# OpenGL texture concatenation tool

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I'm looking for a tool that will automatically arrange several images into a opengl compatible texture using a best fit algorithm and write the co-ordinates to a text file. Does anyone know if a tool like that exists?

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Not sure if this is what you want, but you could give it a try:
http://developer.nvidia.com/object/texture_atlas_tools.html

Rick

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Thanks. Unfortunately, directx only.

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OpenGL applications can use DDS files too ;)

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Ok, I should have mentioned that I'm using opengl es.
Besides that, the nvidia tool assumes that the origonal textures are in power of two dimensions and does no proper bin packing.
The reason I want this is becuase I have a whole load of textures in non opengl compatible dimensions (i.e. 34 x 34 ) if I put each one in a seperate texture that will be a collosal waste, so the obvious solution is to pack them into one texture

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Do the fun task of making your own. What is probably the most obvious solution, but also very slow and not scalable at all is to, for each texture, start at 0,0 and try to stick it in, incrementing the position until it fits or you run out of places to put it.

A much more ideal solution is to use a binary tree to track the memory. First, get a rough guess on the size of the texture. You know it will have to be as wide and as tall as the widest and tallest textures, along with have at least the area of all textures combined. If you want to go for less runs to fit them all instead of smallest size, you can start a little larger, requiring the destination to have at least 125% of the area of the source.

Order your elements from largest to smallest, then start plopping them in. The solution for tracking the space that I found the most idea was using a binary tree. There is a great site out there on how to do this (though they did it for light maps I believe), but I can not remember the link. I'm sure plenty of people here know exactly what I'm talking about and can provide you with the link. ;)

I implemented a texture atlas for my 2d engine doing this, and the results were very pleasing. In very little time, I could fill up a 4096x4096 texture with very minimal amount of unused space. In case you do not want to make your own, I do want to mention that, besides the tool Spek posted, I have not seen very much out there that can help with this problem, but it is not a very hard task as long as you know the way to approach it.

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• Hi guys,
With OpenGL not having a dedicated SDK, how were libraries like GLUT and the likes ever written?
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Obviously this question stems from the fact that there is no OpenGL SDK.
DirectX is a bit different as MS has the advantage of having the relationship with the vendors and having full access to OS source code and the entire works.
If I were to attempt to write the most absolute basic lib to access OpenGL on the GPU, how would I go about this?

• Hello! As an exercise for delving into modern OpenGL, I'm creating a simple .obj renderer. I want to support things like varying degrees of specularity, geometry opacity, things like that, on a per-material basis. Different materials can also have different textures. Basic .obj necessities. I've done this in old school OpenGL, but modern OpenGL has its own thing going on, and I'd like to conform as closely to the standards as possible so as to keep the program running correctly, and I'm hoping to avoid picking up bad habits this early on.
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