Alpha, particles and GPU profiling

This week we learnt how much of a bitch transparency is because of how OpenGL decides which order to draw something.

You will see in games, even these days, sprites that have transparency in them, like leaves or water, get drawn in the wrong order.


I like particles.

We learnt how particle systems work and that the best way is to have single verts flying around and make the geometry shader convert them to billboards.

Usually particles are in the form of “billboards” which basically comes down to “thing will face camera”. There are particles that face the camera from both vertically and horizontally, and also billboards that face only on one axes. Like a barrell or a tree.

The other thing that was covered this week was “GPU PROFILING” which is basically looking at what the GPU is doing udsing nVidia programs and what not. nVidia tools look pretty neat.

This week I basically worked on my node class getting my planets to be attatched to the sun node and also rotate at their own local axis.


Silly Jupiter. WAT U DO. Y R U ON UR SIED?

This is what happens when you try and mess with the matrix’s 4th row and not change the rotation bits:



I also did a bit on vertex shaders. I had already done this but accidentally over-wrote it with another exercise and working on my lava because I’m a dumbass.

Playing around with the Y of the verts accidentally came up with this:


20130325023957It looks so smooth! Almost like looking at something under an electron microscope.

I eventually came up with this thing, which is what the exercise asks:



It looks more impressive when it’s animated.

Anyway… time for another week.


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