lachose1's road to @party 2011

[lachose1]

Introduction
Hey everybody, what's up?
Here is the topic explaining pretty much the main reason I joined dbf forums. I've been looking at demos for about two years now, but I only thought about participating to a demoparty about 2 months ago. Unfortunately, there aren't a lot in Montreal. About two days ago, I learned that on the 26th of November, a mini-compo would take place in Montreal called the @party so I decided to jump on this occasion to participate in my first ever compo. I joined with a friend who's more familiar with the demoscene and another with who I usually program projects. I've been a web developer for about 7 years and I've started developing games for fun about 2 years ago in different languages such as BlitzMax and C++. I know a lot about programming, but I've never tried to make a demo so here I am!

Goal
My goal with this topic is to prepare myself for the competition which takes place on the 26th of November. I created this topic to post any interrogations I'll encounter during the preparation and to post some progress I make (snippets of code to get feedback etc.). I will use C++ as a programming language and probably OpenGL to handle the graphics. I never worked with OpenGL so that's pretty much what I will need to learn. Here are my current goals for the competition :

• Learn to code a plasma effect
• Learn to code a dot matrix
• Learn to create procedural stuff
• Learn to code and use a spectrum analyzer

I will post my progress on those goals and I hope to get some great feedback from you guys I will mostly concentrate on creating great 2D effects with maybe some 3D integration for the compo, but for a first prod, I think this would be the most appropriate goal. I'll keep you updated!
Peace!

[Kirl]

That's awesome! I'll be watching this thread and meaby help if I can. I don't know any C++ but I'm more of a theory person anyway.
Good luck with your demo! 

[lachose1]

Ok so after looking at those two threads I tried something, but I'm stuck :
http://www.dbfinteractive.com/forum/index.php?topic=4469.0
http://www.dbfinteractive.com/forum/index.php?topic=5133.msg68691#msg68691

I try to create a cube with a plasma texture applied to it, but, do I need to create the texture than apply it to the cube and then make it kind of scroll to different pixels or do I need to modify the pixels in the texture? I'm going to try to search more, but up to now, I tried different things and got the cube to kind of flash through the texture which is not smooth.

[Raizor]

If I were doing it, I would create a plasma texture an then use that to texture map the cube. Writing to pixels in a texture is quite slow, so you could either draw the plasma and then grab the texture from the render buffer or use a shader to texture the cube. I'm only just starting to play around with shaders, so haven't tried anything like this yet.

There's a plasma cube included here (source is at the bottom of the page):
http://demo-effects.sourceforge.net/

That might come in handy.

It's probably worth checking out the NEHE OpenGL tutorials, as these are a great starting point for learning OpenGL:
http://nehe.gamedev.net/ (check the legacy tutorial links at the right of the page).

[LittleWhite]

About texture and plasma, even if updating the texture everyframe, this is not so slow.
To do that, you have to have an 2D array in memory (CPU memory) to store the pixel colour. Here you will do the plasma calculation to update each colours.
When you think your texture is ready, you have to send it to GPU. To do that, it's like sending a normal texture to GPU (so, with glTexImage2D()), and finally, display the texture.

The FBO (Frame Buffer Objects) is certainly faster and better, but well, if you are just starting OpenGL, don't try it immediatly. First, apply the first version and then, learn some more OpenGL (like shaders) and you will be able to discover the fantastic world of FBO