing it by one more than the size of the array outside the loop, and overwriting some bit of memory that I shouldn't have been messing with. How that could possibly cause the program to work in the compilation directory but not when I changed it's name, I may never know. But then, that's what happens when you play with arrays, and one of the reason to avoid them when possible.

Unfortunately, OpenGL calls want you to give them raw pointers to arrays. I am doing well enough using smart pointers instead, but until I wrap them up in safer structures, some dangers remain. I should look into using vector, I think it might help. I'm just not sure I can get the pointer to the memory, or that vector has to pack the information in a certain manner. Arrays are ugly, but at least I have control over the packing of the bits in there, and that's what I need.

Now that it's working, however, I'm can get to working on something more important. Currently I'm using a noise function that unfortunately I can't easily reinitialize. Basically, I need to add a 'shuffle' function to rearrange the values in an array, which serves as the seed of the noise generator. Shouldn't be too difficult.

EDIT - Curse you, Skyrim! I'm afraid I got slightly sidetracked this past week. Good thing this scheduling thing works.