Re: [Haskell-cafe] Loading a texture in OpenGL

Thank you both. I'll be sure to try these out. As a matter of fact, I _am_ using JuicyPixels. I didn't realize there was a version on github which uses Vector. Thanks for letting me know. Regards, - clark On Mon, Feb 6, 2012 at 5:55 PM, Jason Dagit wrote:

On Mon, Feb 6, 2012 at 12:00 PM, Clark Gaebel wrote:

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Using the OpenGL package on Hackage, how do I load a texture from an array?

The answer will depend on a few things: * Which OpenGL package you use, for example OpenGL vs. OpenGLRaw * What type of 'array' you use.

In the case of the OpenGL package you need to create a PixelData value and pass that on. You can find example code here:

https://github.com/dagit/nehe-tuts/blob/447f5471f3e7fe07b44dc5d2d87c4a95be35...

https://github.com/dagit/nehe-tuts/blob/447f5471f3e7fe07b44dc5d2d87c4a95be35...

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In the red book[1], I see their code using glGenTextures and glBindTexture, but I can't find these in the documentation. Are there different functions I should be calling?

Yes. As you've noticed the API of the OpenGL package sometimes (often?) differs from that of the C OpenGL api. If that's what you're more familiar with then take a look at OpenGLRaw. Here is how to do the same thing as the previous two links but using OpenGLRaw: https://github.com/dagit/nehe-tuts/blob/master/lesson06.hs https://github.com/dagit/nehe-tuts/blob/master/Util.hs

Instead of using Arrays as defined by Haskell98, I would recommend using something else like Data.Vector. The standard arrays must be converted to something else to work with OpenGL. Data.Vector on the other hand allows direct access to the pinned pointer and is thus suitable for use with OpenGL as is.

Have you seen JuicyPixels? The version on hackage uses arrays, but the version in github uses vector. I'd recommend using the version from github. It's faster and it will be easier to pass the data to OpenGL: https://github.com/Twinside/Juicy.Pixels

Good luck! Jason