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DarkInsanePyro

OpenGL Heat Map & Blobs (Metaballs!)

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My brother brought an interesting request to me and I decided to take upon it. I am coding a heat-map which will be overlaid over the 2d world (platform). The heat-map will be generated from death rates. The question is though, how can I generate a heat map? I did a bit of research but apparently I do not know the proper terms, as everything I search for is very sketchy. From what I understand is I'd need just a weight surface (since its being rendered in OpenGL, maybe an Aux buffer or something?), than calculate if between deaths should there be a blob 'bridge'. The blob idea is only optional, but I figure with a low threshold it will look less 'chunky'. Does anyone have any hints or resources? I got the map rendering working (in the most part) but I am having trouble with the idea behind the heat map, such as where the weights should be stored, and how blobs are calculated. Thanks very much. PS: I am sorry if this post is requesting too much. I would have posted more specific of a question but I cannot even find if 'heat map' is the correct name. Thanks again. [Edited by - DarkInsanePyro on February 3, 2008 8:43:07 AM]

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I use very tricky way to calculate disortion (or as you said - heat map). Just create particles - the best are sphere particles (but u need to use many particles) - which would go little randomly in up direction. You could write normals into their colors. Then render this into texture and in post process phase - in shader (I presume you're using shaders) add this to screen space texcoords of final image.

This isnt physically correct or best method, but it can be used (It has some advantages - easy to implement, fast, looks nice and some disadvantages - not physically correct).

This way you dont need to calculate blobs to create disorting effect.

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Oh you already surpassed what I can do. I have not gotten into shaders yet, planed, but not yet. I was going for more of a raw system, as the heat-map is a 2d plane and isn't generated in real-time. I suppose I should have mentioned this before hand. Sorry about that. I found the term for blobs, "Metaballs", which may have a desired effect. I was considering just using as you said, a particle system, which circular sprites than render it through indexed coloring. The only catch is that it seems once OpenGL is in indexed color, rendering the actual world would be harder/different. I'll see if I can scavenge up some more information, but thanks for your help so far and glad to hear any ideas you got!

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